Key Engineering Materials Vol. 619

Abstract: According to the Chaoyang town east bridge design data, build the model with finite element analysis method. Based on two levels fortification, two stage design ideas of seismic design, modal response spectrum and seismic response of the nonlinear time history analysis method are used respectively. The nonlinear effect of the boundary conditions are considered in the analysis process, and the seismic response of the cable-stayed bridge is obtained, providing bases and presenting methods for aseismic design of Chaoyang town east bridge.

Abstract: In view of the issue of bridge structure safety, this study pointed out the necessity and urgency to build the bridge safety operational monitoring system. The basic idea, system composition, current situation of the development and application of structural health monitoring system were summarized. Finally, the key problems and development trend of bride safety monitoring were proposed.

Abstract: This paper made a thorough influencing parameter analysis on the unstressed state and completed state of main cable of self-anchored suspension bridge. The main cable curve, the amount and the action point of the resultant force of main cable on the main saddle were considered as the controlling objectives, the rational completed state of main cable was defined; Wusong bridge in Jilin city was taken as an example, the finite element mode of main cable was created. The unstressed state and the completed state of main cable under different parameters were calculated, and all the results were compared with the reference state, the influences of each parameter deviation on the state of main cable were studied: the self-weight and erection temperature of main cable had little effect on the state of main cable; the length of the mid-span main cable mainly influenced itself line-shape, while the length of the side-span main cable had significant effect on each controlling objective; made the unstressed line-shape of main cable as the controlling condition, the position deviation of the main saddle and back anchorage facet, happened before the main cable erection stage, had little effect on the completed state, but which will have great effect on the completed state when they happened after the main cable erection stage. Engineering example analysis results showed that, the tensile stiffness of main cable and the boom-completed force would have some effect on the completed state of main cable, and the tensile stiffness of main cable and the self-weight of the main beam should be tested before erecting the main cable, in the same time the deviation should be control within the rational limits; recommended that the unstressed shape of main cable should pre-lift, which could counteract the deformation of the main saddle and the back anchorage facet at the completed stage, this conclusion had a strong guiding significance and reference value on the work of constructing the main cable of self-anchored suspension bridge.

Abstract: This paper presents the results of a study on the fatigue damage of high strength concrete under uniaxial compression. Based on the experimental data, the change laws of fatigue strain and fatigue modulus are put forward. According to the experimental requests, the numerical value of fatigue strain and fatigue modulus when the fatigue failure of concrete occurs can be regarded as the criteria for fatigue failure of concrete. Then the paper presents a fatigue damage model. By reference to the concept about the damage variable defined by some scholars, the formula of the damage variable is proposed and the damage variable curves varying with recycle ratio (n%) are mapped. At last, the fitting curves of the damage variable varying with recycle ratio are proposed. The fitting effect is very good and the correlation coefficients are above 0.95.