The Report of Structure Characteristic of Existing Nielsen-Lohse Bridges

Abstract

The Nielsen bridge proposed by O.F.Nielsen(Sweden) in 1922 is formed that use of the cable on tensional hanger, and is constructed after 1967 in Japan. The Nielsen-Lohse bridge has the structure form of a parallel arch rib or a basket handle arch rib, and it shows the fine sight and good strength as a bridge. Many researches about the seismic performance of a steel bridge are made, and the seismic design method is becoming up. It is required to develop the method of raising the ultimate strength and the earthquake-proof performance about existing Nielsen-Lohse bridges. Especially, the basket handle arch type erected in three dimensions must investigate the relationship of between axial force and bending moment of arch rib member, and the influence of hanger as tension member to refine the performance under big earthquake. However, there is little research which investigated the performance on seismic load or ultimate strength behavior of the Nielsen-Lohse bridge. In this report, to decide the parameter for structural analysis, it shows the investigated result about the structure characteristic of the constructed Nielsen-Lohse bridges.