Arch and it's technical aspects

It is a structure, normally curved. While undergoing vertical loads, it motivates its two end supports to produce reactions with interiorly headed horizontal components.

        Application:

—     Generally, the arches are utilized as a bridge, supporting a roadway, railroad track, or footpath, and as part of a building, where it arranges a large open space uninterrupted by columns. Arches are generally formed with steel, reinforced concrete, or timber.

Technical Aspects:

—     The arch produces a structure that reduces tensile stresses by stretching an open space. All the forces are settled into compressive stresses.

—     It is effective since some of the existing building materials like stone, cast iron and concrete can potently withstand compression but are very feeble when tension, shear or torsional stress is implemented to them. With the use of the arch configuration, substantial spans can be obtained.

       Hinge Introduction:

—     Two unknowns. The reaction are two components of Force, or the magnitude and direction Ф of the consequential force .

—     At the hinge joint moment is zero i.e. it can’t withstand the bending moment generated by external force.

Categorization

      Hinge less Arch:

—     The hinge-less arch applies no hinges and authorizes no rotation at the foundations.

      Two Hinged Arch:

—     The two hinged arch applied hinged bearings which permit rotation. The only forces produced at the bearings belong to horizontal and vertical forces.

Three Hinged Arch:

—     The three-hinged arch includes a supplementary hinge at the top or crown of the arch. The three-hinged arch is affected marginally if there exist movement in either foundation (because earthquakes, sinking, etc.)

Tied Arch:

—     The tied arch is a variation on the arch that facilitates construction although the ground is not solid enough to manage the horizontal forces.

Three hinged circular arch

• A three hinged system may or may not have a vertical axis of symmetry. In the first case the central hinge c will lie on the axis of symmetry and the hinges at the support A and B are at same level.