A series of experiments and numerical analyses were conducted for investigating the compressive behavior of steel cruciform columns subjected to thermal history assuming fire damage. The lower arts of the columns were locally heated up to 600 ℃ and 900 ℃ and rapidly cooled by water. After the heating experiments, the monotonic compressive loading experiments were performed. The elastic stiffness of the heated columns became lower than that of the sound column according to the magnitude of the out-of-plane deformation by the heating. The ultimate compressive strengths of the heated columns were almost the same as that of the sound column. The change in mechanical properties and residual stress by heating did not influence the compressive behavior of the heated columns.

This study employed a simulation method that utilized shell elements to accurately replicate deformation and residual stress during welding processes and confirmed its efficiency compared with that utilized solid elements. Specifically, when these initial imperfections were introduced into the solid model using solid elements and the shell model using shell elements properly, the corresponding loading process with the same boundary condition was analyzed continuously. According to the results of the welding process and the compressive loading process, the efficiency of the proposed method for instance on load–bearing capacity and calculation time spent was able to confirm.

Many corrosion damage are reported in steel bridges. The cross-sectional defects is often repaired by patch plates with high-strength bolts. This study investigated axial force sharing of corroded steel truss members repaired by patch plates. The axial force sharing of truss members with sectional defects does not correspond with that obtained from the defect section and patch plate ratio. In this study, the estimation of axial force sharing of corroded truss members repaired by patch plates subjected to axial forces is proposed. To ensure that this behavior can be applied to actual bridges, the effects of dead and live loads, and yielding conditions are also investigated by FE analysis, and estimation equations were proposed.

In this study, finite element analyses were performed on patch repaired thickness-reduced plate under dead load. In the case of re-corrosion of the main plate and sectional reduction of the inside of the patch plate, the mechanical properties of main and patch plates with shared axial forces of thickness-reduced plates were evaluated for corrosion propagation after the repair. As a result, it was clarified that a part of the dead load carried by the main plate is re-distributed to the patch plates when the sectional defect in the main plate is re-corroded, and that is highly dependent on the re-corrosion direction of the main plate. An estimation equation for the dead load redistributed by re-corrosion was derived, and the FEM analysis and the estimation equation showed similar results.

In recent years, works to improve existing structures and strengthen their seismic resistance have increased. Pile construction in narrow spaces is constrained by the site and the construction process. Therefore, a construction method of soil-cement composite pile using a mechanical agitator was developed. The purpose of this study is to clarify the compression characteristics of pile tip for soil-cement composite pile. This paper briefly summarizes the construction method, then discusses the results of the compression model tests, and finally summarize the results of simulation for the compression model tests by the three-dimensional analysis using the finite element method.

There is concern that the slip coefficient of high-strength bolted joints with different faying surfaces may be lower than that of conventional joints, and it has been reported that the slip coefficient is improved by inserting friction shims. In this study, shims were modified to be disk-shaped, which can be inserted into each bolt hole, for application to arbitrary bolted joints, and their slip resistance was evaluated by slip resistance tests. As a result, it was confirmed that a slip coefficient of 0.6 or higher could be expected with the insertion of shims. Failure modes of the contact surfaces were also investigated by dismantling the specimens after the test and observing the contact surfaces.

Many of the river gates, including steel flap gate, were constructed during the period of rapid economic growth, and more than half of them are now 40 years old. Therefore, more efficient maintenance and management plans are needed. In this study, loading test using experimental model and FEM structural analysis were conducted on steel flap gate. Assuming several types of deterioration and damage conditions, the displacement and stress of the steel flap gate were compared by loading tests using experimental models and FEM analysis. And, by comparing the experimental and analytical results, the effects of deterioration damage due to aging on the soundness of steel flap gate were investigated.

