Research On Flexural Performance Of Superimposed Wide Flat Beam-Hollow Core Slab Synergistic Effect

In recent years,with the change of the traditional construction mode to the environmental and intensive modernization mode,the assembled concrete structures have been developed and applied rapidly,while there are some problems: the precast components are heavy,which need to hoist several times;the joint working procedure is complex,and the steel reinforcements collide in the construction of beam-column joints;the assembled concrete structures need to made templates,which wastes a lot of manpower and resources.To solve the above problems,the paper proposed a new assembled concrete frame structure composed of hollow-core slab,wide flat beam and precast column.As the main members of assembled concrete frame structures,when the bending moment is produced by the vertical load,the hollow-core slabs around the wide flat beam will produce a certain synergistic effect.That is,the upper and lower flange slabs and the steel reinforcements in flange slabs as a part of the wide flat beam will bear the bending moment,which has great influence on the flexural performance of wide flat beams.Therefore,7 specimens are designed to carry out related tests,and the finite element analysis and theoretical analysis are carried out.The work of the full text is as follows:（1）To research on the flexural performance of wide flat beams,a pure wide flat beam,a wide flat beam with single-side slab and five wide flat beams with double-side slab are designed to test.The test results show that the bearing capacity of wide flat beam is improved significantly by surrounding hollow-core slabs,and the bearing capacity is larger with the increase of slab width in a certain range;different loading modes also affect the ultimate bearing capacity of specimens with the same slab width;the longitudinal strain of the top concrete along the slab width direction and the longitudinal reinforcement strain of the bottom slab show shear lag effect,and the plastic stage is more obvious than the elastic stage.（2）Finite element software MSC.Marc is used based on the above tests,and compared with the test results from the load-span mid-deflection curve,the cloud diagrams of concrete strain and the longitudinal reinforcement stress at the bottom of the slab,which verifies the correctness and rationality of the model.（3）On the basis of correct modeling,the parametric analyses of width flat beams with single-side and double-side slab are carried out,and the effective flange width calculation formulas of wide flat beams with flange slabs under two-point loading,one-point loading and uniform loading are given,respectively.Finally,the ultimate flexural bearing capacity calculation formulas of wide flat beams with flange slabs are proposed.