Advanced Materials Research Vols. 446-449

Abstract: Based on the experiment of five full-scale small-sized fly ash hollow block walls under low-cycle reversed load, the influence of aspect ratio, common horizontal reinforcement, size of structural column section to the loading process, failure characteristics, cracking load, ultimate load, deformation, ductility, stiffness and energy dissipation of the walls was studied. Simultaneously the mechanical properties and work mechanism of the small-sized fly ash hollow block wall has been analyzed.

Abstract: Strong column-weak beam failure mode is considered to be a preferable mode for its large capability to absorb earthquake energy and prevent collapse. However, for composite frames composed of steel-concrete composite beams and concrete-filled steel tubular (CFST) columns, strong column-weak beam design methods are not given in Chinese codes. The column-to-beam strength ratio is one of the most important factors that influence the failure mode of frame structures. Moreover, large axial compression ratio of columns may cut down the actual bending capacity of columns, and thus has an adverse effect upon the realization of strong column-weak beam failure mode. In order to investigate the influence of column-to-beam strength ratio and axial compression ratio on the failure mode of concrete-filled square steel tubular frame structures, pushover analysis of a five-story three-bay composite frames with various column-to-beam strength ratios and axial compression ratios are carried out. Based on the analysis results, suggestions about the reasonable value of column-to-beam strength ratio with different axial compression ratios of columns are given to ensure the realization of strong column-weak beam failure mode for concrete-filled square steel tubular frame structures.

Abstract: In this paper, the differential element of constant-section silo wall suffering from axially symmetric load is analyzed. From the results of constant-section silo, the author derives the displacements and internal forces of variable cross-section silo. Through a specific example, this paper compares the displacements , internal forces and concrete consumption of variable cross-section silo with those of constant-section silo, and discusses the merits of variable cross-section silo.

Abstract: Several batches of reinforced concrete (RC) and prestressed reinforced concrete (PRC) beams with 500MPa steel bars were tested in Tongji University, recently. The results indicated that the development of flexural stiffness after concrete cracking was influenced mainly by three parameters including initial elastic flexural stiffness, longitudinal reinforcement ratio and load level. Based on our 20 years' systematic research on crack and stiffness, a simpler unified formula is suggested after theoretical analyses for predicting short term flexural stiffness of concrete beams using high strength steel bars. Comparison with calculations from different codes at home and abroad exhibits that the suggested formula is precise and practical for both RC and PRC beams.

Abstract: According to the nonlinear stress-strain relationship of LAC (lightweight aggregate concrete), in this paper whole process theoretical analysis on normal section bearing capacity has been done on lightweight aggregate reinforced concrete member with circular section under eccentric compressive loading. Fundamental equation of numerical iteration is established for normal section bearing capacity of LAC member with circular section under eccentric compressive loading, which provides theoretical basis for concerned calculation simplification.

Abstract: This paper presents a new approach to thermal field sensitivities and ampacity computations of underground power cables using a proposed algorithm of perturbed finite-element analysis. Domain-specific visual language tools have become important in many domains of software engineering and end user development. Numerical results show that the most significant randomness comes from thermal loads and also that the amount of uncertainty decreases from input to output. We will show that the object-oriented programming greatly simplifies the choice and the implementation of other formalisms concerning polyarticulated systems, thus conferring high flexibility and adaptability to the developed software.Such experimental verification confirmed the accuracy of the new introduced finite-element sensitivity methodology.

Abstract: The scrap rubber powder and the waste plastic compound modified bituminous mixture are used in the first-class highway asphalt concrete pavement. They can not only reduce the environment pollution, but also enhance the operational performance of bituminous pavement. It has the economical, social and the environment three aspect remarkable benefit. This article uses the appraisal system of the rubber asphalt to test the compound modified asphalt performance with the different rubber powder quantity and the waste plastic quantity in different mixture temperature and the time. By text, we can determine the best quantity of the waste plastic.

Abstract: This paper proposed a simplified modeling method of reinforced concrete based on the equivalence of dynamic stiffness, the parameters of simplified model were modified to make the error of nature frequency between reference model and simplified model as small as possible, and an appropriate optimization function was designed. The essentiality of the proposed method is parameter optimization, with the advantages such as fewer elements and calculation assumption. The numerical simulation result indicated that this optimization method is suitable for the dynamic response analysis of complicated reinforced concrete structure.

Abstract: The axisymmetric punching analysis for concrete slabs is researched with the triple-shear unified failure criterion, which can explain the failure properties rationally for concrete under the three dimensional stress states, especially the failure properties of the intermediate principal stress effects. Moreover, a new intermediate principal stress parameter is proposed to interpret the different stress states in failure zones for different concrete. It is shown that the coefficients of b and m, which interprets the effects and the magnitudes of the intermediate principal stress have significant impacts on the axisymmetric punching capacity of concrete slabs. For a given thickness of the concrete slabs, the bearing capacity increases with the b and reaches its maximum value approximately when m=1. Using the Mohr-Coulomb failure criterion to analyze the problem of axisymmetric punching of concrete slabs often underestimate the actual ultimate punching capacity significantly.

Abstract: With the rapid development of high-rise shear-wall structure residence buildings in domestic large and medium-sized cities, it brings the problem that traditional structural design wastes materials, which is now taken seriously. Structural optimization design can save materials more than 10% in general. This paper carries structural optimization design on eight shear-wall structure residence buildings, and proposes a predictive method for concrete dosage of high-rise shear-wall structure residence buildings after analysis. The predictive method makes it easier to obtain the concrete dosage, because it frees from the cumbersome process of engineering budget. The predictive value is economical and reasonable, and it can be used to guide structural design.