The static tests of the column specimens were conducted in order to evaluate the residual structural performance of the columns of steel arch bridges. The twodirectional horizontal displacement and vertical force acting the specimen as seismic excitations were conducted by using the dynamic analysis of the arch bridge model. Compared with the specimens without seismic excitation, the displacement at the maximum strength under the one-directional cyclic loading was reduced despite almost same strength. This tendency was simulated by the FE analyses with constitutive equation we newly developed.

In the proposed deck replacement method, existing steel girder and orthotropic steel deck are connected by “Shear Force Transferring Members (SFTMs)” installed between girder web and longitudinal rib discretely. This paper’s object is to investigate the effect of the arrangement of SFTMs (dense/sparse) on the composite action and to clarify the ultimate behavior in the case of sparse SFTMs arrangement. The girder bending experiment exhibites that the denser the SFTMs are arranged along the girder span, the closer complete composite behavior this structure has. Moreover, SFTMs keep their shear resistance after the girder local buckling, which prevents the whole structure from immediamte deterioration of bending resistance.

The pull-out strength of anchor bolt embedded in concrete is usually estimated by assuming that the stress is uniformly generated on the failure surface. However, it is known that when anchor bolts are subjected to a sudden pull-out load, the stress distribution becomes non-uniform and the load carrying capacity also differs from that under static loading. In this study, the embedment depth and pull-out velocity of bonded anchors were taken as parameters, and their effects on the failure mode and load carrying capacity were investigated based on numerical analysis using the SPH method. As a result, it was confirmed that the failure mode changes from cone fracture to combined fracture, in which cone fracture and adhesion fracture are mixed, as the pull-out speed increases.

This study analyzed the relationship between factors such as weather conditions, geographical conditions, and traffic conditions, and an index considering the rate of deterioration using the degree of soundness in the inspection results, for national highway bridges in Japan. Then, those factors that are likely to influence the deterioration of the soundness were evaluated. The factors with the highest influence were as follows: average temperature, precipitation, years in service, minimum and maximum temperatures for concrete bridges, and years in service, precipitation, minimum and average temperatures for steel bridges.

We perform a series of quasi-static simple shear tests on samples of superdisks using the level set discrete element method (LS-DEM). We then define the shapeinduced clusters as the mesoscopic structure, and relate its characteristics to the critical-state macroscopic properties and microscopic contact anisotropy. We find the following. (1) The shear strength increases as the particle blockiness b_k increases, except when the inter-particle friction μ_p is low. In contrast, the mean solid fraction always reaches the peak value at around b_k = 5. (2) The cluster size distributions collapse onto a single power-law decay curve previously fitted for elliptic packings, although the tails gradually deviate as μ_p increases. (3) The differences in shear strength and mean solid fraction are mainly attributed to the clusters.

GNSS (Global Navigation Satellite System) technology is weather-resistant and can capture 3D displacement. However, it is often challenged by observation noise, especially in real-time construction monitoring. This study investigates real-time displacement monitoring of a bridge under construction based on GNSS. The proposed method uses a formulation incorporating the Robbins-Monro algorithm within Kalman filter to adaptively reduce the observation noise. The vertical displacements of a bridge under construction are estimated based on GNSS and the proposed method. The estimated displacements are compared with those by level survey.

This paper presents an exact three-dimensional elasticity analysis of out-of-plane free vibration of simply-supported homogeneous, isotropic, rectangular plates on elastic foundations. An exact analysis is based on the three-dimensional, linear, small-strain theory of elasticity. The elastic foundation is described by the Winkler model. The fundamental out-of-plane free vibration characteristics of square plates resting on elastic foundations have been studied in detail, with respect to different thickness-width ratios and non-dimensional foundation parameters. In addition, the present paper proposed an added stiffness coefficient to evaluate the effects of interaction between an elastic foundation and a lower surface of plate.

A design method for steel truss bridges using reused members was proposed and evaluated in this study. It consisted of shape and size optimization, with the objective function being steel weight, carbon dioxide emissions, and cost. The case studies showed that the use of reused members led to a reduction in CO2 emissions and lower cost than using new members when the stock of reused members was plentiful. However, when the stock of reused members was not sufficient, the balance between steel weight/cost and CO2 emissions became important. The results of using a weighting factor for the objective function showed that there were only a few discrete structurally reasonable solutions with different reuse rates. This indicates that there is a balancing relationship between the three objectives.

