Advanced Materials Research Vols. 163-167

Abstract: In this paper, Shape Memory Alloy (SMA) Pseudo-Rubber Metal (PRM) was studied, and comparative test on mechanical behavior with common Pseudo-Rubber Metal was carried out, which indicates the damp of SMA PRM overmatches that of common PRM. Moreover, SMA PRM damper device was studied and developed, which can bear pull and press action, dissipate energy by two SMA PRM elements, furthermore, owing to the stiffness of SMA PRM increases with increase of distortion, this device can play role in restricting distortion. In order to study the control efficiency of SMA Pseudo-Rubber Metal damper on aseismic pounding of high-pier bridge, under El Centro, Taft and artificial ground motion respectively, to carry out seismic pounding shaking testing of high-pier bridge steel model and aseismic pounding shaking table testing of high-pier bridge steel model, furthermore, analyze detailedly the control efficiency of SMA Pseudo-Rubber Metal damper, which is adapted to reduce seismic pounding device and restrictor in high-pier and long span bridges.

Abstract: The basal theory of energy method is introduced, which makes use of the idea of energy balance to study the earthquake response of structures. Because of the high stiffness and low-cost of the steel frame-reinforced concrete shear wall hybrid structure, it is being widely used. But the study of the earthquake response prediction method of the structure has not been done yet. In this paper, energy method is used to study the earthquake response of the steel frame-reinforced concrete shear wall hybrid structure. A steel frame structure and a steel frame-reinforced concrete shear wall hybrid structure have been designed. The shear wall in steel frame-reinforced concrete shear wall hybrid structure is simplified as a column for easier study. In order to evaluate the results of the energy method, the time history analysis method is also used to study the earthquake response of the two structures. The shear coefficient, maximal interlaminar displacement and damage ratio of the two structures are studied. After comparison, it is found that the results of energy method and the time history analysis method are almost the same. The energy method can be easily used to study the earthquake response of the steel frame-reinforced concrete shear wall hybrid structure.

Abstract: In this study, an experimental investigation program on a newly proposed seismic isolation technique, namely “Geotechnical Seismic Isolation (GSI) system”, is conducted with an aim of simulating its dynamic performance during earthquakes. The testing procedure is three-fold: (1) A series of cyclic simple shear tests is conducted on the key constituent material of the proposed GSI system, i.e., rubber-sand mixture (RSM) in order to understand its behavior under cyclic loadings. (2) The GSI system is then subjected to a series of shaking table tests with different levels of input ground shakings. (3) By varying the controlling parameters such as percentage of rubber in RSM, thickness of RSM layer, coupled with the weight of superstructure, a comprehensive parametric study is performed. This experimental survey demonstrates the excellent performance of the GSI system for potential seismic hazard mitigation.

Abstract: A model of coupled vehicle-bridge system excited by earthquake and irregular track is established for studying train running performance on high-speed bridge during earthquake, by the methods of bridge structure dynamics and vehicle dynamics. The results indicate that under Qian’an earthquake waves vehicle dynamical responses hardly vary with the increasing-height pier, but vehicle dynamical responses increase evidently while the height of pier is 18m, which the natural vibration frequency is approaching to dominant frequency of earthquake waves. Dynamic responses are linearly increasing with earthquake wave strength. Dynamic response of vehicles including lateral car body accelerations and every safety evaluation index all increase with train speed, so the influences of train speed must be taken into account in evaluating running safety of vehicles on bridge during earthquakes, but lateral displacement of bridge is varying irregularly. Dynamic responses and lateral displacement of bridge reduce under the higher dominant frequency of earthquake wave. Derailment coefficient, later wheel-rail force and lateral vehicle acceleration become small with increasing damping ratio. Vertical vehicle acceleration and reduction rate of wheel load are hardly varying with damping ratio.

