Advanced Materials Research Vols. 446-449

Abstract: The introduction of can reasonable description of transversely isotropic soil micro-element strength parameters - damage variable, according Mohr-Coulomb strength theory and soil micro-element theory of geotechnical failure to obey normal distribution characteristic,the damage variables can true reflection of transversely isotropic soil softening characteristics.Based on the uniaxial stress-strain curve of the geotechnical rupture process of statistical damage constitutive model of geotechnical, statistical damage variable is adjusted, establishing the reflect the complete process of geotechnical failure of 3D statistical damage constitutive model.Model is simple, easy to use, can better reflect the actual.The model reflects the failure process of geotechnical damage not only with geotechnical micro-unit strength changes, and the effect of geotechnical stress state.

Abstract: The stability of Timoshenko columns with elastically supported ends under axially compressive force is analyzed. Characteristic equations are obtained according to an intermediate state between Haringx’s and Engesser’s models. For clamped-free, clamped-clamped, and pinned-pinned columns, buckling loads are given in closed form. The influences of elastic restraint stiffness on the critical loads are elucidated. Haringx’s and Engesser’s models are two extreme cases of the present. Critical buckling loads using Haringx’s model are upper bound, and those using Engesser’s model are lower bound.

Abstract: Based on the fluctuation or vibration failure mechanism of structures under blast vibration, the relationship between the amplitude, frequency of blasting vibration and the stress, strain (deformation) of structures is studied. The assessment method of blasting vibration effects is determined. The results indicate that under the fluctuation failure mechanism, the peak stress and strain of structures are proportional to the peak particle vibration velocity. The peak particle velocity (PPV) can be used to evaluate blasting vibration effects, while under vibration failure mechanisms, PPV, the main frequency and the natural frequency of structures must be considered for blasting vibraton effect safety assessment. The peak particle vibration acceleration should not be a separate evaluation parameter for blasting vibraton effects.

Abstract: When the loading sustained by the foundation is large, employing piled raft foundation is one of the best solutions. In the elasto-plastic design of piled raft, piles could improve the differential settlement and reduce raft thickness. As the raft sustains high earth and water pressures, by reducing the span length of raft and excavation depth, one can get economic design. Using elasto-plastic property of the pile is a better method to avoid increasing the pile length and pile diameter and making full capacity of the piled raft foundation in design compared to normal piled raft. With adoption of few small diameter piles, the raft thickness could be reduced significantly. This makes it much better than raft foundation.

Abstract: Tower nesting is a classic NP-hard problem, which is always solved in manual method or manual method combined with computer in production practice. The manual method is inefficient and impossible to process large amount of data accurately. Furthermore, the utilization rate of materials is not satisfactory. In this paper, we present a strategy based on an improved greedy algorithm to solve the nesting problem. Experimental results show that this algorithm has advantages of time efficiency and utilization rate of material.

Abstract: The stratum uneven settlement of tunnel is main factors that cause damage of tunnel longitudinal structure. a 3d numerical model is established for the force and deformation calculation of tunnel structure based on the elastoplastic theory. In the model, soil material is elastoplastic, and its constitutive model is Mohr Coulomb, the element type of soil is a three-dimensional solid, the element type of tunnel lining structure is space shell element, and tunnel settlement joint is three-dimensional linear spring. Calculation shows that, this calculation model is able to fully consider the impact of tunnel uneven settlement in all factors, and can simulate the vertical force and deformation behavior of tunnel structure in complex ground formation conditions. Research conclusion gives the vertical force and deformation of the tunnel structure under the condition of the stratum uneven settlement. It is very important reference for the longitudinal design and calculation of the tunnel lining structure.

Abstract: The objective of this paper is to investigate the ductility of reinforced high strength concrete (HSC) T-section beams retrofitted with carbon fiber reinforced polymer (CFRP) sheet, and to analyse how such retrofitting affects deflection, curvature and energy ductility of strengthened T-section beams. Two series, a total of nine T-section beams-two control specimen and seven strengthened beams were constructed and tested under flexural load. The effect of longitudinal CFRP amount, type of cross-section of specimen, and the location and configuration of U-anchorage on ductility was studied. The influence of distribution of strain and interface shear stress of CFRP sheets on ductility was analysed as well. This paper also proposes the quantitative relationship between CFRP amount and displacement ductility indiced by means of theoretic calculation method. And relevant suggestions for its design and application are also presented.

Abstract: Studied the arch structure under vertical loads reasonable arch axis problem, regardless of the arch on the role of distributed load or concentrated load, the structure can be simplified into line arch, ignoring axial deformation of bars, the moments at the joints must be equal to zero, the ratio of rise to span for the parameters, derived function of the coordinates of each node to determine the arch of the pressure line, and also determine the horizontal thrusts of the arch. The method is simple and practical, especially for the preliminary design stage, for the arch axis provides the basis for further optimization.

Abstract: Based on refined plastic hinge, this paper considers the effects of second-order effects of structure plastic strength, geometric imperfection ,residual stresses to the structure stability by modifying the element stiffness matrix. Use the modified element stiffness matrix to analyze the force of the staggered truss of steel sturcture and compare the calculation results with ANASYS’s. Use the modified element stiffness matrix to analyze interstory drift of the staggered truss of steel sturcture and compare the calculation results with K Jim’s. The result shows that the developed element matrix can accurately calculate the stability capacity and interstory drift of the staggered truss of steel structure. Design by advanced analysis method is the direction of the analysis and design of modern steel structure.

Abstract: In order to analyze aseismic behavior of the high reinforced concrete (R.C.) shear wall with frame column in the large thermal power plant, the model structure has been taken test with method of low frequency cyclic repeated load that has 1/15 scaling factor to practical structure. At same time the model has been analyzed by the finite element method which takes the Hognestad concrete constitutive model and ideal elastic-plasticity steel reinforcement constitutive equation. It has been found that the hysteretic curve is relatively full and energy dissipation capacity is better through the experiment. The bearing capacity, deformation and fracture results to the Shear wall of finite element analysis are closely with the test results. In general, the R.C. shear wall with frame column in the large thermal power plant has good aseismic performance. The finite element method can be taken to analyzed the similarity structure.