The hierarchical continuum-based shell elements have been developed for the accurate modeling of composite structures such as steel-concrete composite bridges. In these elements, the same displacement field as several shear deformation theory is regulated by the displacement function of a hierarchical solid element. By applying the elements based on first-order and high-order shear deformation theory to free vibration analysis of thin and thick plates, the accuracy and applicability of these elements are demonstrated.

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The measured stresses at the existing dam spillway roller gates were compared with the stresses calculated under the same load conditions with the measurements. The uncertainties in the several types of stress calculations were quantified as the statistical characters of the stress ratio between the measurements and the calculations. The result showed that the uncertainties varied with the types of the calculations. These differences of the uncertainties in the stress calculations should be concerned in establishing the structural safety assessment formula based on the structural reliability theory.

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Damaged stone bridge with cracks, gaps and falling stones have become to increase in recently years. In order to propose the soundness evaluation method for damaged stone arch bridges, the development of the static analytical method of stone arch model is investigated theoretically and experimentally. Numerical analysis for stone arch model is carried out by the discrete finite element method with the friction and the contact models for adjacent stones. The material properties for bridge stones were obtained from material tests. The cracking mechanism of arch stones of stone arch model was clarified by pressure measurement sheets experimentally. The validity and the efficiency of the proposed discrete finite element method were shown by comparing the numerical results and the experimental ones.

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For better design and construction of steel-concrete hybrid structures, it is important to evaluate strength and behavior of the joins. In this study, new torque shear tests were carried out to develop a test method for shear strength between steel and concrete. It has a steel cylinder buried on mortar block, driven by torque arms, and the interface has no end and no stress concentration. The devices were improved and fundamental influences of the specimen size, loading parameters and cracking occasion were examined. As the result, it became clear that additional normal loads on torque arms have little influence and cracks initiate on the surface of the mortar block play important role in the test.

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Structural monitoring with various sensors has been used as a quick quantifying of damages of infrastructures. In this paper, a strain measurement using piezoelectric PVDF (polarized polyvinylidene fluoride) film is studied. First, sensing performance of the PVDF film on static measurement was compared with traditional strain gages. A PVDF film sensor for crack detection was developed. The crack progress on an aluminum specimen was monitored with the developed PVDF film sensor. Moreover, the PVDF film sensor has been used to monitor the initiation and propagation of cracks on RC specimens.

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The representative standards for bridge design, such as the Japan Road Association's Erection Design Manual, the Japan Society of Civil Engineers' Erection Design Guidelines, DASt012 and DIN18800 provide verification equations for checking the safety of the web plates in the steel I-shape and box girder bridges and composite girder bridges applied patch loading. We clarified the background and characteristics of each code, the differences between these equations. Safety factor were calculated comparatively by the actual erection data. In this study, we clarified a characteristic and the difference of the buckling stability verification method of the web plates applied patch loading for 5 codes. As a result of having compared verification equations based on the election data of the actual bridges, we proposed the CASE (1)-7 as the appropriate verification method.

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Recently, High Performance Steel, HPS, especially for bridge construction has been developed, named SBHS. Although SBHS has high strength and high weldability, SBHS steel has not been widely adopted in bridge constructions in Japan, because SBHS steel has not been specified in the Specifications for Highway Bridges in Japan. In this research, bending and shear strength of SBHS I-girder were experimentally investigated, and test results indicated that SBHS I-giders can be designed safely using concepts adopted in current specifications. In addition, residual stress distriutions in SBHS I-girder were measured to confirm no negative impact exist against the strength.

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One of the most important factors that influence the service life of a steel bridge is corrosion. The girder end is often found corroded. For efficient maintenance, therefore, it is quite essential to know the residual strength at the girder end. The present study investigates the influence of the corrosion at the girder end. To be specific, the degradation of the load-carrying capacity of a steel girder due to the corrosion at its end is evaluated numerically. The vertical load is placed at the upper flange right above the support. Steel I-section girders with various corrosion models are constructed and analyzed. It is found that different corrosion models at the girder end lead to significantly different degradation of the load-carrying capacity.

