Researcher List

Department of Civil Engineering and Urban Design

Landscape Analysis of Bamboo Groves by Using Geo-information Technology

Spatial Analysis on Network
Spatial Analysis on Network

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Recently, numerous formerly well-groomed bamboo groves have become neglected, and are spreading toward hillsides in an uncontrolled manner, which has caused hillside landscape destruction. The expected functions of bamboo groves have evolved so that such areas have now become elements of regional landscapes. To create and maintain beautiful landscapes along hillsides, the care and use of bamboo groves must be integrated in the locales where they coexist with people.

We are studying the Nishiyama area of Kyoto Prefecture, and analyzing the transition of the distribution of bamboo groves, using old editions of topographical maps, and satellite images with geo-information technology. We calculate the changes in the area of bamboo groves, and verify the alterations in land use by accurately classifying the type and extent of various types of bamboo grove that are growing.

We are also investigating these bamboo groves as landscape resources. The Arashiyama-Sagano district in the Nishiyama area was selected as a case study area because many locations are beautiful and historical landscapes, and tourist attractions, including bamboo groves. Our networked spatial and visibility analysis techniques verify that the bamboo groves in the Arashiyama-Sagano district are an important tourist attraction and a resource that needs care and protection.

Land Use Analyses(Uses for Unused Factory Sites and Problems in Residential-Industrial Areas Case study of Amagasaki City)

We are clarifying ways to make use of unused factory sites, and investigating the difference in the scale of factory sites between inland and coastal areas in an industrial Japanese city. Most sites for small and medium-sized factories have been reused for factories and houses, and sites with suitable traffic infrastructure have been commercialized. The trends determined from site distributions agree well with the results of our analysis that is based on the theory of two-dimensional random distribution. In a residential-industrial area, residents feel uneasy about noise pollution from factories and traffic. Factory operators strongly want to continue operating in such areas, but many residents are uncomfortable with their presence.

The Database and the Routing System for Pedestrian in Public Space

Visual Design Lab

The application of Universal Design in urban spaces has been discussed for some time, to address the issues in Japan brought about by an aging society. Our study proposes a formula for calculating routes in urban public spaces, depending on user requirements. We also explore laser scanning methods for acquiring detailed data for road configuration measurements, particularly in an Osaka district.

Risk assessment for steel bridges rested on risk based engineering

In our structural mechanics laboratory, we are developing a new retrofitting and strengthening method for the important job of maintaining steel truss bridges, mainly by adjusting the axial forces of damaged members to prevent their failure and bridge collapse. We have verified our method by taking working conditions and procedures into consideration. In addition, we suggest, examine, and compare new measures for preventive maintenance of steel truss bridges, to develop the most effective and practical techniques. To ensure the safety and reliability of such bridges, we examine the redundancy of the structural system as a whole, and study critical members that may fracture, using our method that is based on risk assessment. The flow of our procedures is shown in the figure, which illustrates the use of risk assessment in engineering and construction.

Static and fatigue behaviors of shear studs in double composite twin I-girder bridge

Static and fatigue behaviors of shear studs in double composite twin I-girder bridge

The steel-concrete double composite twin I-girder bridge is an important type of bridge that has two concrete slabs at the upper and lower surfaces of the girder, but only in the region of the intermediate supports. This design effectively reduces construction cost and offers other advantages, but the composite action and optimal design method when headed studs are welded to both the lower flange plate and web plate at the lower concrete slab need further clarification. Therefore, we are conducting static and fatigue push-out tests of such studs, which are arranged both vertically and horizontally.

Improvement of Seismic Performance of Concrete Structures

Half Prefabricated Prestressed Reinforced Column
Half Prefabricated Prestressed Reinforced Column

It is well known that concrete shear resistance deteriorates significantly due to the inelastic deformation reversals that are experienced during large earthquakes. One of the solutions to this problem is to use prestressing technology, combined with prefabrication of members, because the introduced prestress increases the shear capacity of concrete, and decreases its residual deformation after earthquakes. In addition, prefabrication of members helps to guarantee the quality of construction.
We investigate various methods for improving seismic performances of concrete structures, both experimentally and analytically.

