Analysis of biaxial bending of reinforced concrete slabs with simply support under concentrated loads

In the reinforced concrete slab with simply support, the biaxial bending effect under concentrated loads acting on the center of width is obvious, especially on the slabs with larger width to length ratio but smaller loading areas. According to the conventional design method, the longitudinal reinforcement is calculated according to Mx, but the transverse reinforcement is given according to the minimum ratio of reinforcement. Therefore, the phenomenon of cracking extended along the span of slab (longitudinal crack of slab) commonly appears in construction and the width of the cracks along longitudinal direction is far greater than that along transverse direction because of less transverse reinforcement. Based on the experimental research, the biaxial bending effect of reinforced concrete slabs under the concentrated loads is analyzed. For the calculation of My that controls the longitudinal crack of slab, the formula based on the theory of plastic hinge line is deduced and the simplified calculating method is given as a reference for engineering design.