دانلود رایگان مقاله ظرفیت حمل بار تیر اهن با روزنه بازبینی در پل کامپوزیتی

Abstract

A severely corroded end cross-girder is found occasionally, while the girder is expected to play an important role under seismic loading. The prevention of the end cross-girder against corrosion is therefore crucial in the bridge maintenance. To this end, the present research aims at improving its inspectability by installing inspection holes in the end cross-girder. The influences of the holes on the load-carrying capacity are then studied, to be specific. It is revealed that the inspection holes would reduce the load-carrying capacity considerably; the degree of the influence varies with the shape, the position and the size of the hole. Six reinforcement methods are therefore considered. Full recovery of the capacity turns out to be possible if the inspection hole is the same size as that of the standard opening (manhole) in a steel bridge structure, while it is not an easy task when the inspection hole is larger.

7. Concluding remarks

The end cross-girder plays a significant role against seismic loading, while it is located where corrosion tends to occur easily and the inspection is not necessarily easy to conduct. Against this background, the end cross-girder with inspection holes were studied. In short, the load-carrying capacity of the end cross-girder under horizontal load was investigated by the 3-D nonlinear finite element analysis. The following observations were made from the present study: (1) The inspection hole reduces the load-carrying capacity signifi- cantly: the larger the hole is, the greater the reduction becomes. (2) The influence of the inspection hole on the load-carrying capacity depends greatly on the horizontal position: as the hole approaches the center of the web, the reduction in the load-carrying capacity becomes larger. (3) Even though the loading condition is different, the standard reinforcements for a manhole help recover the load-carrying capacity of the end cross-girder with inspection holes. (4) For the reinforcement, the doubling is more effective than the stiffeners. (5) The standard plate thickness of the reinforcement for a manhole is sufficient. Further increase in the plate thickness does not improve the capacity. (6) When the size of the inspection hole is the same as that of the standard manhole, the doubling can recover the load-carrying capacity up to 90% of the original capacity. The combination of the doubling and the stiffener can achieve the almost full recovery. (7) For a larger inspection hole, even the combined reinforcement cannot recover the load-carrying capacity fully. Safety against seismic loading must be verified carefully.