Loading Capacity of RC and PC Beams Damaged by Alkali Silica Reaction

Non destructive teat of concrete
Non destructive teat of concrete

Instances of reinforcing steel fracture in concrete structures damaged by alkali-silica reaction (ASR) have been discovered recently. Japan currently counts some 30 ASR-damaged structures, including highway and railroad bridges, confirmed to have steel bar fractures. Fractured reinforcing steel bars were found at some corners of the hoop reinforcements. It is assumed that reinforcing steel bars were fractured on account of the expansion pressure resulting from ASR. In this study, RC and PC beams, which are damaged by ASR and have steel bar fractures, are tested to valuate the loading capacity. In addition, deteriorated concrete is evaluated using non-destructive tests. From these results, Flexural and Shear Capacity of RC and PC beams, which have steel bar fractures and deteriorated concrete due to ASR are evaluated.

Hydrological index for occurrence of downpour-induced deep-seated landslides in southern Nara and its utilization

Analyzing a deep-seated landslide that occurred in the southern Nara region
Analyzing a deep-seated landslide that occurred in the southern Nara region

This study analyzed the ten deep-seated landslides that occurred in the southern Nara region (the villages of Totsukawa, Nosegawa and Tenkawa and the former village of Oto in Yoshino, Nara) in 2011 by using the Aoki?Hioki tank model and confirmed that the model is capable of qualitatively capturing hydraulic phenomena in the region. This study proposes a hydrological index that can be used to predict and monitor hydraulic phenomena at deep-seated landslide sites in the region and reports that monitoring results obtained by use of that index are proving useful for the local government (Totsukawa municipal government, Yoshino, Nara). The study also points out that a high level of alertness about deep-seated landslide risk is necessary when a rainfall of about 10 to 30 millimeters per hour has continued for a long period of time and cumulative weekly rainfall has exceeded 800 mm.

Restoration of the Yodo River Eco-system

One focus of our research is on the hydraulic and hydrologic properties of the habitat of flora and fauna in the Yodo River and its surrounding area. The hydraulic topic focuses on restoration of habitat for the Japanese bitterling, Acheilognathus Longipinnis, a small fish living in the Yodo River. The estimation of flood disturbance required for the life history of the fish is examined along the Akagawa sand bar and Shirokita Embayments, by monitoring the return periods of the magnitude of the flood discharge, water surface elevations, and the magnitude and distribution of water parameters such as velocity and shear velocity. The hydrologic topic is concerned with the restoration of wetlands for Phragmites australis reeds, an extensive and ancient habitat in Udono, the middle part of the lower reach of the Yodo River. The habitat of reeds is threatened due to the lowering of the water surface by more than 5 meters over the last 100 years. The government has constructed a conveyance channel for water pumped up from the Yodo River, and our laboratory is studying the water distribution system, considering the leakage of water to lower soil layers, and the geographical and geological properties of the field.

Identification of Flood-Related Sedimentary Features for Floodplain Management

Contours of resistivity superimposed on to an old topographical map, published in 1921 by Kyoto City
Contours of resistivity superimposed on to an old topographical map, published in 1921 by Kyoto City

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Flood risk management is of increased importance, in view of enhancement of the extreme value in meteorological events due to projected global warming and of ever diversifying use of flood-plains. This study addresses procedures by which to identify flood-related sedimentary features and incorporate them into community based hazard mapping. The topics discussed include the following: high-resolution determination technique of breaching-induced topographical changes by digital photo-theodolite surveying; applications of non- destructive geophysical explorations to identifying subsurface flood-related features; and GIS-based updating of geographical classification maps in flood-prone areas that may have relevance toward sustainable land-use planning.