Lap splice over a grouted joint in a lattice girder system

Load-carrying in two directions in lattice girder slab systems by complementing with lapped reinforcement across the joints at the construction site was studied. A detailing of load-carrying joints without any reinforcement across the cast joint was considered. The behaviour of the cast joint between the precast concrete and the in situ cast concrete is very important. Two different surface treatments were tested in two types of detail tests of the cast joint: one type in which the cast joint was loaded in shear, and one in tension. Furthermore, the detailing of the joint between two precast concrete panels was tested in bending in full-scale tests. The detail tests were used to calibrate a friction model of the cast joint, which was then used in finite-element analyses (FEAs) of the full-scale tests. In the full-scale tests, the joints were strong enough to carry the applied load; thus, the failure mode was rupture of the reinforcement in all full-scale tests, and only one crack occurred—in the in situ cast concrete above the joint between the precast elements. However, the FEAs of the full-scale tests revealed that the detailing was sensitive to secondary cracking.