Study On Shear Behavior Of High Strength Reinforced Recycled Brick Concrete Beams

With the rapid rise of urban construction,the supply of non-renewable building materials such as sand and stone is in short supply;CRB600H high ductility and high strength steel bar has not been used in the market for a long time,and its adaptability needs further study.Under the above two backgrounds,this project combines recycled concrete with CRB600 H high-strength steel bar,carries out physical experiments and finite element analysis,and compares the two.Its main research contents and conclusions are as follows:In the process of the scheme design of the shear test of recycled concrete beams,the software "Computing and Controlling Platform for Experimental Materials of Reinforced Concrete Beams" has been developed,which can be used to calculate the mix design and reinforcement design of concrete beams in the process of test.Through the shear test of recycled concrete beams,it is found that the strain of stirrups increases slowly with the increase of load at first,then increases rapidly after reaching a certain bearing capacity,and the rate of increase slows down before reaching the ultimate load;the strain of longitudinal reinforcement generally increases with the increase of load.The test beams all suffered from shear-compression failure.With the increase of shear-span ratio,the deflection growth rate of CRB600 H reinforced concrete beams increased.The deflection growth rate of CRB600 H reinforced concrete beams was slower than that of HRB400 reinforced concrete beams.Through the analysis and study of bearing capacity calculation formulas,the revised recommended formula for calculating the shear capacity of recycled concrete beams is obtained,and compared with the common code and other three formulas for calculating the shear capacity,the error is small.The shear ductility coefficient of concrete beams increases with the increase of shear span ratio,decreases with the increase of replacement ratio of recycled aggregate,and increases with the reinforcement strength.The parameters such as load,mid-span deflection,stirrup strain and longitudinal reinforcement strain of recycled concrete beams rich in brick grains are basically consistent with those of ordinary concrete beams in the shear process;however,their shear ultimate bearing capacity is slightly weaker than that of ordinary concrete beams,and the deflection and crack width of beams are slightly larger than that of ordinary concrete beams;generally speaking,their shear resistance is weaker than that of ordinary concrete beams.The shear ductility of CRB600 H high strength steel bar is stronger than that of HRB400 steel bar in the process of concrete beam shearing.The maximum crack width and midspan deflection of concrete beam are smaller than those of HRB400 reinforced concrete beam.By using finite element analysis method to simulate the shear of test beams,it is found that the results of stirrup strain,mid-span deflection and longitudinal reinforcement strain are consistent with the overall trend of measured values,which indicates that the calculation of concrete plastic damage model by ABAQUS software is more accurate;however,it is found that the curves of stirrup strain,mid-span deflection and longitudinal reinforcement strain obtained by finite element analysis are more smooth and in the curve.The simulation curves of some beams in the descending section tend to be smooth,which is closer to the theoretical analysis results.