A system dynamics model is developed for simulation of disaster recovery process of infrastructure systems with detailed consideration of effects of interdependency among infrastructures. The disaster recovery process of the infrastructure system in the Tokyo metropolitan area, where the infrastructures are highly interdependent, from extensive earthquake damage is simulated using the model. Delay of the recovery caused by dysfunction of telecommunications, electric power, and transport is calculated quantitatively by the system dynamics simulation.

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 This paper presents a new analysis method of stress distribution for a steel member multilayered CFRP plates under bending based on semi-analytical approach. In this method, strains in each layer are considered as state variables in the first-order simultaneous differential equations derived from sectional force equilibriums in infinitesimal regions. A general solution for strain is numerically calculated by the eigenvalue analysis of a system matrix formulated from the differential equations. Unknown coefficients in the general solution are determined from continuous and boundary conditions for strains in each layer. The proposed method was validated by a comparison with analytical solutions and finite element analysis. The comparison confirmed that the proposed method included conventional analytical solutions and facilitated analysis of stress distributions on the steel member multilayered CFRP plates under bending.

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 This paper proposes "functional fragility curves" for a production facility of industrial sectors, which represent conditional probabilities of reduction of production capacities given a ground motion. This is an extension of the method of fragility curves for structural vulnerability. The present paper conducts a questionnaire survey regarding economic impacts on business activities of firms after the 2004 Niigata Chuetsu earthquake and estimates the functional fragility curves by using the data. The estimation is conducted for different industrial sectors and the results imply that functional fragility curves are different between sectors. The information of functional fragility curves in this paper are helpful for conducting quick estimation of economic impacts on business sectors in case of large scale earthquake. In addition, the functional fragility curves can be used by individual firms for understanding the potential impacts of future disasters on their businesses and preparing countermeasures for the risk such as business continuity plan (BCP).

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 This paper describes the results of shaking table tests and effective stress analyses to investigate effect of seismic reinforcement for gravity type quay walls using ground anchors. As a result, the following conclusions are obtained. 1) Caisson displacement is constrained with the ground anchors due to the tensile force. 2) Dynamic behavior of quay walls with ground anchors is not affected by the difference of rubble mound layer thickness. 3) The relationship of the ground anchors between the tensile force and the elongation shows a hysteresis loop. 4) Effect of the ground anchors is confirmed by the analyses considering of both non-linear characteristic of the sand and the ground anchors.

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 In this paper, a solution of six-order differential equation for steel plate strengthened with CFRP plates under uni-axial loading, high-precision solution, is given. In the previous paper, second-order and forth-order differential equations for steel-CFRP system were approximately solved to give the stress distribution. By the comparison of high-precision and approximate solutions, it was found that the stress distributions of both solutions were almost same. However, the share and normal stress in adhesive layer at the end of CFRP plate given by the approximate solution is slightly higher than that given by the highprecision solution. Finally, numerical analysis solution method that matches the high-precision solution was introduced by using eigenvalue analysis of the first order simultaneous differential equations.

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 Recently, it was found out by authors' numerical analysis that superior performance of CFT piers under unidirectional alternate loading is primarily attributed to a unique behavior that restrains the progress of local buckling deformations in steel tube. Herein, the validity of this behavior under more realistic seismic loads is examined experimentally by carrying out bi-directional shaking table test as well as bi-directional cyclic loading test. From the responses of strains and deformations measured in the cyclic loading test, it was observed that the axial compressive force acting on steel tube is mostly transmitted to the in-filled concrete by diaphragm as soon as local buckling deformation occurs in steel tube. This phenomenon slows down a progress of buckling deformations. Furthermore, under the cyclic loading subsequent to the occurrence of the local buckling, opening and closing of a major horizontal crack along with dilation in the in-filled concrete results in tensile stresses in a locally buckled steel tube. This tensile stresses remove the local buckling bulges by stretching them. From the shaking table test, a remarkable self-centering behavior was observed in CFT piers, although their hysteretic curves are not originoriented. The numerical analysis showed that the unique behavior of CFT piers to remove local buckling deformations occurred during the shaking table test. Therefore, this behavior might have some effect on the self-centering behavior of CFT piers.

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 In order to decrease the life cost of steel bridges, we propose to use hybrid stiffened plates of stainless steel plates stiffened with mild carbon steel ribs. The mechanical properties of stainless steels, however, differ from those of mild structural steel. The effect of those different properties on the ultimate strength of the hybrid plates should be clarified. This paper described analytical result on the ultimate compressive strength of the hybrid plates and found that the hybrid plates show almost same strength of ordinary stiffened steel plates. The analytical model used in the parametric analysis was validated with experimental results.

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 It is important for periodical inspection and evaluation of bridge substructures facing a danger from earthquake, wind or flood. One of the representative evaluation methods of bridge substructures is a percussion test. The percussion test is to measure a natural frequency obtained from free vibration of the bridge substructure after applying an impact force. The merit of this percussion test is easy, quick and possible to evaluate the performance of the structure quantitatively in the field. Conversely, this percussion test has portability and safety problems. Therefore, a new vibration measurement method with a small vibration exciter is presented in this paper. The proposed method was verified to measure a natural frequency of railway bridge substructures.

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 The accuracy of fatigue crack propagation analysis for surface crack length of out-of-plane gusset joints under bending have not been investigated, although fatigue damage cases on the joints under bending have been reported. The purpose of this research is to investigate accuracy of the fatigue crack propagation analysis for the out-of-plane gusset joints under bending based on the authors previous fatigue tests. There was a good agreement between the propagation analysis results and the fatigue test results for depth crack length. However, the results have not shown a good agreement of the propagation analysis in evaluation of surface crack lengths when surface crack length becomes longer. A simple improvement method for evaluating the surface crack length by using crack aspect ratio obtained from experimental data including the authors fatigue tests was applied. As a result, it was shown an improvement in evaluation of longer surface crack length.

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 For the joints with metal-sprayed surfaces, hot-dip galvanized bolts are applied and such bolts are tightened by turn-of-nut method. However, it had been unclear how much axial force is induced into the bolts in the joints with metal-sprayed surfaces. To clarify the induced axial force of the bolts, we had carried out bolt-tightening tests. On the basis of above examinations, we had been proposed nut rotation angles in relation to different bolt size. In this paper, to confirm the induced axial force of the bolts, bolt-tightening tests were carried out using the proposed nut rotation angles. Considering bolt diameter, bolt length, coating thickness, induced axial forces and their relaxation, the applicable conditions of the proposed nut rotation angles were clarified.

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