In order to restore the damaged bridges quickly, the modular bridges are used in which standardized bridge's components are combined according to the site conditions. In this study, the truss topology optimization based on the ground structure method was conducted to determine the optimal panel layout for the modular bridges considering its periodicity. The truss topology optimization for the modular bridges with different the support and load positions, and number of the modular units shows that the optimal panel layout is a square panel with single X by crossed diagonal member in it for the short span model, while the optimal panel layout is a square panel with X s by crossed diagonal members in it for the longer span model.

Due to climate change, extreme rainfall events have become more frequent, causing notable damage to road bridges near small-to-medium-sized rivers. In past research, we identified vulnerable bridges during major floods. This study assesses bridges spanning small-to-medium-sized rivers, examining how regional and catchment variations impact flood probabilities. Our results show that flood likelihood varies by region and river conditions. We also observed varied rainfall patterns due to global warming and identified areas with increasing or decreasing rainfall. We suggest risk assessment techniques and measures for protecting bridges against potential flooding.

Experimental and analytical investigations focusing on shear span ratio, structural details of hoops, and ratio of main bars were conducted for the purpose of appropriately evaluating the bearing capacity of existing cast-in-place piles, which are the most common type of existing pile foundations. As a result, it was found that the evaluation of shear capacity of cast-in-place piles can be made on the safe side by applying the shear span ratio to the shear capacity of concrete. In addition, it was found that even when hooks are not provided, the shear reinforcement effect is also effective.

In the seismic evaluation of dam gated piers, which are a part of dams, it is necessary to construct an analytical model that is separate from the dam body. For that purpose, it is important to grasp the relationship between behaviors of the dam body and the dam gated pier. In this study, push-over analysis using a solid model realized that the behavior of the dam body and the characteristic shape of the dam crest affect the behavior of the dam gated pier. In addition, by reproduction analysis using seismic observation results, it was shown that when using the M-φ model to simplify the analysis model, the effect can be considered by installing a spring element at the foundation.

We investigated the applicability of a seismic safety assessment method that employs the load-bearing capacity of the entire structure as a limit value. Firstly, shake table tests were conducted on a steel frame model to examine the accuracy of numerical analysis methods was verified. Next, the verified analysis software was utilized on a supercomputer to analyze a large-scale model of a steel arch bridge using shell elements. As a result, it was confirmed that the maximum capacity of the entire structure calculated through Pushover analysis was up to about 16% lower than the seismic forces from dynamic analysis at the corresponding time. In indeterminate structures, the differential progression of damage in each component causes their maximum capacity to be influenced by the loading history.

Bulging is a coupled vibration between tank wall and content fluid. This phenomenon is induced by seismic ground motion. Generally, SUS panel tanks are divided into two parts by partition plates. There is a case of water leakage due to damage to partition plates caused by the earthquake. In this paper, we perform the eigenvalue analysis to calculate the natural frequency of the partition plate. Next, we perform a time history response analysis using this natural frequency to measure the von Mises stress and water pressure acting on the partition plate. The measured von Mises stress confirm the resonance with the partition plate section. Furthermore, water pressure becomes extremely greater when resonating, and we find that the current design guideline is improper.

In this paper, the influence of seismic shear deformation of crush zone on the capacity and failure pattern of RC underground structure is studied by loading experiments using 1/10 scale tunnel models. The number of specimens is four and each specimen has different condition of crush zone as intersection angle of crush zone and tunnel, loading direction, thickness of crush zone. As a main conclusion of studies, it was verified that the capacity and failure pattern of tunnel depends on the above conditions of crush zone. Especially in the case of deforming accompanied by longitudinally compression, it was observed that major cracks propagate in the direction orthogonal to the tunnel axis rather than along the crush zone.

