Christian Otto Mohr was a German

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 civil engineer

Civil engineer

A civil engineer is a person who practices civil engineering; the application of planning, designing, constructing, maintaining, and operating infrastructures while protecting the public and environmental health, as well as improving existing infrastructures that have been neglected.Originally, a...

.

Biography

He was born on October 8, 1835 to a landowning family in Wesselburen

Wesselburen

Wesselburen is a municipality in the district of Dithmarschen in the German Federal State of Schleswig-Holstein. It is situated near the North Sea coast, approximately 11 km west of Heide....

 in the Holstein

Holstein

Holstein is the region between the rivers Elbe and Eider. It is part of Schleswig-Holstein, the northernmost state of Germany....

 region. At the age of 16 attended the Polytechnic School in Hanover

Hanover

Hanover or Hannover, on the river Leine, is the capital of the federal state of Lower Saxony , Germany and was once by personal union the family seat of the Hanoverian Kings of Great Britain, under their title as the dukes of Brunswick-Lüneburg...

.

Starting in 1855, his early working life was spent in railroad engineering for the Hanover

Kingdom of Hanover

The Kingdom of Hanover was established in October 1814 by the Congress of Vienna, with the restoration of George III to his Hanoverian territories after the Napoleonic era. It succeeded the former Electorate of Brunswick-Lüneburg , and joined with 38 other sovereign states in the German...

 and Oldenburg

Oldenburg (state)

Oldenburg — named after its capital, the town of Oldenburg — was a state in the north of present-day Germany. Oldenburg survived from 1180 until 1918 as a county, duchy and grand duchy, and from 1918 until 1946 as a free state. It was located near the mouth of the River Weser...

 state railways, designing some famous bridge

Bridge

A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle...

s and making some of the earliest uses of steel

Steel

Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...

 truss

Truss

In architecture and structural engineering, a truss is a structure comprising one or more triangular units constructed with straight members whose ends are connected at joints referred to as nodes. External forces and reactions to those forces are considered to act only at the nodes and result in...

es.

Even during his early railway years, Mohr had developed an interest in the theories of mechanics and the strength of materials

Strength of materials

In materials science, the strength of a material is its ability to withstand an applied stress without failure. The applied stress may be tensile, compressive, or shear. Strength of materials is a subject which deals with loads, deformations and the forces acting on a material. A load applied to a...

. In 1867, he became professor

Professor

A professor is a scholarly teacher; the precise meaning of the term varies by country. Literally, professor derives from Latin as a "person who professes" being usually an expert in arts or sciences; a teacher of high rank...

 of mechanics at Stuttgart

Stuttgart

Stuttgart is the capital of the state of Baden-Württemberg in southern Germany. The sixth-largest city in Germany, Stuttgart has a population of 600,038 while the metropolitan area has a population of 5.3 million ....

 Polytechnic, and in 1873 at Dresden

Dresden

Dresden is the capital city of the Free State of Saxony in Germany. It is situated in a valley on the River Elbe, near the Czech border. The Dresden conurbation is part of the Saxon Triangle metropolitan area....

 Polytechnic. Mohr had a direct and unpretentious lecturing style that was popular with his students.In addition to a lone textbook, Mohr published many research papers on the theory of structures and strength of materials.

In 1874, Mohr formalised the idea of a statically indeterminate

Statically indeterminate

In statics, a structure is statically indeterminate when the static equilibrium equations are insufficient for determining the internal forces and reactions on that structure....

 structure.

Mohr was an enthusiast for graphical tools and developed the method, for visually representing stress

Stress (physics)

In continuum mechanics, stress is a measure of the internal forces acting within a deformable body. Quantitatively, it is a measure of the average force per unit area of a surface within the body on which internal forces act. These internal forces are a reaction to external forces applied on the body...

 in three dimensions, previously proposed by Carl Culmann

Carl Culmann

Carl Culmann was a German structural engineer.Born in Bad Bergzabern, Rhenish Palatinate, in modern-day Germany, Culmann's father, a pastor, tutored him at home before enrolling him at the military engineering school at Metz to prepare for entry to the École Polytechnique...

. In 1882, he famously developed the graphical method for analysing stress known as Mohr's circle and used it to propose an early theory of strength based on shear stress

Shear stress

A shear stress, denoted \tau\, , is defined as the component of stress coplanar with a material cross section. Shear stress arises from the force vector component parallel to the cross section...

. He also developed the Williot-Mohr diagram for truss displacements and the Maxwell-Mohr method for analysing statically indeterminate

Statically indeterminate

In statics, a structure is statically indeterminate when the static equilibrium equations are insufficient for determining the internal forces and reactions on that structure....

structures, it can also be used to determine the displacement of truss nodes and forces acting on each member. The Maxwell-Mohr method is also referred to as the virtual force method for redundant trusses.

He retired in 1900, yet continued his scientific work in the town of Dresden until his death on October 2, 1918.