Harvard Bridge
Encyclopedia
The Harvard Bridge carries Massachusetts Avenue
(Route 2A) from Back Bay, Boston to Cambridge
, Massachusetts
. It is the longest bridge over the Charles River
.
Named for the Reverend John Harvard
, it was originally built between 1887 and 1891 with a swing span
. The bridge was revised over the years until its superstructure was completely replaced in the late 1980s. It is locally known for being measured in the idiosyncratic unit called the smoot
.
The bridge was to have a draw with an opening of at least 38 feet (11.6 m). Unfortunately, Boston did not like this act, mainly because it did not provide for an overhead crossing of the Grand Junction Branch
of the Boston and Albany Railroad
. So nothing happened until the act was amended by Acts of 1885, Chapter 129, which changed the draw to a clear opening of at least 36 feet (11 m) and no more, until the other bridges below the proposed location were required to have a larger opening. Still nothing happened, until the City of Cambridge petitioned the Massachusetts Legislature in 1887 to compel Boston to proceed. This resulted in Acts of 1887, Chapter 282, which was mandatory for both cities. It required that each city pay for half the bridge, and allowed Boston to raise up to US$
250,000 (US$
with inflation) for this purpose, in excess of its debt limit. This implied an estimated cost of US$
500,000 (US$
with inflation) for the bridge.
The act authorized a commission to build the bridge. The commission was to consist of the mayors of Boston and Cambridge plus one additional person to be appointed by the mayors. If the mayors failed to appoint a third commissioner, the governor was to do it for them. The mayors of Boston and Cambridge, Hugh O'Brien
and William E. Russell
, appointed Leander Greeley of Cambridge as the third commissioner. This changed over time.
The bridge opened on 1 September 1891. The original cost of construction to 1 March 1892 was US$
510,642.86. This is equivalent to US$
with inflation.
The expectations of having built the bridge were clear.
Embankment extension was expected to take that space, but that was changed such that the whole distance would be of iron spans on stone piers. The general plans were approved on 14 July 1887. The engineers were William Jackson
(Boston City Engineer), John E. Cheney (assistant Boston City Engineer), Samuel E. Tinkham (assistant engineer), and Nathan S. Brock (assistant engineer at bridge).
The subsurface conditions at the bridge location are extreme. Much of Boston is underlain with clay, but the situation at the bridge is exacerbated by a fault which roughly follows the path of the Charles River
itself. From a depth of approximately 200 foot below existing ground, is a very dense till composed of gravel and boulders with a silt-clay matrix. Above that to approximately 30 feet (9 m) below the surface is Boston blue clay (BBC). Over this are thin layers of sand, gravel, and fill. The BBC is overconsolidated up to a depth of approximately 70 foot.
The substructure originally consisted of two masonry abutments and twenty-three masonry piers, as well as one pile foundation with a fender pier
for the draw span. The superstructure was originally twenty-three cantilevered fixed spans
and suspended spans, of plate girders with one swing span
. The Boston abutment rests on vertical piles, while the Cambridge end is directly on gravel.
Originally, the bridge was built across the Charles River
connecting West Chester Park, in Boston, with Front Street, in Cambridge. This is now called Massachusetts Avenue
on both sides of the river. As originally built, the total length between centers of bearings on abutments was 2164 in 9 in (659.82 m) with a draw 48 in 4 in (14.73 m) wide between centers. The width of the bridge was 69 in 4 in (21.13 m) except near and on the draw.
The bridge as built was composed of fixed and suspended spans roughly 75 feet (22.9 m) long and piers 90 feet (27.4 m) apart, center to center. The span lengths alternated between 75 foot. The longer spans were cantilevered, while the shorter spans were suspended between the cantilevers.
The original roadway contained two lanes for horse-drawn vehicles and two street car tracks, for a total width of 51 feet (15.5 m). There were also two 9 inch sidewalks. The original roadway and sidewalk stringers were of wood, with an approximately 1.25 inches (31.8 mm) thick covering of asphalt on the sidewalk.
The exception was at the swing span, which was 48 feet (14.6 m) wide. This span was approximately 149 feet (45.4 m) long, and sat on a wooden pier. It was a double-cantilevered, electrically-driven structure also carrying a bridge caretaker's house.
The bridge was named for the Reverend John Harvard
, for whom Harvard University
is also named, rather than after the university itself. Other names suggested included Blaxton, Chester, Shawmut, and Longfellow. The structure now called the Longfellow Bridge
opened 15 years later. John Harvard was an early donor to what later became the university; not, as is often assumed, its founder.
Possibly due to its proximity to the bridge, there have been a number of tales reported at MIT
as to how the bridge came to be named "Harvard", all apocryphal. The Harvard Bridge was first constructed in 1891. MIT did not move to its current location adjacent to the bridge until 1916.
The bridge was declared unsafe in 1909, requiring all of the iron and steel to be replaced. The draw was elevated slightly and the trolley rails were replaced as well.
When the Metropolitan District Commission (MDC) took control of the bridge in 1924, they rebuilt much of the bridge superstructure. They replaced the wooden stringers with steel "I" beams, topped wooden deck elements with concrete and brick, and replaced the street car rails. Structural steel hangers replaced wrought iron. The swing span was converted into two 75 feet (22.9 m) fixed spans the same width as the rest of the bridge. The wooden pier was heavily modified with concrete and stone to make it resemble the other piers, increasing the number of stone piers from 23 to 24.
Heavy traffic at the Mass Ave
and Memorial Drive intersection on the Cambridge end of the bridge led to the construction of an underpass in 1931. The underpass eliminated the at-grade intersection.
The bridge was often known as the "Xylophone Bridge" because of the sound its wooden decking made when traffic traveled over it. This decking was replaced in 1949 with 3 inches (76.2 mm) concrete-filled "I-beam lok" grating topped with a 2.25 inches (57.2 mm) thick bituminous wearing surface. At this time, all bearings were replaced, and the trolley car tracks were removed, as were granite blocks. The trolley car poles were reused for street lights. Ramps between the bridge and the under-construction Storrow Drive
were added.
The 1924 sidewalk slabs were replaced by precast, prestressed slabs in 1962.
The fifteen expansion dams were replaced or repaired in 1969.
) in 1971-1972 due to complaints by bridge users of excessive vibration. The bridge was found to be understrength for its load. Before the final study was complete, the recommendation was to place a load limit of 8 short tons (7.3 MT) per axle and a total of 15 short tons (13.6 MT) per vehicle, or to restrict trucks to the interior lanes, where the bridge was stronger. A 25 short tons (22.7 MT) limit was imposed.
Suggestions made included strengthening the existing structure by adding either struts or plates to make the existing four beams along the length of the bridge into a stiffening truss, or to replace the superstructure with a new one, made of either steel or concrete, which would be up to current standards. The recommendation was to replace the superstructure with one weighing approximately the same in order to reuse the piers, which were in good condition.
The reasoning was that the cost of a new structure could be predicted much more easily than the cost of repairing and reinforcing the existing bridge. The resulting new bridge would be of known materials and quality, such as ductile structural steel rather than brittle wrought iron, and rated at AASHO HS-20. Repairing the existing structure would leave old wrought iron of uncertain quality and condition standing, and would not bring the design up to (then) current standards. Detailed engineering calculations were included. The price was estimated at 2.5 million to 3 million U.S. dollars (US$
to US$
with inflation).
The action taken based on this study was to establish load restrictions on the bridge, 15 short tons (13.6 MT) in the outer lanes, 25 short tons (22.7 MT) on the inner lanes. This was expanded in 1979 to a flat limit of 15 short tons (13.6 MT) on the whole bridge.
at Greenwich, Connecticut
in 1983, the Harvard Bridge was shut down and inspected because it contained similar elements, specifically the suspended spans. Traffic was restricted to the inner two lanes due to the discovery of two failed hangers on span 14. A few days later, all trucks and buses were banned from the bridge.
In 1986, a report was published containing the plan to replace the superstructure on the existing supports. Alternatives considered were very similar to the 1972 report, and were similarly decided. Structural modifications included an upgrade from four longitudinal girders to six of the same shape, elimination of ramp "B", and replacement of a stairway with a handicapped pedestrian ramp on the Boston end of the bridge.
The historic value of the bridge was considered significant, so the plan was to make the replacement superstructure appear similar, with similar railing and lighting. In order to document the pre-existing structure, a Historic American Engineering Record (HAER) would be prepared.
Ramp "B", from southbound (Boston bound) bridge lanes to eastbound Storrow Drive
, caused traffic to merge onto Storrow Drive from the left (high speed) lanes using a short acceleration lane, causing safety issues. The MDC requested elimination of this ramp. Compared to overall bridge traffic of 30,000 vehicles per day, traffic on ramp B was found to be low, approximately 1,500 vehicles per day with a peak of 120 vehicles per hour.
Pier 12 was exhibiting inappropriate movement and was scheduled for reinforcement.
The work would be done in two phases. Phase 1 would reinforce the downstream side of the bridge to allow MBTA bus traffic, and was expected to take 5 months. Most of this effort would be spent on the underside of the bridge and would not affect existing traffic. Phase 2 would replace the entire superstructure and was expected to take three construction seasons to implement. Cost was estimated to be (US$
with inflation). Phase 1 finished in 1987, and Phase 2 in 1990.
The Harvard Bridge is measured, locally, in smoot
s.
In 1958, members of the Lambda Chi Alpha
fraternity at MIT
measured the bridge's eastern sidewalk by carrying or dragging the shortest pledge that year, Oliver Smoot, end over end.
Crossing pedestrians are informed by length markers painted at 10-smoot intervals that the bridge is 364.4 smoot
s long, "plus one ear". The qualifier "plus or minus" was originally intended to express measurement uncertainty, but over the years the words "or minus" have gone missing in many citations, including the markings on the bridge itself. The marks are repainted twice each year by members of the fraternity.
During the reconstruction in the 1980s, the smoot markings were repainted on the new deck, and the sidewalks were divided into smoot
-length slabs rather than the standard six feet. The Boston police use the smoot marks as a coordinate system when reporting accidents on the bridge.
The Harvard Bridge (also known locally as the MIT bridge or the "Mass Ave" bridge) carries Massachusetts Avenue
(Route 2A) from Back Bay, Boston to Cambridge
, Massachusetts
. It is the longest bridge over the Charles River
.
Named for the Reverend John Harvard
, it was originally built between 1887 and 1891 with a swing span
. The bridge was revised over the years until its superstructure was completely replaced in the late 1980s. It is locally known for being measured in the idiosyncratic unit called the smoot
.
The bridge was to have a draw with an opening of at least 38 feet (11.6 m). Unfortunately, Boston did not like this act, mainly because it did not provide for an overhead crossing of the Grand Junction Branch
of the Boston and Albany Railroad
. So nothing happened until the act was amended by Acts of 1885, Chapter 129, which changed the draw to a clear opening of at least 36 feet (11 m) and no more, until the other bridges below the proposed location were required to have a larger opening. Still nothing happened, until the City of Cambridge petitioned the Massachusetts Legislature in 1887 to compel Boston to proceed. This resulted in Acts of 1887, Chapter 282, which was mandatory for both cities. It required that each city pay for half the bridge, and allowed Boston to raise up to US$
250,000 (US$
with inflation) for this purpose, in excess of its debt limit. This implied an estimated cost of US$
500,000 (US$
with inflation) for the bridge.