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The port facilities have been recognized as emergent supply transporting base in order to provide assistance for rehabilitation of disaster-affected areas. A system to evaluate the residual structural performance of the damaged facilities is required to judge whether the facility can be used or not. This paper deals with the residual structural performance of RC superstructure of open-type wharf damaged by earthquake. From the results of loading tests on the 1/4 scaled model, the failure process and the residual load carrying capacity of the RC superstructure after the earthquake are investigated.

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Radial gates used for a long term and worried about the corrosion deterioration are necessary to clarify the current state of the stress distribution adequately. It was investigated to relax standards on allowable stresses for maintenance from design allowable stresses based on the reliability theory. However, FEM analytical accuracy improvement is necessary step towards surcharge of allowable stresses. In this paper, paying attention to the fact that shape imperfection and thickness reduction are not necessarily reflected appropriately, we show the investigation results of the analytical accuracy improvement by using measured plate thickness and stress values at minimum measurement points. In addition, the concept of numerical maintenance model of radial gates is proposed, and the effectiveness is shown according to the numerical examples.

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When deformation was caused due to base displacement in transmission towers, measures such as reinforcement, replacement, and rebuild had been taken depending on the deformation state. Numerical simulation results on performance recovery of the deformed tower are important in the choice of the repair strategy. In this paper, various replacement processes are tried analytically by using element birth and death techniques in nonlinear finite element method, and the results are compared from the viewpoint to eliminate the structural deformation and to reduce residual stresses as much as possible. Investigation results are summarized as common findings of appropriate member replacement procedure concerning the transmission towers with base displacement.

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Load bearing deterioration of existing transmission towers due to base displacement is estimated by numerical analyses and in situ measurements. As an extension of a previous paper concerning a numerical method of transmission towers with base displacement, we study another load bearing analysis method by direct iteration. The purpose of this paper is to verify in situ axial force measurement accuracy of tower brace members and to confirm the proposed analysis method paying attention to nonlinear behaviors practically. It was clarified that the present method is improved from the practical standpoint, such as machine run-time and on-site computation, compared with the previous detailed method.

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This paper is concerned with an evaluation method of the remaining capacity of corroded steel column members. We introduced 4 different levels of artificial corrosion to bracing members in actual 50-years-old steel truss bridge. In this paper, we described compression load test, mechanical test, measurement of residual stress, measurement of initial deformation and simplified remaining capacity prediction equation based on minimum section area of the member.
With respect to compression test, in the specimen which has small amount of artificial corrosion showed overall buckling mode at the ultimate state. On the other hand, local buckling mode was dominant in the case of large amount of corrosion. In addition, it is found that we are able to simulate the load capacities and buckling modes by non-linear FE-analysis.

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In this paper, a compressive loading test of a severely corroded gusset plate connection cut out from a demolished truss bridge was conducted to clarify the failure mode and remaining ultimate strength. Also, FE analyses were conducted to assess the effects of section loss and examine the method of modeling of a gusset plate with uneven section loss. The failure mode was the local buckling of the gusset plates. The compressive behavior of the gusset plates was properly evaluated by a shell element model in consideration of the average section loss.

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Investigated in this study is the ultimate strength of a compression chord member in a truss bridge, which is designed according to the Specification for Highway Bridges in Japan. An adequate modeling method of the member, and the support condition of the member considering gusset plates at the end of the member are checked through FEM analysis. It is revealed that the ultimate strength and deformation of the member in the truss bridge is very much similar to those of a fixed supported column in compression. Also proposed is an economic and rational design of the truss bridge.

