Research On Static Performance Of Corrugated Steel-reinforced Concrete Composite Shallow Shell

The corrugated steel structure has the advantages of fast construction speed,low engineering cost and good durability,and has been widely used in highway pipe culverts,tunnels,utility tunnels and protection fields.Among them,some application scenarios such as utility tunnels and underground tunnels are more suitable for using corrugated steel shallow shell(arch with a rise-span ratio less than 1/5)due to space constraints.As the structure develops towards large span and high load,the stability problem of the existing corrugated steel structure gradually becomes prominent,and structural failure may occur when it bears a large load.This paper proposes a corrugated steel-reinforced concrete composite shallow shell structure.The section stiffness of the new structure is greatly improved,which can solve the existing problems of insufficient stability and bearing capacity of the corrugated steel structure.At present,there is a lack of experimental research and calculation methods for the bearing capacity performance of corrugated steel-reinforced concrete composite shallow shells,and its failure mode and stress mechanism under common loads are still unclear.For this reason,experimental studies of corrugated steel-reinforced concrete composite shallow shell with the single-point load and the three-point load were carried out in this paper.Finite element models were established,and the influence of key parameters was analyzed.Finally,the calculation formulas of the stable bearing capacity under the axial compression and the compression-bending state considering the variation of rise-span ratio were established.The main research contents are as follows:(1)Taking loading conditions,rise-span ratio,stud spacing and material strength as research parameters,single-point loading tests of eight corrugated steel-reinforced concrete composite shallow shells were carried out.Its failure mode,ultimate bearing capacity and load-displacement curve were obtained.The failure mode changes of shells with different rise-span ratios were also investigated.Based on the strain distribution of corrugated steel,the section stress development law of the composite shallow shell along the span was analyzed,and the composite effect and restraint effect of the shell under different load conditions were revealed.(2)Three-point loading tests of three corrugated steel-reinforced concrete composite shallow shells and one reinforced concrete shallow shell were carried out with cross-sectional size and structural form as research parameters.Its failure mode,ultimate bearing capacity and load-displacement curve were obtained.The differences of failure mode and ultimate bearing capacity were compared and analyzed.Based on the strain distribution of corrugated steel,the development law of section stress along the span of the shell was analyzed,and the composite effect and restraint effect of the composite shallow shell were revealed.(3)The nonlinear finite element models were established by ABAQUS software,and the rationality and accuracy of the models were verified by comparing with the test results.The influence of material strength,section size,foot displacement and other parameters on the bearing capacity of the composite shell was analyzed.On the basis of the existing bearing capacity calculation formulas,the calculation formula of the composite shell with axial compression stability was established,and the overall stability coefficient under axial compression was obtained.(4)On the basis of the finite element models,the distribution laws of axial force and bending moment along the span of the composite shell with different rise-span ratios under common working conditions were obtained.The influence of material strength,section size,foot displacement and other parameters on the bearing capacity of composite shells under different load conditions was analyzed.The compressive-bending capacities of composite sections under the elastic-plastic theory and the plastic theory were calculated.The N_u-M_u curve of the composite section was obtained,and an automatic calculation program was compiled.The elastic and elastic-plastic finite element analysis with different rise-span ratios,slenderness ratios and load cases was carried out.Compared with the existing calculation formula of the reinforced concrete arch,the calculation formula of the stable bearing capacity of the composite shell considering the influence of load conditions and rise-span ratio under the compression-bending state was proposed.