The act authorized a commission to build the bridge. The commission was to consist of the mayors of Boston and Cambridge plus one additional person to be appointed by the mayors. If the mayors failed to appoint a third commissioner, the governor was to do it for them. The mayors of Boston and Cambridge, Hugh O'Brien
and William E. Russell
, appointed Leander Greeley of Cambridge as the third commissioner. This changed over time.
The bridge opened on 1 September 1891. The original cost of construction to 1 March 1892 was US$
510,642.86. This is equivalent to US$
with inflation.
The expectations of having built the bridge were clear.
Embankment extension was expected to take that space, but that was changed such that the whole distance would be of iron spans on stone piers. The general plans were approved on 14 July 1887. The engineers were William Jackson
(Boston City Engineer), John E. Cheney (assistant Boston City Engineer), Samuel E. Tinkham (assistant engineer), and Nathan S. Brock (assistant engineer at bridge).
The subsurface conditions at the bridge location are extreme. Much of Boston is underlain with clay, but the situation at the bridge is exacerbated by a fault which roughly follows the path of the Charles River
itself. From a depth of approximately 200 foot below existing ground, is a very dense till composed of gravel and boulders with a silt-clay matrix. Above that to approximately 30 feet (9 m) below the surface is Boston blue clay (BBC). Over this are thin layers of sand, gravel, and fill. The BBC is overconsolidated up to a depth of approximately 70 foot.
The substructure originally consisted of two masonry abutments and twenty-three masonry piers, as well as one pile foundation with a fender pier
for the draw span. The superstructure was originally twenty-three cantilevered fixed spans
and suspended spans, of plate girders with one swing span
. The Boston abutment rests on vertical piles, while the Cambridge end is directly on gravel.
Originally, the bridge was built across the Charles River
connecting West Chester Park, in Boston, with Front Street, in Cambridge. This is now called Massachusetts Avenue
on both sides of the river. As originally built, the total length between centers of bearings on abutments was 2164 in 9 in (659.82 m) with a draw 48 in 4 in (14.73 m) wide between centers. The width of the bridge was 69 in 4 in (21.13 m) except near and on the draw.
The bridge as built was composed of fixed and suspended spans roughly 75 feet (22.9 m) long and piers 90 feet (27.4 m) apart, center to center. The span lengths alternated between 75 foot. The longer spans were cantilevered, while the shorter spans were suspended between the cantilevers.
The original roadway contained two lanes for horse-drawn vehicles and two street car tracks, for a total width of 51 feet (15.5 m). There were also two 9 inch sidewalks. The original roadway and sidewalk stringers were of wood, with an approximately 1.25 inches (31.8 mm) thick covering of asphalt on the sidewalk.
The exception was at the swing span, which was 48 feet (14.6 m) wide. This span was approximately 149 feet (45.4 m) long, and sat on a wooden pier. It was a double-cantilevered, electrically-driven structure also carrying a bridge caretaker's house.
The bridge was named for the Reverend John Harvard
, for whom Harvard University
is also named, rather than after the university itself. Other names suggested included Blaxton, Chester, Shawmut, and Longfellow. The structure now called the Longfellow Bridge
opened 15 years later. John Harvard was an early donor to what later became the university; not, as is often assumed, its founder.
Possibly due to its proximity to the bridge, there have been a number of tales reported at MIT
as to how the bridge came to be named "Harvard", all apocryphal. The Harvard Bridge was first constructed in 1891. MIT did not move to its current location adjacent to the bridge until 1916.
The bridge was declared unsafe in 1909, requiring all of the iron and steel to be replaced. The draw was elevated slightly and the trolley rails were replaced as well.
When the Metropolitan District Commission (MDC) took control of the bridge in 1924, they rebuilt much of the bridge superstructure. They replaced the wooden stringers with steel "I" beams, topped wooden deck elements with concrete and brick, and replaced the street car rails. Structural steel hangers replaced wrought iron. The swing span was converted into two 75 feet (22.9 m) fixed spans the same width as the rest of the bridge. The wooden pier was heavily modified with concrete and stone to make it resemble the other piers, increasing the number of stone piers from 23 to 24.
Heavy traffic at the Mass Ave
and Memorial Drive intersection on the Cambridge end of the bridge led to the construction of an underpass in 1931. The underpass eliminated the at-grade intersection.
The bridge was often known as the "Xylophone Bridge" because of the sound its wooden decking made when traffic traveled over it. This decking was replaced in 1949 with 3 inches (76.2 mm) concrete-filled "I-beam lok" grating topped with a 2.25 inches (57.2 mm) thick bituminous wearing surface. At this time, all bearings were replaced, and the trolley car tracks were removed, as were granite blocks. The trolley car poles were reused for street lights. Ramps between the bridge and the under-construction Storrow Drive
were added.
The 1924 sidewalk slabs were replaced by precast, prestressed slabs in 1962.
The fifteen expansion dams were replaced or repaired in 1969.
) in 1971-1972 due to complaints by bridge users of excessive vibration. The bridge was found to be understrength for its load. Before the final study was complete, the recommendation was to place a load limit of 8 short tons (7.3 MT) per axle and a total of 15 short tons (13.6 MT) per vehicle, or to restrict trucks to the interior lanes, where the bridge was stronger. A 25 short tons (22.7 MT) limit was imposed.
Suggestions made included strengthening the existing structure by adding either struts or plates to make the existing four beams along the length of the bridge into a stiffening truss, or to replace the superstructure with a new one, made of either steel or concrete, which would be up to current standards. The recommendation was to replace the superstructure with one weighing approximately the same in order to reuse the piers, which were in good condition.
The reasoning was that the cost of a new structure could be predicted much more easily than the cost of repairing and reinforcing the existing bridge. The resulting new bridge would be of known materials and quality, such as ductile structural steel rather than brittle wrought iron, and rated at AASHO HS-20. Repairing the existing structure would leave old wrought iron of uncertain quality and condition standing, and would not bring the design up to (then) current standards. Detailed engineering calculations were included. The price was estimated at 2.5 million to 3 million U.S. dollars (US$
to US$
with inflation).
The action taken based on this study was to establish load restrictions on the bridge, 15 short tons (13.6 MT) in the outer lanes, 25 short tons (22.7 MT) on the inner lanes. This was expanded in 1979 to a flat limit of 15 short tons (13.6 MT) on the whole bridge.
at Greenwich, Connecticut
in 1983, the Harvard Bridge was shut down and inspected because it contained similar elements, specifically the suspended spans. Traffic was restricted to the inner two lanes due to the discovery of two failed hangers on span 14. A few days later, all trucks and buses were banned from the bridge.
In 1986, a report was published containing the plan to replace the superstructure on the existing supports. Alternatives considered were very similar to the 1972 report, and were similarly decided. Structural modifications included an upgrade from four longitudinal girders to six of the same shape, elimination of ramp "B", and replacement of a stairway with a handicapped pedestrian ramp on the Boston end of the bridge.
The historic value of the bridge was considered significant, so the plan was to make the replacement superstructure appear similar, with similar railing and lighting. In order to document the pre-existing structure, a Historic American Engineering Record (HAER) would be prepared.
Ramp "B", from southbound (Boston bound) bridge lanes to eastbound Storrow Drive
, caused traffic to merge onto Storrow Drive from the left (high speed) lanes using a short acceleration lane, causing safety issues. The MDC requested elimination of this ramp. Compared to overall bridge traffic of 30,000 vehicles per day, traffic on ramp B was found to be low, approximately 1,500 vehicles per day with a peak of 120 vehicles per hour.
Pier 12 was exhibiting inappropriate movement and was scheduled for reinforcement.
The work would be done in two phases. Phase 1 would reinforce the downstream side of the bridge to allow MBTA bus traffic, and was expected to take 5 months. Most of this effort would be spent on the underside of the bridge and would not affect existing traffic. Phase 2 would replace the entire superstructure and was expected to take three construction seasons to implement. Cost was estimated to be (US$
with inflation). Phase 1 finished in 1987, and Phase 2 in 1990.
The Harvard Bridge is measured, locally, in smoot
s.
In 1958, members of the Lambda Chi Alpha
fraternity at MIT
measured the bridge's eastern sidewalk by carrying or dragging the shortest pledge that year, Oliver Smoot, end over end.
Crossing pedestrians are informed by length markers painted at 10-smoot intervals that the bridge is 364.4 smoot
s long, "plus one ear". The qualifier "plus or minus" was originally intended to express measurement uncertainty, but over the years the words "or minus" have gone missing in many citations, including the markings on the bridge itself. The marks are repainted twice each year by members of the fraternity.
During the reconstruction in the 1980s, the smoot markings were repainted on the new deck, and the sidewalks were divided into smoot
-length slabs rather than the standard six feet. The Boston police use the smoot marks as a coordinate system when reporting accidents on the bridge.
The Harvard Bridge (also known locally as the MIT bridge or the "Mass Ave" bridge) carries Massachusetts Avenue
(Route 2A) from Back Bay, Boston to Cambridge
, Massachusetts
. It is the longest bridge over the Charles River
.
Named for the Reverend John Harvard
, it was originally built between 1887 and 1891 with a swing span
. The bridge was revised over the years until its superstructure was completely replaced in the late 1980s. It is locally known for being measured in the idiosyncratic unit called the smoot
.
The bridge was to have a draw with an opening of at least 38 feet (11.6 m). Unfortunately, Boston did not like this act, mainly because it did not provide for an overhead crossing of the Grand Junction Branch
of the Boston and Albany Railroad
. So nothing happened until the act was amended by Acts of 1885, Chapter 129, which changed the draw to a clear opening of at least 36 feet (11 m) and no more, until the other bridges below the proposed location were required to have a larger opening. Still nothing happened, until the City of Cambridge petitioned the Massachusetts Legislature in 1887 to compel Boston to proceed. This resulted in Acts of 1887, Chapter 282, which was mandatory for both cities. It required that each city pay for half the bridge, and allowed Boston to raise up to US$
250,000 (US$
with inflation) for this purpose, in excess of its debt limit. This implied an estimated cost of US$
500,000 (US$
with inflation) for the bridge.
The act authorized a commission to build the bridge. The commission was to consist of the mayors of Boston and Cambridge plus one additional person to be appointed by the mayors. If the mayors failed to appoint a third commissioner, the governor was to do it for them. The mayors of Boston and Cambridge, Hugh O'Brien
and William E. Russell
, appointed Leander Greeley of Cambridge as the third commissioner. This changed over time.
The bridge opened on 1 September 1891. The original cost of construction to 1 March 1892 was US$
510,642.86. This is equivalent to US$
with inflation.
The expectations of having built the bridge were clear.