The Non-linear Response Spectrum Method is one of the methods for calculating seismic response values for railway bridges and viaducts. In this study, a method to express the non-linear response spectrum was proposed by a simple mathematical expression. In addition, a procedure for estimating the parameters was proposed to be input into this equation. The proposed method was applied to seismic records. As a result, it was confirmed that the proposed method can automatically represent the overall trend of the spectra of seismic records while significantly reducing the number of parameters compared to the conventional method.

In this study, a relation between the displacement and the pixels considering the projection distortion which occurs when projecting the 3D displacement of the object onto the 2D image sensor is formulated. T he error caused by the displacement in the longitudinal direction can be suppressed to 10% or less when considering camera posture and a ngle of view A method for estimating the multi point synchronous displacement of bridges during train passage is proposed by using single high resolution camera with w ide angle lens . The proposed method is applied to three actual bridges and compared with the results of Doppler laser displacement sensor s . V ibration modes contributing resonance phenomenon of the entire bridge deformation can be identified by the method.

In recent years, studies has been conducted to detect bridge damage from changes of vibration characteristics. We studies estimation method of bridge vibration characteristics from dynamic responses with high accuracy using stochastic subspace identification (SSI) with frequency bands separation method. However, trial and error is necessary to determine the estimation parameters. In this study, we examine the optimum value of model order and singuler vector length in SSI and freqency threshold in frequency bands separation method. As a result of examination, optimal value for the three parameters are found, and frequencies are estimated by SSI using these parameters. In addition, dominant frequencies are detected from kernel density estimation.

Noise barrier panels are often installed on the scaffoldings of building demolition works in order to cope with the environmental problem caused by noise and dust. However, these panels are difficult to remove and left even when strong wind is forecasted. A technical guideline can estimate wind load on the scaffoldings with panels. Still, the wind force distributions with various shape of scaffoldings corresponding to the demolition steps are not clear yet. Therefore, wind tunnel tests were conducted to get the wind force coefficient distributions on the panels for various steps of a building demolition work. Larger wind force coefficients were obtained with a model with an opening. The possible cause of such a large wind load was discussed.

This study investigates effective measures to suppress rail corrugation by theoretically analyzing ballastless tracks. First, a method to evaluate the degree of rail corrugation growth using a theoretical analysis model that considers the dynamic interaction between a track and vehicle is proposed. Then, the parameters of the track structure and track materials that are effective in suppressing rail corrugation on the outer rail of curves are examined for various ballastless track structures including newly developed floating supported ballastless track with under sleeper pad. Consequently, reducing the elasticity and damping of the undersleeper pad was considered the most effective in suppressing outer rail corrugation.

This paper experimentally investigates the effects of wind barrier parameters including porosity, hole scheme, installation method, height and vortex-induced vibration (VIV) countermeasures on the aerodynamic responses of bluff-box girders with different side ratios and the wind flow characteristics above them. The results show that wind barriers effectively reduce the mean wind speed above the girders but intensify vertical VIV and decrease the critical wind velocity for flutter. However, the proposed countermeasures completely suppress the VIV in a certain side-ratio girder. Generally, porosity is the most crucial parameter in both the aerodynamic performance of the bridge and wind-speed reduction above the bridge while other parameters show limited effects.

Strong crosswinds sometimes cause vehicle accidents on a bridge. Traffic regulations such as speed restriction and bridge closure are enforced to prevent these accidents. Wind fields on a bridge deck are complex and key parameters to affect crosswind-induced vehicle accidents. In addition, not only bridge structures but also vehicle itself cause complex wind fields on a bridge deck. This study investigates vehicle interaction effects of aerodynamic forces on a vehicle running on a bridge by using a specially developed model vehicle driving and its aerodynamic force measurement devise in a wind tunnel. It was found that a windward vehicle largely changes aerodynamic forces on a leeward vehicle by aerodynamic interaction. In particular, an overshoot phenomenon in the side force and yawning moment was observed just after vehicle passing.

