Research On Key Structure Details Of Large-span Steel Bridges

Cable-beam anchorage, orthotropic steel bridge deck and integral joint are the key structures of large-span steel bridge during the design and manufacture. Because whose force features and fatigue performances are complicated, and where cracks are easily induced, the reliability of these details is directly related to the safe use of the entire bridge. The research of these details is the difficulty and the hotspot in the present bridge research.The purpose of this paper is to verify the reliability and the safety of the new structure. Their patterns of stress and fatigue performance were studied, and in a targeted manner to carry out structural optimization. Three major researches was carried out,â‘ through theoretical analysis and model testing, the force situation of a new cable-beam anchorage was analyzed under five load cases.â‘¡the fatigue stress and performance of the structural details in orthotropic steel bridge decks is researched, the optimization of the structure where the fatigue damage is most serious was conducted.â‘¢the fatigue structural problems of the integral joints in new structure were analyzed.The main research results are as follows.â‘ the reliability of this new anchorage used in design was verified. In the same time, its stress distribution, load transfer path and main control details were obtained.â‘¡the fatigue performance of the structural details and the impact of near and remote load was analyzed. The optimization of the structure details where the fatigue damage is most serious was conducted.â‘¢the fatigue S-N curves of a series of new structurure in the connection part of the integral joints and the bridge deck system were worked out, as well as the effects of main board thickness to the fatigue performance of welds in the connection on the diaphragm and the impact of secondary stress to the fatigue.The following points of innovation are included in this paper.(Dby a way combined theoretical analysis and model testing, the reliability of this new anchorage used in design was verified through contrasting and optimized anlysis. In the same time, its load transfer path and main control details were obtained.â‘¡based on the whole system and the local system first time, analyze the impact of the proximal and distal load to the stress of construction details of the orthotropic steel bridge panel. The fatigue performances of a variety of the structure details are summed up to consider manufacturing and construction, through the establishment of innovative optimization function, the rational distribution of the structure details in the intersection part among the vertical limb bottom flange and secondary beam or web of transverse beam was gained.â‘¢In allusion to the new structures emerging in the integral joints, their fatigue performance was gained firstly through the fatigue test, and through a new perspective point of view, the thickness coefficient of box element and secondary stress to research the fatigue problem.