Experimental Study On Buckling Capacity Of High-strength Concrete-filled High-strength Steel Tubular Arches

Concrete-filled steel tube(CFST)arches are widely used in bridge engineering and construction engineering due to their advantages such as high bearing capacity,light weight and large span,and beautiful shapes.With the rapid development and mature application of high-strength materials,and the increasing demand for large-span structures,high-strength concrete filled high-strength steel tube(HS-CFST)arches have broad application prospects.However,the current research on the HS-CFST arch is quite scarce,and its elastoplastic stability is not well understood,and there is no reference to relevant design specifications,which seriously restricts its application and development in practical engineering.In this paper,an in-depth study on the elastoplastic stability of the HS-CFST arch is conducted by combining experiments and finite element analysis.The main contents are as follows:(1)Experimental study on the in-plane bearing capacity of HS-CFST arch.On the basis of the previous study on the in-plane bearing capacity of the HS-CFST arch of the research group,three groups of normal-strength-concrete filled high-strength steel tube arch and three groups of high-strength steel arch in-plane bearing capacity tests were supplemented.The corresponding finite element model was established using ABAQUS software.The comparison between the actual measurement results and the finite element calculation results verifies the reliability of the experiment and the accuracy of the finite element model.By comparing and analyzing the test results of hollow steel tube,ordinary-concrete filled steel tube,and high-strength concrete filled steel tube specimens,the quantitative analysis of the gain effect of the core concrete strength on the ultimate bearing capacity of the concrete filled steel tube arch,and the difference between the failure modes of different specimens are analyzed.(2)HS-CFST arch out-of-plane bearing capacity test.Designed and processed 6 sets of high-strength concrete-filled steel tube parabolic arch specimens with different strengths,andproposed a set of loading devices suitable for the out-of-plane bearing capacity test of HS-CFST arch.An HS-CFST arch surface out-of-plane stability test was carried out.The displacement and strain change with load during the test were measured,and the effects of the high-strength steel tube strength and concrete strength on the out-of-plane bearing capacity of the HS-CFST arch were analyzed.(3)Numerical simulation of the out-of-plane bearing capacity of HS-CFST arch.Based on the consideration of geometric-material nonlinearity,initial defects,and hoop effects,the finite element model was established using ABAQUS software for numerical analysis.The obtained out-of-plane(internal)load-displacement curve and overall out-of-plane deformation curve were compared with the test results.The results show that the two results are in good agreement.Taking the ultimate bearing capacity as an example,the maximum error is only2.91%,which proves the reliability of the test results and the correctness of the finite element model.(4)Using ABAQUS finite element software,considering the geometric-material nonlinearity,more than 600 finite element models with different parameters were established to analyze the influence rules of steel strength,concrete strength,vector-span ratio,slenderness ratio and steel content ratio on the out-of-plane stability bearing capacity of HS-CFST parabolic arch.On this basis,the formula for calculating the out-of-plane stability bearing capacity of HS-CFST parabolic arch under uniform vertical load is proposed.