A series of experiments were conducted to investigate the applicability of unsaturated AC magnetic flux leakage testing for fatigue crack detection at the paint-coated welded joints. Fatigue cracks were generated at the weld toes of Tshaped joints by applying cyclic bending loads. The signals were measured at the weld toe parts by the unsaturated AC magnetic flux leakage testing with a highsensitive sensor. The ratio of the measured signal magnitude at the cracked welded joints to the initial signal magnitude measured at sound welded joints was defined as the evaluation index. The fatigue cracks could be detected over the assumed 1 mm and 2 mm thick paint coating when the signal magnitude ratio was larger than 1.1.

Tsunami protection wall at the Hamaoka Nuclear Power Station is steel structure with high strength bolted frictional joints. Tsunami protection wall at nuclear power stations is required to control the inundation of the site even in repeated tsunami attacks or huge tsunamis that exceed expectations. Therefore, it is important to confirm the strength and deformation properties in the region exceeding the design load. In this study, cyclic tensile loading test assuming repeated tsunamis using specimens of high strength bolted frictional joints of tsunami protection wall due to confirm strength and deformation properties up to the ultimate state was conducted. Furthermore, we proposed a modeling method of the load-displacement relationship of the joints in the full-scale model.

While large-scale renovation work is being carried out, it is desirable to reduce the social impact of long-term traffic restrictions. By applying Precast Guard Fence to steel deck, the construction period can be significantly shortened compared to conventional cast-in-place protective fence. However, there are not examples of applying Precast Guard Fence to steel deck, and the design method of anchorages are not clear at present. In this study, we proposed a joining method for the anchorage of the Precast Guard Fence applied to the steel deck. The purpose is to clarify the behavior and fracture properties by conducting static horizontal loading experiment on full-scale specimen.

The authors are investigating the joint structure that can be applied only from the upper surface of the composite deck using high strength stud bolt. The bottom steel plate is 6mm steel plate, which limits the axial force that can be introduced by the stud bolts to about half that of high-strength bolts. We focused on the tendency of friction coefficient to decrease with increasing contact pressure when the joint surface treatment is inorganic zinc. In this study, FEM was conducted to increase the slip coefficient of stud bolt friction joint by cutting around the bolt holes on the top side of the splice plate. It is found that the contact area increased and the contact pressure decreased as the splice plate cloud follow the deformation of the main plate. It is also concluded that the cutting the splice plate improved slip coefficient.

This study aims to investigate the fatigue strength improvement effect of welded joints peened by ICR treatment using a chargeable electric device. First, flat plates were peened in different positions, residual stresses around the peened flat plates were measured and workability and efficiency of the ICR treatment using the chargeable electric device was discussed from the point of the finished surfaces view, and then a suitable treatment condition was determined. Finally, plate bending fatigue tests of out-of-plane gusset welded joints under stress ratio of R=-1 were performed and fatigue cracks developed in different lengths were ICR-treated using the device based on the determined treatment condition to investigate the fatigue strength improvement effect.

In this study, an FE model of a structure was constructed by the extending algorithm for constructing point cloud FE models that the authors have studied. The point cloud FE model was built from dense point cloud data by box-grid downsampling of the point cloud, segmentation of structural parts, finding contour in each section, 2D Delaunay triangulation in the section, making solid elements by connecting triangles, reconnecting structural parts and exporting to a formatted file. Static loading tests for a removed railway bridge and a linear static analysis of the FE model were conducted to verify the method. The point cloud FE model provided quantitative structural stresses, and the experimental and analytical results generally agreed with each other at the location of maximum stresses.

