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A Y-shaped eccentrically braced high-strength steel frame is a novel structure. For such structure to exhibit good plastic deformation ability under severe earthquake, the links are made of ordinary steel (fy ≤ 345 MPa), whereas high-strength steel (fy ≥ 460 MPa) is used in the frame beam and column to reduce the cross section while ensuring the elasticity of the non-energy consuming component. The new structure has good ductility and energy-dissipating capacity. The response modification factor R is crucial to the performance-based seismic design. For an appropriate and economical seismic design, the R value should be reasonably selected. In the 2016 edition of China's code for Seismic Design of Buildings (GB50011-2010), it is obviously not reasonable to hide the R concept and adopt a constant value for all structural systems. It is important to study R and Cd of a Y-shaped eccentrically braced high-strength steel frame, it can not only improve the structural performance design, but also provide reference for the future, and promotes the application of the structure in seismic areas, which presents excellent seismic performance. Therefore, in this study, structures with different stories (4, 8, 12, and 16 stories) and link lengths (700, 900, and 1100 mm) were designed via the performance-based seismic design method. A static elastic–plastic analysis (Pushover analysis) and an incremental dynamic analysis (IDA) were conducted and the data thus obtained was fitted to reach the IDA performance curve of the structure. The R and Cd value of each prototype were calculated using the capability spectrum method, the number of structural story N and the link length e is considered. The results of the pushover analysis and IDA were compared; the values of each performance coefficient obtained can serve as a reference for the performance design of the new structural systems in the future. [ABSTRACT FROM AUTHOR]

Glass Fiber Reinforced Plastic (GFRP) composite material has good insulation and stain resistance, and can be efficiently used in an electric transmission tower. Based on static tension and compression research, full-scale tests for GFRP were carried out on composite steel casing joints. The fatigue life and the failure mode of this kind of connection were analysed in different stress amplitude and loading conditions. The whole process of development of cracks at the adhesive joint was revealed under constant amplitude cyclic loading. Also, the load-displacement curves and the load-strain curves were received and analysed. The results showed that when the end of the connection using epoxy resin adhesives as bonding materials between the composite bar and the steel sleeve were pulled out, there was a typical brittle failure. Additionally, the bearing capacity only decreased by 6.8% after 2 million cycles under the tension-compression conditions, indicating that the adhesive joints had excellent shock absorption and anti-fatigue performance. Finally, some suggestions were proposed to provide a basis for engineering applications and theoretical analysis of complex tower structure. [ABSTRACT FROM AUTHOR]

Fibre reinforced plastic (FRP) composite has been widely used in engineering due to its light weight, high strength, and corrosion resistance. Joint behaviour is important in structural design. This research investigated the ultimate tensile and compressive bearing capacities of bonding joints of Φ200 mm × 10 mm steel casing. By conducting full-scale tests, the load-displacement curve and strain distribution in joints in an FRP composite steel casing were analysed, and the ultimate bearing capacity, stiffness, and failure mode were obtained. The research showed that under axial compression, joints underwent brittle failure, and the steel casing exerted a greater lateral restraint to the composite pipe, which resulted in a decrease of bearing capacity of its components. While under axial tension, the failure mode of joints was such that the FRP composite pipe was pulled off and the bearing capacity of its joints was determined by the strength of the binders used. This study forms an experimental basis for engineering application. [ABSTRACT FROM AUTHOR]