Advanced Materials Research Vols. 446-449

Abstract: Structural behavior of concrete integral abutment bridge subjected to temperature rise was investigated through a numerical modeling and parametric study. Long-term, field monitoring through the summer was performed on Industrial Park Bridge located in Heilongjiang province, China from June 13, 2010 until June 28, 2010. The collected data was used to validate the accuracy of a 3D-finite element model of the bridge which took into account soil-structure interaction. Based on the calibrated finite element model a parametric study considered two parameters, bridge length and abutment height, was carried out to investigate the effects of this parameters on structural behavior of integral abutment bridge subject to temperature rise. It was determined that Thermal load in the superstructure of the integral bridge develop significant magnitudes of bending and axial forces in the superstructure. The largest magnitude of thermally induced moment always occurs near the abutment, and axial force is constant across the length of each span. For bridge thermal expansion, longer bridges and taller abutments cause larger thermally induced superstructure axial force due to development of higher backfill pressure. Generally span length has a higher influence for thermally induced superstructure forces in terms of axial force and bending moment than the abutment height.

Abstract: This paper presents the results of a numerical investigation aimed at evaluation of damage accumulation in structures under different seismic sequences. For this purpose, a multi-story RC frame model representing the typical buildings was built and subjected to four sets of different repeating seismic sequences with different magnitude. The results indicate that the aftershock sequences will increase the damage accumulation in structures, and the damage index based on the Park and Ang model can qualitatively and quantitatively ascertain the damage state of the structure instead of the single index based on the lateral drift demands. Additionally, different sequences with the identical energy input will cause the same damage state in structures.

Abstract: A concise finite element model for the analysis of simple wire strand with a broken helical wire under axial load is presented in this paper. Due to the implementation of accurate helically symmetric boundary condition, the analysis model can be established based only on a small slice of the wire strand cross-section consisting of all of the remaining intact wires excluding the broken helical wire. Full three-dimensional solid elements were used for structural discretization. The finite element results showed that the sharing of loads among the remaining helical wires is highly non-uniform. The two helical wires adjacent to the broken helical wire bear higher loads. The helical wire opposite to the broken wire bears least load.

Abstract: Analysis earthquake response of the long-span tube shell structure under multi-support excitations. The response of the long-span structure in the earthquake is different between multi-support excitations and uniform excitation. Using sap2000 finite element software with time history analysis, this paper analyzes the impact of the different visual velocities combining with the engineering Projects, and its internal forces and displacements. The results show the impact of the long-span tube shell structure under multi-support excitations. Draw structure peaking acceleration and displacement of time-histories. Result shows that: The appearances of structure under multi-support excitations and under uniform excitation have the same trend. The peak of acceleration and displacement of the structural is different from multi-support excitations and uniform excitation, and the time of occurrence of the peak acceleration and peak displacement is also different.

Abstract: In this work, four series of SCC specimens which cement replacement ratio by fly ash was 30, 40, 50, and 60% , respectively, and one series of normal concrete comparative specimens were designed. For the same series specimens, the fly ash addition was fixed, but the loading value was 0.0, 0.2, 0.4, and 0.6 times of the 28 d concrete flexural strength, respectively. Using accelerated carbonation test, the effects of fly ash additions, tensile stress rates, and compressive stress rates on carbonation rate of SCC are studied. Based on the test results, a model considered both effects of fly ash addition and stress rate for predicting the carbonation depth of SCC under real environment conditions is set up. These results can provide a reference for carbonation resistance design of SCC.

Abstract: This paper gives a new rock burst prediction method of potential index, according to the rock deformation and failure of the rock and the relationship between energy transfer, the characteristics of uniaxial compression stress-strain entire process curve. The new prediction method of rock burst of energy with existing method for forecasting index was compared and analyzed. Testing study was made on the typical rocks of rhyolite, from the deep deposit of Niba mountain tunnel, Combined with the actual phenomen of rock burst, the rock burst potential index is verified to be able to show fairly well the rock burst proneness. Finally, a criterion of rock burst proneness is put forward.

Abstract: To study the seismic performance of autoclaved aerated concrete (AAC) block masonry composite wall with reinforced concrete (RC) columns, a non-linear finite element analysis has been carried out for the walls with openings using the finite element software ABAQUS. First results of finite element analysis were verified with experiment results of full-scale specimen. And then the effect of the opening’s position on seismic performance was studied with finite element analysis. The result indicates that the ultimate load capacity and ultimate displacement are both increased with the upward and outward movement of the openings.

Abstract: Reinforced concrete grid frame core-tube structure system is a new system. This article draws the conclusion that grid frame core-tube has high stiffness and obvious space affection, and that its basic mechanics properties is better than frame core-tube structure and similar to tube structure through the comparison of two tube structure systems, which the Inner tube is similar to grid frame core-tube and the outer tubes respectively are frame and high beam - column frame tube. It puts forward some reasonable suggestions for the future designation of this structural system.

Abstract: This article expounds the floor ends and sides joint constructions of prestressed concrete floor and prestressed concrete hollow floor with added surface，as well as prestressed concrete hollow floor without added surface，and the comparation are available。Finally，some new construction methods are raised based on improving the seismic performance of integrally assembled prestressed concrete floor。

Abstract: In this paper, in combination with the specific conditions of light rail traffic volume, fatigue load spectrum parameters of light rail support are to be determined by background project light rail line 3 of Chongqing Caiyuanba Yangtze Bridge, through which the internal force history is then calculated. Three million constant amplitude fatigue loads that the test needs are finally determined through linear fatigue damage cumulative theory.