Experiment on the Hysteretic Behaviors of Light-Weight Steel Portal Frame with Tapered Members

2011 ◽  
Vol 368-373 ◽  
pp. 206-210
Author(s):  
Qi Cai Li ◽  
Zhen Shan Wang ◽  
Ming Zhou Su ◽  
Xue Chao Shao ◽  
Lin Shen

In order to study the seismic behavior of steel portal frame structures, Cyclic loading test on a 1:3-scaled model of single-story single-bay steel portal frame with tapered members has been carried out. Based on test results, hysteretic curve, skeleton curve, stiffness degradation and transverse displacement of the structure are obtained. Meanwhile, the seismic performances of the structure are analyzed from aspects of ductility, energy consumption, stiffness degradation, bearing capacity, etc. It is concluded that ductility and energy consumption capacity of this structure are poor; because of its light weight, the structure attracts little seismic load; when portal frame structure designed according to current Chinese design codes suffers from small seismic action, it has enough seismic bearing capacity.

2012 ◽  
Vol 446-449 ◽  
pp. 3659-3662
Author(s):  
Jin Ming Dong ◽  
Xi Kang Yan ◽  
Guo Liang Zhao

During an earthquake, many construction damage for columns, not for the beam. This does not meet the standard design.This paper, we will study the phenomenon such as any and construction joint. There nine specimens, divided into three groups. Every group has three specimens, the first no construction seam, the second simple processing In construction joints, the third has good processing construction three groups will be loaded axial compression coupling than 0.23, 0.34, 0.46. This paper will study the differece of different processing construction joint limit bearing capacity, energy consumption and stiffness degradation.


2018 ◽  
Vol 175 ◽  
pp. 02033
Author(s):  
Yuxiao Lang ◽  
Lianguang Jia

In order to study the seismic performance of wedge-shaped light steel castellated portal frame, the finite element analysis software Abaqus is used to simulate the seismic behavior of the portal frame with a single span hexagonal hole with a span of 24m. The influence of the opening ratio and the distance between the first hole of the near column and the end to the column edge on the hysteretic curve, skeleton curve, stiffness degeneration, ductility and energy dissipation capability are analyzed and the ultimate destructive form is also obtained. The results show that under the low cycle reciprocating load, the castellated light steel portal frame forms the plastic hinge on both sides of the structure near the first hole, and the structure loses its carrying capacity. The greater the opening ratio is, the lower the ultimate bearing capacity is, and the stiffness degeneration is more notable, ductility and energy dissipation are worse. The distance between the first hole of the near column and the end to the column edge has great influence on the ultimate bearing capacity, stiffness degradation and ductility. The greater the distance is, the better the ultimate bearing capacity and the ductility are.


2021 ◽  
Author(s):  
Wang Qing-li ◽  
Kuan Peng ◽  
Guo Yi-Huan ◽  
Shao Yong-bo

Abstract In order to study the hysteretic behavior of concrete filled square CFRP steel tubular Beam-Column under different influence factors, 12 specimens were designed, and the failure mode, middle section lateral force-deflection(P-Δ) curve, middle section bending moment-curvature(M-φ) curve and middle section deflection-deformation(Δ−Δ') curve were studied. Axial compression ratio and longitudinal CFRP reinforcement coefficient as influencing factors, the effects of axial compression ratio and longitudinal CFRP reinforcement coefficient on P-Δ skeleton curve, M-φ skeleton curve, strength and stiffness degradation, ductility, cumulative energy consumption and other indexes were studied; the P-Δ curve and deformation mode of the specimens were simulated by ABAQUS, and the effects of axial compression ratio, slenderness ratio and other main parameters on the hysteretic performance of the members were studied. The test results show that CFRP has good lateral restraint and longitudinal reinforcement effect on CFST, and the local buckling of CFST is delayed. The P-Δ curve and M-φ curve of all specimens are full. In addition, the steel tube and CFRP have good synergy in both longitudinal and transverse directions. The change of axial compression ratio and longitudinal CFRP reinforcement coefficient has no significant effect on the strength degradation. The increase of axial compression ratio and longitudinal CFRP reinforcement coefficient can improve the flexural capacity and stiffness of the specimens, and slow down the stiffness degradation, but reduce the ductility and cumulative energy consumption of the specimens. The finite element software ABAQUS is used to simulate the P-Δ curve and deformation mode of specimens. It is found that the simulation results are in good agreement with the experimental results. Based on the model analysis of the main parameters, it is found that the increase of steel yield strength and CFRP layers can improve the bearing capacity of the specimens, and the axial compression ratio has the most significant effect on the specimens.


