Experimental Investigation and Finite Element Analysis on the Hysteretic Behavior of New Steel Beam-to-Column Connections

By the hysteretic experiments and the finite element analysis of the proof-of-concept connections, the mechanical properties and energy dissipation capacity of the new steel beam-to-column connections are investigated. These connections are semi-rigid ones improved by adding threaded rods into the angle connections and can be designed to limit the structural damage only to the angles and threaded rods. It is found, by the comparative analysis of six connections tested with the same loading sequence, that the performance degradation of the connections may be resulted from the plastic damage, crack propagation of the angles and the buckling and fatigue crack of the rods. The rotation capacity and failure modes of the connections with threaded rods depend on the ability of anti-fatigue crack of the rods, and the better ductility the rods have, the better energy dissipation capacity the connections have. In addition, the hysteretic behavior and the deformation modes of the connections prior to the significant strength degradation or the fracture of the rods could be well simulated by the finite element method. Meanwhile, the stiffening effect from pre-stressing the angles, the plastic distribution of the angles and the degradation induced by the rod buckling were strongly verified by the FEA. Finally, the advantages and disadvantages of such new beam-to-column dissipative connections were analyzed, and the proposal for further connection improvement and in-depth study was made.     

Experimental Research on the Seismic Behavior of the Interior Joint with High Shear - Compression Ratios in the Frame

The reversed cyclic loading tests of 5 nearly full-scale beam-column assembly specimens with high shear-compression ratio under different axial loads in reinforced concrete plane frames have been completed,which cover the shortage in the field of high shear-compression parameter among seismic joint experiments in the world.Based on relatively complete measuring and analyses of the law for the bond and slip of the beam bar through the joint,the stress of the level stirrup legs and hysteretic dissipated energy and the change of rigidity,the characteristic of shear transfer mechanisms and damage development and comprehensive seismic behavior of the assembly are proposed in this paper.It makes it possible to improve design codes and to establish relatively reasonable analytic modes and hysteretic modes in inelastic dynamic response analyses of the frame.     

Experimental Study on Seismic Behavior of Penetrated Interior Diaphragm on One Side Beam-to-Column Connection for Concrete-Filled Square Steel Tube

A total of three experimental specimens of penetrated interior diaphragm on one side had been tested under low-cyclic reversed loading to study the hysteric behavior,strength and stiffness degradation,ductility,energy dissipation capacity and the failure modes.The only difference of all specimens was the axial compression ratio.Experimental results show that the story drift ductility ratios are 2.11~2.32,and the energy dissipation ratios are 1.141~1.502 at the peak load.Additional anti-seismic design and research recommendations are presented.     

Model Test and Mechanical Behavior Analysis of Steel-concrete Joint of Hybrid Girder

To study the bearing behavior, failure mode and mechanical behavior of different structural forms of steel-concrete joint of hybrid girder, based on the hybrid girder of Jiujiang Yangtze River Highway Bridge with 818-metre main 8pan, select a pressure-resistant shear-transferred steel-concrete joint, redesign a shear-transferred only joint for contrast, carry out two scale 1:2 model specimens bearing behavior experiment, measure the strain and relative slip of steel and concrete. The results show that:the bearing capacity of the pressure-resistant shear-transferred specimen is twice than the other;the bearing plate carries about 62.5% of the axial load, the force transmission of the bearing plate reduces the steel stress、steel-concrete relative slip and the force transmission ratio of connectors, makes the load transferred more effectively.     

Finite Element Analysis of Hysteretic Behavior of PR Steel Frame-steel Plate Shear Wall

In order to investigate the seismic behavior of partially-restrained steel plate shear wall (Steel Plate Shear Wall, SPSW), the effects of partially-restrained connection on the hysteretic behavior, lateral bearing capacity, stiffness, energy dissipation of SPSW with strong and weak steel frame were simulated under low cyclic loading via equivalent strip model that had been verified by experiment. The results show that hysteretic behavior of SPSW has dual characters. The hysteretic curves of SPSW with strong surrounding steel frame become fat, and the hysteretic curves of SPSW with weak surrounding steel frame become narrow. With the increase of the bending capacity of PR connection, the hysteretic curves of SPSW become fat gradually, and the capacity of energy dissipation and lateral bearing increase. However, the effect on lateral stiffness of PR connection of SPSW with strong steel frame is higher than the one with weak steel frame.