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ABSTRACTIn order to study the mechanical behavior of Chinese traditional style architecture dual-lintel-column joint, a typical Chinese traditional style architecture dual-lintel-column joint was selected as the model structure. Two specimens with viscous damper and one specimen without viscous damper were designed and tested under fast harmonic load. On the basis of experimental study, the key indexes of mechanical properties are analyzed, such as the load–displacement hysteretic curve of specimens and viscous damper, skeleton curve, and load-bearing capacity. The results indicate that mechanical properties of antique buildings dual-lintel-column subassemblages with steel and composite structures and viscous damper can significantly increase the mechanical properties. The hysteretic curve of the damping joint is plump. The descending phase of skeleton curves is smoother. The carrying capacity is increased by 13.9%–14.1%, and displacement ductility is increased by 13.0%–18.6%. The viscous damper and the dual-lintel-column subassemblages work together. They significantly improve the deformation performance of structures at the failure stage and enhance the collapse resistance of the structure. The study of traditional architecture can also provide valuable insights into the development of structural engineering and construction technology. Also, people can learn the wisdom and experience of ancestors and apply it to modern engineering practices.

Out-of-plane (OOP) damage is one of the main failure modes for infill walls in frames during earthquakes, which can result in significant economic losses, injuries, and fatalities, and is difficult to repair. This paper investigates the effect of in-plane(IP) damage on the out-of-plane performance of infill walls using recycled concrete blocks with the finite element software ABAQUS and t was used to model and analyse the infill walls with recycled concrete block frames, and the modelling method is verified by the test results. The out-of-plane performance of 20 infill walls with recycled concrete block specimens of different aspect ratios and block sizes was investigated under various inter-story drift damage conditions. The results indicate that in-plane damage has little effect on the out-of-plane bearing capacity when the inter-story drift is 0.15%, and the initial out-of-plane stiffness of the infill walls increases by 5.4%. However, when the in-plane inter-story drift reaches 0.5%, the out-of-plane bearing capacity decrease by more than 50%, and the initial stiffness and ductility also decrease significantly. The study found that the thickness-to-diagonal length ratio of the infill walls has a prominent effect on the out-of-plane strength reduction, and an empirical formula for the in-plane damage and the out-of-plane strength reduction coefficient was proposed and fitted to the data obtained from the finite element analysis with a root mean square error of 0.18.

Seismic performance of SRC–RC transfer column was analyzed based on the experiment of 16 transfer columns specimens under low cyclic reversed loading, which mainly focus on the extension length of shape steel. Analysis of ductility, bearing capacity, energy dissipation capacity and degeneration ratio of strength were completed. Displacement ductility promotes at first and then reduces with increasing of extension length of shape steel, reaching the peak value when extension length gets close to three fifths of column height. Extension length of shape steel has little effect on bearing capacity, while energy dissipation capacity of transfer columns is influenced by many factors. Three fifths of column height is the rational extension length of shape steel, of which specimens have advanced in energy dissipation, good stability of stiffness and strength. The bond performance between concrete and shape steel decreases with the increasing of extension length of shape steel, and hence the stability of strength decreases. Minimum extension length of shape steel was confirmed and the calculation method was proposed, which is mainly used to ensure the bend yielding of shape steel at bottom section. Moment at the truncation section leads to pull-out effect of steel bars, which enhances with increasing of the moment and section ratio of shape steel. Contraflexure point is at three fifths of column height. If the shape steel extends to contraflexure point, moment of steel truncation section will reach minimum. So the reduce the concrete damage with better deformation ability and mechanical behavior of transfer column.

This paper presents experimental study and finite-element analysis (FEA) on seismic performance of steel joints between double beams and column (DBC) in Chinese traditional style buildings. Eight 1/2-scaled DBC joints were designed according to the principle of “strong-member and weak-joint” and tested under low cyclic reversed loading. The failure modes, hysteresis loops, skeleton curves, ductility and energy-dissipation capacity of the joints were analyzed. It is shown that the failure modes of the joints were shear buckling at lower panel zone, bending failure at middle panel zone, and welds fracturing at the panel zone of the joints. The section types of beams, axial compression ratio, and joint forms between double beams and column had significant impacts on the bearing capacity of the joints. The bearing capacity of the joints decreased as the axial compression ratio increased. Moreover, the bearing capacity of the joints with box beams was larger than that of the joints with H-section beams. Elaborate FEA models of the joints were presented, and a preliminary FEA was first performed to predict the mechanical properties and hysteretic behaviors of the joints. The results of FEA were correlated well with those of test, and the effect of the panel zone thickness on mechanical behaviors of the joints was analyzed, which indicated that the simplified FEA model could provide a powerful tool for future research in design methods of DBC joints in Chinese traditional style buildings.

