Applied Mechanics and Materials Vols. 193-194

Abstract: Arch is a structure suffers press mainly, and the problem of stability is very standout. As the continuous increase of arch’s spanning capability, application of new materials, arch structural integral and partial rigidity comparative declines and makes the problem of arch’s stability even more standout. In this article, through study on stability of arch bridge by finite element method, we discussed arch bridge’s linear and nonlinear finite element solve method.

Abstract: As advanced foundation treatment technologies, geogrid reinforcement and pile supporting are widely applied to the reinforcement of subgrade and giant oil storage tank foundations. The service behaviors of geogrid-reinforced and pile-supported composite foundations are explored through static tests. The focus is on its performance in the control and prevention of general and differential settlement and valuable conclusions are drawn of the study

Abstract: The quantitative influence of tensile steel bars size on the concrete crack width is analyzed. According to the engineering experience, the smaller diameter steel bars are superior to the bigger ones with the same reinforcement ratio consideration. However, the quantitative analyses have not been well treated. The criterion of “element with the maximum tensile stress will crack” and classic formula of the crack width in “Design code for hydraulic concrete structures”, are combined to analyze the uniaxial tensile specimens. Finally, three conventional diameters of tensile steel bars (14, 16 and 20mm) are adopted to verify the finite element model (FEM), and the quantitative analyses can be employed to the engineering reinforcement design.

Abstract: This paper introduces the development of cement concrete pavement in China and makes simple comparison with aspect concrete pavement and concludes that the cement concrete pavement has good development prospect. But there are some defects of cement concrete pavement, to solve these problems, this paper introduces the concept and methods of the preventive maintenance, which has enormous economic benefits.

Abstract: In order to studying the failure patterns under impact compression of Hybrid Fiber Reinforced Concrete(HFRC), tests focused on static and dynamic compression properties according to steel fiber reinforced concrete(SFRC) and HFRC are adopted. The equipment of dynamic compression properties test is Ф74mm split Hopkinson pressure bar (SHPB). The static and dynamic compressive strength at four different strain rates of the two materials are obtained, while failure mechanism has been analyzed from specimens’ failure modes in static and dynamic compressive tests, which in turn provides theory basis for the application of HFRC.

Abstract: Optimizing design of parameters is essential for the underwater blasting. The key point of optimizing model is to reflect the relation of blasting parameters, rock fragmentation and operation cost. In this paper, the blasting optimization mathematical model is established, and the optimization of the blasting parameters is obtained using the complex method with computer. Calculation results show that the blasting parameters designed by the optimizing model make the engineering cost lowest.

Abstract: The urban heat pipe network fault diagnosis system was designed in this paper so as to realize the automation diagnosis. The paper uses the simulation calculation method and the heat pipe network fault diagnosis system to analyze and study an urban heat pipe network leak fault. The diagnosis results of the heat pipe network fault diagnosis system are almost the same to that of the simulation calculation method. Moreover, the system can accurately locate the leak point and the positioning accuracy is 5%. Thus the heat pipe network fault diagnosis system which is designed has a certain practical value.

Abstract: In foundation pit engineering, the presence of pile plays an important role on the pit stability and deformation control. The bottom upheaval of deep foundation pit is a key criterion of judging the foundation stability and deformation. This paper built the 3D finite element model to analyze the influence of different factors (pile diameter, pile length and pile spacing) on the bottom upheaval, and concluded that: when pile length and pile spacing is constant, changing the pile diameter can hardly affect the bottom upheaval; as the pile length increased, the inhibitory effect to the bottom upheaval grew stronger with a gradually decreased growth rate; increasing pile spacing can significantly reduce the bottom upheaval, and the smaller the pile spacing, the smaller the upheaval. The concept of upheaval inhibition rate was defined to evaluate the influence of different factors of pile layout on the bottom upheaval. A correction method of calculating the bottom upheaval of foundation pit with engineering pile was proposed. An engineering instance of Shanghai Natural History Museum foundation pit was studied, and the result showed that the bottom upheaval calculated by the correction method is less than the upheaval calculated by method of residual stress, which was more close to the monitoring data. The influence of engineering pile on bottom upheaval of foundation pit should not be neglected where a large number of piles were present in deep foundation pit.

Abstract: With the constantly increasing height of the ultra-high-rise buildings in the world, the high pumping technology of high-performance concrete has become the feature of the constructions. This article has briefly introduced the preparation technology of the high-performance concrete in the world, then elaborated some key technologies such as the mixture ratio and mixture properties of high-performance concrete combining the West Tower project in Guangzhou Pearl River New Town (building height: 440.7m) contracted by Fourth Engineering Bureau of Chinese Construction.

Abstract: This paper presents static and dynamic analysis of wind turbine towers which is supporting a 1.5MW wind turbine based on the theory of FEM. In static analysis, the modal frequencies of the towers are analyzed without wind load. In dynamic analysis, by the fluid-coupling theory, the dynamic effect of wind loads on the towers is calculated. It can be concluded that the main errors under the different load situations is caused by the impact of fluid structure coupling.