Reinforced Concrete Filled Double-skin Corrugated Steel Pipes

Circular reinforced concrete-filled double skinned corrugated steel pipes(DSCSP)is a new composite structure using outer and inner corrugated steel pipes to constraint reinfored concrete.In this thesis,circular reinforced concrete-filled double skinned corrugated steel pipes short columns and circular hollow reinforced concrete short columns were made for axial load compression experiment.with the results of experiment,ABAQUS analysing programe(finite element model)is used for modeling circular reinforced concrete-filled double skinned corrugated steel pipe short columns,and then compare the results of the modeling with the experiment results.After that,comparing the bearing capacity formular of circular reinforced concrete-filled double skinned corrugated steel pipe short columns with the results of modeling and experiment.The main contents are as below:(1)9 circular reinforced concrete-filled double skinned corrugated steel pipes short columns and 3 circular hollow reinforced concrete short columns were made for axial load compression experiment.For DSCSP experiment,Inner corrugated steel pipe thickness 1.19 mm,outer corrugated steel pipe thickness 1.19 mm,1.42 mm and 1.65 mm were used in this experiment with the amount of the steel ratio 4.1%,4.6% and 5.1%,steel content 0.95%,0.93% and 0.94%.For RC experiment,steel content 5.05% was used the experiment.(2)In this thesis,the analysing of the failure mode,axial load-displacement graph,axial load-strain graph,axial load-stress graph and corrugated steel pipe stress are provided.from the experiment results,circular reinforced concrete-filled double skinned corrugated steel pipes short columns failure mode is shear failure and circular hollow reinforced concrete short columns is crush failure.when the amount of steel ratio is equal,circular reinforced concrete-filled double skinned corrugated steel pipes short columns bearing capacity is nearly the same with circular hollow reinforced concrete short columns bearing capacity,but the ductility of circular reinforced concrete-filled double skinned corrugated steel pipes short columns is far more superior to the ductility of circular hollow reinforced concrete short columns.For circular reinforced concrete-filled double skinned corrugated steel pipes short columns,when the the thickness of corrugated steel pipes are increased,the bearing capacity of the specimens and the ductility are all improve.The corrugated steel pipe has crest,middle and trough part.crest part generates the most confining pressure than middle and trough part,and trough part generates less confining pressure than middle and crest part.(3)ABAQUS analysing programe is used to model circular reinforced concrete-filled double skinned corrugated steel pipes short columns and study its behavior during axial load compression.The results of the ABAQUS are compared with the results of the experiment,and it is shown that the results of both of them fit well together.Moreover,ABAQUS analysing programe is used to analyse the affect of concrete compressive strength,corrugated steel pipe yield strength and steel ratio to modeling results.when the concrete compressive strength is increasing,the stiffness and bearing capacity of column are increasing,but the ductility of column is decreasing.when corrugated steel pipe yield strength and steel ratio are increasing,the ductility and bearing capacity of column are incresing,but there is no changing for the stiffness of the column.(4)using modeling results and experiment results compare with theorical bearing capacity formular.The comparing results show that when the thickness of corrugated steel pipe is small,the bearing capacity formula of circular reinforced concrete-filled double skinned corrugated steel pipe short column can be defined by the formular of reinforced concrete short column.