THE SYNTHETIC RESEARCH ON CONSTRUCTION OF LARGE-SCALE WOODEN BRIDGE STRUCTURE

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The main purpose of this research is to set up a database that collects an enormous amount of information on timber bridges. The first-hand information are obtained from the systematic investigation into the actual circumstance of overseas timber bridge, by study of material properties of timbers produced in Japan and foreign countries. During establishing the database, the methods adopted for diagnosis and rehabilitation of timber bridge in various nations are compared to each other and analyzed. Finally, an indicator for the design and maintenance management of large scale timber bridges will be pres ented.During the research, great attention was paid to the material properties characteristic of timber. The properties effect the design of a timber bridge very much. For example, if the main structure of a timber bridge is made from wood possessing smaller specific gravity, the substructure could be properly designed in a rather smaller scale, too, since the deadweight of the bridge su … More perstructure is lighter. Such structure is very effective to proof against earthquake. In addition to, in case unfortunately, the bridge suffered from an earthquake, it could be repaired or removed in quite short time. From this viewpoint, such timber structure is comparatively more favorable than steel or concrete structure. Besides, taking into consideration of the specific gravity of timber, since its compressive and tensile strength are all five times stronger, its specific heat is about three times greater than steel, a bridge with timber main structure is also effective against fire. From the experience of Hanshin-Danji Great Earthquake and because earthquake frequently happens in our country, it is presupposed that timber bridge is promisingstructure in the future.Now, some interesting study programs and active research actions are still underway. The information related to internal and external timber bridges, material properties of various woods are exchanged. The techniques adopted in each timber structure own are studied.Diverse technologies, glued-laminated timber that might be applied to design and to construct large scale timber bridge in the future are investigated. The factors that are necessary and indispensable to construction of a large scale timber bridge are extracted. A numerically analytical method to study the specific material properties of timber is being developed. Less