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In this study, to show the impact coefficient and stress redistribution of steel truss bridges when truss members of the bridges fracture, a field test used existing steel truss bridge was conducted. To measure the dynamic force responses of the members in the fracture test, the dynamic strains of the members were measured by dynamic data loggers. The truss members which were a middle vertical member and a neighbor vertical member of the bridge were cut off by gas cutter. The result of the field test showed the actual value of impact coefficient and stress redistribution due to fracture of the truss members.

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In conventional strengthening techniques for existing steel structures, steel plates are additionally welded or bolted to the existing steel members to reduce working stress. Here, FRP materials can be alternatives of conventional techniques in terms of easier applicability. Among the FRPs, CFRP strips of high elastic modulus provide higher strengthening effects. Then, carried out in this paper are loading tests of eccentric and more effective compression steel columns adhered the CFRP strips separately onto the flange plates. It is concluded that strengthening effect of the CFRP strips for bending not for axial loading decreases when the CFRP strips are separately adhered onto the flange plates of the steel columns subjected to predominant compression axial force.

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In this paper, a method to determine the shape of the cross-section of aluminum alloy plates with projections under in-plane bending is proposed. A way to reduce the cross-sectional area of plates with projections, while retaining the constant buckling strength, is provided. The elastic-plastic large deflection analysis with FEM reveals that the ultimate strength of aluminum alloy plates with projections of which cross-section shape is determined by the proposed method, is larger than that without projections.

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This paper proposes an estimation method on the shear resistance of the filled boulder in the flexible steel frame gabion by using the DEM. In order to take into account the inter-rocking effect of the ruggedness of the boulders surface, the assembled element is used in the DEM. The ruggedness of assembled elements is adjusted so that the angle of repose of the assembled elements is identical to the angle of the real boulders. Those results of both stair shape frame and semi-real size gabion are simulated by the proposed method. The simulation results are in good agreement with the test results.

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The global warming environmental impact is most important problem all over the world. In this study, the volumes of steel of bridges are considered social resource, and the volume of steel is one of the parameter for analyses. The analytical methods are performed by Data Envelopment Analysis (DEA) and super DEA, also parameters are CO2 emissions of lifecycle and lifecycle cost are used as input data, life length and volume of steel are used as an output data.
In the present bridges system, when considering the social steel resource environmental impact of the all type of bridges are not larger deference occurred in DEA analyses. In the case of analyses are performed by using super DEA, high reliable ranking carried out for the environmental impact of bridges.

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The governments of many communities have been trying to create their bridge maintenance planning. Generally their economic conditions are not good, the low maintenance costs and the smooth annual expenditure are required. For these requirements, the good approximation of the maintenance costs corresponding to the members and the materials of bridges are necessary. And also the real deterioration curves of the members of bridges are required. Some better models of these items are proposed in this paper with the improved GA process and make it possible to formulate the realistic BMS optimization problem. 300 really existed bridges problems are solved and show the effectiveness of the proposed optimization system.

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In this study, a fundamental study on the game theory (Nash bargaining solution) based approach for giving a priority to anti-earthquake reinforcements of road structures is presented. When a road structure is reinforced at appropriate time, the gain of the road structure is maximized. Each road structure or rosd link is considered as a player, and the road network gain is maximized at the same time as pursuing the maximization of a road link gain by adapting Nash bargaining solution with proper utility function. Also, importance of each road structure is shown by using properly multiattribute utility function.

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The approach slabs are installed at the both ends of a bridge in order to ensure smooth and comfortable driving of vehicles. They have no response against the deformation of super-structure in normal bridge which has the bearings and the expansion joints. However, the deformation of super-structure due to temperature changes mainly in the Integral Abutment Bridge (IAB) gives a significant effect to the behaviors of approach slabs. The analytical results by FE Analysis (DIANA) and their discussions regarding the suitable shape and placement depth of approach slab applied to IAB are given in this paper. Some field survey results regarding the asphalt pavement at IAB in Japan are also introduced in addition to the analytical results and discussions.

