Mechanical Behavior Analysis Of Flat Slab Structure During Construction

As a special structural form,the beamless floor is widely used in the basement structure: it can both short construction period and reduce the engineering cost.This paper takes the finite element analysis of slab-column joints and the effect of local stacking on the stress of beamless floors as the starting point,the main research contents include:(1)Finite element simulation software ABAQUS was used to conduct modeling analysis on the existing slab-column node test,evaluate the selection of each parameter in the modeling process and give the recommended value.By comparing with the experimental results,the feasibility of applying finite element method to the study of plate and column joints is verified.The stress in the slab-column joint area is analyzed,discuss the failure mechanism of the slab-column joint under the influence of different concrete strengths and longitudinal reinforcement ratios from a finite element perspective,and explore the connection between the slab-column joint failure and the stress development in the nearby area.The results show that through reasonable constitutive input,mesh division,and parameter input,the finite element simulation results fit the test results well;the concrete near the slab-column node is in a complex stress state under three-way compression during failure,in which Longitudinal stress plays a controlling role.(2)The stress state of backfill floor was taken as the research object,the paper studies the possible vehicle load after the backfill in the construction stage.ABAQUS is equipped with a DLOAD subroutine to realize the load input with special action form,so as to determine the corresponding equivalent uniformly distributed load.On this basis,various factors affecting the equivalent uniformly distributed load are analyzed to provide reference for actual construction operations.The results show that the size of the equivalent uniformly distributed load of the construction equipment is related to the equivalent principle,the number of equipment,the height of the covering soil and the span of the plate;The converted equivalent uniform load is generally larger than the live load value in the design stage,and the construction process needs to be controlled(3)The similarities and differences between shear failure and punching shear failure were compared and analyzed from two aspects of failure mechanism and calculation formula of bearing capacity stipulated in the code.In view of the fact that the current code does not clearly specify the punching bearing capacity under the random localized loading,a set of formulas for calculating the bearing capacity of plate and column joints under local load based on China’s concrete design code is derived through mechanical deduction.Which expands the applicable range of punching capacity.