Static Test Study On Precast Concrete Frame Beams Of Large Diameter And High Strength Steel Bars

At present,the prefabricated concrete members are arranged with smaller diameters and lower strength,which leads to complicated reinforcement of prefabricated components when assembled on site,complicated construction procedures,unconsolidated concrete pouring and large steel consumption,which is not conducive to ensuring the quality of concrete components and construction efficiency.In order to make the components simple,easy to install,reduce the construction difficulty and construction cost,this paper integrates the development of prefabricated buildings at home and abroad,and proposes the concept of high-efficiency reinforcement,that is,the large-diameter,large-pitch high-strength steel bars are arranged in the precast concrete members,and the high-strength reinforcement is used.The concept can optimize the assembly connection,improve the installation efficiency,and promote the industrialization of the building.At present,the application of domestic large-diameter high-strength steel bars in prefabricated concrete buildings is still in the exploratory stage,the research theory is immature,and the experimental research and numerical simulation results are less.In this paper,the static mechanical properties of large-diameter high-strength steel precast concrete frame beams assembled at the beam end are studied.In this paper,two full-scale test pieces are designed and manufactured.The frame beam dimensions are 350mm×700mm,the frame beams cantilever length are 3200mm,the longitudinal reinforcement of the test piece KL-32-25 is 2(?)32.and the lower longitudinal reinforcement was 2(?)25,no additional reinforcement is added at the joint,the upper longitudinal reinforcement of the test piece KL-40-32F is 2(?)40,the lower longitudinal reinforcement is 2(?)32,and the joint is added with additional reinforcement.The monotonic static load test is carried out by applying concentrated force to the free end of the frame beam.The development and fracture modes of the cracks of the large-diameter high-strength steel precast concrete frame beam are observed,and the stress process is analyzed.The test results show that the bearing capacity of the prefabricated frame beam is high,and the development of cracks in the test beam will be accelerated after the cracking of the test piece.It is feasible to use double-sided adhesive welding anchors in the large-diameter high-strength steel bar.Set the shearing force at the assembly.And the rough surface is feasible.The additional waist reinforcement has no obvious effect on the bearing capacity and crack resistance of the test piece,and the sleeve assembly connection performance at the beam end is reliable.The finite element analysis software was used to establish the model,the mechanical properties of the experimental model were analyzed and the parameters were verified.The finite element analysis software was used to compare the mechanical properties of the concrete frame beam and the traditional reinforcement concrete pouring concrete frame beamwith large diameter and high strength steel bar.The comparative analysis shows that the bearing capacity of large-diameter high-strength steel precast concrete frame beam can reach the level of concrete frame beam with large diameter and high strength steel bar,and the bearing capacity of concrete frame beam with small diameter steel bar with the same reinforcement ratio.quite.