Embankment extension was expected to take that space, but that was changed such that the whole distance would be of iron spans on stone piers. The general plans were approved on 14 July 1887. The engineers were William Jackson
(Boston City Engineer), John E. Cheney (assistant Boston City Engineer), Samuel E. Tinkham (assistant engineer), and Nathan S. Brock (assistant engineer at bridge).
The subsurface conditions at the bridge location are extreme. Much of Boston is underlain with clay, but the situation at the bridge is exacerbated by a fault which roughly follows the path of the Charles River
itself. From a depth of approximately 200 foot below existing ground, is a very dense till composed of gravel and boulders with a silt-clay matrix. Above that to approximately 30 feet (9 m) below the surface is Boston blue clay (BBC). Over this are thin layers of sand, gravel, and fill. The BBC is overconsolidated up to a depth of approximately 70 foot.
The substructure originally consisted of two masonry abutments and twenty-three masonry piers, as well as one pile foundation with a fender pier
for the draw span. The superstructure was originally twenty-three cantilevered fixed spans
and suspended spans, of plate girders with one swing span
. The Boston abutment rests on vertical piles, while the Cambridge end is directly on gravel.
Originally, the bridge was built across the Charles River
connecting West Chester Park, in Boston, with Front Street, in Cambridge. This is now called Massachusetts Avenue
on both sides of the river. As originally built, the total length between centers of bearings on abutments was 2164 in 9 in (659.82 m) with a draw 48 in 4 in (14.73 m) wide between centers. The width of the bridge was 69 in 4 in (21.13 m) except near and on the draw.
The bridge as built was composed of fixed and suspended spans roughly 75 feet (22.9 m) long and piers 90 feet (27.4 m) apart, center to center. The span lengths alternated between 75 foot. The longer spans were cantilevered, while the shorter spans were suspended between the cantilevers.
The original roadway contained two lanes for horse-drawn vehicles and two street car tracks, for a total width of 51 feet (15.5 m). There were also two 9 inch sidewalks. The original roadway and sidewalk stringers were of wood, with an approximately 1.25 inches (31.8 mm) thick covering of asphalt on the sidewalk.
The exception was at the swing span, which was 48 feet (14.6 m) wide. This span was approximately 149 feet (45.4 m) long, and sat on a wooden pier. It was a double-cantilevered, electrically-driven structure also carrying a bridge caretaker's house.
The bridge was named for the Reverend John Harvard
, for whom Harvard University
is also named, rather than after the university itself. Other names suggested included Blaxton, Chester, Shawmut, and Longfellow. The structure now called the Longfellow Bridge
opened 15 years later. John Harvard was an early donor to what later became the university; not, as is often assumed, its founder.
Possibly due to its proximity to the bridge, there have been a number of tales reported at MIT
as to how the bridge came to be named "Harvard", all apocryphal. The Harvard Bridge was first constructed in 1891. MIT did not move to its current location adjacent to the bridge until 1916.
The bridge was declared unsafe in 1909, requiring all of the iron and steel to be replaced. The draw was elevated slightly and the trolley rails were replaced as well.
When the Metropolitan District Commission (MDC) took control of the bridge in 1924, they rebuilt much of the bridge superstructure. They replaced the wooden stringers with steel "I" beams, topped wooden deck elements with concrete and brick, and replaced the street car rails. Structural steel hangers replaced wrought iron. The swing span was converted into two 75 feet (22.9 m) fixed spans the same width as the rest of the bridge. The wooden pier was heavily modified with concrete and stone to make it resemble the other piers, increasing the number of stone piers from 23 to 24.
Heavy traffic at the Mass Ave
and Memorial Drive intersection on the Cambridge end of the bridge led to the construction of an underpass in 1931. The underpass eliminated the at-grade intersection.
The bridge was often known as the "Xylophone Bridge" because of the sound its wooden decking made when traffic traveled over it. This decking was replaced in 1949 with 3 inches (76.2 mm) concrete-filled "I-beam lok" grating topped with a 2.25 inches (57.2 mm) thick bituminous wearing surface. At this time, all bearings were replaced, and the trolley car tracks were removed, as were granite blocks. The trolley car poles were reused for street lights. Ramps between the bridge and the under-construction Storrow Drive
were added.
The 1924 sidewalk slabs were replaced by precast, prestressed slabs in 1962.
The fifteen expansion dams were replaced or repaired in 1969.
) in 1971-1972 due to complaints by bridge users of excessive vibration. The bridge was found to be understrength for its load. Before the final study was complete, the recommendation was to place a load limit of 8 short tons (7.3 MT) per axle and a total of 15 short tons (13.6 MT) per vehicle, or to restrict trucks to the interior lanes, where the bridge was stronger. A 25 short tons (22.7 MT) limit was imposed.
Suggestions made included strengthening the existing structure by adding either struts or plates to make the existing four beams along the length of the bridge into a stiffening truss, or to replace the superstructure with a new one, made of either steel or concrete, which would be up to current standards. The recommendation was to replace the superstructure with one weighing approximately the same in order to reuse the piers, which were in good condition.
The reasoning was that the cost of a new structure could be predicted much more easily than the cost of repairing and reinforcing the existing bridge. The resulting new bridge would be of known materials and quality, such as ductile structural steel rather than brittle wrought iron, and rated at AASHO HS-20. Repairing the existing structure would leave old wrought iron of uncertain quality and condition standing, and would not bring the design up to (then) current standards. Detailed engineering calculations were included. The price was estimated at 2.5 million to 3 million U.S. dollars (US$
to US$
with inflation).
The action taken based on this study was to establish load restrictions on the bridge, 15 short tons (13.6 MT) in the outer lanes, 25 short tons (22.7 MT) on the inner lanes. This was expanded in 1979 to a flat limit of 15 short tons (13.6 MT) on the whole bridge.
at Greenwich, Connecticut
in 1983, the Harvard Bridge was shut down and inspected because it contained similar elements, specifically the suspended spans. Traffic was restricted to the inner two lanes due to the discovery of two failed hangers on span 14. A few days later, all trucks and buses were banned from the bridge.
In 1986, a report was published containing the plan to replace the superstructure on the existing supports. Alternatives considered were very similar to the 1972 report, and were similarly decided. Structural modifications included an upgrade from four longitudinal girders to six of the same shape, elimination of ramp "B", and replacement of a stairway with a handicapped pedestrian ramp on the Boston end of the bridge.
The historic value of the bridge was considered significant, so the plan was to make the replacement superstructure appear similar, with similar railing and lighting. In order to document the pre-existing structure, a Historic American Engineering Record (HAER) would be prepared.
Ramp "B", from southbound (Boston bound) bridge lanes to eastbound Storrow Drive
, caused traffic to merge onto Storrow Drive from the left (high speed) lanes using a short acceleration lane, causing safety issues. The MDC requested elimination of this ramp. Compared to overall bridge traffic of 30,000 vehicles per day, traffic on ramp B was found to be low, approximately 1,500 vehicles per day with a peak of 120 vehicles per hour.
Pier 12 was exhibiting inappropriate movement and was scheduled for reinforcement.
The work would be done in two phases. Phase 1 would reinforce the downstream side of the bridge to allow MBTA bus traffic, and was expected to take 5 months. Most of this effort would be spent on the underside of the bridge and would not affect existing traffic. Phase 2 would replace the entire superstructure and was expected to take three construction seasons to implement. Cost was estimated to be (US$
with inflation). Phase 1 finished in 1987, and Phase 2 in 1990.
The Harvard Bridge is measured, locally, in smoot
s.
In 1958, members of the Lambda Chi Alpha
fraternity at MIT
measured the bridge's eastern sidewalk by carrying or dragging the shortest pledge that year, Oliver Smoot, end over end.
Crossing pedestrians are informed by length markers painted at 10-smoot intervals that the bridge is 364.4 smoot
s long, "plus one ear". The qualifier "plus or minus" was originally intended to express measurement uncertainty, but over the years the words "or minus" have gone missing in many citations, including the markings on the bridge itself. The marks are repainted twice each year by members of the fraternity.
During the reconstruction in the 1980s, the smoot markings were repainted on the new deck, and the sidewalks were divided into smoot
-length slabs rather than the standard six feet. The Boston police use the smoot marks as a coordinate system when reporting accidents on the bridge.
performed one of his "well known escapes" from this bridge on 1 May 1908. Other sources have it as 30 April 1908.
Massachusetts Avenue (Boston)
Massachusetts Avenue, known to locals as Mass Ave, is a major thoroughfare in Boston, Massachusetts, and several cities and towns northwest of Boston...
(Route 2A) from Back Bay, Boston to Cambridge
Cambridge, Massachusetts
Cambridge is a city in Middlesex County, Massachusetts, United States, in the Greater Boston area. It was named in honor of the University of Cambridge in England, an important center of the Puritan theology embraced by the town's founders. Cambridge is home to two of the world's most prominent...
, Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...
. It is the longest bridge over the Charles River
Charles River
The Charles River is an long river that flows in an overall northeasterly direction in eastern Massachusetts, USA. From its source in Hopkinton, the river travels through 22 cities and towns until reaching the Atlantic Ocean at Boston...
.
Named for the Reverend John Harvard
John Harvard (clergyman)
John Harvard was an English minister in America whose deathbed bequest to the Massachusetts Bay Colony's fledgling New College was so gratefully received that the school was renamed Harvard College in his honor.-Biography:Harvard was born and raised in Southwark, England, the fourth of nine...
, it was originally built between 1887 and 1891 with a swing span
Swing bridge
A swing bridge is a movable bridge that has as its primary structural support a vertical locating pin and support ring, usually at or near to its centre of gravity, about which the turning span can then pivot horizontally as shown in the animated illustration to the right...
. The bridge was revised over the years until its superstructure was completely replaced in the late 1980s. It is locally known for being measured in the idiosyncratic unit called the smoot
Smoot
The smoot is a nonstandard unit of length created as part of an MIT fraternity prank. It is named after Oliver R. Smoot, a fraternity pledge to Lambda Chi Alpha, who in October 1958 lay on the Harvard Bridge , and was used by his fraternity brothers to measure the length of the bridge.-Unit...
.
Conception
In 1874, the Massachusetts Legislature passed two acts, Chapters 175 and 314 to authorize the construction of a bridge between Boston and Cambridge. Nothing further happened until 1882, when a follow-up act (Chapter 155) with more specifics was enacted. The location was expressed asThe bridge was to have a draw with an opening of at least 38 feet (11.6 m). Unfortunately, Boston did not like this act, mainly because it did not provide for an overhead crossing of the Grand Junction Branch
Grand Junction Railroad
The Grand Junction Railroad is an 8.55-mile long railroad in the Boston, Massachusetts area, connecting the railroads heading west and north from Boston...
of the Boston and Albany Railroad
Boston and Albany Railroad
The Boston and Albany Railroad was a railroad connecting Boston, Massachusetts to Albany, New York, later becoming part of the New York Central Railroad system, Conrail and CSX. The line is used by CSX for freight...
