Flexible fence has been used widely to against rockfall impact and attracted a lot attention from engineers and researchers. In order to better understand utilization of sand -pack for this structure and to clarify application ability of sand-pack cushion, this research was done dealing with the fence. Sand -packs covering the fence were taken into account for a numerical study by using finite element approach. The numerical model was validated very well through a comparison with fundamental experiment. The effects of sand -pack on structural characteristics were clearly shown. It finally became clear that impact absorbing ability of sand -pack and redistribution of impact load as absorbing element function for rockfall fence.

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Our mechanical and civil engineers should find the methods and guidance on how to design structures to resist various accidental events and hostile acts. This study is to know experimentally a local failure mode of thin steel plates due to contact explosion. The authors previously reported the spalling and perforating limit thicknesses of SS400 steel plate subjected to contact and close-in explosions. In this explosive tests, SUS304 stainless steel plates with different thicknesses are tested under various conditions. From test results, a perforating limit line for contact explosion is formulated.

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This study presents numerical simulation s on the characteristics of impulsive load of flowing water by using the MPS method with a turbulent flow model. In order to improve an accuracy of the numerical simulation, a modeling of whole channel test bed and a turbulent flow model are taken in to account in the numerical model. The improvements of the numerical mode l enhanced the reproduction of the complicated flow and energy loss of the water, as compared to the previous simulation the authors conducted. The proposed model showed good agreement with the test data, regardless of the channel angle. Based on the numerical analysis, the occurrence mechanism of the impulsive fluid load and the role of turbulent flow model were discussed.

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This thesis was discussed about the method of evaluating the damages for the highway steel bridge RC slabs of Kansai region. First, the grouping of RC slabs is carried out paying attention to the specifications for the construction annual. Second, it analyzed about the influence of various factors which have on each evaluating point. The degradation of RC slab end which was es-pecially built before 1979 and by which undersurface increase thickness is not carried out is remarkable. Third, it analyzed paying attention to the relation between the period after upper surface increase thickness construction, and each evaluating point. The RC slab in which upper surface increase thickness not less than 60 mm thickness was constructed showed clearly that it has 15 years or more of life to re-construction. Fourth, the trial calculation was made about degradation prediction based on these analysis.

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In this study, stiffening effects and fatigue resistance of RC slabs with shear reinforcement are investigated. Wheel running fatigue tests were carried out and the stiffening effects and fatigue resistance were evaluated. The test results showed that the fatigue resistance of the shear reinforced specimens with no damages increased 39.7 times as large as that of the unreinforced one. In addition, for the damaged specimen to which both top and bottom surface reinforcements were applied, the stiffening effect was observed 15.7 times as large as that of the specimen with damage. Consequently, shear reinforcement of RC slabs is effective against restrain occurrence of diagonal and horizontal cracking, and also spalling of top increase thickness reinforcement and the fatigue resistance is successfully increased.

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This experimental study evaluates two different reinforcing methods of strengthening RC-slabs. One is Carbon Fiber Reinforced Polymer-Grid (CFRP-Grid) method and the other is steel reinforce bar (rebar) method. Both reinforcements are applied with PCM and/or epoxy adhesive to bottom surfaces of RC-slabs. The fatigue resistances of the reinforced RC-slab specimens were examined using the load-carrying wheel tracking machine. Five types of RC-slab specimens were investigated and the results were compared with each other in terms of equivalent number of cycles, crack patterns and deflection at the center. As results, the specimen reinforced with CFRP-grid applied with epoxy adhesive showed the highest fatigue resistance.

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There is an overlaid method as one of the main reinforcement method for road bridge decks. In this method, the steel fiber reinforced concrete (SFRC) is generally used, but there is poor workability with SFRC. Then methyl methacrylate (MMA) concrete is proposed as alternate material of SFRC. But there are few data of MMA concrete used as overlaid material.
The authors prepared RC beam overlaid with MMA concrete and evaluated the reinforcement effect by a static loading test in this research. Moreover, examination in FEM analysis was also advanced.

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Adhesive method is a kind of gluing technology to apply damaged upper layer of RC-slabs by using cement mortar and adhesives. Fatigue resistance was evaluated for new developed method using 2 types of ultra-rapid fiber reinforced cement mortar (URFCM) and traditional method using ultra-rapid cement mortar (URCM). This paper showed that URFCM method was superior to URCM method in fatigue durability. The URFCM method did not show peeling off of interfacial layer and crack. In the case of URFCM method, 2 cycles repair showed enough fatigue durability. On the other hands, URCM method needed more than 3 cycles repair.

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In this paper a combine method to aim shortening of operation time and improvement of calculated accuracy is developed by reconciling harmonic analytical method to point matching method. As a basic example of multi-layer square slab subjected to uniformly distributed loading, numerical results obtained from three methods are respectively compared with. Next displacements and stresses by this method and usual point matching method are calculated respectively in the case of multi-layer slab with released portion. Furthermore mimetic influence lines related to bond stresses on interface at neighbor of released region in actual slab strengthened by carbon sheet is calculated in consideration of variations with respect to magnitude of wheel running load nearly presumed by introduce of random number.

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This paper investigates the temperature distribution of four steel-concrete composite decks and one RC deck under freeze-thaw temperature by laboratory experiment and finite element analysis. Differences of temperature distribution among five decks are discussed, and the comparison between experiment and analysis is made. There is a good agreement between analysis and experiment, and it is found that differences arise due to structural details. Furthermore, the amount of freeze-thaw in concrete is estimated for two simplified cases, and it is found that environmental conditions affect the temperature distribution inside the decks together with structural details.

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This study presented a new sidewalk widening method using FRP for narrow highway bridges. To validate the load carrying performance, both a static loading test and 3D-FEA of a full-scale slab specimen were conducted focusing on vertical crowd load on overhang part and horizontal load on protective fence for a pedestrian and a bicycle. The result revealed that (1) the proposed widening slab sufficiently ensured load carrying capacity against design load; almost 5 times and 2 times of design loads for vertical and horizontal loads respectively, and (2) load carrying capacity could be designed by considering stress distibution characteristics.

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In Japan, as so many highway bridges constructed in the last four decades are getting old, the maintenance of these bridges has become the most serious problem to extend their service lives with appropriate rehabilitation works. In concerning with bridge slabs, replacement of severely deteriorated slabs is a recent trend to minimize the LCC. The authors have developed a rationalized connection for precast PC slab panels that can shorten the construction period by reducing the joint width accompanying with decrease of concrete volume. This paper reports a series of experimental results to find out the smallest joint width by using anchoring nuts at the ends of reinforcements to be jointed. Also, durability of the joint is checked through a fatigue test.

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For highway bridge slabs with significant deterioration, replacing work is generally taken to recover a structural performance; in accordance with a current design specification, however, slab thickness is often forced to be increased, that requires the reinforcement of substructures. Here, application a precast PC slab was proposed because it did not require the thickness increasing and has high durability. In this study a narrow joint structure were proposed and its structure durability was verified with wheel load running test. The result indicated that the joint structure ensured sufficient durability against wheel load both under dry environment and water environment.

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