Abstract: The design conception of composite liners consisting of a geomembrane (GM), geosynthetic clay liners (GCLs) and compacted gravel soils for landfill is presented based on the climate characteristic, gravel soils material storage in abundance, and GCLs having been exported all over the world for various applications. The analyses results suggested that the capacity to resist the collapse of wetting-drying and freezing-thawing, long-term barrier performance, and the general sliding stability of barrier system are enhanced obviously by using GCLs/GM as barrier and displacing clay by gravel soils as protector in this paper. It will be plausible as effective design for the barrier system of landfill under wet-dry and freeze-thaw alternating cycles in northwest China.

Abstract: The purpose of this study was to establish an alternative method in preparing the residual soil samples for laboratory tests. The soil was compacted by using the modified method in order to get the desired values of dry unit weight that was equivalent to the values obtained from standard compaction method. The advantage of using this method was that, due to its larger size, more samples could be taken and tested under the same compaction condition and the mould could be directly mounted on the shaking table with the addition of the air bags to avoid the occurrence of boundary effects. The soil was compacted in a 300mm x 300mm x 300mm mould by using the vibrating hammer. The results of this study showed that the average dry unit weight value of 13.4 kN/m³, 13.6 kN/m³ and 13.7 kN/m³ obtained from 5 rounds/layer, 6 rounds/layer and 7 rounds/layer of compaction of modified method, was equivalent to about 92%, 93 % and 94% of maximum dry unit weight obtained from standard compaction method, respectively.

Abstract: The new ways of anti-rutting was put forward by improving modulus of asphalt concrete and the effect of HMAT(high modulus asphalt concrete) on rutting is studied in view of mechanics; The cause of asphalt pavement track is closely related to pavement structure under load. Starting from the mechanism of rutting, the mechanical property of HMAT and the effect of modulus in middle layer on the rutting were analyzed; the dynamic stability and modulus of HMAC were analyzed by text and the result show that Increase of the dynamic stability and modulus of HMAC went against rutting; The mechanism of pavement structure was analyzed by the numerical analysis show that the maximum shear stress occurred in middle layer of pavement structure according to mechanical calculation. HMAC can raise modulus of elasticity of middle layer. HMAC can also improve stress state of pavement structure, reduce shear strain and prevent asphalt pavement track.

Abstract: A three dimensional structural testing system for static and pseudo dynamic test is developed, in which a coordinate system has been used in the measurement. The center of the ball joint hinge in an almost neutral position for the displacements of three actuators was the origin. However n process since the initial error cannot be controlled. This makes it difficult to exactly compare the results for different coordinate systems though the error is small. In this paper, to eliminate this difference, we set up a new coordinate system with the origin being the point of absolute zero of the actuator displacements. Since the origin usually cannot be measured directly, the new coordinate system is determined by appending three unknowns and a set of equations at the origin. The transformation between the new coordinate system and the previous one is obtained using a shift and Eulerian angles.

Abstract: The thermoelastic problem of a heat flux over a region with a crack near a rigid inclusion is studied. The inclusion is assumed fixed, which implies the translation and the rotation are restrained. The crack faces are assumed free of stress. Both of the inclusion and the crack are under thermal adiabatic condition. In the analysis, the original problem was reduced to a series of displacement boundary value problems by using the principle of superposition. The Green’s function method is used to obtain the solution of the prescribed problem in the forms of integral equations. The basic problems therefore become those for an edge dislocation, and for a heat source couple, as well as the problem of a plane containing the inclusion under a uniform heat flux. These problems are solved using the complex variable method along with the rational mapping function technique. The variations of the stress intensity factors at the crack tips with various crack lengths and heat flux angles are shown. The effects of the inclusion shape and size are also investigated.

Abstract: The vertical slice method is generally adopted for calculation of slope stability safety factor. The algebraic expression of stability safety factor of the slope under horizontal seismic forces is deduced based on the idea of calculation via the inclined slice method and according to the force limit equilibrium conditions of inclined slices. It replaces conventional integral or differential expressions with advantages such as simplified calculation process, convergence performance guarantee and rapid calculation via simple iterative. The example shows that the slope stability safety factor derived from this method is very similar with that from conventional methods, which proves that this method is feasible and brings convenience to technical personnel of slope engineering.