| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2001: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 2000: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Research Abstract |
Reducing the amount of welding in fabrication is effective to decrease the construction cost of steel bridges. To achieve this, steel mill products (pipes, rolled H and so on) and cold formed steel sections are advantageous. At the same time. When steel sections is filled with concrete, it restricts the buckling and improves strength, Based on these ideas, five new types of composite bridges were proposed and their structural behaviors and design methods were studied analytically and experimentally. (1) The cable-stayed bridge with two edge girders of concrete filled pipes was proposed. It was found by analyses that this bridge was feasible in the long span, and the tower height could be 20% lower than the conventional cable-stayed bridge with steel box girder. (2) The composite tower with concrete filled steel sections for suspension and cable-stayed bridges was proposed. It was found by static and seismic analyses that this new composite tower was feasible, economical and rational. (3) The suspended arch bridge was proposed and a pedestrian bridge with a 200m span was designed. The cables and arch ribs shared the load resistance. The new bridge had higher rigidity than the conventional suspension bridge and the compression in arch rib was smaller than in the conventional steel arch bridge. (4) The composite bridge using rolled H-girders was proposed, The new bridge worked as the normal composite girder in the span center but the steel girder was covered with concrete in the intermediate supports. A trial design was conducted, which showed that the new composite girder had a superior economic advantage and the applicable span length was expanded. (5) The partially encased girder was proposed. The steel I-girder in the intermediate supports, the part in between the flanges and the web ws filled with concrete. Experiments were conducted and the bending strength and shear strength were more than double those of the bare steel I-girder.
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