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The vibrational property of the bridge structure such as the natural period and the damping ratio are measured under various vibration level such as an ambient vibration level and the larger vibration level. The vibrational property generally varies with the vibration level. Therefore, it is important to confirm the relation between the vibrational property under an ambient vibration level and the one under the larger vibration level like an earthquake motion level.
In this paper, the vibration test of the simple viaduct bridge model is conducted under the various vibration level from very small level to the larger level like an earthquake motion level, and the vibrational property of the bridge model are investigated under respective vibration level.

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In this study, on the straddle-type monorail PC girder viaducts, the displacements and accelerations at the tops of piers and the span center of the girder in the three directions under moving trains are measured to clarify the dynamic behavior of the PC girder viaducts. The measured data is investigated in two traffic cases, which are in a train passing through the observation girder and through the opposite girder. Moreover, the effects of ground conditions and substructures on the dynamic responses are also examined from the measured results at two sites with different ground conditions.

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Many viaducts and bridges have been aging in Japan and various types of damage are reported. In order to maintain them properly, we have to have a FEM model which predicts traffic-induced response accurately. For this purpose, extensive measurement of traffic-induced response such as accelerations and strains was carried in 6 spans of the viaducts in Tokyo Metropolitan Expressway. This paper describes the results of this measurement and the individual difference of the responses among the spans is also discussed. The responses under a 25-tonsf truck computed by a FEM model using the measure road roughness is provided and some discussions on the predictability are made.

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This study is intended to establish a numerical approach to the site vibration around Shinkansen viaducts under running bullet trains. In this approach, the entire train-bridge-ground interaction system is divided into two subsystems: train-bridge interaction and foundation-ground interaction. Applying the dynamic reaction forces at the pier bottoms obtained from the train-bridge interaction analysis as input excitation forces, the ground vibration around the viaducts is simulated and evaluated taking advantage of a general-purpose program. The numerical results are compared with the experimental ones to confirm the validity of the analysis.

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To prevent the falling of a broken concrete piece from tunnel lining is important issue in the maintenance of railway tunnel. It may be effective to quantitatively monitor the strain of lining, deformation of tunnel section, crack width and others. However, this kind of monitoring method cannot estimate the progress of defectiveness, such as the progress of cracks, when the progress occurs at the deep part of lining. Therefore, this paper proposes the monitoring method by means of train-induced vibration, focusing on the change of characteristic of vibration on the tunnel lining and investigates its applicability by means of the field-measurement of train-induced vibration inside a railway tunnel and the loading tests with 1/5 scaled railway tunnel concrete lining.

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By using piezoelectric actuator bridge can be accelerated locally to detect the effect of small damage like fatigue crack as a response change of vibration. Transfer function (TF) of the vibration response can give us the indication of existence of damage before and after the damage. Detail analysis of TF before and after damage can inform us location and size (area) of damage. This paper shows the result of numerical analysis of damage detection on beam member by using local force excitation method.

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Vehicle response-based bridge damage detection is an indirect method for bridge health monitoring, in which the sensors are installed only on the travelling vehicle. However, there still exist some technical issues on the accuracy. This study suggests the estimation accuracy of the bridge mode shape as a damage index, instead of utilizing the mode shape itself. To estimate the bridge mode shapes, an interpolation matrix and singular value decomposition (SVD) are applied to extract information about mode shapes of the bridge from the vehicle acceleration responses. Validity of this method is verified through the numerical simulation and field experiment. Observations show that the proposed method provides a way to realize the damage since the change of self-correlation of bridge vibration components due to the bridge damage affects the estimation accuracy.

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The purpose of this study is to identify human walking vertical force by using FFT power spectrum from the experimental acceleration data of the human body. An experiment on human walking is carried out on a stationary surface paying attention to higher components of dynamic vertical walking force. Based on measured acceleration data of the human lumbar, not only in-phase component with frequency of 2f_w, 3f_w, but also in-opposite-phase component with frequency of 0.5f_w, 1.5f_w, 2.5f_w where f_w is the walking rate is observed. Characteristics of these higher components of dynamic force by walking are revealed from the dynamic design viewpoint of pedestrian bridge.

