In-plane Stability Of Parabolic Concrete-filled Steel Tubular Arches With Low Rise-span Ratios

Since the90s of last century, concrete-filled steel tubular arches have gained ahuge development in bridge engineering, large-span structures and undergroundstructures due to high load-carrying capacity, spanning ability, light weight,convenient construction procedure and brilliant appearance. It is estimated roughlythat there are more than400concrete-filled steel tubular arch bridges built in China,and the maximum span is longer than500m. On the other hand, the designrecommendation and theoretical study on CFST arch bridges are not as perfect as itswide application. So the research of CFST arch bridges is necessary.This paper is intended to investigate the in-plane stability of parabolic CFSTarches with low rise-span ratio experimently. The experimental results includebuckling process, in-plane strength, confinement effect between steel and concrete,influence of rise-span ratio. Specific contents are as follows:(1) Design of the in-plane stability experimentFour concrete-filled tubular parabolic arches with different rise-span ratios andload types are designed. The span of all specimens is9m. Hot rolling steel tubes areused as the outer pipe. The diameter of steel pipe is159mm and the thickness is4.5mm. Strength grade of the structural steel is designed as Q345. Concrete’sstrength grade is designed as C40. Loading devices are comosed of fixed supports,transform supports, self-balance system and loading equipments. In order toguarantee that the loading quipments have enough stiffness and reliability, theloading quipments are checked by both theoretical calculation and finite elementmodelling.(2) Results of the in-plane stability experimentThe experimental results include buckling mode; load–displacement curve;Specimen deformation curve; load–strain distribution curve; loading point sectionload–strain curve; transverse deformation analysis and rise-span ratio influence.(3) Finite element model analysis based on the experimentA finite element model built using the software ABAQUS is verified by theresults of in-plane stability experiments of parabolic CFST arches Then based on thefinite element model, the influences of the horizontal displacements of the supportsand the initial geometric imperfection on the in-plane stability load-carryingcapacity. are analyzed.