Xiao Lin Yu

Parameter Sensitivity Analysis of Vertical Deflection for Long-Span Continuous Rigid-Frame Bridge

The excessive long-term deflections of a long span continuous girder bridge may induce vehicles to move unsafely and hazard to the bridge operation, thus to limit the development of this bridge type. In this paper the main parameters influencing the long-term deflections of a continuous rigid-frame bridge, such as pre-stressed losses, mass distribution of the box girder and Young’s modules of concrete etc., were investigated. With the establishment of the finite element model of a real bridge and the premise of describing mechanism of each parameter, detailed parameter sensitivity analysis of long-term deflections were carried out with numerical simulation method. The results of this study may help to understand the main mechanism about the long-term deflection of continuous rigid-frame bridge and provide some reference for the wide use of this type of bridges.

A Least Square Support Vector Machine Approach Based on Uniform Design Method for Structural Reliability Analysis

Since the performance functions of large complex structures can not be expressed explicitly in the process of reliability analysis, support vector machines (SVM) with good ability of generalization are used as the response surface function based on the small training samples. The uniform design method was adopted in selecting the training data. The least support vector machines (LS-SVM) were used to find the support vectors. The limit state function was expressed by the LS-SVM regression. Reliability analysis was then performed by the usual reliability method (e.g., the first-order reliability method, the second-order reliability method or Monte Carlo) on the response surface. The results of calculations of numerical examples and a typical cable-stayed bridge show that LS-SVM using the uniform design method can well approximate the real response of complex structures which has a good efficiency and accuracy and can be applied in complex structures.

Full-Scale Model Test for Anchorage Zone of Pylon of Cable-Stayed Bridge

In this paper, the construction technology for main pylon of cable-stayed bridge is researched through test of full-scale model of anchorage zone of pylon of Guangzhou Bridge. Stress distribution and deformation condition of model under prestressed tendons and cable force are analyzed. Numerical simulation on this anchorage zone model is carried out. By comparing FEM results to the test results, some important conclusions are drawn out and give some advices to the optimum design of the bridge pylon. Parts of the achievements have been applied to actual bridge work and obtained successful engineering experience.

Study on Dynamic Behavior and Seismic Performance of Cable-Stayed Bridge with Different Auxiliary Pier Positions

Choosing the Panzhong Bridge of the Guangzhongjiang highway as the research object, the dynamic behavior and seismic performance of cable-stayed bridge with different auxiliary pier positions were studied. The results show that the position of the auxiliary pier has limited influence on dynamic behavior. Under the action of the earthquake, auxiliary pier restricts the deformation of side span effectively and reduces the bending moment at bottom of the pile caps.

Study on the Prestressed Arrangement in Cable-Pylon Anchorage Zone of Cable-Stayed Bridge

According to the study on the practical Chaolianxijiang bridge, the stress state of cable-pylon anchorage zone of cable-stayed bridge under two kinds of prestressed arrangements (that is, U-shaped arrangement and parallel arrangement) were calculated and compared. The results suggested that parallel prestressed arrangement could avoid the difficulty caused by other arrangements in the construction. Parallel prestressed arrangement with clear concept, simple structure, clear stress and small amount of work is suitable for the thick walled cable-pylon.

The Reliability Sensitivity Analysis of Composite Beam Cable-Stayed Bridge during Construction Stage

A 10DOF composite beam element was developed, which had taken the interface slip effect and geometric nonlinearity into consideration. The method to obtain structural response gradients of composite beam was analyzed, meanwhile the reliability index was achieved by using the FORM method and on this basis, and the sensitivity of random variable parameters could be finished. At last the control of target elevation was took as state performance function, the sensitivity analysis of random variable parameters which might have an effect on the elevation control reliability was effectively completed, and some useful conclusions which were be beneficial to construction control of composite beam cable-stayed bridge obtained.

Large Span Continuous Girder Bridge Jacking Steel Hoop Stress Analysis

Bridge jacking technology is a new technology in the field of old bridge reconstruction. Based on the case of Beijiang River Bridge jacking of Fokai highway extension engineering, the paper designs steel hoop as jacking force platform. By using ANSYS software, it makes finite element analysis and calculation as well as compares with the experimental data to check the reliability of models. In addition, the paper puts forward the optimization methods of steel hoop based on the analysis of the results. At last, it achieves the objective of saving materials and simplifying installation and use as well as provides guidance for the similar engineering.

Application of Improved Response Surface Method Based on Kriging Model to Structural Reliability Analysis

The paper aims to do the reliability analysis by the Kriging model. Its excellent approximating capability is taken into consideration, which is superior to traditional response surface method. An improved response surface method has been proposed based on the Kriging model. The seismic response of structure is characterized by nonlinear and complexity, more difficulties in the reliability analysis have been found as well. Compared to other methods of reliability analysis, the response surface method is regarded as an effective way to solve such problems. Thus the improved response surface method based on the Kriging is utilized to analyze the structural first excursion dynamic reliability problem under random seismic excitation. Meanwhile, the influence on the reliability due to the randomness of structural parameters is analyzed.

Construction Monitoring of Dukeng Bridge

In this paper, a continuous beam arch bridge Dukeng bridge was introduced. Its construction process and its construction monitoring were discussed. In the construction process, the elevations of the box girders measured were closer to the values theoretical calculated. Though construction monitoring, although there were some construction errors, they can be timely adjusted and rectified and the main beam was ensure to smoothly closure.

Ultimate Bearing Capacity Analysis of Concrete Filled Steel Tubular Arch Considering the Initial Defects’ Influence

In the CFST arch bridge construction process, for the reasons of arch axis deviation as prefabricated or constructed, the bearing capacity of arch-rib decreased. This paper considers material and geometric non-linear double factors, calculates the arch-rib ultimate bearing capacity of a CFST arch/continuous beam bridge with defects of arch axis deviation and steel yield stress decrease because of heat treatment, obtain the influence of defects to arch bearing capacity.