Applied Mechanics and Materials Vols. 405-408

Abstract: In this paper, the bridge impact coefficient was researched under conditions of the same section form and different width-span ratio. Five bridge models were set up based on the finite element method. Static and dynamic load simulation analysis for the same form of bridge was conducted firstly. Then the impact coefficient was calculated. Finally, According to the variation of impact coefficient along with the bridge width-span ratio, the method of probabilistic statistical regression analysis is applied to analyze the changing rule of the impact coefficient change with width-span ratio. Results showed that the influence of width-span ratio on impact coefficient should considered preferably for ordinary highway bridges with its width-span ratio less than 1. But for taxiway bridges which the width-span ratio is generally between 2 to 3, the influence of width-span ratio on impact coefficient can be ignored.

Abstract: Peak displacement is one of the most important parameters for the performance based seismic design of bridge structure, while the peak displacement is often significantly impacted by the P-Δ effect. In this study, the influence of the P-Δ effect on the statistics of peak displacement of bridge structure was quantificationally investigated based on a series of nonlinear time-history analysis. The bridge structure was idealized as the single degree of freedom (SDOF) system and the hysteretic behaviour was represented by the improved Bouc-Wen model. The statistic analysis was implemented based on the inelastic dynamic responses of the SDOF system under 69 selected earthquake records. The results show that the P-Δ effect has significant impact on the mean and dispersion of peak displacement of bridge structures, especially if the normalized yield strength and the natural vibration period are small.

Abstract: Residual displacement has been identified as one of the most important parameter to assess the reparability and usability of bridge structures after strong earthquake, which is significantly impacted by the P-Δ effect. In this study, the influence of the P-Δ effect on the probabilistic characteristics of residual displacement of bridge structure was quantificationally investigated based on a series of nonlinear time-history analysis. The bridge structure was idealized as the single-degree-of-freedom (SDOF) system and the hysteretic behaviour was represented by the improved Bouc-Wen model. The statistic analysis was implemented based on the inelastic dynamic responses of the SDOF system under 69 selected earthquake records. The results show that the P-Δ effect has significant impact on the residual displacement, especially for systems with large stability factor and/or small post-yield stiffness ratio and yield strength.

Abstract: With the bridge maintenance reinforced gradual increase in demand, the maintenance and repair of bridges and related facilities need to spend a lot of money. And the bridge of the limit line, weight limit, demolition and reconstruction measures will have a significant impact on traffic. Therefore, bridge maintenance decisions had become a problem faced by the facilities management department. In the case of limited funds, how can we determine the order of bridge repair and reinforcement, take the maintenance of the extent to which the urgent need for a systematic, efficient and practical method to develop optimal bridge maintenance and repair strategies to ensure that high-risk bridge timely conservation maintenance. This paper proposes a method of bridge maintenance and repair ranking The paper analyze a multivariate method, get result of multivariate, and verify the feasibility of the approach by using an example.

Abstract: A finite element model of an existing reinforced concrete arch bridge was established. The reliability index was investigated based on the PDF module in ANSYS software. Taking the maximum concrete stress and tendon stress as limit state, the limit state functions of main arch, upright column and deck are established respectively. There are taken as series system to study the bridge system reliability according to the structural characteristics of reinforced concrete arch bridge. The lowest reliability index superstructure is selected as the whole structure reliability index. Based on JC method and made-up MATLAB program, the reliability index of the example bridge is calculated.

Abstract: For layout space in the limited land resources and improving the utilization efficiency of urban transportation bridge and traffic conditions, in this paper, according to the request of four lanes of roof, two-way urban light rail traffic in the box, considering the requirements of pipeline layout, water supply and drainage, and fire escape, lighting, ventilated at the same time, based on the existing related specification, give full play to the characteristics of the concrete box girder, preliminarily design out of the single box three rooms inclined web box girder for double-deck traffic of urban bridge, in order to provide the reference design.

Abstract: To get the ideal cable forces of the arch bridge with spatial oblique cables,Rigid Support Continuous Beam Method and Rigid Suspender Method are discussed.The results show that the former is unsuitable for the spatial structure with smaller horizontal stiffness,and the latter does not consider the elastic deformations of the cables.An improved cable force optimization method is provided,which takes Rigid Suspender Method as the initial stage to obtain initial cable forces and takes Influence Matrix Method as the subsequent stage for cable force increments.The method by test is proved to be effective to spatial structure and nonlinear structure with spatial cables.

Abstract: The problem of form-finding for the suspended cable is actually the problem of determining all key points coordinates on main cable, which are by equilibrium relation on the horizontal force, main cable sagitta and lifting point force under the precondition of determining the endpoints boundary conditions of cable segment. According from the static equilibrium relationship of cable element, based on the analysis of its analytical solution process, in this paper, the cable elements are divided into two types in accordance withthe vertical distribution load along the arc length and along the string length , the corresponding shape curve of cable element is the parabola and the catenary, and with parabolic results as its initial value for the iteration of nonlinear solution, then cable element eventually converge for the catenary. And based on the exact coordinates results ,the calculation method of the length without stress is presented,and compiled corresponding computational procedures. By comparing the results of form-finding and the cable-length in non-stress according to program compiled and the results from the finite element software and the measured value of Aizhai suspension bridge, compared with the nonlinear finite element method,it confirmed the method requireing smaller dividing element density, the convergence speed is quicker and the results can ensure the precision.

Abstract: At present, among the methods of cable force measurement, the frequency method is applied extensively for its mature theory and rapid and repeated operation procedure. Based on the theory of frequency method measurement, it generally uses the numerical method with beam element to analysis the parameters of cables under the given conditions. However, the conventional beam element is not able to simulate the bending stiffness in beams section. Therefore, it turns to degenerated beam element to simulate cables and the results agree well with the results based on beam element and formulas calculation, and it provides theoretical basis for the later cable force testing system.

Abstract: Based on the Jiujiang Bridge Structural Health Monitoring System, lots of data of cable tension and temperature have been acquired. The preliminary analysis of the cable tension and the corresponding temperature shows that there is a long-term growth trend for the cable tension, and exists a certain correlation between the cable tension and the temperature. Using linear fitting method, the growth trend term of the cable tension and the correlation between the cable tension and the temperature of the typical cable are analyzed rationally. By getting rid of the long-term growth trend term and the influence of temperature for the cable tension, the early warning limit of the cable tension state evaluation is determined.