. So nothing happened until the act was amended by Acts of 1885, Chapter 129, which changed the draw to a clear opening of at least 36 feet (11 m) and no more, until the other bridges below the proposed location were required to have a larger opening. Still nothing happened, until the City of Cambridge petitioned the Massachusetts Legislature in 1887 to compel Boston to proceed. This resulted in Acts of 1887, Chapter 282, which was mandatory for both cities. It required that each city pay for half the bridge, and allowed Boston to raise up to US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
250,000 (US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
with inflation) for this purpose, in excess of its debt limit. This implied an estimated cost of US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
500,000 (US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
with inflation) for the bridge.
The act authorized a commission to build the bridge. The commission was to consist of the mayors of Boston and Cambridge plus one additional person to be appointed by the mayors. If the mayors failed to appoint a third commissioner, the governor was to do it for them. The mayors of Boston and Cambridge, Hugh O'Brien
Hugh O'Brien
Hugh O'Brien was the 31st mayor of Boston, from 1884–1888. O'Brien is notable as Boston's first Irish mayor, having emigrated from Ireland to America in the early 1830s...
and William E. Russell
William Russell (governor)
William Eustis Russell was a U.S. political figure. He served as the 37th Governor of Massachusetts between 1891 and 1894, becoming the state's youngest ever elected Governor at age 34.-Family:...
, appointed Leander Greeley of Cambridge as the third commissioner. This changed over time.
| Year(s) | Mayor of Boston | Mayor of Cambridge | Third Commissioner |
|---|---|---|---|
| 1887–1888 | Hugh O'Brien Hugh O'Brien Hugh O'Brien was the 31st mayor of Boston, from 1884–1888. O'Brien is notable as Boston's first Irish mayor, having emigrated from Ireland to America in the early 1830s... |
William E. Russell | Leander Greeley |
| 1889–1890 | Thomas N. Hart Thomas N. Hart Thomas Norton Hart was an American manufacturer, businessman, and politician from Massachusetts who served as mayor of Boston from 1889 to 1890 and from 1900 to 1902.- References :... |
Henry H. Gilmore | |
| 1891 | Nathan Matthews, Jr. Nathan Matthews, Jr. Nathan Matthews, Jr. was an American politician from Massachusetts who served as Mayor of Boston from 1891–1894.-Biography:... |
Alpheus B. Alger | Leander Greeley (died 15 February 1891) George W. Gale |
The bridge opened on 1 September 1891. The original cost of construction to 1 March 1892 was US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
510,642.86. This is equivalent to US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
with inflation.
The expectations of having built the bridge were clear.
Engineering
In the Act of 1887, the bridge was to be a wooden pile structure with stone pavement for the first 200 feet (61 m) because the Charles RiverCharles River
The Charles River is an long river that flows in an overall northeasterly direction in eastern Massachusetts, USA. From its source in Hopkinton, the river travels through 22 cities and towns until reaching the Atlantic Ocean at Boston...
Embankment extension was expected to take that space, but that was changed such that the whole distance would be of iron spans on stone piers. The general plans were approved on 14 July 1887. The engineers were William Jackson
William Jackson (engineer)
William Jackson was the Boston, Massachusetts city engineer from 1885 to 1910. He was responsible for a number of the major bridges in the city, including Harvard Bridge, Longfellow Bridge, and Charlestown Bridge....
(Boston City Engineer), John E. Cheney (assistant Boston City Engineer), Samuel E. Tinkham (assistant engineer), and Nathan S. Brock (assistant engineer at bridge).
The subsurface conditions at the bridge location are extreme. Much of Boston is underlain with clay, but the situation at the bridge is exacerbated by a fault which roughly follows the path of the Charles River
Charles River
The Charles River is an long river that flows in an overall northeasterly direction in eastern Massachusetts, USA. From its source in Hopkinton, the river travels through 22 cities and towns until reaching the Atlantic Ocean at Boston...
itself. From a depth of approximately 200 foot below existing ground, is a very dense till composed of gravel and boulders with a silt-clay matrix. Above that to approximately 30 feet (9 m) below the surface is Boston blue clay (BBC). Over this are thin layers of sand, gravel, and fill. The BBC is overconsolidated up to a depth of approximately 70 foot.
The substructure originally consisted of two masonry abutments and twenty-three masonry piers, as well as one pile foundation with a fender pier
Fender pier
A fender pier is a structure built to protect another structure from damage, such as by ship collision.800px|centerThe structure in the river around the swing span is a fender pier...
for the draw span. The superstructure was originally twenty-three cantilevered fixed spans
Cantilever bridge
A cantilever bridge is a bridge built using cantilevers, structures that project horizontally into space, supported on only one end. For small footbridges, the cantilevers may be simple beams; however, large cantilever bridges designed to handle road or rail traffic use trusses built from...
and suspended spans, of plate girders with one swing span
Swing bridge
A swing bridge is a movable bridge that has as its primary structural support a vertical locating pin and support ring, usually at or near to its centre of gravity, about which the turning span can then pivot horizontally as shown in the animated illustration to the right...
. The Boston abutment rests on vertical piles, while the Cambridge end is directly on gravel.
Charles River
The Charles River is an long river that flows in an overall northeasterly direction in eastern Massachusetts, USA. From its source in Hopkinton, the river travels through 22 cities and towns until reaching the Atlantic Ocean at Boston...
connecting West Chester Park, in Boston, with Front Street, in Cambridge. This is now called Massachusetts Avenue
Massachusetts Avenue (Boston)
Massachusetts Avenue, known to locals as Mass Ave, is a major thoroughfare in Boston, Massachusetts, and several cities and towns northwest of Boston...
on both sides of the river. As originally built, the total length between centers of bearings on abutments was 2164 in 9 in (659.82 m) with a draw 48 in 4 in (14.73 m) wide between centers. The width of the bridge was 69 in 4 in (21.13 m) except near and on the draw.
The bridge as built was composed of fixed and suspended spans roughly 75 feet (22.9 m) long and piers 90 feet (27.4 m) apart, center to center. The span lengths alternated between 75 foot. The longer spans were cantilevered, while the shorter spans were suspended between the cantilevers.
The original roadway contained two lanes for horse-drawn vehicles and two street car tracks, for a total width of 51 feet (15.5 m). There were also two 9 inch sidewalks. The original roadway and sidewalk stringers were of wood, with an approximately 1.25 inches (31.8 mm) thick covering of asphalt on the sidewalk.
The exception was at the swing span, which was 48 feet (14.6 m) wide. This span was approximately 149 feet (45.4 m) long, and sat on a wooden pier. It was a double-cantilevered, electrically-driven structure also carrying a bridge caretaker's house.
Naming
John Harvard (clergyman)
John Harvard was an English minister in America whose deathbed bequest to the Massachusetts Bay Colony's fledgling New College was so gratefully received that the school was renamed Harvard College in his honor.-Biography:Harvard was born and raised in Southwark, England, the fourth of nine...
, for whom Harvard University
Harvard University
Harvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...
is also named, rather than after the university itself. Other names suggested included Blaxton, Chester, Shawmut, and Longfellow. The structure now called the Longfellow Bridge
Longfellow Bridge
The Longfellow Bridge, also known to locals as the "Salt-and-Pepper Bridge" or the "Salt-and-Pepper-Shaker Bridge" due to the shape of its central towers, carries Route 3 and the Massachusetts Bay Transportation Authority's Red Line across the Charles River to connect Boston's Beacon Hill...
opened 15 years later. John Harvard was an early donor to what later became the university; not, as is often assumed, its founder.
Possibly due to its proximity to the bridge, there have been a number of tales reported at MIT
Massachusetts Institute of Technology
The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...
as to how the bridge came to be named "Harvard", all apocryphal. The Harvard Bridge was first constructed in 1891. MIT did not move to its current location adjacent to the bridge until 1916.
Maintenance and updates
In 1898, 3 foot (0.9144 m)-wide bicycle lanes were installed next to each curb.The bridge was declared unsafe in 1909, requiring all of the iron and steel to be replaced. The draw was elevated slightly and the trolley rails were replaced as well.
When the Metropolitan District Commission (MDC) took control of the bridge in 1924, they rebuilt much of the bridge superstructure. They replaced the wooden stringers with steel "I" beams, topped wooden deck elements with concrete and brick, and replaced the street car rails. Structural steel hangers replaced wrought iron. The swing span was converted into two 75 feet (22.9 m) fixed spans the same width as the rest of the bridge. The wooden pier was heavily modified with concrete and stone to make it resemble the other piers, increasing the number of stone piers from 23 to 24.
Heavy traffic at the Mass Ave
Massachusetts Avenue (Boston)
Massachusetts Avenue, known to locals as Mass Ave, is a major thoroughfare in Boston, Massachusetts, and several cities and towns northwest of Boston...
and Memorial Drive intersection on the Cambridge end of the bridge led to the construction of an underpass in 1931. The underpass eliminated the at-grade intersection.
The bridge was often known as the "Xylophone Bridge" because of the sound its wooden decking made when traffic traveled over it. This decking was replaced in 1949 with 3 inches (76.2 mm) concrete-filled "I-beam lok" grating topped with a 2.25 inches (57.2 mm) thick bituminous wearing surface. At this time, all bearings were replaced, and the trolley car tracks were removed, as were granite blocks. The trolley car poles were reused for street lights. Ramps between the bridge and the under-construction Storrow Drive
Storrow Drive
Storrow Drive is a major cross town expressway in Boston, Massachusetts, running south and west from Leverett Circle along the Charles River. It is a parkway—it is restricted to cars; trucks and buses are not permitted on it...
were added.
The 1924 sidewalk slabs were replaced by precast, prestressed slabs in 1962.
The fifteen expansion dams were replaced or repaired in 1969.
Engineering study, 1971-1972
There was an engineering study done by the Metropolitan District Commission (later merged into the Department of Conservation and RecreationDepartment of Conservation and Recreation (Massachusetts)
The Department of Conservation and Recreation is a state agency of the Commonwealth of Massachusetts, situated in the Executive Office of Energy and Environmental Affairs. It is best known for its parks and parkways. As of May 24, 2011 the Commissioner of the DCR is Edward M. Lambert, Jr...
) in 1971-1972 due to complaints by bridge users of excessive vibration. The bridge was found to be understrength for its load. Before the final study was complete, the recommendation was to place a load limit of 8 short tons (7.3 MT) per axle and a total of 15 short tons (13.6 MT) per vehicle, or to restrict trucks to the interior lanes, where the bridge was stronger. A 25 short tons (22.7 MT) limit was imposed.
Suggestions made included strengthening the existing structure by adding either struts or plates to make the existing four beams along the length of the bridge into a stiffening truss, or to replace the superstructure with a new one, made of either steel or concrete, which would be up to current standards. The recommendation was to replace the superstructure with one weighing approximately the same in order to reuse the piers, which were in good condition.
The reasoning was that the cost of a new structure could be predicted much more easily than the cost of repairing and reinforcing the existing bridge. The resulting new bridge would be of known materials and quality, such as ductile structural steel rather than brittle wrought iron, and rated at AASHO HS-20. Repairing the existing structure would leave old wrought iron of uncertain quality and condition standing, and would not bring the design up to (then) current standards. Detailed engineering calculations were included. The price was estimated at 2.5 million to 3 million U.S. dollars (US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
to US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
with inflation).