Fatigue cracks have been reported at the upper ends of vertical stiffeners in the main girder-cross beam connections of steel H-beam bridges. In this paper, fatigue behavior and its mechanism were investigated through finite element analysis of the entire bridge, as a case study of fatigue damage in an H-beam bridge. The effects of structural conditions and loading positions on the local stress near the crack initiation point were analytically examined. Furthermore, the relations between the local stress and deformation parameters related to main girder and concrete deck were also discussed in order to clarify the influence of the behavior of the entire bridge system on the local stresses.

In this study, FEM analysis was carried out to evaluate the shared shear forces on thickness-reduced plates repaired by patch plates with high-strength bolts. From the FEM analysis results, it was clarified that the shared shear force on the thickness-reduced plate repaired by patch plates is not corresponding with that given by the composite theory of the thickness-reduced plate and patch plates. Therefore, a simple equation was theoretically derived based on the shear displacement conformity conditions of the main plate and the patch plates between the high-strength bolts containing the thickness-reduced plate. The theoretically derived equation provides the shared shear force on the thickness-reduced plate repaired with patch plates within a 5 % error of FEM results.

Carried out dynamic analysis as a countermeasure for a large earthquake, stress of some main members in a Sky Gate Bridge R (steel truss bridge) are exceeded these yield stress. We make these members reinforced by using bolted cover plates to improve member resistance. However, regarding this reinforcement, it is not clearly regulated. And the mechanism of stress transfer of base and cover plate under the tensile or compressive load is not obvious enough. Therefore, assuming design conditions for such as required numbers of bolts to transfer stresses from base plate to cover plate, FEM analysis by using models designed these conditions is carried out by noticing thickness of plates and load conditions. It is concluded that the mechanism of stress transfer is obvious.

In orthotropic steel deck, many fatigue crack has been found at the weld joint between deck plate and vertical stiffeners. As a counter measure for the fatigue, semi-circular notch has been adopted to reduce the stress concentration around boxing weld. However, more effective notch geometry should be considered from viewpoint of ease of construction and fatigue improvement. In this study, reduction of stress and stress intensity factor were investigated for newly developed slit-like notch and sigma-shaped notch. In addition, fatigue tests were performed for the weld joints between deck plate and vertical stiffener with sigma-shaped notch. The crack initiation life and crack propagation can be extended by constructing sigmashaped notch at the top of vertical stiffener.

High strength bolted frictional joints with slotted holes perpendicular to each other have more space for adjustment to be joined. On the other hand, the slip coefficient and the strength after slip of such joints didn’t study much. Therefore, in this study, tensile loading experiments were carried out to clarify the slip coefficient and the strength after slip of the joints. As a result, it was found that the shifted slotted hole centers have a small effect on the slip coefficient, but it affects the yield strength. Also, the strength after slip in the experiment was more than the strength calculated from the assumed fracture line.

A series of experiment and analysis was carried out to investigate the influence of deformation and residual stresses due to induction heating for paint-coating removal on the compressive behavior of welded steel members, with L-shaped section. The induction heating increased the out-of-plane deformation of the panels of L-section. Tensile residual stresses were generated in the centre of the L-shaped cross-section by the heating. The increase in out-of-plane deformation reduced the elastic stiffness under the compressive loads by about 65% compared to the nonheated members. The influence of the variation of the residual stresses due to induction heating on the maximum compressive load was small.

The objective of this paper is to develop a semi-automatic method for constructing a practical finite element model from point cloud data of an entire of steel truss bridge. The members are converted to fiber-based models by automatically creating central axis lines and cross-sections from the point cloud. The slab is converted to shell models by obtaining surfaces and thickness from the point cloud. The effectiveness of the proposed method was confirmed by comparing the analysis results from the model manually created from the design drawing with the model generated by this method. The proposed method is more efficient than reading drawings and creating the models manually, and shows response values close to those of the drawing-model within the design load.

In this study, the transmission of axial force by high-strength bolted joints was modeled by shear springs, and a simple equation was given for the load transmission of the plate considering the range where the axial force is transmitted by friction and the area without transmission between high-strength bolts. Finite element analysis was performed, and the analytical results are possible to be estimated by the simple equation. In the case of a thickness-reduced plate, the equation was also driven by changing the boundary conditions. The analytical results of thickness-reduced plates repaired by patch plates were also estimated from the simple equations.

