Soseibashi, an arch-shaped bridge in Sapporo, was dismantled for reconstruction of infrastructure in city center of Sapporo. Through the literature and in-situ survey of Soseibashi, it was found that the bridge had a unique structural system same as that of Nihonbashi, well known bridge as a national treasure in Tokyo. This paper introduces the characteristics of those bridges and the technical improvement in design and construction methods for arch-shaped bridge as well as their historical background.

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After World War 2, bridge technology in Japan has been developed rapidly with high economic growth. Consequently, it is thought that important bridges exist which denote bridge technology development. However, too many bridges were constructed to be found their value. Therefore in this research, the genealogy chart of bridges constructed at the high economic growth period was made through the document investigation and the hearing investigation, and bridges that had played an important role in that was specified, and the characteristic at the high economic growth period as the background of the bridge design was organized. As a result, 28 important bridges were specified, and it is clarified that there were “The engineer's challenge” and “Overcame of the construction condition” in the background of the bridge development. Additionally, it was confirmed that there were conversion periods in the design system and the design subject in 1960's.

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KORAKU-EN (GOKOH-EN) in Okayama was established in the GENROKU Era, 1689 as a Daimyo garden by Brigadier General Tsunamasa Ikeda-Matsudaira. The landscape of the KORAKU-EN is the space of lawn yard after Meiji revolution. The beginning of the garden, rice field was spread on the space and farmers work there and natural water was derived into the garden through the artificial canal. These facts are investigated and analyzed by using documents of the Ikeda families' archives of Okayama University. This paper discusses the fact of the usage of the rice fields of the garden historically.

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Yoshii Locks, being a prefecturally protected historic landmark, are the oldest remains in Japan, although its value has not been thoroughly acknowledged nationwide. The reason is the third old Minuma Tusenbori Canal Locks in Saitama Prefecture has been too excessively advertised as the oldest based on the wrong data, and also they has been located close to the Capital. In this paper, the fact that Yoshii Locks are the oldest remains is proved from the viewpoints of historiographical materials, nationwide survey of sluices and also authenticity of the locks themselves. That is to say, the historical value of the locks is described by combining their planner, Nagatada Tsuda who was a “gundai” of the fief of Okayama. And the authenticity of the locks is checked by the detailed examination of stonework.

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“The mazume-ishi method” is a kind of repair method for castle masonry walls, which is the method to replacing stone that fell from masonry walls. The case of engineering examination for evaluating the stable improvement effect of the masonry walls by this method is not found. In this study, the analysis by the distinct element method (DEM) was carried out on an actual castle stone masonry wall which was repaired by this method. The analytical model was made accurately based on the information of the back side of the stone masonry wall employing the radar exploration. As the result, it was confirmed that this method improves the stability of the masonry walls under static conditions or in an earthquake.

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Several castle masonry stone walls in Japan become too old for their sufficient stability and are in need of some preservation works. Furthermore, Kameyama Castle in Mie Prefecture was severely damaged by Mie-ken Tyubu Earthquake in April, 2007. So, it is important to investigate the stability and dynamic property of stone wall for the preservation works of it. In this report, distinct element method (DEM) was employed to investigate the seismic behaviors of stone wall by way of example of Nagoya Castle. The main results from DEM analysis are as follows; the method for modeling of the stone walls has influence on their dynamic behavior, also the mutual relationship of engineering properties between the stone wall and the back fill soil has large effects on the stability under the seismic loading.

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As for the survey of Civil Engineering Heritage in Japan, it was started since 1989 for the modernized structures constructed after the Meiji Restoration, while it has been nothing done for the older traditional structures before the Restoration. The reason was quite simple. At that time, the modernized structures were considered in the critical situation of demolition and replacement so that it must have been taken preference over the older traditional structures constructed before the Restoration. We also considered those older structures had been survived more than 130 years, therefore they might have been preserved by the local people. However it was mistaken. We had seen so many cases that the older traditional structures were destroyed without any hesitation, because their value as historical monument were not defined and authorized at all. That is the reason why the authors have started this project.
The modernized structures and the older traditional structures are both civil engineering heritage, but there is a large difference among them especially concerning the condition of preservation. In the case of the modernized ones, it is quite necessary to survive almost whole part of structures when they are constructed. But, in the case of the older ones, such kind of restriction is almost nonsense, because the majority of surviving structures have been repaired and renovated up to nowadays.
In this paper, the authors try to show a proposal concerning “how to classify the degree of preservation of the older traditional structures before the Restoration, that is, constructed in the Edo period and prior to that” Before this trial, we have been done a survey covering the whole country. They are divided into three parts. The first one is the previous document study using, and the second one is the census survey for all the municipalities. The third one is more individual survey by limiting the objects. The proposal is made based on such experience

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The cooperation of self-help, regional-help and administrative-support is the effective step to deal with natural disasters. To live in the area where is likely to damaged by disaster, it is important that each of stakeholders (i.e. individuals, local communities, and administrative authorities) work in close cooperation with each other, and take measures to prevent disasters in their own role. However, the local communities collapsed today, and it is difficult to maintain the cooperation.
In this paper, we find out the way to overcome catastrophe, learned from the historical sayings of disasters in Shikoku region, Japan.

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During the first half of the Meiji Era, the raw silk industry developed in Naganoand the newly wheeled vehicles such as horse carriages increased gradually. To accommodate such wheeledvehicle traffic, the construction of new main roads were proposed., namely the construction plan of the seven new main highway lines were started in 1882 and the construction of another four main highways were started form 1888.
At that time these were most important large scale undertaking in the road administration of Nagano prefecture in Meiji Era. The various documents including route survey maps, drawings of bridges and specifications were made before construction works started. The private enterprise contracted to construct these works by competitive bidding.
In addition to this, the technical report of De Reijke on roads and bridges affected these construction works.
As new highway roads were constructed, the traffic density of horse carriages increased largely and the raw silk industry developed rapidly. There is a close connection between these two events.

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