Experimental Study On Reinforced Concrete Perpendicular Wall -Beam Joints

The perpendicular shear wall-frame beam joint is very important and also it's the weakest point of the reinforced concrete frame-shear wall and frame-tube structure systems,which are widely used in the high-rise buildings. So its design and calculation method is needed to resolve urgently, but so far the research on this respect is very few. Therefore the further research on this kind of joint is very necessary.On the basis of the former experimental study on R.C. perpendicular wall-beam joints, in this paper three R.C. perpendicular wall-beam joints with visible beam were tested under constant axial load on the top of the wall and cyclic vertical load at the end of the beam. The main purposes of this paper are working out the primary method to design the visible beam and calculate the out-of-plane flexural capacity of shear wall, and placing the visible beam to avoid"Locally Pulling Out"damage.Through the tests and analysis on R.C. perpendicular wall-beam joints, the conclusions are obtained as following:1. If the shear wall is a thin wall and without any special strengthening measures, The"Locally Pulling Out"damage usually happens in the perpendicular wall-beam joint. Once this kind of damage happens, not only the bearing capability of the joint cannot be satisfied, but also the ductility will be quite poor.2. If the torsion resisting bars of the visible beam are designed reasonably, the out-of-plane flexural capacity of the wall can be increased, and the"Locally Pulling Out"damage will not happen, also the ductility of the joint can be improved.3. If the torsion resisting bars of the visible beams in perpendicular wall-beam joints are placed by calculation, the out-of-plane flexural capacity of shear wall under low cyclic loading is resisted by three parts: the torsional capacity formed by the asymmetric shear stresses on damaged sections, the flexural moment of wall in effective sections and the torsional capacity of the visible beam. At last, on the basis of the above conclusion, a formula for calculating the out-of-plane flexural capacity of shear wall and a primary design method of visible beams are proposed.