The action taken based on this study was to establish load restrictions on the bridge, 15 short tons (13.6 MT) in the outer lanes, 25 short tons (22.7 MT) on the inner lanes. This was expanded in 1979 to a flat limit of 15 short tons (13.6 MT) on the whole bridge.
Superstructure replacement, 1980s
After the failure of the Mianus River BridgeMianus River Bridge
The Mianus River Bridge carries Interstate 95 over the Mianus River in the Cos Cob section of Greenwich, Connecticut. The bridge suffered a 1983 collapse, killing several motorists. The replacement span is officially named the Michael L...
at Greenwich, Connecticut
Greenwich, Connecticut
Greenwich is a town in Fairfield County, Connecticut, United States. As of the 2010 census, the town had a total population of 61,171. It is home to many hedge funds and other financial service companies. Greenwich is the southernmost and westernmost municipality in Connecticut and is 38+ minutes ...
in 1983, the Harvard Bridge was shut down and inspected because it contained similar elements, specifically the suspended spans. Traffic was restricted to the inner two lanes due to the discovery of two failed hangers on span 14. A few days later, all trucks and buses were banned from the bridge.
In 1986, a report was published containing the plan to replace the superstructure on the existing supports. Alternatives considered were very similar to the 1972 report, and were similarly decided. Structural modifications included an upgrade from four longitudinal girders to six of the same shape, elimination of ramp "B", and replacement of a stairway with a handicapped pedestrian ramp on the Boston end of the bridge.
The historic value of the bridge was considered significant, so the plan was to make the replacement superstructure appear similar, with similar railing and lighting. In order to document the pre-existing structure, a Historic American Engineering Record (HAER) would be prepared.
Ramp "B", from southbound (Boston bound) bridge lanes to eastbound Storrow Drive
Storrow Drive
Storrow Drive is a major cross town expressway in Boston, Massachusetts, running south and west from Leverett Circle along the Charles River. It is a parkway—it is restricted to cars; trucks and buses are not permitted on it...
, caused traffic to merge onto Storrow Drive from the left (high speed) lanes using a short acceleration lane, causing safety issues. The MDC requested elimination of this ramp. Compared to overall bridge traffic of 30,000 vehicles per day, traffic on ramp B was found to be low, approximately 1,500 vehicles per day with a peak of 120 vehicles per hour.
Pier 12 was exhibiting inappropriate movement and was scheduled for reinforcement.
The work would be done in two phases. Phase 1 would reinforce the downstream side of the bridge to allow MBTA bus traffic, and was expected to take 5 months. Most of this effort would be spent on the underside of the bridge and would not affect existing traffic. Phase 2 would replace the entire superstructure and was expected to take three construction seasons to implement. Cost was estimated to be (US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
with inflation). Phase 1 finished in 1987, and Phase 2 in 1990.
Bridge length measurement
Smoot
The smoot is a nonstandard unit of length created as part of an MIT fraternity prank. It is named after Oliver R. Smoot, a fraternity pledge to Lambda Chi Alpha, who in October 1958 lay on the Harvard Bridge , and was used by his fraternity brothers to measure the length of the bridge.-Unit...
s.
In 1958, members of the Lambda Chi Alpha
Lambda Chi Alpha
Lambda Chi Alpha is one of the largest men's secret general fraternities in North America, having initiated more than 280,000 members and held chapters at more than 300 universities. It is a member of the North-American Interfraternity Conference and was founded by Warren A. Cole, while he was a...
fraternity at MIT
Massachusetts Institute of Technology
The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...
measured the bridge's eastern sidewalk by carrying or dragging the shortest pledge that year, Oliver Smoot, end over end.
Crossing pedestrians are informed by length markers painted at 10-smoot intervals that the bridge is 364.4 smoot
Smoot
The smoot is a nonstandard unit of length created as part of an MIT fraternity prank. It is named after Oliver R. Smoot, a fraternity pledge to Lambda Chi Alpha, who in October 1958 lay on the Harvard Bridge , and was used by his fraternity brothers to measure the length of the bridge.-Unit...
s long, "plus one ear". The qualifier "plus or minus" was originally intended to express measurement uncertainty, but over the years the words "or minus" have gone missing in many citations, including the markings on the bridge itself. The marks are repainted twice each year by members of the fraternity.
During the reconstruction in the 1980s, the smoot markings were repainted on the new deck, and the sidewalks were divided into smoot
Smoot
The smoot is a nonstandard unit of length created as part of an MIT fraternity prank. It is named after Oliver R. Smoot, a fraternity pledge to Lambda Chi Alpha, who in October 1958 lay on the Harvard Bridge , and was used by his fraternity brothers to measure the length of the bridge.-Unit...
-length slabs rather than the standard six feet. The Boston police use the smoot marks as a coordinate system when reporting accidents on the bridge.
Length discrepancy
Given that Smoot was 5 in 7 in (1.7 m) tall in 1958, the given measurement in smoots of 364.4 yields a "bridge length" of about 620 metres (2,034.1 ft). Published sources give the length of the bridge as approximately 660 metres (2,165.4 ft). The difference in length between the sidewalk markings and the published figure represents a 40 metres (131.2 ft) discrepancy.The Harvard Bridge (also known locally as the MIT bridge or the "Mass Ave" bridge) carries Massachusetts Avenue
Massachusetts Avenue (Boston)
Massachusetts Avenue, known to locals as Mass Ave, is a major thoroughfare in Boston, Massachusetts, and several cities and towns northwest of Boston...
(Route 2A) from Back Bay, Boston to Cambridge
Cambridge, Massachusetts
Cambridge is a city in Middlesex County, Massachusetts, United States, in the Greater Boston area. It was named in honor of the University of Cambridge in England, an important center of the Puritan theology embraced by the town's founders. Cambridge is home to two of the world's most prominent...
, Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...
. It is the longest bridge over the Charles River
Charles River
The Charles River is an long river that flows in an overall northeasterly direction in eastern Massachusetts, USA. From its source in Hopkinton, the river travels through 22 cities and towns until reaching the Atlantic Ocean at Boston...
.
Named for the Reverend John Harvard
John Harvard (clergyman)
John Harvard was an English minister in America whose deathbed bequest to the Massachusetts Bay Colony's fledgling New College was so gratefully received that the school was renamed Harvard College in his honor.-Biography:Harvard was born and raised in Southwark, England, the fourth of nine...
, it was originally built between 1887 and 1891 with a swing span
Swing bridge
A swing bridge is a movable bridge that has as its primary structural support a vertical locating pin and support ring, usually at or near to its centre of gravity, about which the turning span can then pivot horizontally as shown in the animated illustration to the right...
. The bridge was revised over the years until its superstructure was completely replaced in the late 1980s. It is locally known for being measured in the idiosyncratic unit called the smoot
Smoot
The smoot is a nonstandard unit of length created as part of an MIT fraternity prank. It is named after Oliver R. Smoot, a fraternity pledge to Lambda Chi Alpha, who in October 1958 lay on the Harvard Bridge , and was used by his fraternity brothers to measure the length of the bridge.-Unit...
.
Conception
In 1874, the Massachusetts Legislature passed two acts, Chapters 175 and 314 to authorize the construction of a bridge between Boston and Cambridge. Nothing further happened until 1882, when a follow-up act (Chapter 155) with more specifics was enacted. The location was expressed asThe bridge was to have a draw with an opening of at least 38 feet (11.6 m). Unfortunately, Boston did not like this act, mainly because it did not provide for an overhead crossing of the Grand Junction Branch
Grand Junction Railroad
The Grand Junction Railroad is an 8.55-mile long railroad in the Boston, Massachusetts area, connecting the railroads heading west and north from Boston...
of the Boston and Albany Railroad
Boston and Albany Railroad
The Boston and Albany Railroad was a railroad connecting Boston, Massachusetts to Albany, New York, later becoming part of the New York Central Railroad system, Conrail and CSX. The line is used by CSX for freight...
. So nothing happened until the act was amended by Acts of 1885, Chapter 129, which changed the draw to a clear opening of at least 36 feet (11 m) and no more, until the other bridges below the proposed location were required to have a larger opening. Still nothing happened, until the City of Cambridge petitioned the Massachusetts Legislature in 1887 to compel Boston to proceed. This resulted in Acts of 1887, Chapter 282, which was mandatory for both cities. It required that each city pay for half the bridge, and allowed Boston to raise up to US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
250,000 (US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
with inflation) for this purpose, in excess of its debt limit. This implied an estimated cost of US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
500,000 (US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
with inflation) for the bridge.
The act authorized a commission to build the bridge. The commission was to consist of the mayors of Boston and Cambridge plus one additional person to be appointed by the mayors. If the mayors failed to appoint a third commissioner, the governor was to do it for them. The mayors of Boston and Cambridge, Hugh O'Brien
Hugh O'Brien
Hugh O'Brien was the 31st mayor of Boston, from 1884–1888. O'Brien is notable as Boston's first Irish mayor, having emigrated from Ireland to America in the early 1830s...
and William E. Russell
William Russell (governor)
William Eustis Russell was a U.S. political figure. He served as the 37th Governor of Massachusetts between 1891 and 1894, becoming the state's youngest ever elected Governor at age 34.-Family:...
, appointed Leander Greeley of Cambridge as the third commissioner. This changed over time.
| Year(s) | Mayor of Boston | Mayor of Cambridge | Third Commissioner |
|---|---|---|---|
| 1887–1888 | Hugh O'Brien Hugh O'Brien Hugh O'Brien was the 31st mayor of Boston, from 1884–1888. O'Brien is notable as Boston's first Irish mayor, having emigrated from Ireland to America in the early 1830s... |
William E. Russell | Leander Greeley |
| 1889–1890 | Thomas N. Hart Thomas N. Hart Thomas Norton Hart was an American manufacturer, businessman, and politician from Massachusetts who served as mayor of Boston from 1889 to 1890 and from 1900 to 1902.- References :... |
Henry H. Gilmore | |
| 1891 | Nathan Matthews, Jr. Nathan Matthews, Jr. Nathan Matthews, Jr. was an American politician from Massachusetts who served as Mayor of Boston from 1891–1894.-Biography:... |
Alpheus B. Alger | Leander Greeley (died 15 February 1891) George W. Gale |
The bridge opened on 1 September 1891. The original cost of construction to 1 March 1892 was US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
510,642.86. This is equivalent to US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
with inflation.
The expectations of having built the bridge were clear.
Engineering
In the Act of 1887, the bridge was to be a wooden pile structure with stone pavement for the first 200 feet (61 m) because the Charles RiverCharles River
The Charles River is an long river that flows in an overall northeasterly direction in eastern Massachusetts, USA. From its source in Hopkinton, the river travels through 22 cities and towns until reaching the Atlantic Ocean at Boston...
Embankment extension was expected to take that space, but that was changed such that the whole distance would be of iron spans on stone piers. The general plans were approved on 14 July 1887. The engineers were William Jackson
William Jackson (engineer)
William Jackson was the Boston, Massachusetts city engineer from 1885 to 1910. He was responsible for a number of the major bridges in the city, including Harvard Bridge, Longfellow Bridge, and Charlestown Bridge....
