Applied Mechanics and Materials Vols. 275-277

Abstract: Lightweight technology is to transform the discarded materials, such as dredged silt, construction waste soil, waste foam plastics, industrial waste fly ash, waste gypsum, etc., into lightweight soil. This kind of soil has been utilized comprehensively, which can produce good economic benefit, environmental and social benefits. In order to further investigate the properties of mixed lightweight soil, this paper uses indoor test method to study the recycled sludge lightweight soil samples prepared from the construction waste soil by mixing with EPS particles and cement according to certain mass/volume ratio and cured in standard curing conditions. The strength properties and failure mode are analyzed using the direct shear test and unconfined compressive strength test, and the effect of curing period, cement content, EPS particle fraction, etc., on the strength and failure mode is analyzed.

Abstract: Unstable productivity analysis method was used to obtain the equivalent radius of 77 wells and the result shows that the equivalent radius ranges from 30 to 970m with an average value of 230m in McKittrick Hills. The difference range of the radius is mainly caused by varying formation properties, gas saturation, production time, etc. Permeability anisotropy changes the drainage from round to ellipse. The major axis and the minor axis of the ellipse are determined by the ratio of major and minor permeability. Current pressure distribution was obtained and was found to be consistent with the modified drainage results, which demonstrates that the unstable productivity analysis method is applicable in the study of gas well drainage radius. An interference well and an observation well’s model was constructed to study well interference quantitatively. When the well spacing is larger than 750m, the productivity will be reduced by 20%. The production rate of interference well is more sensitive to the cumulative production of observation well, when the production rate of interference well is below 16.8×104m3/d.

Abstract: Numerical simulation of intra-explosion in multilayer medium is computed by using of AUTODYN-2D code based on TCK subroutines. To investigate phenomena of conical crater damage in multilayer medium, the intra-explosion efficiency law of different weight and depth of explosive charge is studied, and relation of explosive weight and detonation depth with thickness of cover medium is modeled to predict the optimal detonation depth.

Abstract: It is one of the most important issues for finite element analysis of lining structures that how to describe anchor rod reasonably and effectively and simulate the interaction between rod and concrete or rock. Virtual nodes are constructed in concrete/rock element at the ends of anchor rod and bond-slip element is set between virtual nodes and beam element which describes anchor rod. An embedded combined element with bond slip and shear deformation is established through the transformation of nodal force at nodes of bond-slip element to those of concrete/rock element via shape functions. The element is convenient for meshing element because the location and direction of anchor rod are not necessary to be considered. Meanwhile, the element has the advantage of low computing cost. Finally, the validity and efficiency are verified by numerical examples.

Abstract: The random nature of structural parameters is to affect the behavior of the structure which cannot be detected in the context of deterministic analyses. Taking into account the randomness in the material parameter, we evaluate probabilistic behavior of the shell structures made of isotropic material. Specifically, the elastic modulus is taken to be random since the parameter plays an utmost important role in the behavior of structures. The results of the proposed scheme are compared with those based on Monte Carlo simulation. It is observed that the proposed scheme is in good agreement with the MCS, which shows the adequacy of the proposed scheme.

Abstract: The interface zone in concrete is the weak link and its structures and properties are the key factors determining overall performance of concrete. In this paper, the cohesive strength on the interface zone is tested through the in- situ drawing test of the aggregate from the concretes of C15,C20, C25, C30,C35,C40. and the tensile strength and the shear strength on the interface zone are analyzed by the simple assumptions about the uniform drawing and well distributed stress on the interface. As a result, It’s showed that with the pebble size increased, normalized pull strength of low grade concrete has a tendency to increase, while high grade concrete is in the vicinity of 7% fluctuation; when pebble diameters are the same, with the concrete strength increases, the normalized pull-out strength decreases. As the particle size less than 30mm or more than 110mm, tensile strength seems to limit value. the macro pull strength is on the range of 4%—12% of concrete compressive strength.

Abstract: In this paper,time-history analysis comparison of different parts of the displacement on eight floor three span Frame Strengthened with viscoelastic damper under the action of EI Centro earthquake wave .The results indicate that setting viscoelastic damper Strengthened structure can well inhibition Seismic response function, reducing the earthquake response of the structure,decreasing amplitude are relatively obvious, achieving a better seismic condition, meeting the needs of the standard, it is a kind of performance very good seismic energy dissipation strengthening methods.

Abstract: The original concept of self-centering system was first proposed under the PRESSS research project in 1991 in UC San Diego. The particularly promising and effective structural solution was initially defined as hybrid system in literature and then self-centering system recently. In the ductile connection of self-centering system, inelastic demand is accommodated through the opening and closing (control rocking) of a pre-existing gap at the critical interface, with no consequent damage such as the plastic hinges in traditional structural elements. This paper provides an overview of the recent advances of self-centering system, especially for bridge piers, to summarize several analytical models and experimental tests that were widely recognized. Besides, a brief introduction of the study conducted by Tsinghua University is presented, including a stiffness degrading analytical model and a series of experimental tests.

Abstract: Steel and concrete are the main buiding material of the civil engineering community, but with its easily errosion behaviour and CO2 discharge, it should be substituded with new materials.Fiber reiforcement polymer (FRP) is such a developped material, with its high strength to weight ratio, durability prolongation, hight stiffness to weight ratio and its fatigue resistance behaviour, it is now getting widely used in civil engineering. This article focused on how to design, built and operate a structure health monitoring system for the noval steel-free cable stayed bridge, and a knowledge discovery model, SG（Simplified-General）modle was provided for analyzing the collected data.

Abstract: The nonlinear dynamic response of piles in uniform foundation under earthquake loading is investigated. Based on the established nonlinear equations of motion of piles under earthquake loading, the approximate solution of the pile for the case of the resonance is obtained by the method of multiple scales. The effects of major parameters on seismic force are studied, such as, frequency ratio, shear wave velocity, soil thickness. And the effects of the major parameters on the frequency response curves of the pile in single layer soil are studied. Comparing with the non-resonant response of the pile, the effect of the resonance on the actual dynamic response is analyzed. The results shows that shear wave velocity and soil thickness have significant effect on the seismic force in soft clay, which have little effect on the seismic force in the other soil layers; soil thickness has the most important influence on the nonlinear dynamic response of pile and it is followed by the earthquake coefficient, the shear wave velocity in the effects.