The Study Of Effect On Capacity Of Scfst With Shrinkage And Creep

Production of Self-stressing concrete filled steel tube (SCFST) has solved the slap shortcoming of conversional Concrete Filled Steel Tube (CFST). Concrete core r restrained by steel tube is compressed in three directions before loading because of existence of self-stress.The lateral confinement of steel tube is fully utilized for loading. Compared with conversional CFST, the mechanical performance of self-stressing concrete-filled steel tube is improved.The creep of the SCFST will affect its dynamic performance, just like the common CFST. However the existence of the self-stress makes the creep of the SCFST different from the common CFST, the related studies are still not enough.Based on"The development maintenance test research of SCFST",which is the item of Ministry of Communications West Transportation Foundation and technology project"The study of effect on capacity of SCFST with shinkage and creep"(contract No. 200631881422), the following researches have been copleted in the dissertation:①Based on the creep of expansive concrete research, gets proper expansive concrete creep models by Curve Fitting supplied by ANSYS.②Chosen the fitting creep computation schema after compared with the common computation methods, and established the solid-model. Based on this, did the experimental and program verification to the formulated program.③Discussed the methods of calculate the SCFST's bearing capacity. Based on the old constitutive relationships, overall considered the influence of the factors of self-stress and creep, determined the new constitutive relationships for analysizingd the capacity of SCFST.④Formulated the finite element program to calculate the SCFST short column under axial load and accentric load. The calculated results indicate that the SCFST short column has higher carrying capacity than common CFST short column due to self-stress.⑤Influenceof long-term load on capacity performance of SCFST members are experimental investigated. Bulit analysical model for SCFST under function of long-term load. Modified core-concrete constitutive relationships of SCFST to cauculate and analysize the capacity of SCFST after creep.⑥The effects of different design parameters, like the size of self-stress, steel ratio compressive strength of concrete on the ultimate bearing capacity are studied.