Earthquake-induced Permanent Ground Deformation (PGD) can affect significantly underground gas or water pipelines. This paper describes large-scale experiments to investigate the effect of PGD on buried steel pipelines with elbows, and to validate and calibrate Finite Element (FE) modeling. There is good agreement between both the magnitude and distribution of measured strains and deformation and those modeled with FE analyses. The analytical models are able to simulate real performance in a reliable way for dry sand, and for partially saturated sand with an adequate correction factor. Using the analytical model, recommendations are proposed for enhancing the earthquake-resistance of buried pipelines with elbows subjected to PGD.

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An optimization procedure for the design seismic coefficient for gravity type quay walls is discussed based on the risk management concept. First, seismic risk evaluation for 280 ports in Japan is conducted to obtain the optimum design seismic coefficient. Second, the variation of the optimum seismic coefficient for the important quay wall or the quay wall with longer service life than usual is examined. Finally, the relationship between peak ground acceleration given by seismic hazard analysis and the optimum design seismic coefficient is examined. The results indicate that the current design seismic coefficient is regarded as reasonable since it is close to or conservative of the optimum design seismic coefficient.

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In this study, we studied the fatigue strength of sleeper supports, which are attached to upper flange of open floor type steel railway bridges with uneven leg length type fillet welding and receives direct vertical load. We used the method of crack investigation on actual bridges and fatigue test. Results tell us that fatigue cracks always propagate from weld root area at transverse fillet weld and the main cause will be bending stress on the girder. Also, the result of fatigue tests clarified that fatigue strength without direct vertical load will be level F, but with direct vertical load, or without sufficient leg length, it doesn't reach the level F, and the fatigue strength of actual bridges can be even below this level.

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35 years has passed since the Japan's main stem line-Tokaido Shinkansen opened. Recently, a metal girder, which has been used since the opening of Tokaido Shinkansen, was removed due to the construction of a new station. We took this opportunity to carry out non-destructive inspection and destructive inspection in a factory in order to understand the production condition and any discrepancies between design and production. It made clear the quality level of initial metal material and welding together with the repair method for fatigue damage, which was applied afterwards. I believe that it doesn't only give us useful information for future maintenance, but also supplies precious information for discussing the durability of metal bridges.

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Composite bridge girder with concrete slabs and corrugated steel webs is a prospective form because of such advantage as the lightness of the girder. However the behavior of this type of girder around middle support, where severe and complicated stress field may be formed in many cases of continuous girder, has not been fully investigated as yet. The authors conducted several experiments and finite element analyses in order to study the ultimate flexural and shear behavior of this type of composite girder around middle support. The results indicated that the girder could provide significantly higher flexural and shear strength than assumed in conventional design, due to mutual aid of concrete slabs and steel webs. It was also found that the behavior of the girder after cracking of the slab can be suitably predicted by the employed finite element analysis up to the buckling of the web.

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Seismic performance of a 160m long reinforced concrete arch bridge is clarified based on a series of nonlinear dynamic response analyses. Since an arch rib is subjected to large flexural moment as well as axial force in an extreme earthquake, the effect of axial force N vs. flexural moment M interaction should be included in the analysis. It is found from the analyses that the maximum bending moment was 36% overestimated while the maximum curvature was 30% underestimated at a springing by taking the N-M interaction into account. It is also found that brittle failure is likely to occur in the arch rib resulting from high axial force.

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Introduction of new high-speed trains and low stiffness girders such as PRC ones requires reviewing the present technical design standards of railway bridges and viaducts from a viewpoint of dynamic response of girders as well as of train run comfort. In this study, dynamic interaction of train and continuous concrete girders is formulated and parametric simulations are made extensively. The results are compared with the dynamic responses of 21 existing bridges and good agreement is presented. The resonance of the girder under the passage of train with the speed of 500km/h is also confirmed. The damping ratio of concrete girders is found to be as low as 0.01 and the value of 0.02 is suggested to use in simulations and design. Dynamic response of running trains is compared with the results of the field measurement of 17 bridges and good agreement is also found. The filed measurement shows that the maximum acceleration of trains during the passage of bridges is below 1.5m/s², indicating good ride condition and implication of this result in conjunction with the design standards is discussed.

