Analysis of establishment of modern bridges technology based on a comprehensive survey of historical bridges

所有调查人员负责调查位于日本各地的历史现代桥梁，分为北海道、东北、中部、近海、四国和九州9个地区。他们调查了有关历史桥梁的记录和文献，并进行了实地调查。调查的桥梁仅限于第二次世界大战前明治时代建造的桥梁，根据格式记录了当前外观、尺寸、技术和设计特征的照片等数据。在桥梁数据较多的地区，从不同角度对桥梁数据进行了分析。可以收集到大量的数据，特别是关于桁架和拱桥的数据，尽管由于更换的原因，关于悬索桥的数据很少。许多梁桥主要采用主梁系统的事实表明，当时的设计者对新娘基础没有信心。值得注意的是，大多数拱桥都是罗塞桥，许多钢拱桥都采用系杆拱桥体系。

All investigators took charge of investigation of historical modern bridges located in each parts of Japan divided into 9 areas : Hokkaido, Touhoku, Chubu, Kinki, Shikoku, and Kyusyuu. They investigated records and documents on the historical bridges and conducted field investigation. The investigated bridges were restricted to bridges constructed from the Meiji era before World War II.Data such as photos of current appearance, dimensions, technical and designing characteristics were recorded according to a format. In areas where a lot of bridge data were available, the bridge data were analyzed from various points of view. A lot of data could be collected, especially on truss and arch bridges, although data on suspension bridges is hardly available because of replacement.The fact that the girder system was mainly adpted in many girder bridges shows that designers of those days had no confidence in bride foundations. it is interesting to note that most arch bridges are Rhose bridges, and that tied arch system was adopted in many steel arch bridges.