The Bearing Capacity Assessment And The Reliability Analysis Of Long-span Special-shaped Pedestrian Arch Bridge

With the rapid increase of traffic pressure in China and the contradiction between people and vehicles gradually prominent,the pedestrian bridge as a three-dimensional,efficient solution has been widely used.And the graceful pedestrian bridge can add some color to the urban landscape.The shape of the pedestrian arch bridge is changeable,and it is very suitable to use in urban long-span pedestrian bridge.The pedestrian bridge is related to the safety of pedestrians and undercrossing vehicles in the city,and the safety,applicability and durability of its structure are vital important.Therefore,we should pay more attention to the bearing capacity and working performance of the long-span pedestrian bridge that has been built.This paper takes a long-span profiled pedestrian arch bridge as the engineering background,and it makes a reasonable judgement to the actual bearing capacity and working performance of the bridge by using static and dynamic load test,modal parameter identification,the bearing capacity assessment and reliability analysis under the normal usage limitation state.This paper aims to provide scientific and effective judgment methods for similar engineering problems.The MIDAS/Civil finite element model was established to analyze the structure.Control sections are determined according to the most adverse loading conditions.This paper uses static load test to observe the deflection and strain of arch rib and main beam,and to test the cable force increment of the hanger rod.Finally,we can draw the following conclusions through data analysis: the overall strength and stiffness of the bridge meet the specification requirement,the bridge is in a flexible working state and the bearing capacity of the bridge meets the design requirements.This paper establishes the ANSYS finite element model of the structure and analyzes the natural vibration frequency and vibration mode of the structure.Through modal test,we use EFDD method in test software to identify modal parameters,and we also use the peak method and the data-driven stochastic subspace method of MATLAB program to recognize the test signal.Through comparative analysis,we can get the most credible modal parameters.Through the identified structural natural frequency,this paper uses the finite element model modified of the response surface method to modify the ANSYS finite element model of the structure,obtaining the modified model in line with the actual situation of the structure,which is used for structural reliability analysis in chapter five.The paper uses PDS technology of ANSYS software to analyze the reliability of the pedestrian arch bridge,and it draws a conclusion that the reliability of the pedestrian arch bridge in the limitation state of normal usage meets the standard requirements.