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During the construction of composite steel-tube reinforced concrete bridge piers, the steel cylinders are exposed under wind and their safety becomes critical. In order to establish a rational wind resistant design, the aerodynamic characteristics of a group of 9-12 steel cylinders were extensively studied in a series of wind tunnel experiments. The experimental results indicate that: 1) Vortex-induced oscillation is influenced by the steel pipe spacing rather than the arrangement of the steel cylinders. 2) There are two causes of the mechanism of vortex-induced oscillation. One is the vortex street resulted from individual steel pipes and the other is the vortex street resulted from the whole group of steel pipes. 3) The amplitude of vortex-induced oscillation is maximum when the steel pipe spacing is 1.4 times the diameter of the pipe. Based on these results, the required damping ratio for reducing vortex-induced oscillation to the acceptable level is evaluated.

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In order to reduce the dead road, composite pre-stressed concrete bridges with corrugated steel webs are increasingly used. High strength bolted joints, butt-welded joints are usually used to join the corrugated webs at site and recently lapped joints are started to investigate to adopt this joints, because it is easy to absorb tolerance associated to erection. In the design process, corrugated steel webs are beard only shear forces, but fatigue strength of these joints is not clear yet.
In this study, fatigue tests of butt-welded joints with welding line inclined were carried out. Crack propagation was also evaluated numerically by fatigue crack propagation analysis using fracture mechanics. Finally, the fatigue strength of corrugated steel webs under the criteria of shear stress exceeded.

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Mechanical properties of lead are studied experimentally with aid of image processing technique. At first, a new image processing technique is developed. In this method, three-dimensional material points are initially projected to the images and their displacements are traced in each image by a two-dimensional image processing technique. These displacement fields are combined to recover the three dimensional deformation. Then, the mechanical properties of lead are studied through material tests, in which the proposed image processing technique is applied. From these experiments, it is clarified that lead has rate dependency and that stress shows softening because of the accumulated damage in the large strain range.

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In designing structures that are subjected to impact/impulsive loads, the equivalent static force, which is based upon consideration of the dynamic load factor (D. L. F), have been currently employed. For this design procedure, which focuses attention on the maximum of forces, deflections and stresses even though they are time varying values, it may be hardly assured the safety of structures against impact/impulsive loads. From the perspective that how to enhance the reliability of the data from impact tests, this study is to disclose the problems on both measuring the impact force-time variations in tests and processing their recorded data waves. Consequently, the low-velocity impact tests for RC beams are performed, and then the data processing procedure proposed in this study is validated.

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The authors conducted a larger scale shake table test that incorporated soil-structure interaction on reinforced concrete two-box type model structures having overburden depth 3.0m and 1.5m, respectively. Then, the authors corroborated the followings regarding the model structure deformation: 1) Shear force on the upper played a major role on structural deformation among other forces. 2) Maximum relative displacement between upper and lower slabs reached twelve or thirteen times as large as yield relative displacement, showing that the degree structure flexibility was considerably large. 3) Structural deformation was fully controlled by surrounding ground deformation. 4) The model structure experienced flexural failure mode type residual deformation and damage.

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Steel piers with octagonal cross-section filled with concrete are often used in practice because of its excellent view and better resistance against wind than the conventional box cross-section, but its seismic design method is not established. The aim of this study is to propose a simplified numerical method for seismic design of such a steel bridge pier. From model tests, stress-strain relations of inner concrete are determined. The equivalent stress-strain relations of the outer steel plate including its local buckling effect are determined from a nonlinear FEM analysis of stub column with octagonal cross-section. The equivalent stress-strain relations are applied to formulate the stiffness matrices in a frame analysis. The accuracy and the efficiency of the proposed method are examined by comparing the numerical results with those of the experimental tests.