(Boston City Engineer), John E. Cheney (assistant Boston City Engineer), Samuel E. Tinkham (assistant engineer), and Nathan S. Brock (assistant engineer at bridge).
The subsurface conditions at the bridge location are extreme. Much of Boston is underlain with clay, but the situation at the bridge is exacerbated by a fault which roughly follows the path of the Charles River
Charles River
The Charles River is an long river that flows in an overall northeasterly direction in eastern Massachusetts, USA. From its source in Hopkinton, the river travels through 22 cities and towns until reaching the Atlantic Ocean at Boston...
itself. From a depth of approximately 200 foot below existing ground, is a very dense till composed of gravel and boulders with a silt-clay matrix. Above that to approximately 30 feet (9 m) below the surface is Boston blue clay (BBC). Over this are thin layers of sand, gravel, and fill. The BBC is overconsolidated up to a depth of approximately 70 foot.
The substructure originally consisted of two masonry abutments and twenty-three masonry piers, as well as one pile foundation with a fender pier
Fender pier
A fender pier is a structure built to protect another structure from damage, such as by ship collision.800px|centerThe structure in the river around the swing span is a fender pier...
for the draw span. The superstructure was originally twenty-three cantilevered fixed spans
Cantilever bridge
A cantilever bridge is a bridge built using cantilevers, structures that project horizontally into space, supported on only one end. For small footbridges, the cantilevers may be simple beams; however, large cantilever bridges designed to handle road or rail traffic use trusses built from...
and suspended spans, of plate girders with one swing span
Swing bridge
A swing bridge is a movable bridge that has as its primary structural support a vertical locating pin and support ring, usually at or near to its centre of gravity, about which the turning span can then pivot horizontally as shown in the animated illustration to the right...
. The Boston abutment rests on vertical piles, while the Cambridge end is directly on gravel.
Charles River
The Charles River is an long river that flows in an overall northeasterly direction in eastern Massachusetts, USA. From its source in Hopkinton, the river travels through 22 cities and towns until reaching the Atlantic Ocean at Boston...
connecting West Chester Park, in Boston, with Front Street, in Cambridge. This is now called Massachusetts Avenue
Massachusetts Avenue (Boston)
Massachusetts Avenue, known to locals as Mass Ave, is a major thoroughfare in Boston, Massachusetts, and several cities and towns northwest of Boston...
on both sides of the river. As originally built, the total length between centers of bearings on abutments was 2164 in 9 in (659.82 m) with a draw 48 in 4 in (14.73 m) wide between centers. The width of the bridge was 69 in 4 in (21.13 m) except near and on the draw.
The bridge as built was composed of fixed and suspended spans roughly 75 feet (22.9 m) long and piers 90 feet (27.4 m) apart, center to center. The span lengths alternated between 75 foot. The longer spans were cantilevered, while the shorter spans were suspended between the cantilevers.
The original roadway contained two lanes for horse-drawn vehicles and two street car tracks, for a total width of 51 feet (15.5 m). There were also two 9 inch sidewalks. The original roadway and sidewalk stringers were of wood, with an approximately 1.25 inches (31.8 mm) thick covering of asphalt on the sidewalk.
The exception was at the swing span, which was 48 feet (14.6 m) wide. This span was approximately 149 feet (45.4 m) long, and sat on a wooden pier. It was a double-cantilevered, electrically-driven structure also carrying a bridge caretaker's house.
Naming
John Harvard (clergyman)
John Harvard was an English minister in America whose deathbed bequest to the Massachusetts Bay Colony's fledgling New College was so gratefully received that the school was renamed Harvard College in his honor.-Biography:Harvard was born and raised in Southwark, England, the fourth of nine...
, for whom Harvard University
Harvard University
Harvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...
is also named, rather than after the university itself. Other names suggested included Blaxton, Chester, Shawmut, and Longfellow. The structure now called the Longfellow Bridge
Longfellow Bridge
The Longfellow Bridge, also known to locals as the "Salt-and-Pepper Bridge" or the "Salt-and-Pepper-Shaker Bridge" due to the shape of its central towers, carries Route 3 and the Massachusetts Bay Transportation Authority's Red Line across the Charles River to connect Boston's Beacon Hill...
opened 15 years later. John Harvard was an early donor to what later became the university; not, as is often assumed, its founder.
Possibly due to its proximity to the bridge, there have been a number of tales reported at MIT
Massachusetts Institute of Technology
The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...
as to how the bridge came to be named "Harvard", all apocryphal. The Harvard Bridge was first constructed in 1891. MIT did not move to its current location adjacent to the bridge until 1916.
Maintenance and updates
In 1898, 3 foot (0.9144 m)-wide bicycle lanes were installed next to each curb.The bridge was declared unsafe in 1909, requiring all of the iron and steel to be replaced. The draw was elevated slightly and the trolley rails were replaced as well.
When the Metropolitan District Commission (MDC) took control of the bridge in 1924, they rebuilt much of the bridge superstructure. They replaced the wooden stringers with steel "I" beams, topped wooden deck elements with concrete and brick, and replaced the street car rails. Structural steel hangers replaced wrought iron. The swing span was converted into two 75 feet (22.9 m) fixed spans the same width as the rest of the bridge. The wooden pier was heavily modified with concrete and stone to make it resemble the other piers, increasing the number of stone piers from 23 to 24.
Heavy traffic at the Mass Ave
Massachusetts Avenue (Boston)
Massachusetts Avenue, known to locals as Mass Ave, is a major thoroughfare in Boston, Massachusetts, and several cities and towns northwest of Boston...
and Memorial Drive intersection on the Cambridge end of the bridge led to the construction of an underpass in 1931. The underpass eliminated the at-grade intersection.
The bridge was often known as the "Xylophone Bridge" because of the sound its wooden decking made when traffic traveled over it. This decking was replaced in 1949 with 3 inches (76.2 mm) concrete-filled "I-beam lok" grating topped with a 2.25 inches (57.2 mm) thick bituminous wearing surface. At this time, all bearings were replaced, and the trolley car tracks were removed, as were granite blocks. The trolley car poles were reused for street lights. Ramps between the bridge and the under-construction Storrow Drive
Storrow Drive
Storrow Drive is a major cross town expressway in Boston, Massachusetts, running south and west from Leverett Circle along the Charles River. It is a parkway—it is restricted to cars; trucks and buses are not permitted on it...
were added.
The 1924 sidewalk slabs were replaced by precast, prestressed slabs in 1962.
The fifteen expansion dams were replaced or repaired in 1969.
Engineering study, 1971-1972
There was an engineering study done by the Metropolitan District Commission (later merged into the Department of Conservation and RecreationDepartment of Conservation and Recreation (Massachusetts)
The Department of Conservation and Recreation is a state agency of the Commonwealth of Massachusetts, situated in the Executive Office of Energy and Environmental Affairs. It is best known for its parks and parkways. As of May 24, 2011 the Commissioner of the DCR is Edward M. Lambert, Jr...
) in 1971-1972 due to complaints by bridge users of excessive vibration. The bridge was found to be understrength for its load. Before the final study was complete, the recommendation was to place a load limit of 8 short tons (7.3 MT) per axle and a total of 15 short tons (13.6 MT) per vehicle, or to restrict trucks to the interior lanes, where the bridge was stronger. A 25 short tons (22.7 MT) limit was imposed.
Suggestions made included strengthening the existing structure by adding either struts or plates to make the existing four beams along the length of the bridge into a stiffening truss, or to replace the superstructure with a new one, made of either steel or concrete, which would be up to current standards. The recommendation was to replace the superstructure with one weighing approximately the same in order to reuse the piers, which were in good condition.
The reasoning was that the cost of a new structure could be predicted much more easily than the cost of repairing and reinforcing the existing bridge. The resulting new bridge would be of known materials and quality, such as ductile structural steel rather than brittle wrought iron, and rated at AASHO HS-20. Repairing the existing structure would leave old wrought iron of uncertain quality and condition standing, and would not bring the design up to (then) current standards. Detailed engineering calculations were included. The price was estimated at 2.5 million to 3 million U.S. dollars (US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
to US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
with inflation).
The action taken based on this study was to establish load restrictions on the bridge, 15 short tons (13.6 MT) in the outer lanes, 25 short tons (22.7 MT) on the inner lanes. This was expanded in 1979 to a flat limit of 15 short tons (13.6 MT) on the whole bridge.
Superstructure replacement, 1980s
After the failure of the Mianus River BridgeMianus River Bridge
The Mianus River Bridge carries Interstate 95 over the Mianus River in the Cos Cob section of Greenwich, Connecticut. The bridge suffered a 1983 collapse, killing several motorists. The replacement span is officially named the Michael L...
at Greenwich, Connecticut
Greenwich, Connecticut
Greenwich is a town in Fairfield County, Connecticut, United States. As of the 2010 census, the town had a total population of 61,171. It is home to many hedge funds and other financial service companies. Greenwich is the southernmost and westernmost municipality in Connecticut and is 38+ minutes ...
in 1983, the Harvard Bridge was shut down and inspected because it contained similar elements, specifically the suspended spans. Traffic was restricted to the inner two lanes due to the discovery of two failed hangers on span 14. A few days later, all trucks and buses were banned from the bridge.
In 1986, a report was published containing the plan to replace the superstructure on the existing supports. Alternatives considered were very similar to the 1972 report, and were similarly decided. Structural modifications included an upgrade from four longitudinal girders to six of the same shape, elimination of ramp "B", and replacement of a stairway with a handicapped pedestrian ramp on the Boston end of the bridge.
The historic value of the bridge was considered significant, so the plan was to make the replacement superstructure appear similar, with similar railing and lighting. In order to document the pre-existing structure, a Historic American Engineering Record (HAER) would be prepared.
Ramp "B", from southbound (Boston bound) bridge lanes to eastbound Storrow Drive
Storrow Drive
Storrow Drive is a major cross town expressway in Boston, Massachusetts, running south and west from Leverett Circle along the Charles River. It is a parkway—it is restricted to cars; trucks and buses are not permitted on it...
, caused traffic to merge onto Storrow Drive from the left (high speed) lanes using a short acceleration lane, causing safety issues. The MDC requested elimination of this ramp. Compared to overall bridge traffic of 30,000 vehicles per day, traffic on ramp B was found to be low, approximately 1,500 vehicles per day with a peak of 120 vehicles per hour.
Pier 12 was exhibiting inappropriate movement and was scheduled for reinforcement.
The work would be done in two phases. Phase 1 would reinforce the downstream side of the bridge to allow MBTA bus traffic, and was expected to take 5 months. Most of this effort would be spent on the underside of the bridge and would not affect existing traffic. Phase 2 would replace the entire superstructure and was expected to take three construction seasons to implement. Cost was estimated to be (US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
with inflation). Phase 1 finished in 1987, and Phase 2 in 1990.