Fatigue cracks were initiated at slotted tubular joints in a testing overhead transmission tower. It was estimated that the cracks were caused by vortex induced vibration (VIV). In this study, the fatigue evaluation for steel tub ular memb ers in the tower was conducted with observed wind data and a response estimation method for VIV. The fatigue damage ratios of horizontal members and web members on the north side of the tower were good agreement with the actual failure state. However, those of members in the cross arm section were low accuracy because stress ranges were similar to the cut-off limit and wind was disturbed by upwind members Moreover, it was clarified that slenderness ratio of a member with a high fatigue damage ratio was limited to a certain range.

Many of older steel bridges with rivets have historical value due to their appearance. Repairing damaged rivets with new rivets is desirable from both mechanical and landscape perspectives; however, this repairing method is not being actively adopted at present due to constructability issues. Although a smaller rivet flange allows rivets to be formed with smaller loads, it is not known how much axial force is introduced into rivets. The mechanism to introduce axial force in the rivet due to cooling process is also unknown. In this study, the mechanism of introduction of axial force into the rivet during cooling process and the relationship between the axial force and rivet flange size were analytically investigated.

This study conducted FEM analysis with the aim of elucidating the mechanical behavior of high-strength bolted tension joints with varying edge distances and bolt pitches and assessing the applicability of existing design equations. The analysis results revealed that the influence of edge distance and bolt pitch on bolt force and the maximum load-carrying capacity of the joint is minimal, confirming that the existing bolt force estimation formulas can be applied. Conversely, as the edge distance or bolt pitch decreases, a noticeable reduction in the yield strength of the joint flange becomes evident. Furthermore, we proposed a correction method for the strength equation, which varies with the size of the edge distance and bolt pitch, to account for the changing yield strength of the joint flange.

The damage identification method using deflection influence line (DIL) is studied based on measured data in a damaged bridge model. Since the damage on the girders reduces the bending stiffness, a correction factor (CF) for bending stiffness is introduced as a damage index. DIL of the damaged bridge model is estimated based on MAP (Maximum A Posterior) estimation. Hyperparameters necessary for estimating the CF are calculated by maximization of marginal likelihood. Although the use of DIL calculated by MAP estimation with prior information improves the accuracy of identification of the damage locations, it is possible that the damage locations and their level are roughly identified without the prior information.

Conducting vibration measurements of stiffened aqueduct bridges using a small accelerometer which is easy to handle in the field, the results have been analyzed in comparison with the natural vibration analysis of beam models. The vibration characteristics obtained from the field measurements are fundamental information at the time of the design of the stiffened aqueducts, and can be used as basic information during inspections. The method of measuring by moving one small accelerometer can be used for periodic inspection of aqueduct bridges.

Several corner weld failures of steel piers during large earthquakes have been attributed to the rupture of corner welds with unwelded section. First, both of tensile tests and finite element analysis of the corner weld model were conducted parametrically in order to clarify the fracture mechanism of corner welds. As a result of the study, a fracture process was observed in which the cracks firstly occurred in the inner corner welds and then in the outer welds. Next the simplified verification method for the corner weld was also investigated. As a result of the investigation, it was found that the approximate bending strength can be calculated without considering the effects of stress concentration. In the future, we plan to investigate structural models through experiments and finite element analysis.

It's important to clarify the residual bearing capacity after a slipping in high strength bolted connections, in order to diagnose a corroded spliced plate. In this study, tensile fracture tests were conducted on high strength bolted connections with corroded spliced plates to clarify the tensile fracture behaviour. Moreover, the residual bearing capacity of corroded spliced plates after a slipping were examined by the experimental results. From the experimental results, the fracture behaviour of the corroded spliced plates was clarified and also provided an evaluation for the residual bearing capacity after a slipping.