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In this study, ERA was applied to investigate the estimation accuracy of dynamic characteristics of the structures which have close eigenvalues. Series of numerical analysis to estimate structural frequency and modal damping were conducted for a two-dof model using the simulated external forces induced by impulse force and white noise. The estimation results obtained by these simulations demonstrated good agreement with assumed values. Next, the method was applied to the vibration data induced by human impact excitation for three existing stress ribbon bridges. The results showed that the method can estimate the dynamic characteristics accurately for the structures which have close eigenvalues.

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In order to control vibration on a structure having two degrees of freedom system of swaying and twisting vibrations during harmonic ground shaking, two kinds of tuned system damper are installed on the structure. In this paper, one method is proposed to determine approximate optimum dynamic parameters of these two dampers (optimum frequency ratio, mass ratio of a damper to that of the structure and optimum damping constant). A five dimensional nonlinear simultaneous equation which satisfy conditions minimizing response of acceleration of two corners of structure was deduced. This equation was resolved by using iterative procedure by Newton's method and five optimum values of dynamic parameters were obtained.

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Tuned cradle mass dampers (TCMDs) use the motion of a swing mass on a curved surface to dissipate structural vibration energy. In this study, we develop a TCMD that has a constant swing period. We verify its performance by performing experiments and numerical analysis for a structure undergoing free vibrations. To obtain a device with a constant period, variable radii of the curved surfaces were calculated using simple pendulum dynamics. In this study, the damper was installed in a simple one-story rigid-frame model with a frequency of approximately 1 Hz and free vibrations were excited. The numerical analysis results agree well with the experimental results.
When the mass ratio of TCMD to the model is 0.01∼0.025, numerical experiments are carried out to find the optimum parameters of TCMD.

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Application of the modal filtering technique to active control of floor vibration under impact excitation is expected to be effective and advantageous in reducing the floor impact sound associated with the vibration. While the modal filtering technique relies on the premise that the modal shapes of the floor panel consist of real numbers, implying that proportional damping in the structural system, it is often the case that floor panels of actual practice in buildings do not obey this assumption. Complex modal shapes render the modal filtering technique ineffective. In this paper, a sensor layout design procedure to avoid this problem is developed. Verification tests are conducted to investigate the performance of the modal filtering based on the sensor location determined by the proposed procedure.

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During the 2011 off the Pacific coast of Tohoku Earthquake, Iwakiri Railway Bridge, Sendai City, Miyagi Prefecture, Japan, suffered significant damage. In order to analyze the damage mechanism, it is important to evaluate strong ground motions at the bridge site with high accuracy, taking into account site effects. In this study, strong ground motions at the bridge site were estimated based on a super asperity model considering empirical site amplification and phase effects. The same approach was also applied to estimate ground motions at strong motion stations surrounding the bridge site to confirm its applicability for the 2011 main shock. Site effects at the application sites were evaluated based on the records of temporary aftershock observation. The estimated ground motions will be useful in the detailed study of the failure mechanism of the bridge.

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This study estimates the number of demolished wooden houses after the scenario Tokyo Metropolitan earthquake and the amount of associated debris in Metropolis of Tokyo. This study defines the damage index of wooden houses to predict the number of demolitions after the earthquake. The threshold value of damage index is determined based on the actual dataset after the 2004 Mid-Niigata earthquake. Lastly, the amount of debris after the scenario earthquake in Metropolis of Tokyo is estimated and the treatment of debris is discussed.

