Advanced Materials Research Vols. 250-253

Abstract: With rapid development in automobile industry and increasing environment problems, a difficulty confronting many countries is how to recycle scrape tires. The earthship comes out as an effective way to make full use of scrap tires in building design. By introducing its construction procedure, current conditions at home and abroad, and two case studies abroad, the paper concludes its advantages in environment protection, building performance, economy and technology. Besides, in view of the present condition in China, It suggests to first build earthships in less developed areas, or areas with extreme weather conditions, and try to popularize them in temporary structures, garden buildings, or special buildings.

Abstract: The construction, operation and demolition of building have tremendous impacts on the global energy and environment. However, initial construction costs are overly concerned in traditional construction projects and the economic, social and environmental impacts are neglected, which is a crucial barrier to the promotion of the sustainable construction. Through borrowing the theory from manufacturing industry, this paper analyzed the concept of lean construction, and combined the advantage of lean thinking with the sustainable development, promoting the sustainability and maximum value of construction projects besides the realization of three main objectives - the quality, schedule, cost of the construction project. Then, this article introduced the implementation of lean construction in the sustainable construction projects based on the view of transfer, flow, and value, and finally constructed the building objectives system which is composed of the minimum cost, the condensed duration, the superior quality and the sustainability of the construction.

Abstract: This paper reports a set of experiments on the ultimate strength and fractural performance of structural steel welds at elevated temperatures. The results show that structural steel welds show distinctly different behavior below (including) 400°C and above 400°C. Below 400°C, the ultimate failure resistance fluctuates about the room temperature resistance and the failure was brittle fracture occurring to various locations of the welded region. Above 400°C, the ultimate failure resistance reduces quickly and the failure was by the tensile fracture of the interface between the weld and the steel with noticeable tensile elongation of the specimen. The results were supposed to help the design of structural steel connections for fire safety.

Abstract: Based on the numerical simulation of the basic behavior of multi-ribbed composite wall under low frequency cyclic load, the skeleton curve is consistent with the experimental results. Also, the factors such as axial compression ratio, the intensity of filling blocks and the shear span ratio which may influence the shape of the skeleton curves are analyzed. The results shows that the yield load of multi-ribbed composite wall as well as the limit load are positively related to the block strength, while are negatively related to shear span ratio. Besides, by the method of finite element model, 9 groups of skeleton curve data of multi-ribbed composite wall in different axial compression ratio, shear span ratio and the intensity of filling blocks were simulated. On the basis of multiple linear regression analysis of the numerical results, the equations for calculating the feature points in the skeleton curve are given.

Abstract: For RC beams strengthened with prestressed carbon fiber reinforced polymer (CFRP) plates, calculate methods for the cracking load, the yield load and the ultimate load are derived base on the analysis of normal section stress. The test of reinforced concrete beams strengthened with prestressed CFRP plates were carried out, and analytical results are compared with experimental results. Comparisons show that the calculated values agree well with the experimental results.

Abstract: As we all know, Jing-wei river system provides the ecological support for the development of Great Xi’an Metropolitan Area. However, the town’s random development, unreasonable planning and destructive construction causes bad effects on the Jing-wei river, like the area’s decreasing, and function’s degradation, which greatly limits the sustainable development. According to the conflict between development of Great Xi’an Metropolitan and ecological construction, the thesis comes up with idea of building up the ecological corridor, which gives a detail analysis about environmental characteristics of the Jing-wei river system, the spatial relation between the Jing-wei river system and construction zone of the town, the important function, characteristics of structure, and width of the ecological corridor, and its landscape evaluation system.

Abstract: Geopolymer has been gradually attracting world attention as a potentially revolutionary material that is one of the ideal substitutes of Portland cement, and fundamental studies on geopolymer are increased rapidly because of its potential commercial applications. However, little work has been done in the field of curing system of geopolymer. In this paper, influence of curing temperature, curing time and curing humidity on the mechanical properties of slag-based geopolymer was studied by using the compressive strength as benchmark parameter. Results have shown that the early age compressive strength of geopolymer increased and the long-term compressive strength decreased at first and then increased as the curing temperature increased, 80°C was the best curing temperature. With prolonging the curing time, it was found that the compressive strength of early age of geopolymer reached the maximum ( 116.3 MPa for 1d, 97.5 MPa for 3d) as the curing time was 12h, and that of 28d geopolymer was 91.3 MPa as the curing time was 10h. It was also found that the compressive strength of geopolymer reduced evidently as the humidity increased.

Abstract: Based on the heterogeneity of rock, by using the RFPA^2D, influene of the horizontal in-situ stresses on the distributions of plastic zones is discussed. Among the current problems that rock or civil engineers face, perhaps there is none as challenging as the characterization of fluid flow though fracturing rocks, especially when they are highly stressed. In mining and civil engineering projects, the re-distribution of the stress field during the excavation of tunnels and underground chambers lead to the formation of new fractures. These damages may cause dramatic changes in the permeability of the rock masses. As a result, the rate of water flowing into the tunnels and chambers will increase.

Abstract: In order to study the influences of structure parameters on the structure mechanical characteristics of long-span suspension bridge. The Shiduhe bridge in Hubei Province was taken as the background of this study, The influence on structure line shape and free vibration characteristics of suspension bridge with the change of structure parameters was studied. The results show that main cable stiffness not only has greater effect on the structure shape of long-span suspension bridge, it also has obvious impact on structure free vibration frequency, in addition, the torsion displacement of stiffening girder can be reduced effectively by adding central buckle, it improves structure bending and torsion stiffness significantly, central buckle also can improve free vibration frequency of structure and enhance structure dynamic stability, It shows that the influencing factors of structure static characteristics are restricted by rigidity of main cable, free vibration characteristics are affected by main cable and central buckle, they are not very sensitive to the variations of the parameters of suspender cable, stiffening girder and main tower.

Abstract: The characteristics of effect are expounded for different structure under the specific load. These internal force and deformation characteristics in conceptual design should be caused take attention seriously. After summing up a lot of engineering structure calculation based on the results of different structure, some typical characteristics of load effect can be reduced , usually these typical effects called conceptual design features. Understanding of these internal force and deformation characteristics of structures is beneficial for deepening professional quality, and improving the professional foundation. Readers with diligence paid to various structure and further study, will be able to cognitively find more conceptual design features, make innovations, and constantly enrich itself the experience of conceptual design.