Research On Behavior Of Bolted Connection Of Steel Beam To Concrete Column In Retrofitting

Nowadays, inserting new steel stories to an existing reinforced concretestructures is becoming a popular way to diversify the architectural function of thebuildings. Newly sandwich steel story is light and easily to be connected with theexisting structure. However, it is very complicated for design of such hybrid structure,because both update seismic design and restrengthening design should be taken intoaccount. Thus, it is necessary to research on this kind of retrofit structures especiallythe connection of steel beam to existing RC column.This paper describes a new type of semi-rigid connection with the aim to solvethis problem. A new bolted connection is brought forward in this paper based on thestudy of the seismic behavior of typical beam-column joints. This joint is designedwith the idea of semi-rigid joint in steel frame system, and it combines the new steelbeam with existing concrete column using the endplate and high strength bolts. Thecharacter of the joint is strengthening the core of column by angle to meet the seismicdesign and connecting the beam. This joint is expected to combine retrofit withreinforcement effectively.In order to investigate the strength, stiffness, failure mode and seismic behaviorof the new connection, one specimen in full scale was tested under cyclic loading inThe State Key Laboratory of Disaster Reduction in Civil Engineering of TongjiUniversity. Good agreement is found between experimental results and FEA results. Itshows that the thickness of endplate, the strength of high-strength bolts and use of thesteel plate to resisting shear in the core of the joint are important factors to improvethe bearing capacity and seismic behavior.Based on the experimental results and numerical analysis, some suggestions aregiven to the design of the bolted steel beam to RC column joints. Issues for furtherstudy are also discussed at the end.