Research On Modularized Prefabricated Structural Systems Of UHPC Sandwich Panel

Based on the Ultra-high performance concrete(UHPC),this paper proposes a prefabricated structural system of UHPC sandwich panel which is suitable for low-rise buildings.This structural system has the advantages of light weight,high strength,convenient transportation and rapid installation.Experimental researches were carried out on the key components,joints and substructure of the system to reveal the mechanical performance and failure mode.Calculation methods of the bearing capacity of each part were proposed and testified.Numerical simulations were conducted to evaluate the seismic performance of this structural system.The main research results are as follows:(1)Based on the casting test of two large panels and four small panels,a convenient and reliable casting method of UHPC sandwich panel was proposed.This method can effectively avoid the void phenomenon after formwork removal,and the short columns in the sandwich layer were completely casted without obvious defects.(2)The flexural performance test of five slab specimens and the seismic performance test of five wall specimens were completed,focusing on the mechanical performance,deformation characteristics and failure mode under different UHPC layer thickness,reinforcement ratio and other parameters.Based on the test results,the calculation method of flexural bearing capacity and initial stiffness were proposed.Besides,suggestions on the reasonable design parameters of UHPC sandwich panel were proposed.(3)The seismic performance test of two wall to wall joints with different connection forms and two wall to slab joints with different connection forms were completed.The wall to wall joints adopted the soft cable connecting ring and welding connection of embedded steel plate respectively,and the wall to slab joints adopted the bolt connection and slotted connection respectively,focusing on the seismic performance,failure mode and deformation characteristics of the joint.Calculation method of bearing capacity of the joint and rotational stiffness of wall to slab joint were proposed.(4)The prefabrication assembly and seismic performance test of a 1:2 scale substructure of UHPC prefabricated sandwich panel structural building system was completed.The mechanical performance,deformation characteristics and failure mode under vertical loading and horizontal cyclic loading were revealed.The slip deformation and failure of each joints were investigated,and the strip method was used to analyze the cracking load and bearing capacity of the substructure.(5)Based on the test results of the above components,joints and substructure,the general finite element software MSC.MARC was used to simulate each part of the structure and compare with the experimental results.Finally,a two-story prototype structure model was established to assess its seimic performance,which laid a foundation for the popularization and application of this new prefabricated structural system.