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After the 2011 Great East Japan Earthquake, it is becoming important to consider the influence by tsunami flotsam colliding with an important structure. Also, the collision analysis method is being received much attention. However, practical applications of the collision analysis have not been investigated yet. Therefore the purpose of this study is to develop and evaluate a collision analysis method capable of simulating the phenomenon to which large flotsam collides with an important structure like the long-span bridge, particularly damaged in mega earthquakes. Moreover, the marginal size of tsunami flotsam which can avoid collapse to an object bridge is computed using this method.

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The damage of 39 bridges by tsunami due to Great East Japan Earthquake was evaluated with the application of β value (ratio to girder resistance and acting force of the tsunami) focusing on the girder shape. As a result, β is an effective parameter to evaluate outflow condition of girder. Besides, it have shown that width, and height of girder affected β value significantly. Furthermore, based on the tsunami velocity that represented the characteristics of tsunami in the area got from video analysis, the conformity between β value and outflow condition was improved.

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Utatsu Bridge, a prestressed concrete bridge, suffered enormous damage from the destructive tsunami waves triggered by Great East Japan Earthquake, on March 11^th, 2011. Based on the field survey, it is clear that the bridge girders S3~S10 flowed out. With the application of the video recording tsunami-hit, the wave height and velocity histories are plotted. Meanwhile, the outflow mechanism of girder (S9) is analyzed, based on video result. On the other hand, two dimensional (2-D) simulation is conducted for Utatsu Town. The tsunami process, wave height and velocity histories are obtained. Besides, the outflow mechanism of girder (S9) is analyzed by simulation result once more. From video and simulation, it is known that the wave height rises slowly, which indicates no bore wave occurs; furthermore, it is found that when girder of Utatsu Bridge is flooded, the friction resistance is insufficient to resist tsunami force.

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Due to the tsunami triggered by the 2011 Great East Japan Earthquake on 11 March 2011, Tohoku area suffered tremendous destructions. Shizugawa area (Minamisanriku Town) is taken as the study area. From simplified evaluations of bridge outflow, β₁ and β₂ values (ratio between bridge resistance and impact force) are confirmed to be efficient for evaluation of bridge girder and pier. From the investigation by recording videos, tsunami height was rising in relatively small pace inferring the wave shape not to be the bore type. Further, precisely evaluated β₁ can explain the survival of Hachiman Bridge in both two mechanisms (one as tsunami just acted on girder and did not submerge it, with consideration of hydrodynamic and static force; other as girder was impacted and entirely inundated, using the maximum velocity during the inundation and considering hydrodynamic force and buoyancy).

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This paper examines the tsunami wave forces acting on the I- girder bridges using the two numerical simulation methods, because many I-girder bridges were washed away by the tsunami flow generated by the 2011 off the Pacific Coast of Tohoku earthquake. In this paper the effects of the forces due to the air confined between the I-girder and tsunami flow surface investigate using the one-phase flow analysis taken into account for the water only as well as the two-phase flow analysis considering the water and the air effects. It is found that the effects of the forces by the confined air on the I-girder bridges are significant.

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Xiaoyudong Bridge, a RC rigid-frame arch bridge, suffered enormous damage during the Wenchuan earthquake which occurred in China, on May 12^th, 2008. Based on the field damage survey, the bridge structure was briefly summarized, as well as the ranked damage condition. Furthermore, dynamic analysis for Span 1 & 2 and Span 3 & 4 was conducted separately by using both E-W and U-D seismic waves. The damage condition of Span 1 & 2 were roughly well reappeared, while the possible collapse reason of Span 3 & 4 was verified. It was found that the damage of local members reduced the degree of static indeterminacy, which caused the gradual loss of entire stability. Consequently, these two spans collapsed into the river finally.

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Many steel bridge piers have been used to highway bridges in urban area. Beam-to-column connections of steel bridge piers have been fabricated by thicker plates compared to general sections due to considering shear-lag phenomenon in the design calculation of beam-to-column connections. After the Kobe Earthquake, plate thickness of beam-to-column connections increases with increase design earthquakes. Consequently, there are many difficulties in fabrication, design, and transportation of the connections. The purpose of this study is to grasp effects of beam-flange geometry on elasto-plastic behavior of beam-to-column connections of steel bridge piers with circular columns by using experimental and analytical investigations.

