Advanced Materials Research Vols. 255-260

Abstract: With the propose of solving the problem of inappropriate adoption of construction technology while constructing infrastructure in western rural area, technical characters of specific construction technology is measured from three aspects as economic benefit, social benefit and ecological benefit through introducing compensation cost method (CC), thereby the construction technical proposal is found out of which the technical character suits the local technical environment character the best. The conclusions drawn from the study are as follows: High-tech may not be the appropriate technology; The technical characters of appropriate technology must suit the technical environment characters of the applied areas.

Abstract: The numerical model for analysis of fire behavior of the spatial pre-stressed steel structure is established based on the software Marc. Analysis of thermal response and structural response of a suspended pre-stressed steel reticulated lattice shell are computed for the key nodes of the structure. For comparison, the air temperatures near the key nodes are also calculated based on the practical formula of large space air temperature rise. The different location of fire source is considered for analysis of response temperature, displacements and stresses of the nodes of the pre-stressed lattice shell. It is shown that the air temperatures obtained from the practical formula was always higher than the response temperatures of the nodes of the lattice shell during a quite long time after a fire takes place. The results show that the displacement of the node near the center of the gymnasium in fire is close to that of the node right above the inner cable, and the displacement of the node right above the outer cable is much less than the result of the center node.

Abstract: Mechanical behavior and bearing capacity of ceramsite concrete filled steel tubular short column (noted as CCSSC) subjected to fire load are experimentally investigated. Effect of the parameters, such as the maximum value of fire temperatures, fire duration on the strength and ductility of the two types of specimens were especially discussed. The experimental results show that all the specimens of CCSSC have higher post-fire bearing capacity and better ductility, and there was no descent segment in load-displacement curves of the most specimens after the fire load was subjected. It was concluded that the maximum response temperature of specimens and fire duration time has great effect on the axial bearing capacity of concrete-filled steel tubular short columns subjected to fire, and the concrete mix proportion has some effect on both of bearing capacity and ductility of CCSSC subjected to fire load.

Abstract: For study of the post-fire characteristics of the profiled sheet-ceramsite concrete composite floor (noted as PSCCF) subjected to fire load, the experimental research on post-fire bearing capacity of a PSCCF after fire is carried out. Based on the experimental results, effect of the fire on post-fire bearing capacity of the profiled sheet-ceramsite concrete composite floor is discussed, and the failure phenomenon and mechanism are analyzed. It is shown that the failure form of the profiled sheet-ceramsite concrete composite floor after fire has great change compared with the floor not subjected to fire load, but the composite floor subjected to fire still exhibits higher bending capacity, and the ultimate value of the equivalent distributed load is up to 25kN/m², which may be used as basis of strengthening and repairing of the profiled sheet-ceramsite concrete composite floor after exposure to fire.

Abstract: There are lots of various goods in large-scale wholesale market, and all these goods were stacked together. Huge fire loads were formed and there is a great fire risk in this kind of architecture. Through investigation in a large-scale wholesale commercial building in Xi'an, some data such as fire load, fuel types, room size were collected .All these data were analyzed and the types of fuel composition in different kinds of shop were comprehended. The research will contribute to management of fire prevention in wholesale market.

Abstract: In recent years, lots of urban disasters have happened in China. All these disasters caused damage to economic growth and tremendous effect on people's lives. This paper aims to search for effective methods of urban disaster prevention and mitigation. Through investigation and induction, the paper summarized definition of urban disaster and destructions to city. Finally, the paper put forward some suggestions to disaster prevention and mitigation. The research will contribute to disaster prevention and mitigation in city, and it is conducive to establishment of comprehensive disaster prevention system.

Abstract: The paper addresses the derivation of a concentrated plastic-hinge finite element modelling for nonlinear analysis of space steel frames. The interpolation functions considering shearing deformation are adopted and cubic polynomial interpolation functions based on Kollbrnner-Dajdin modified constraint torsion theory are used to consider the warping deformation, with these functions the effect of the secondary shear stress can be taken into account. With the expanded Orbison’s yielding surface, the plastic-hinge method used to do nonlinear analysis of space steel frames is derived by introducing elastic-plastic hinge parameter of element cross section. Numerical examples are presented to illustrate the validity and the universality of the proposed approach and the results show the new model is accurate and suitable for the nonlinear analysis of steel frameworks.

Abstract: Deployable Structures are generally those space structures being capable of turning from a folded and compact configuration into a predefined deployed configuration. These structures bear the loading in a deployed configuration. Scissor-type structures are one of the most complicated deployable structures, being stress-free in both deployed and folded configuration, but stresses could increase when explored deployment and perform a highly nonlinear behavior. There are mostly some defects and imperfections observed in fabricating such members and assembling the whole structure compared to the ideal model. The existence of these defects and geometric imperfections could influence the total or partial behavior of the structure. These imperfections could highly affect the structural deployability, the required force for deployment procedure and load bearing capacity of the deployed configuration. In the present study, the effect of member’s length imperfection due to inner, outer and a hybrid configuration of scissor-link Elements on the behavior of curved scissor-type structure are investigated.

Abstract: This paper expatiates the prominent effect of axial compression ratios on the ductility of reinforced concrete frame columns and the limits of the ratios in Code for Seismic Design of Buildings and summarizes the ductility design methods of frame columns with high compression ratios. The principles of value engineering were adopted to analyze the major factors affecting the ductility of reinforced concrete frame columns. The cost of columns with high compression ratios and different types of ties in a real project was calculated and relevant analysis and evaluations were conducted according to Value Coefficient Discriminance. At last the optimum ductility design method for frame columns with high compression ratios was put forth, with which reference can be made in design.

Abstract: Fibre is a small piece of reinforcing material described by a numerical parameter, called aspect ratio which is the ratio of its length to its equivalent diameter (l/d). In the Biblical period Romans introduced the concept of “Fibres” in the building material by using the “HORSE HAIR” as the fibrous material and since then the use of fibres was incorporated. Recently, however, the development of Fibre Reinforced Concrete (FRC) in various fields has provided a technical basis for improving the deficiencies in mortar and concretes. At hydration stage, water tends to escape through various routes and cracks develop on the surface. These leads to water penetration resulting in dampness and need repainting of walls and other repair. The aim of the present experimental investigation is to study the effect of addition of synthetic fibres on the ultimate strength and behavior of the concrete and mortar. The fibre content (by volume) is the main parameter considered in the study. A combination of a low ratio of conventional fibre reinforcement together with synthetic fibers may provide a practical solution, increasing the strength of the beams without causing congestion of the reinforcement. Fibres in the concrete act as crack arresters and considerably enhance the ductility. In the investigation a total of 240 full-scale specimens with and without fibre contents were casted, and tested to failure under symmetrically applied loads. The fibres volume Vf is vary from 0% to 1.5%. As the test was in progress, the development and propagation of cracks, the load at first crack and the mode of failure was noted. The results were compared to control sample and the viability of adding synthetic fibre to concrete and mortar was verified.