Seismic Performance Of Double-steel Encased Transfer Beam And SRC Column Connections

Based on a high-rise building in Guangdong Province and its large-spanconversion structure, this dissertation put forward new constructional measurecombinations of the double-steel reinforced concrete transfer (DSRCT) beam andjoint, solved the problems in engineering design. The DSRCT beam is comprised ofoutside reinforcements, concrete, and a composite shaped steel, which is made of twoI-shaped steel connected to each other by batten plates. For simplicity in construction,the upper transferred shaped steel columns are connected to the DSRCT beam by e ndplate bolt connection. In this dissertation, four aspects of research are conducted, i.e.structural members, joints, structure, and construction, in order to determine theseismic performance indicators of the DSRCT beam and joint.Firstly, six groups of the four point static bending tests of the DSRCT beams areconducted. The influences of the stirrup ratio, flange size and spacing of shaped steel,ratio of longitudinal reinforcements, and layout of pins on cracking load and ultimateload of the DSRCT beam. It is found that the DSRCT beam has high strength and wellductility. A formula of the flexural strength of the DSRCT beam is gived. Accordingto the test data and the superposition design principles, the flexural strength ofconfined concrete and the integrity of the formula are both revised. The short-termstiffness of the DSRCT beam is composed of the stiffness of reinforced concrete,double-steel, and confined concrete. The calculation formulas of the short-termstiffness and the associated deflection of the DSRCT beam are established. Throughthe analysis of the calculation formulas of the yield and ultimate bending moments,the ductility coefficient formulas of the DSRCT beam are established, includingmember and sectional ductilities.Secondly, low-cyclic reversed loading tests, including vertical and horizontalloads, of the joints of two DSRCT beams are conducted. Failure pattern, bendingstrength, stiffness, hysteretic characteristics, ductility, and energy dissipation capacityof the joints, and strain of reinfocements and shaped steel in key positions are allstudied. Experimental results reveal that the joints of the DSRCT beams have wellcharacteristics of the transfer structures and are satisfied with the principles of―Strong beam and column, stronger joints‖and―Strong transfer structure‖in theseismic design. This chapter discusses the shear-resistant mechanism of the joint of the DSRCT beam, and puts forward a calculation formula of the shear strength.Comparison with the Japanese Code, Chinese JGJ Code, and YB Code reveals that thecalculation formula of the shear strength of the joint is reasonable. Furthermore, thedesign methods of the end plate bolt connections of the upper transferred shaped steelcolumns are compared and summarized.Thirdly, shaking table tests of a high-rise building at a scale of1:35areconducted, including one-way, two-way, and three-way loading actions of earthquake,studying the seismic performance of the DSRCT beam in structure. The shaking tabletest results reveal that the DSRCT beam structure has three typical failure mechanism.By performance analysis, the DSRCT beam structure meets the performanceindicators under frequent earthquake, design intensity earthquake, and rare earthquake,showing good deformation and seismic performance. The stress, deformation, anddamage index of the DSRCT beams and joints are studied through response spectrummethod, elastoplastic time-history analysis, elastoplastic pushover, and multi-levelcapacity spectrum method. Results show that the DSRCT beams and joints have wellseismic performance, especically the shear-resistant performance.Fourthly, suggestions of the material, structure, and construction of the DSRCTbeams and joints are provided, accoding to the current specifications, experimentaldata, and on-site construction situation. Specifically, suggested provisions of thecomponent materials of the DSRCT beams and joints are determined according toseveral shaped steel specifications in China; the structural configurations of theDSRCT beams and joints comply with the general provisions but with their owncharacteristics; the techniques of the on-site construction procedure is alsosummarized in this chapter.