Bridge length measurement
Smoot
The smoot is a nonstandard unit of length created as part of an MIT fraternity prank. It is named after Oliver R. Smoot, a fraternity pledge to Lambda Chi Alpha, who in October 1958 lay on the Harvard Bridge , and was used by his fraternity brothers to measure the length of the bridge.-Unit...
s.
In 1958, members of the Lambda Chi Alpha
Lambda Chi Alpha
Lambda Chi Alpha is one of the largest men's secret general fraternities in North America, having initiated more than 280,000 members and held chapters at more than 300 universities. It is a member of the North-American Interfraternity Conference and was founded by Warren A. Cole, while he was a...
fraternity at MIT
Massachusetts Institute of Technology
The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...
measured the bridge's eastern sidewalk by carrying or dragging the shortest pledge that year, Oliver Smoot, end over end.
Crossing pedestrians are informed by length markers painted at 10-smoot intervals that the bridge is 364.4 smoot
Smoot
The smoot is a nonstandard unit of length created as part of an MIT fraternity prank. It is named after Oliver R. Smoot, a fraternity pledge to Lambda Chi Alpha, who in October 1958 lay on the Harvard Bridge , and was used by his fraternity brothers to measure the length of the bridge.-Unit...
s long, "plus one ear". The qualifier "plus or minus" was originally intended to express measurement uncertainty, but over the years the words "or minus" have gone missing in many citations, including the markings on the bridge itself. The marks are repainted twice each year by members of the fraternity.
During the reconstruction in the 1980s, the smoot markings were repainted on the new deck, and the sidewalks were divided into smoot
Smoot
The smoot is a nonstandard unit of length created as part of an MIT fraternity prank. It is named after Oliver R. Smoot, a fraternity pledge to Lambda Chi Alpha, who in October 1958 lay on the Harvard Bridge , and was used by his fraternity brothers to measure the length of the bridge.-Unit...
-length slabs rather than the standard six feet. The Boston police use the smoot marks as a coordinate system when reporting accidents on the bridge.
Length discrepancy
Given that Smoot was 5 in 7 in (1.7 m) tall in 1958, the given measurement in smoots of 364.4 yields a "bridge length" of about 620 metres (2,034.1 ft). Published sources give the length of the bridge as approximately 660 metres (2,165.4 ft). The difference in length between the sidewalk markings and the published figure represents a 40 metres (131.2 ft) discrepancy.The Harvard Bridge (also known locally as the MIT bridge or the "Mass Ave" bridge) carries Massachusetts Avenue
Massachusetts Avenue (Boston)
Massachusetts Avenue, known to locals as Mass Ave, is a major thoroughfare in Boston, Massachusetts, and several cities and towns northwest of Boston...
(Route 2A) from Back Bay, Boston to Cambridge
Cambridge, Massachusetts
Cambridge is a city in Middlesex County, Massachusetts, United States, in the Greater Boston area. It was named in honor of the University of Cambridge in England, an important center of the Puritan theology embraced by the town's founders. Cambridge is home to two of the world's most prominent...
, Massachusetts
Massachusetts
The Commonwealth of Massachusetts is a state in the New England region of the northeastern United States of America. It is bordered by Rhode Island and Connecticut to the south, New York to the west, and Vermont and New Hampshire to the north; at its east lies the Atlantic Ocean. As of the 2010...
. It is the longest bridge over the Charles River
Charles River
The Charles River is an long river that flows in an overall northeasterly direction in eastern Massachusetts, USA. From its source in Hopkinton, the river travels through 22 cities and towns until reaching the Atlantic Ocean at Boston...
.
Named for the Reverend John Harvard
John Harvard (clergyman)
John Harvard was an English minister in America whose deathbed bequest to the Massachusetts Bay Colony's fledgling New College was so gratefully received that the school was renamed Harvard College in his honor.-Biography:Harvard was born and raised in Southwark, England, the fourth of nine...
, it was originally built between 1887 and 1891 with a swing span
Swing bridge
A swing bridge is a movable bridge that has as its primary structural support a vertical locating pin and support ring, usually at or near to its centre of gravity, about which the turning span can then pivot horizontally as shown in the animated illustration to the right...
. The bridge was revised over the years until its superstructure was completely replaced in the late 1980s. It is locally known for being measured in the idiosyncratic unit called the smoot
Smoot
The smoot is a nonstandard unit of length created as part of an MIT fraternity prank. It is named after Oliver R. Smoot, a fraternity pledge to Lambda Chi Alpha, who in October 1958 lay on the Harvard Bridge , and was used by his fraternity brothers to measure the length of the bridge.-Unit...
.
Conception
In 1874, the Massachusetts Legislature passed two acts, Chapters 175 and 314 to authorize the construction of a bridge between Boston and Cambridge. Nothing further happened until 1882, when a follow-up act (Chapter 155) with more specifics was enacted. The location was expressed asThe bridge was to have a draw with an opening of at least 38 feet (11.6 m). Unfortunately, Boston did not like this act, mainly because it did not provide for an overhead crossing of the Grand Junction Branch
Grand Junction Railroad
The Grand Junction Railroad is an 8.55-mile long railroad in the Boston, Massachusetts area, connecting the railroads heading west and north from Boston...
of the Boston and Albany Railroad
Boston and Albany Railroad
The Boston and Albany Railroad was a railroad connecting Boston, Massachusetts to Albany, New York, later becoming part of the New York Central Railroad system, Conrail and CSX. The line is used by CSX for freight...
. So nothing happened until the act was amended by Acts of 1885, Chapter 129, which changed the draw to a clear opening of at least 36 feet (11 m) and no more, until the other bridges below the proposed location were required to have a larger opening. Still nothing happened, until the City of Cambridge petitioned the Massachusetts Legislature in 1887 to compel Boston to proceed. This resulted in Acts of 1887, Chapter 282, which was mandatory for both cities. It required that each city pay for half the bridge, and allowed Boston to raise up to US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
250,000 (US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
with inflation) for this purpose, in excess of its debt limit. This implied an estimated cost of US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
500,000 (US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
with inflation) for the bridge.
The act authorized a commission to build the bridge. The commission was to consist of the mayors of Boston and Cambridge plus one additional person to be appointed by the mayors. If the mayors failed to appoint a third commissioner, the governor was to do it for them. The mayors of Boston and Cambridge, Hugh O'Brien
Hugh O'Brien
Hugh O'Brien was the 31st mayor of Boston, from 1884–1888. O'Brien is notable as Boston's first Irish mayor, having emigrated from Ireland to America in the early 1830s...
and William E. Russell
William Russell (governor)
William Eustis Russell was a U.S. political figure. He served as the 37th Governor of Massachusetts between 1891 and 1894, becoming the state's youngest ever elected Governor at age 34.-Family:...
, appointed Leander Greeley of Cambridge as the third commissioner. This changed over time.
| Year(s) | Mayor of Boston | Mayor of Cambridge | Third Commissioner |
|---|---|---|---|
| 1887–1888 | Hugh O'Brien Hugh O'Brien Hugh O'Brien was the 31st mayor of Boston, from 1884–1888. O'Brien is notable as Boston's first Irish mayor, having emigrated from Ireland to America in the early 1830s... |
William E. Russell | Leander Greeley |
| 1889–1890 | Thomas N. Hart Thomas N. Hart Thomas Norton Hart was an American manufacturer, businessman, and politician from Massachusetts who served as mayor of Boston from 1889 to 1890 and from 1900 to 1902.- References :... |
Henry H. Gilmore | |
| 1891 | Nathan Matthews, Jr. Nathan Matthews, Jr. Nathan Matthews, Jr. was an American politician from Massachusetts who served as Mayor of Boston from 1891–1894.-Biography:... |
Alpheus B. Alger | Leander Greeley (died 15 February 1891) George W. Gale |
The bridge opened on 1 September 1891. The original cost of construction to 1 March 1892 was US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
510,642.86. This is equivalent to US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
with inflation.
The expectations of having built the bridge were clear.
Engineering
In the Act of 1887, the bridge was to be a wooden pile structure with stone pavement for the first 200 feet (61 m) because the Charles RiverCharles River
The Charles River is an long river that flows in an overall northeasterly direction in eastern Massachusetts, USA. From its source in Hopkinton, the river travels through 22 cities and towns until reaching the Atlantic Ocean at Boston...
Embankment extension was expected to take that space, but that was changed such that the whole distance would be of iron spans on stone piers. The general plans were approved on 14 July 1887. The engineers were William Jackson
William Jackson (engineer)
William Jackson was the Boston, Massachusetts city engineer from 1885 to 1910. He was responsible for a number of the major bridges in the city, including Harvard Bridge, Longfellow Bridge, and Charlestown Bridge....
(Boston City Engineer), John E. Cheney (assistant Boston City Engineer), Samuel E. Tinkham (assistant engineer), and Nathan S. Brock (assistant engineer at bridge).
The subsurface conditions at the bridge location are extreme. Much of Boston is underlain with clay, but the situation at the bridge is exacerbated by a fault which roughly follows the path of the Charles River
Charles River
The Charles River is an long river that flows in an overall northeasterly direction in eastern Massachusetts, USA. From its source in Hopkinton, the river travels through 22 cities and towns until reaching the Atlantic Ocean at Boston...
itself. From a depth of approximately 200 foot below existing ground, is a very dense till composed of gravel and boulders with a silt-clay matrix. Above that to approximately 30 feet (9 m) below the surface is Boston blue clay (BBC). Over this are thin layers of sand, gravel, and fill. The BBC is overconsolidated up to a depth of approximately 70 foot.
The substructure originally consisted of two masonry abutments and twenty-three masonry piers, as well as one pile foundation with a fender pier
Fender pier
A fender pier is a structure built to protect another structure from damage, such as by ship collision.800px|centerThe structure in the river around the swing span is a fender pier...
for the draw span. The superstructure was originally twenty-three cantilevered fixed spans
Cantilever bridge
A cantilever bridge is a bridge built using cantilevers, structures that project horizontally into space, supported on only one end. For small footbridges, the cantilevers may be simple beams; however, large cantilever bridges designed to handle road or rail traffic use trusses built from...
and suspended spans, of plate girders with one swing span
Swing bridge
A swing bridge is a movable bridge that has as its primary structural support a vertical locating pin and support ring, usually at or near to its centre of gravity, about which the turning span can then pivot horizontally as shown in the animated illustration to the right...
. The Boston abutment rests on vertical piles, while the Cambridge end is directly on gravel.
Charles River
The Charles River is an long river that flows in an overall northeasterly direction in eastern Massachusetts, USA. From its source in Hopkinton, the river travels through 22 cities and towns until reaching the Atlantic Ocean at Boston...
connecting West Chester Park, in Boston, with Front Street, in Cambridge. This is now called Massachusetts Avenue
Massachusetts Avenue (Boston)
Massachusetts Avenue, known to locals as Mass Ave, is a major thoroughfare in Boston, Massachusetts, and several cities and towns northwest of Boston...
on both sides of the river. As originally built, the total length between centers of bearings on abutments was 2164 in 9 in (659.82 m) with a draw 48 in 4 in (14.73 m) wide between centers. The width of the bridge was 69 in 4 in (21.13 m) except near and on the draw.