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A method of synthetic data processing of seismic intensity information and actual damage information is presented for decision support in post-earthquake emergency management. Immediately after the earthquake, a prior distribution of damage probability is estimated using seismic intensity information and fragility relations. According to actual damage information, the posterior distribution of damage probability is updated using Bayesian approach in a sequential manner. The technique of SPRT (sequential probability ratio test) is employed to model the emergency decision process. Numerical examples are shown to identify most disaster-stricken area in the 1995 Hyogoken-Nanbu Earthquake, Japan.

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In the capacity spectrum method, i. e., force and displacement based seismic design method, demand spectrum ADRS (acceleration-displacement response spectrum) acts an very important role. In this study, therefore, the ADRS of SDOF systems with elastic-perfectly plastic bi-linear restoring force characteristics are obtained by inelastic response analyses, provided that the value of modified Park-Mg's damage index D of the system equals D_r (=0.4) which means the repairable limit of the SDOF systems. Regression equations of the ADRS are derived and are compared with the analytical ones. Then the regression equations are applied to a force and displacement based seismic design of a single RC pier. And the design result obtained by the proposed method is compared with the one obtained through the ultimate lateral strength method.

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Various shapes of piers in urban highway viaducts are adopted according to their different constriction site conditions. Inverted L-shaped steel piers (ILSP) may cause higher amount of residual displacement than that of centrally loaded steel piers after strong earthquake. In this study, out-of-plane cyclic loading test has been performed on the LISP. The eccentricity ratio e/r is selected as 0, 2 and 3, and its influences on the inelastic behavior, ultimate strength and ductility are investigated. It is found that the ILSP deformed largely in the in-plane direction although the pier was loaded in the out-of-plane direction. Moreover, comparisons show that the behavior of the ILSP without torsional deformation is close to that of the T-shaped steel pier before the peak load, but the subsequent strength deterioration is significant due to the presence of eccentric load.

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A two-step model has been proposed for evaluation of post-earthquake serviceability of utility lifelines in terms of an estimate of seismic intensity at the site concerned. From the experience of 1995 Hyogoken-nanbu earthquake, Japan, a GIS database containing high-density distribution of seismic intensity, utility lifeline disruption and outage time was compiled. Then, a two-step model was developed on this basis; the first model being a logit model for probabilistic assessment of occurrence of lifeline disruption, and the second model being a statistical prediction model for the evaluation of outage time. Combining these two models, one can conveniently perform both pre- and post-event evaluations of serviceability of electric power, water, and city gas supply systems, providing rapid estimates solely on the basis of seismic intensity information.

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When a railway vehicle is running on a steep curve section, the wheel flanges of the outside wheel are prone to ride on the rail top surface. In this study, a simulation method for numerical analysis of a railway vehicle running on a curved track with short radius at a relatively low speed is developed and some numerical examples are shown. It is concluded that the small difference between the relative longitudinal velocity of the right rail and that of the left rail generated by the turning motion of the vehicle plays an important role in the numerical analysis, and that the dropping of the wheel from the rail top may occur, in the case that the static wheel load of vehicle holds a large unbalance number and the friction at the contact surface between the wheel and the rail reaches to a certain high value.

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We propose a formulation of nonlinear homogenization for media with lattice-like periodic microstructures. For continuum media, the conventional homogenization method leads classical boundary value problems of continuum for both micro-and micro-scales. However, it is rational to discretize lattice-like micro-structures such as cellular solids by frame elements. The main difficulty to apply the frame elements into micro-scale problems is due to inconsistency between kinematic field of the frame elements and the micro-scale displacement field. Some numerical examples of cellular solids show not only the feasibility but also the advantage on the computational efficiency of the present method.

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