The Hanshin/Awaji Earthquake (Hyogo-ken Nanbu Earthquake) of January 17, 1995 caused destructive damage to highway bridges. Obviously this was the first experience to suffer such destructive damage since the 1923 Great Kanto Earthquake. Various tentative measures were taken for seismic design of repair and reconstruction of highway bridges which suffered damage due to the earthquake. This paper summarizes the damage feature of high way bridges and a series of actions taken for seismic design and seismic strengthening of highway bridges in about half year since the earthquake.

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First, definitions and classifications of composite constructions in the civil engineering field are described. Next, outline of the studies on them, which can be read from the papers mainly published for the last decade, are introduced. A brief review on each paper is done in accordance with the following terms: Shear connectors, elastic theories of composite beams and plates, inelastic behavior and design of composite girder bridges, composite decks, composite piers, mixed systems, and composite walls and shells.

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This paper presents the modal superposition method in the application of wave-induced response analysis of mat-like floating plates. This method separates the coupled hydroelastic problem into uncoupled usual hydrodynamic problem and structural dynamic problem by expanding the motion of the plate as a superposition of modal functions which include rigid-body motions and bending modes of the plate. Effects of important parameters such as wave period, direction of incident waves and plate rigidity on the response of the plate are discussed. Comparisons between the two-dimensional analytical solutions and the three-dimensional solutions are also made.

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When continuous (arc-welded) steel pipelines fail, they show different appearances of fracture depending on the type or process of loading owing to the ductile property of steel. Based on this fact, morphological observation was made on twelve failures in continuous steel pipelines that took place during the 1983 Nihonkai-chubu earthquake. The greater part of them appeared to have been caused by reciprocal (or dynamic) compression and tension, rather than by static (or permanent) ground displacement. The mechanism of dynamic ground motion associated with soil liquefaction, therefore, should be made clear in order to establish effective countermeasures for buried pipelines.

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This research is aiming at studying local stress and deformation and effect of asphalt pavement on fatigue behavior of structural details such as scallop of orthotropic steel deck. It consists of stress measurement on a actual bridge with orthotropic steel deck and finite element analysis for investigating local stress and deformation at the vicinity of scallops. The results show that the asphalt pavement affected stress at longitudinal rib, scallop and slit at transverse beam where longitudinal ribs cross, and scallop at field bolted joints of transverse and longitudinal ribs. The local stress and deformation were well explained by finite element analysis. The use of thicken deck plate which result high fatigue performance.

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Time-resolution of ultrasonic inspection test can be improved by numerical deconvolution analisys of scattered ultrasonic echo from a defect. We used maximum entropy method in a process of deconvolution analysis and show a method that prevent noise effect and have high time-resolution. An experiment was done and an artificial notch width was calculated accurately by applying the method to an experimental scattered ultrasonic echo.

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In practical elastic-plastic problems, plastic flow is often contained. From this viewpoint, an elastic-plastic analysis method, in which most computational effort is associated with plastic region, is developed in the present study. The characteristic of this method is to replace the material stiffness of plastic region with that of elastic region. To justify the replacement, plastic strain increment is introduced in the plastic region. The main computational task is to determine the distribution of this plastic strain increment. The method is computationally very efficient in problems with contained plastic flow, which is demonstrated by solving numerical examples.

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The stability analysis requires innovated computational strategies to overcome bifurcation points and limit points on the equilibrium path of geometrically nonlinear structures. The present paper describes computational strategies to study the bifurcation phenomenon of structures. The validity of all the proposed computational procedures is examined on numerical examples including simple, multiple and hill-top bifurcation.

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Tests of cylindrical shells subjected to the constant axial compressive force and the cyclic lateral force have been performed to study the characteristic behavior of the shells. The effects of longitudinal stiffeners on the ultimate strength have been investigated. The ductility and energy absorption of the shells have also been discussed. New parameters have been proposed for predicting the ultimate strength of stiffened cylindrical shells. The accuracy of the present approach is confirmed through the present and exisiting experimental results.

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The Hyogoken-nanbu earthquake which struck Kobe area on January 17, 1995 caused considerable loss of lives and properties. Although a variety of Civil Engineering structures were damaged, the damage to bridge piers was the most prominent. In this study, six steel box column specimens modeling steel bridge piers were tested pseudodynamically using the accelerograms obtained during the Hyogoken-nanbu earthquake. The piers were also analyzed using the hysteretic model developed in Nagoya University. The results indicate that the natural period and presence of in-filled concrete have a significant effect on the seismic response of such piers.