Author(s):  
Kengo Goda ◽  
Osamu Furuya ◽  
Kohei Imamura ◽  
Kenta Ishihana

At the present, base isolation system has been recognized by general earthquake resistant technique since the Great Hanshin Earthquake 1995. The seismic isolation will be aggressively applied to not only architectural and civil structures but also various structures, because the effectiveness on seismic safety had been demonstrated again in the Great East Japan Earthquake. In generally, although the base isolation system is divided into laminated rubber bearing type and friction sliding bearing type. In the case of former type, shape factor, maximum or minimum outer shapes and so on are restricted by the material characteristics in visco-elastic material. In general, the isolation structure is used in high damping rubber. However, we pay attention to base isolation using urethane elastomer. Urethane elastomer has excellent elasticity, mechanical strength, abrasion resistance, weather resistance, oil resistance, impact resistance the absorbent, anti-vibration and excellent low-temperature properties. Furthermore, it is possible to impart various characteristics by a combination of isocyanate and polyol and chain extender, requires no large-scale apparatus, it has the advantage molecular design is easy. In previous study, the research and development of laminated type base isolation device using urethane elastomer was carried out to upgrade a seismic safety for various structures. The fundamental characteristics was investigated from several loading test by using various experimental devices, and the design formula for the stiffness and equivalent damping coefficient is formulated as an approximate expression of mechanical characteristics until now. It was confirmed that urethane elastomer is not hardening up to 500% shear strain. Moreover, the experimental examination for aged deterioration in the urethane material has been continuously carried out. As the results, it was confirmed that the laminated type seismic isolation device using urethane elastomer is possible to develop as a practicable device from the stable mechanical properties as considering in design step. In this study, the small-scale laminated type base isolation device using urethane elastomer is advanced to the direction of further technical upgrading and of scale down for light-weight structure as a sever rack. The first stage, basic properties of the urethane elastomer has been investigated by loading test. Furthermore, the design equation is created by loading test using urethane elastomer. The validity of the design equation has been confirmed. The second stage, the compression creep test with laminated type base isolation device has been investigated to confirm an effect on light-weight mechanical devices.


2021 ◽  
Author(s):  
Xing Wang ◽  
YANG WU ◽  
Jie Cui ◽  
Chang-qi Zhu ◽  
Xin-zhi Wang

Abstract The landforms and vertical strata distribution characteristics of Yongxing Island show that the reclaimed reef island is characterized by soft upper strata (calcareous sand) and hard lower strata (reef limestone). In this study, a series of plate loading tests was conducted to examine the influences of particle gradation, compactness, and moisture condition on the bearing mechanism and deformation properties of the calcareous sand foundation. When the foundation is shallowly buried, the relative density range corresponding to a calcareous sand foundation exhibiting local shear failure is narrower than that of a terrigenous sand foundation. For the same compactness, dry calcareous medium sand has a much larger bearing capacity and deformation modulus than dry calcareous fine sand. The effect of water on the bearing capacity of the calcareous medium sand is greater than the effect on calcareous fine sand. Its weak cementation and low permeability make the initial deformation of saturated calcareous fine sand slightly smaller than that under dry conditions. The stress dispersion angle of the calcareous medium sand foundation is 52°, which is larger than that of terrigenous sand. A larger stress dispersion angle leads to a higher bearing capacity and deformation modulus than those of terrigenous sand.


2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Jianlei Liu ◽  
Meng Ma ◽  
Flavio Stochino

The bearing capacity evaluation of bridge substructures is difficult as the static loading test (SLT) cannot be employed for the bridges in services. As a type of dynamic nondestructive test technique, the dynamic transient response method (TRM) could be employed to estimate the vertical bearing capacity when the relationship between static stiffness and dynamic stiffness is known. The TRM is usually employed to evaluate single piles. For the pier-cap-pile system, its applicability should be investigated. In the present study, a novel full-scale experimental study, including both TRM test and SLT, was performed on an abandoned bridge pier with grouped pile foundation. The test included three steps: firstly, testing the intact pier-cap-pile system; then, cutting off the pier and testing the cap-pile system; finally, cutting off the cap and testing the single pile. The TRM test was repeatedly performed in the above three steps, whereas the SLT was only performed on the cap-pile system. Based on the experimental results, the ratio of dynamic and static stiffness of the cap-pile system was obtained. The results show that (1) in the low-frequency range (between 10 and 30 Hz in this study), the dynamic stiffness of the whole system is approximately four times of that of a single pile; (2) the ratio of dynamic and static stiffness of the cap-pile system tested in the study is approximately 1.74, which was similar to other tested values of a single pile; (3) to evaluate the capacity of similar cap-pile system and with similar soil layer conditions by TRM, the value of Kd/Ks tested in the study can be used as a reference.


2020 ◽  
pp. 136943322096527
Author(s):  
Longji Dang ◽  
Rui Pang ◽  
Rui Liu ◽  
Hongmei Ni ◽  
Shuting Liang

This paper aims to investigate the seismic performance of hollow floor interior slab-column connection (HFISC). In this new connection system, several tube fillers are placed in slab to form hollow concrete. Moreover, locally solid zone, shear components, and hidden beam around the connections are installed to improve the bearing capacity and ductility of specimens. Three slab-column connections with different shear components were tested under cyclic loading and every specimen was constructed with parallel tube fillers in the north direction and orthogonal tube fillers in the south direction. The seismic behavior of specimens was evaluated according to the hysteretic response, skeleton curve, ductility, stiffness degradation, and energy dissipation. A finite element model was then developed and validated by a comparison with the experimental results. Based on experimental results and finite element analysis results, the relative effects of the hollow ratio of slab, the ratio of longitudinal reinforcement, the shear area of bent-up steel bars, and the arm length of welding section steel cross bridging were elucidated through parametric studies. This new slab-column connection showed better plastic deformation capacity while the bearing capacity was kept. Specimens with parallel tube fillers showed better seismic behavior than those of specimens with orthogonal tube fillers.


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