The bridge as built was composed of fixed and suspended spans roughly 75 feet (22.9 m) long and piers 90 feet (27.4 m) apart, center to center. The span lengths alternated between 75 foot. The longer spans were cantilevered, while the shorter spans were suspended between the cantilevers.
The original roadway contained two lanes for horse-drawn vehicles and two street car tracks, for a total width of 51 feet (15.5 m). There were also two 9 inch sidewalks. The original roadway and sidewalk stringers were of wood, with an approximately 1.25 inches (31.8 mm) thick covering of asphalt on the sidewalk.
The exception was at the swing span, which was 48 feet (14.6 m) wide. This span was approximately 149 feet (45.4 m) long, and sat on a wooden pier. It was a double-cantilevered, electrically-driven structure also carrying a bridge caretaker's house.
Naming
John Harvard (clergyman)
John Harvard was an English minister in America whose deathbed bequest to the Massachusetts Bay Colony's fledgling New College was so gratefully received that the school was renamed Harvard College in his honor.-Biography:Harvard was born and raised in Southwark, England, the fourth of nine...
, for whom Harvard University
Harvard University
Harvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...
is also named, rather than after the university itself. Other names suggested included Blaxton, Chester, Shawmut, and Longfellow. The structure now called the Longfellow Bridge
Longfellow Bridge
The Longfellow Bridge, also known to locals as the "Salt-and-Pepper Bridge" or the "Salt-and-Pepper-Shaker Bridge" due to the shape of its central towers, carries Route 3 and the Massachusetts Bay Transportation Authority's Red Line across the Charles River to connect Boston's Beacon Hill...
opened 15 years later. John Harvard was an early donor to what later became the university; not, as is often assumed, its founder.
Possibly due to its proximity to the bridge, there have been a number of tales reported at MIT
Massachusetts Institute of Technology
The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...
as to how the bridge came to be named "Harvard", all apocryphal. The Harvard Bridge was first constructed in 1891. MIT did not move to its current location adjacent to the bridge until 1916.
Maintenance and updates
In 1898, 3 foot (0.9144 m)-wide bicycle lanes were installed next to each curb.The bridge was declared unsafe in 1909, requiring all of the iron and steel to be replaced. The draw was elevated slightly and the trolley rails were replaced as well.
When the Metropolitan District Commission (MDC) took control of the bridge in 1924, they rebuilt much of the bridge superstructure. They replaced the wooden stringers with steel "I" beams, topped wooden deck elements with concrete and brick, and replaced the street car rails. Structural steel hangers replaced wrought iron. The swing span was converted into two 75 feet (22.9 m) fixed spans the same width as the rest of the bridge. The wooden pier was heavily modified with concrete and stone to make it resemble the other piers, increasing the number of stone piers from 23 to 24.
Heavy traffic at the Mass Ave
Massachusetts Avenue (Boston)
Massachusetts Avenue, known to locals as Mass Ave, is a major thoroughfare in Boston, Massachusetts, and several cities and towns northwest of Boston...
and Memorial Drive intersection on the Cambridge end of the bridge led to the construction of an underpass in 1931. The underpass eliminated the at-grade intersection.
The bridge was often known as the "Xylophone Bridge" because of the sound its wooden decking made when traffic traveled over it. This decking was replaced in 1949 with 3 inches (76.2 mm) concrete-filled "I-beam lok" grating topped with a 2.25 inches (57.2 mm) thick bituminous wearing surface. At this time, all bearings were replaced, and the trolley car tracks were removed, as were granite blocks. The trolley car poles were reused for street lights. Ramps between the bridge and the under-construction Storrow Drive
Storrow Drive
Storrow Drive is a major cross town expressway in Boston, Massachusetts, running south and west from Leverett Circle along the Charles River. It is a parkway—it is restricted to cars; trucks and buses are not permitted on it...
were added.
The 1924 sidewalk slabs were replaced by precast, prestressed slabs in 1962.
The fifteen expansion dams were replaced or repaired in 1969.
Engineering study, 1971-1972
There was an engineering study done by the Metropolitan District Commission (later merged into the Department of Conservation and RecreationDepartment of Conservation and Recreation (Massachusetts)
The Department of Conservation and Recreation is a state agency of the Commonwealth of Massachusetts, situated in the Executive Office of Energy and Environmental Affairs. It is best known for its parks and parkways. As of May 24, 2011 the Commissioner of the DCR is Edward M. Lambert, Jr...
) in 1971-1972 due to complaints by bridge users of excessive vibration. The bridge was found to be understrength for its load. Before the final study was complete, the recommendation was to place a load limit of 8 short tons (7.3 MT) per axle and a total of 15 short tons (13.6 MT) per vehicle, or to restrict trucks to the interior lanes, where the bridge was stronger. A 25 short tons (22.7 MT) limit was imposed.
Suggestions made included strengthening the existing structure by adding either struts or plates to make the existing four beams along the length of the bridge into a stiffening truss, or to replace the superstructure with a new one, made of either steel or concrete, which would be up to current standards. The recommendation was to replace the superstructure with one weighing approximately the same in order to reuse the piers, which were in good condition.
The reasoning was that the cost of a new structure could be predicted much more easily than the cost of repairing and reinforcing the existing bridge. The resulting new bridge would be of known materials and quality, such as ductile structural steel rather than brittle wrought iron, and rated at AASHO HS-20. Repairing the existing structure would leave old wrought iron of uncertain quality and condition standing, and would not bring the design up to (then) current standards. Detailed engineering calculations were included. The price was estimated at 2.5 million to 3 million U.S. dollars (US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
to US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
with inflation).
The action taken based on this study was to establish load restrictions on the bridge, 15 short tons (13.6 MT) in the outer lanes, 25 short tons (22.7 MT) on the inner lanes. This was expanded in 1979 to a flat limit of 15 short tons (13.6 MT) on the whole bridge.
Superstructure replacement, 1980s
After the failure of the Mianus River BridgeMianus River Bridge
The Mianus River Bridge carries Interstate 95 over the Mianus River in the Cos Cob section of Greenwich, Connecticut. The bridge suffered a 1983 collapse, killing several motorists. The replacement span is officially named the Michael L...
at Greenwich, Connecticut
Greenwich, Connecticut
Greenwich is a town in Fairfield County, Connecticut, United States. As of the 2010 census, the town had a total population of 61,171. It is home to many hedge funds and other financial service companies. Greenwich is the southernmost and westernmost municipality in Connecticut and is 38+ minutes ...
in 1983, the Harvard Bridge was shut down and inspected because it contained similar elements, specifically the suspended spans. Traffic was restricted to the inner two lanes due to the discovery of two failed hangers on span 14. A few days later, all trucks and buses were banned from the bridge.
In 1986, a report was published containing the plan to replace the superstructure on the existing supports. Alternatives considered were very similar to the 1972 report, and were similarly decided. Structural modifications included an upgrade from four longitudinal girders to six of the same shape, elimination of ramp "B", and replacement of a stairway with a handicapped pedestrian ramp on the Boston end of the bridge.
The historic value of the bridge was considered significant, so the plan was to make the replacement superstructure appear similar, with similar railing and lighting. In order to document the pre-existing structure, a Historic American Engineering Record (HAER) would be prepared.
Ramp "B", from southbound (Boston bound) bridge lanes to eastbound Storrow Drive
Storrow Drive
Storrow Drive is a major cross town expressway in Boston, Massachusetts, running south and west from Leverett Circle along the Charles River. It is a parkway—it is restricted to cars; trucks and buses are not permitted on it...
, caused traffic to merge onto Storrow Drive from the left (high speed) lanes using a short acceleration lane, causing safety issues. The MDC requested elimination of this ramp. Compared to overall bridge traffic of 30,000 vehicles per day, traffic on ramp B was found to be low, approximately 1,500 vehicles per day with a peak of 120 vehicles per hour.
Pier 12 was exhibiting inappropriate movement and was scheduled for reinforcement.
The work would be done in two phases. Phase 1 would reinforce the downstream side of the bridge to allow MBTA bus traffic, and was expected to take 5 months. Most of this effort would be spent on the underside of the bridge and would not affect existing traffic. Phase 2 would replace the entire superstructure and was expected to take three construction seasons to implement. Cost was estimated to be (US$
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
with inflation). Phase 1 finished in 1987, and Phase 2 in 1990.
Bridge length measurement
Smoot
The smoot is a nonstandard unit of length created as part of an MIT fraternity prank. It is named after Oliver R. Smoot, a fraternity pledge to Lambda Chi Alpha, who in October 1958 lay on the Harvard Bridge , and was used by his fraternity brothers to measure the length of the bridge.-Unit...
s.
In 1958, members of the Lambda Chi Alpha
Lambda Chi Alpha
Lambda Chi Alpha is one of the largest men's secret general fraternities in North America, having initiated more than 280,000 members and held chapters at more than 300 universities. It is a member of the North-American Interfraternity Conference and was founded by Warren A. Cole, while he was a...
fraternity at MIT
Massachusetts Institute of Technology
The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...
measured the bridge's eastern sidewalk by carrying or dragging the shortest pledge that year, Oliver Smoot, end over end.
Crossing pedestrians are informed by length markers painted at 10-smoot intervals that the bridge is 364.4 smoot
Smoot
The smoot is a nonstandard unit of length created as part of an MIT fraternity prank. It is named after Oliver R. Smoot, a fraternity pledge to Lambda Chi Alpha, who in October 1958 lay on the Harvard Bridge , and was used by his fraternity brothers to measure the length of the bridge.-Unit...
s long, "plus one ear". The qualifier "plus or minus" was originally intended to express measurement uncertainty, but over the years the words "or minus" have gone missing in many citations, including the markings on the bridge itself. The marks are repainted twice each year by members of the fraternity.
During the reconstruction in the 1980s, the smoot markings were repainted on the new deck, and the sidewalks were divided into smoot
Smoot
The smoot is a nonstandard unit of length created as part of an MIT fraternity prank. It is named after Oliver R. Smoot, a fraternity pledge to Lambda Chi Alpha, who in October 1958 lay on the Harvard Bridge , and was used by his fraternity brothers to measure the length of the bridge.-Unit...
-length slabs rather than the standard six feet. The Boston police use the smoot marks as a coordinate system when reporting accidents on the bridge.
Length discrepancy
Given that Smoot was 5 in 7 in (1.7 m) tall in 1958, the given measurement in smoots of 364.4 yields a "bridge length" of about 620 metres (2,034.1 ft). Published sources give the length of the bridge as approximately 660 metres (2,165.4 ft). The difference in length between the sidewalk markings and the published figure represents a 40 metres (131.2 ft) discrepancy.Houdini
According to a marker near the southeast end of the bridge, Harry HoudiniHarry Houdini
Harry Houdini was a Hungarian-born American magician and escapologist, stunt performer, actor and film producer noted for his sensational escape acts...
performed one of his "well known escapes" from this bridge on 1 May 1908. Other sources have it as 30 April 1908.