Advanced Materials Research Vols. 368-373

Abstract: Based on the flexural-shear and press-flexural-shear test of four scale HSW model building with High Shear-Span Ratio, The seismic behavior of the slit and integral HSW are discussed, then the failure characteristics and capacity of HSW under Vertical load and seams are analyzed. The result of experimental study proves that the ductility and the property of energy dissipation of HSW are well; Vertical load could increase the capacity and deformation, decrease the energy dissipation of HSW. And the seams of wall could improve the ductility and the property of energy dissipation of HSW , lower the capacity.

Abstract: Light wood diaphragms are the main horizontal structural components in light wood frame constructions. Their lateral performance has a close relationship with the seismic performance of whole structure. There are various configurations such as sheathing thickness, nail size, nail spacing and joist spacing which affect the lateral performance of light wood diaphragms. In this paper, nine light wood diaphragms with different structural configurations under monotonic load are studied using FEM analysis. It is found sheathing thickness, nail size and nail spacing all have a lot to do with the overall lateral performance of light wood diaphragms, while the influence of joist spacing is limited.

Abstract: In order to investigate the seismic behavior of the new circular hybrid Steel–Concrete– CFRP–Concrete column (simply called SCCC column), low cyclic reciprocating load tests are carried out for three SCCC columns. The failure mode and hysteretic characteristics are researched, and the effects of changes of CFRP tubes diameter on seismic behavior of SCCC columns are analyzed. The results show that with the diameter increase of CFRP tube, the seismic behavior of SCCC column is also increased.

Abstract: Based on the fast freeze-thaw test in 3.5% NaCl solution, the frost resistance of steel fiber reinforced concrete (SFRC) was studied in this paper. On the basis of scanning electron microscope (SEM) and mercury intrusion method, the microstructure and pore structure of SFRC was analysed. The reinforced mechanism of SFRC under the cooperation of freeze-thaw and NaCl solution was discussed. The test results show that adding appropriate amount of steel fibers into concrete can reduce the pore porosity and improve the compactness of concrete. The effects of steel fiber with proper volume fraction can inhibit the peeling of the concrete and reduce its damage rate. The volume of steel fiber on the frost-resisting property of SFRC is obvious.

Abstract: Under action of repeated freeze-thaw cycles, different changes of pore structure features has occurred in different varieties of concrete.In this study, the average pore size of concrete and total porosity was discussed especially with the trends.Based on this, the gas diffusion model and the chloride ion diffusion model in concrete was also discussed with the pore structure,which indicated that the freeze-thaw damage of concrete pore structure will have a greater impact to the durability of concrete, and so the life of concrete structures would be affected.

Abstract: The reinforced concrete U-shaped composite beam which is composed of precast U-shaped beam, precast slabs and cast-in-place (CIP) concrete, is investigated in this paper. The performance of the reinforced concrete U-shaped composite beam and the cast-in-place concrete control specimen subjected to positive moment was evaluated in terms of failure pattern, flexural strength of normal section, ductility and slips based on the monotonic static loading tests. The results showed that both specimens behaved in ductile manner. The flexural strength of reinforced concrete U-shaped composite beam was about 11% lower than that of the control specimen. The displacement ductility and curvature ductility of the precast specimen were about 33% and 18% lower than those of corresponding control specimen, respectively. The slip between precast beam and precast slab and the slip between precast slab and CIP concrete were less than 0.16mm and 0.17mm, respectively. The results in this paper are useful to expand the application of reinforced concrete U-shaped composite beam in the field of civil engineering.

Abstract: The tests are order to investigate the axial compressive performance of the new circular hybrid Steel-Concrete- CFRP-Concrete column (simply called SCCC column).SCCC column is composed of steel tube, annular concrete, CFRP tube and core concrete. Axial ultimate bearing capacity test was performed on 3 SCCC columns, from which we gains the law of affecting SCCC columns, the load-strain curve and load-displacement curve of SCCC columns, and compare the test results of the test specimen with different annular concrete thicknesses, from which we finds that after the relationship curve of test specimen with small annular concrete thickness reaches yield load, the bearing capacity starts to decline, and then continues to rise till the ultimate load is reached and the test specimen is damaged. The result shows that the smaller the annular concrete thickness is, the greater the axial ultimate bearing capacity of SCCC column is, and also indicates that CFRP tube plays a role of binding and constraining to the core concrete in later period of loading the test specimens.

Abstract: For the further study on stress concentration and fatigue property of tubular joints of concrete-filled steel, we designed the fatigue test on tubular joints of concrete-filled steel.Associating with the calculation of finite element, we studied the stress concentration, cracking source of fatigue, and fatigue -related rules including cracking expansion. I did the equivalent calculating under variable amplitude loading. We proposed the criterion of fatigue failure when surface length of penetrated crack is about 3 times as the thickness of the wall. According to the experiment we verified that the tubular joints under the amplitude load this criterion is reasonable, secure and feasible.

Abstract: Time domain analysis on earthquake response of soil-asymmetric structure interaction system was carried out in this paper in order to study the feasibility of the forced decoupling method. Acoording to lateral-torsional coupling vibration equations of soil-asymmetric structure system, the direct integral MATLAB program in time domain were made used method. Feasibility of forced decoupling method was carried out by comparing the result in time domain with the result in frequency domain. Finally, it is derived that the results are very close to each other, which verify the feasibility of forced decoupling method. This conclusion can supply references to engineering calculation and design of structure.

Abstract: As the shape of the spatial helical irregular steel sculpture is singularly, this paper studies the structure’s stability and dynamic properties with finite element analysis software in order to determine its ultimate bearing capacity, The structure’s natural vibration characteristics are obtained by modal analysis. The structure’s deformation characteristics within a small time history is also obtained by transient dynamic analysis. Feasibility of the new irregular steel structure is verified by calculation and analysis in this article which can lay the foundation for the development of the irregular steel structure.