The shear key is a structural element designed and provided in different structures to provide resistance against lateral forces like earthquake forces and sliding forces in the different structures such as bridges, retaining walls, the basement of residential buildings, precast buildings and culverts, masonry walls in seismic regions, and steel columns.
A shear key can be made from concrete as in precast constructions, residential building basement, or fabricated from steel such as in the case of steel column base plate, and sometimes steel reinforcement is utilized to play a shear key role for instance between basement wall and footing.
They play vital roles in structure for example in bridges or prevent movement of different components of the structure as in precast structures. The primary purpose of shear keys is to improve the stability of structures.
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Purpose of Shear Key in Structures
Shear keys provide to resist structures from lateral forces such as earth pressure and water pressures, earthquakes, and wind.
Shear key in retaining wall
Shear keys are given at the base of holding dividers to expand its sliding obstruction. Basically, it is helpful to put the shear key underneath the stem of the holding divider since it rearranges the situation of fortification that can be reached out from the stem legitimately into the stem.
The shear key should be proportioned with the end goal that its width is at any rate twice its profundity to build up the quality of the key in shear rather than flexural, according to ACI 318-17. The shear key is built 0.91m from the toe of the balance, with width and profundity of 0.508m and 0.381m, individually.
Shear key in the bridge structure
Shear keys are put in the abutments of the little to medium-sized bridge structures to offer parallel cross-over help to the superstructure under sidelong loads. The shear keys in the connecting structure assume a critical part in opposing seismic burdens.
During a strong earthquake, shear keys should work as a conciliatory basic component to forestall the transmission of huge seismic powers to the projection heaps. There are two sorts of shear keys in connect structure: outside and inside shear keys. The previous has the fault of the simplicity of investigation and fix.
Shear Key in Beams
It is impossible to construct a floor slab in one pour due to the scale of the limitation of the resources, time is taken to complete one pour, etc.
Therefore, we have to have two or more pours to complete the concreting of slabs. The construction joint will be in the slab and beams. Shear keys need to provide in each beam and slab.
Beam shear keys are placed similar manner to the slabs. However, additionally, most of the time, we place shear dowels in the beam construction joints.
Shear Keys in Raft Foundations
Shear keys in the mat foundations are provided because of the volume to be poured and to restrict the thermal effects. There are typical measurements for keys to be provided to carry the shear forces in the foundations.
