The Research Of The Slab On RC Frame Structure To Realize’strong Column And Weak Beam’

Reinforced concrete frame structure is a commonly and widely used lateral force resistance system. While seriously damaged RC frame in the previous earthquake rarely achieved the expectation of’strong column and weak beam’ductility frame in the building structure we have designed and constructed, for the insufficient consideration of impact on floor is an important cause of this phenomenon. The analysis of pure frame and floor frame numerical model of this paper are created on the ANSYS general finite element software was focus on a typical RC frame engineering examples. The pushover analysis with two types distribution of lateral force, prestress modal and elasto-plastic time-history with3series of earthquake acceleration has been done on the pure frame and floor frame numerical model to study the impact on the slab in the RC frame affects RC frame achieve "strong column and weak beam" ductile frame, and the comparative analysis on the influence of slab affect frame to achieve’strong column and weak beam’are from aspects of static and dynamic response result. The main points are as follow:Firstly, the results of pushover analysis indicated that the amplitude of slab improves the bearing capacity of structure resisting lateral displacement is limited, however, the slab affects structure deformation obviously, and pure frame’s ductility is better than floor frame’s. it is common practice to simplify the frame for pure frame when we do the mechanical analysis of the RC frame structure, the simplification will cause the frame structure’s actual ductility insufficient in the strong earthquake, and it is difficult to form a "strong column and weak beam" ductile frame. The comparative analysis of yield mechanism between with and without slab frame confirmed that the slab has adverse impact to realize the goal of "strong column and weak beam" ductile frame.Secondly, the results of modal analysis indicated that the way of simulate slab mass impact on the evaluation of the dynamic characteristics of the whole structure, the simulation results of slab mass which is equivalent to the concentration mass applied to the column-beam joints and the distribution mass without equivalent suggest that slab affect of structure higher modes significantly (the influence of higher modes was insufficient considered during structure design procedure), which directly affects the judgment of structural actual dynamic characteristics in the earthquake.Thirdly, the elasto-plastic time-history analysis results indicated that the floor slab and the slab reinforcement strengthen the bearing capacity of the frame beam end. The effect of slab reinforcement on both sides of beam should be calculated in the design of frame beam, numerical simulation results suggest that the slab reinforcement width range of4.0times thickness of slab at the beam end with both side of slab,5.0times thickness of slab at the beam with single side of slab, should be calculated in the structure analysis.