To study the seismic performances of steel frame structures in traditional-style buildings, the pseudo-dynamic test was carried out on a 1/2 ratio model built in the areas with a seismic design intensity of eight. The input earthquake waves included El Centro, Lanzhou and Wenchuan, and the maximum peak accelerations of these ground motions were 70, 200, 400 and 620 gal (0.7, 2, 4 and 6.2 m/s2). The seismic responses such as displacement, reaction force, acceleration were recorded. The hysteretic behavior, energy dissipation capacity, time-history curves of acceleration and displacement, bearing capacity and stiffness degradation were analyzed. The results show that the traditional-style steel frame structure stayed in the elastic stage subjected to no more than 400 gal (4 m/s2) PGA. There was no obvious pinch phenomenon in the hysteretic loops and the structural energy dissipation increased significantly with the increase of the seismic wave amplitude. When the 9-intensity seismic wave was applied, some unique members in traditional-style buildings yielded, and the spectral characteristic of the input seismic wave had a great influence on the seismic response of the structure. The modal analysis and time-history analyses were applied to the structure, the vertical deformation of the second and third modes of the steel frame was larger than that of the first modal shape, the reaction force value of finite element was a little larger than that of the test under the same loading condition. When the structure subjected to more severe earthquake, some unique members in traditional-style buildings acted as the first earthquake fortification line and dissipate most energy, and  the structural most obvious reaction took place in advance or delayed a bit.

This paper presents experimental investigation on the local and overall buckling capacity of Q690 high-strength circular steel tubes under axial compression. Coupon tests are undertaken to obtain the Young’s modulus, Poisson’s ratio, tensile yield stress and ultimate tensile strength of Q690 steel material. Forty-two specimens under axial compression are tested to evaluate the buckling behavior and the failure mode. Test results indicate that most of the existing design standards are conservative for the design of Q690 steel tubes. The distribution model of residual stress is measured by cutting ring method. Then, a finite element model based on modified column deflection curve method (CDC) is built to assess the effects of initial imperfection and residual stress on the stability capacity of the steel tubes. Finally, design methods and recommendations are provided for estimating the stability capacity of high-strength circular steel tubes.

AN innovative amplified viscously damped outrigger (AVDO) is newly proposed to improve the seismic damping effect of conventional viscousl damped outrigger (VDO) on super high-rise structures by mechanically increasing the displacement of the viscous damper (VD). To investigate the advantages of the damping effect on AVDO over VDO, the dynamic cyclic tests on VDO and AVDO were conducted to verify the feasibility of AVDO and superiority of AVDO over VDO. On this basis, six finite element models of a 258 m-high building with two types of damped outriggers placed at different heights were established and analyzed by dynamic time-history method. By comparing the seismic responses of numerical models, it is shown that upgrading VDO to AVDO can improve the damping efficiency of VDs and effectively expand the applicable damping placement in structural height, thus, the structure can achieve a better damping effect. An equivalent theoretical model of AVDO was established and validated by numerical analysis, which contributes to facilitating the modelling work and analysis of AVDO. However, experimental results showed that the outrigger deformation reduced the working displacement of VD seriously, indicating that the stiffness of the outrigger should be designed reasonably to withstand the damping force in motion. On this basis, the relationship between the working efficiency of VD and the stiffness ratio of outrigger to VD was derived and verified. To ensure the high work efficiency of the damper, the recommended stiffness limit of the outrigger supporting nonlinear VD was put forward, which fills a gap in the specification for practical applications.

According to an analysis of the mechanical behaviour of irregular joints between steel box columns and beams, the deformation mechanism of the steel irregular joint panel zone is established based on the plastic hinge theory. A formula for calculating the yield shear force of the panel zone is also proposed. Through analysis of strain and simplified calculation models of the panel zone of a steel irregular joint, the shear mechanism in the panel zone of the joint is studied. Based on the stress state in the panel zone, a simplified formula is presented for calculating the shear resistance of the steel irregular joint. Experimental and theoretical study results indicate that irregular joints between steel box columns and beams exhibit good seismic performance and energy dissipation capacity. Ductility is consistent with the requirements of plastic ultimate deformation; bearing capacity degradation of all specimens is not significantwhen the displacement of the layer exceeds the ultimate displacement. The experimental results indicate that shear buckling failure in the small core area of the panel zone is the main failure mode. Comparison of the experimental andtheoretical results show that only the shear capacity of a small core area needs to be examined if the strength of the panel zone has been ensured. Calculation results for the shear capacity are in agreement withto the test results.

This paper describes a series of tests on steel tubular short columns of circular section filled with normal concrete (NA) and recycled aggregate concrete (RAC). Twenty-two specimens, including 11 small diameter of RAC-filled steel tubular (RACFST) columns named CA series and 11 larger diameter of RACFST columns called CB series, were tested to research the influence of variations in confinement index and replacement ratio of recycled coarse aggregate (RCA), from 0% to 100% with 10% increasing. The test results show that both types of RACFST columns and normal concrete-filled steel tubular (CFST) columns failed due to oblique shear pressure damage with a drum-like. Comparisons are made with predicted bearing capacities of RACFST columns using the existing theories, such as Unified Strengthen theory (I), Confinement theory (II) and Superposition theory (III). The equation for axial compression stress-strain curves of the whole process are proposed in this investigation for RACFST short columns, which can be directly used in theoretical and numerical analysis as well as practical engineering design and evaluation of RACFST structures.