Advanced Materials Research Vols. 194-196

Abstract: Foam concrete is provided with light weight, thermal insulation, sound insulation and fire resistance, good seismic performance and other characteristics. To improve properties of foam concrete microstructure is studied with the help of fractal theory, fractal dimension related to mechanical properties and thermal performance of foam concrete is calculated by MATLAB language program. The results indicate that the microstructure of foam concrete showed significant fractal character, the fractal dimension is between 1.3 and 2.0. Apparent density, 28d compressive strength, and thermal conductivity decreases with the increase of fly ash and foaming agent content, fractal dimension increased. Formulas of fractal dimension and the fly ash, foaming agent content were established. Foam concrete with low density, high strength, and good thermal insulation property will be prepared conducted by the formulas.

Abstract: The kinetics of corrosion process on five Ni—Cr—Mo—Cu alloys designed by the empirical formula APF=4Cr/ (2Mo+Cu) in HCl solution have been investigated at the concentration range from 0.002mol/cm³ to 0.012 mol/cm³ and 20°C. It is developed that the kinetic parameters and the dependence of the corrosion resistance on the APF have discussed.

Abstract: The purpose of high-limit protection rack under railway bridge is to protect railway bridge, and avoid passing vehicles under railway bridge colliding bridge. The paper discusses dynamic response and energy transfer of two different structures by analyzing the internal force, deformation, displacement and energy transfer of the steel tube and concrete-filled steel tube protection racks in collision. The result shows that the displacement of concrete-filled steel tube protection rack is smaller, and it can bear larger impact force and have good effect of energy absorption.

Abstract: In this paper, a new type of rolling ball isolator was developed. The rolling ball isolator isolates horizontal earthquake with SMA dampers to restore to normal position, and dissipate energy. The optimization of SMA-Rolling ball isolator is studied. Adopt MATLAB to build the shear model, and contrasts the earthquake response between the isolated structure and the un-isolated structure.

Abstract: In the domestic and international, experimental study for the Buckling Restrained Braces(BRBs) focuses on concrete type BRBs at present, but the type of BRB has a larger weight, and can change structure vibration characteristics, thus puts forward a new type BRB which is no longer filling in with concrete between kernel and outer components, meanwhile under monotonic loading and cycle repeated loading tests for the new BRBs, the experimental results show that the steel type BRB has good energy dissipation capacity, and can be applied to structure as passive control device.

Abstract: Based on seismic damage data of gas pipeline network, obtained through scientific investigation in 18 cities/counties, seismic damage appearances of gas pipeline which are made of different materials are summarized and compared, and their impacts on gas supply function are studied. Then the use status of pipeline of different materials and the reasons of causing damages are analyzed. And some earthquake resistant countermeasures are proposed to reduce the seismic damages.

Abstract: In this study, Expanded Polystrene (EPS) geofoam is used as seismic buffer to mitigate shock damage of tunnel by earthquake. Four types of EPS layer with different elastic modulus are selected to investigate their isolation effect. Four kinds of thickness are also selected to study the effect of thickness. All tunnels with different EPS layers are compared with each other and with the tunnel without EPS layer. Detailed simulation technology is described in this paper, including the infinite element boundary, initial ground stress balance and material models. The numerical analysis show that the axial strain and section force of lining are greatly reduced compared with the tunnel without EPS. With the decreasing elastic modulus and increasing EPS layer thickness, the mitigation effect is more obvious. And the isolation effect of reducing modulus is greater than that of increasing thickness. So modulus of EPS layer is a more important factor for mitigating dynamic damage.

Abstract: In order to understand the seismic performance and functional failure feature of water supply system, the seismic damage phenomena, damage feature and degree of several kinds of water supply pipeline under different earthquake intensities are investigated based on the post earthquake survey data of water supply system in over 20 cities and counties.

Abstract: In terms of the characteristics of Beijing masonry Structure, the quasi-static test is performed to the rural single-storey brick structure in the study. There are four sets of test specimens discussed in the paper. The first and second specimens are the unreinforced wall with different mortar strength and used for reference purpose, the others are the specimens which are strengthened by using steel mesh mortar and reinforced concrete columns with ring beam respectively. The testing phenomena of all specimens are compared in the paper. Meanwhile, the three parameters of lateral load resistance，hysteretic curve and deformability capacity are concerned in comparison process. Moreover, the mechanism of resistance and energy dissipation capacity of both reinforcement methods are analyzed in the study, and then the steel mesh mortar will be a proper method to use in the Beijing rural brick building seismic reinforcement. The systematic analysis in the paper provides theory basis on the seismic reinforcement in the Beijing rural reconstruction.

Abstract: A comparative study is conducted on the seismic behaviors of three recycled aggregate concrete (RAC) frame columns under low cyclic load. The recycled aggregate replacement rate is 0%, 50%, 100% respectively. The mechanical characteristics, failure mode, hysteresis loops, ductility and consumption characteristics of frame columns with different recycled aggregate replacement rate and same axial compression ratio are analyzed in this paper comparatively. The rule characteristics between ordinary concrete and recycled aggregate concrete frame columns are found. The result indicates that failure process of recycled aggregate concrete frame columns is similar to that of ordinary concrete. The seismic behaviors of recycled aggregate concrete frame columns, including the ductility etc., still meet the related requirements of earthquake-resistance designing. So it is concluded in this paper that the recycled aggregate concrete can be applied in concrete structures. Because of its properties are certain deficiencies, some tectonic measures must be enhanced.