The mechanical performance of concrete shear key for prefabricated structures

Abstract

The mechanical performance of concrete connection plays an important role in the response of precast concrete structures. Unlike conventional small concrete shear key which is mainly to help with alignment at installation, large concrete shear keys have been often designed in recent engineering practice to improve joint shear resistance. However, the mechanical properties of large concrete shear keys have not been properly studied. This paper utilizes experimental and numerical methods to investigate both direct shear and flexural bending properties of shear keys. Four types of shear keys comprised of trapezoidal shape, semi-spherical shape, dome shape and wave shape are investigated, which are found to strongly influence the mechanical properties of the keyed joint. Laboratory shear test found unlike conventional shear key, with increased tenon size failure moves to concrete mortise. A detailed numerical model is built to help understand stress developed at the key joint. Flexural bending tests are carried out to evaluate the flexural bending properties of these key joints. Through comparing with theoretical derivation for plain flat joint, similar bending moment resistances from the keyed joints are measured with that of plain flat joint, but larger rotation angles are recorded probably because more damages at the key joint. Among the four different joint patterns, shear key with smoothed pattern could effectively relief concrete damages.

Experimental and numerical investigation on the compressive properties of interlocking blocks

“…Some researchers found low axial loading capacity of interlocking bricks because of the relatively small contact area due to joint imperfection [27,28]. Crack and failure of stacked pier with interlocking bricks initiated from the mortise of the connection due to lateral expansion and stress concentration [14,18,29,30].…”

An Experimental Study on the Flexural Behavior of Precast Concrete Modular Beam Systems Using Inserted Steel Plates

“…The shear keys act to inhibit the generation of shear slip in the connections, and the shear performance of the connections is greatly influenced by the shape of the shear keys. In PC construction, there are male-to-female [13,14] or female-to-female keys [15,16], as shown in Figure 1, and steel bars between the modules are connected using spliced sleeves or lapped splices. Finally, epoxy is used to fill in the non-shrinkage mortar between the shear keys to splice the two modules together [12,17].…”

Behaviour of the joint between slabs and walls composed of light steel and foam concrete

“…The concrete in the cast-in place area of the joint is not tightly bound to the concrete of the prefabricated member, which is also a weak shear key to some extent. The boundary between two batches of concrete is more likely to break and thus affect the energy dissipation as well as the failure modes (Zhang et al, 2020a(Zhang et al, , 2020b. It can also be seen from the table that the modelling value of the equivalent viscous damping coefficient at the end of loading is 0.286, which is close to 0.3 and it indicates that the energy dissipation capacity of the joint can reach the energy dissipation level of the steel reinforced concrete joint under the ideal condition.…”