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In this paper, a new procedure is presented for simulation of near-field motion in irregular ground. After dividing a total wave field into free field and scattered field, a discrete wave-number method is employed for free field excited by faulting, and an FE-BE method is employed for scattered field. Following a simple analysis, seismic motion at Sylmar site during the 1994 Northridge earthquake is simulated by the present procedure. The agreement between the analytical results and the observations is good and shows usefulness of the procedure.

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In this paper, near-filed motion in irregular ground is simulated by a 3-D FE-BE method. This method makes it feasible to model arbitrarily-shaped 3-D basin structure and simulate its response to seismic faulting. Following a simple analysis, seismic motion of San Fernando valley during the 1994 Northridge earthquake is simulated. At Sylmar site, the peak horizontal displacement of the synthesized motion is consistent with that of the observed motion. Peak velocity map obtained by the simulation is also discussed in comparison with that based on observations.

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To protect art objects and artifacts from earthquake damage, a new display stand has been developed, and its efficiency has been demonstrated by vibration experiments and numerical simulations. The stand is equipped with a sensor and a deployable guard-frame which is usually folded under the diplay stand. When the sensor detects shaking stronger than 60cm/s/s in acceleration, the frame is triggered to be instantly deployed around the object concerned and prevents it from overturning.

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Although actual submerged floating tunnels have not yet been constructed, they are seen as one of the most promising structures for strait crossings. In order to make the tunnel a reality, it is necessary to analyze the dynamic response of the whole structure with adequate models that cover a wide range of many parameters such as buoyancy, leg arrangement and flexibility of tunnel joint. The authors proposed a suitable model for a super-long submerged floating tunnel using the modified Morison's equation. The response calculated by this method shows a close coincidence with those obtained by the diffraction theory. Super-long tunnels of 5km in length were therefore analyzed, and the fundamental characteristics of their response due to waves were obtained.

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A Limitation of amplitude of ground vibration for running safety of railway vehicle on a track being oscillated by earthquake is numerically analyzed using a 3 dimensional vehicle mechanical model having vertical wheel flanges. As the results, it is clarified that the conventional estimation of running safety by 2 dimensional simple plane mechanical model have to be improved, and that the limitation of amplitude of the track will be defined by the rocking motion in case of low frequency as 0.9Hz, but that will be defined by the lateral load of wheel in case of rather high frequency as 1.8Hz. Some trial calculations for running safety of vehicle on structure for real, earthquake are shown.

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The purpose of this paper is to identify parameters on nonlinear structures which have a base isolation system. A linear shear beam model is used for the superstructure while two types of a hysteretic model by Masing criterion are chosen for the base isolation system. The method is based on the extended Kalman filter using earthquake excitation or control force excitation by an actuator. And Numerical examples are demonstrated to show the efficiency of the proposed method in detail.

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The extended kalman filter is applied to the simultanious identification of flexual rigidity and tension of cables. The one degree of freedom model reduced to first or second order natural frequency mode is used as the mathmatical model of cables on the extended kalman filter. The approximate formula proposed on the practical formulas of the vibration method is used on the relation between natural frequency and cable tension and flexual rigidity. The calculated response values obtained by the same order model and finite element model are first used and the effecs of the method are confirmed. Next, the experiment is carried out by using Al plates as cable spcimens and the effecs of the method are examined.

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A new simulator for human evacuation behavior using virtual reality (VR) is developed and applied to study evacuation from a maze. Comparing the results of experiments using the real and VR mazes of same structure, applicability and potential of VR for evacuation behavior are examined. It is found that evacuation behavior can be simulated by the VR system, and the training using VR helps smooth evacuation from the maze. Considering the issues related to disaster drill, such as its mannerism, decrease of participants and their low volition, and safety of the drill, this VR simulator has high potential and can be a useful tool for disaster mitigation. The simulator can also be applied to study the safety of the structures in the planning and design stages as well as existing ones from the view point of human evacuation.

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In the Great Hanshin Earthquake, the effects of water supply cut-off on other lifeline systems and waste incinerator were very severe. The disruption of the water supply systems caused great difficulties in the medical services and fire-fighting. Gas pipes were filled with water leaking from the water and sewerage systems. The inability to operate pumps and emergency generators due to lack of industrial water was a common problem. The recovery of malfunction of sewerage system was affected by water supply cut-off and its restoration process. The effects of breakdown in the electric power system on water supply system were also examined.

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