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Since HYOGOKEN-NANBU Earthquake in 1995, a large number of researches on the seismic performance of steel bridge pier have been carried out. However, there is very few research for the repair method of the steel bridge pier that has been damaged by earthquake. The research on how to repair severely damaged steel bridge pier has been conducted by the authors, but the effectiveness of repair for the steel bridge pier that suffered minor damage has not been revealed. In this study, the repairing effect of filling concrete for rectangular cross sectional steel bridge piers which have different degrees of damage is to be verified. First, four damage levels were assumed from general load-deflection relationship. Static cyclic loading tests until reaching their predetermined damage levels were conducted. After filling the concrete inside the specimens, the same static cyclic loading tests were carried out to clarify the seismic performance of repaired piers.

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This paper presents the shake table tests and the analysis for evaluating the dynamic interaction of a RC column with a pile foundation and soil system. In case of a small input motion, both the structure and the soil were linear and the inertial interaction was dominant in the response of the pile foundation. Increasing the shaking level, the effect of kinematic interaction on the response became major and when the RC column became nonlinear, the pile's behavior was strongly affected by the soil deformation and the dynamic interaction between the structure and the soil became smaller.

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This paper presents a study on the seismic performance assessment of the precast concrete pile foundation based on dynamic analysis. The precast concrete pile foundation for existing bridges exhibits the inferior seismic performance. In order to evaluate the seismic performance of those foundations rationally, parameters of structural patterns and geological conditions were discussed through the analytical results. It is found that seismic performance of those foundations is dependent on ground conditions of the layer at pile head, and the pile-arrange pattern.

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The natural rubber bearings of Tobu viaduct and Rifu viaduct ruptured due to the 2011 off the Pacific coast of Tohoku Earthquake.
In order to investigate into reasons for the rupture, we performed material testing using some specimen obtained from the ruptured bearings. We also made the performance testing using the existing natural rubber bearings which appeared to be undamaged under visual examination located near the ruptured natural rubber bearinga and the new bearings which were reproduced by rubber compsition at the time of construction.
As a result, it turned out that the allowable design force of the existing natural rubber bearings was above the standard values,but that the ultimate shear defomation perfomance of them was lower than that of the the newly made bearings.

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The purpose of this investigation is to clarify analytically the main mechanism of ruptures of elastomeric bearings used on the East viaduct due to the 2011 off the Pacific coast of Tohoku Earthquake. We made reproduction analysis using the acceleration waveform that was observed in Sendai Higashi interchange near this viaduct. The response of the non-linear dynamic analysis with the general design model did not match the real situation of the damages. Therefore, the influences of the bridge accessories were incorporated into the design model. As a result, the elastomeric bearings were ruptured by the shear strain and the up-lift force exceeding the performance. We hypothesize the main factors of the ruptures are attributed to a mixture of different structural types of piers, a considerable change of the bridge width, the influence of enforced displacement.

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Energy dissipating devices do not necessarily reduce the residual displacements of structures, unless they have any inherent self-centering capability. Herein, an innovative self-centering composite metal damper consisting of super-elastic and super-plastic metals is proposed. An excellent re-centering capability of the super-elastic metal under large strains makes possible a self-centering characteristic for dampers with wider ranges of length, while the large energy dissipating capacity of the super-plastic metal make up for the insufficient energy dissipating capacity of the super-elastic metal. An extraordinary fatigue resistance of the two metals together with the re-centering characteristic of the super-elastic metal will enable a maintenance-free damper. The validity of this damper is numerically confirmed when applied to the seismic retrofitting of an elevated highway bridge supported by a thin-walled steel pier.

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