More than two hundred cases of effective stress analyses with variation of seismic coefficients and liquefaction resistance were conducted. Among the parameters considered in this study, the most sensitive parameter affecting the wall displacement under a prescribed level of shaking is the SPT N-value of subsoil below and behind the wall. With the results of parametric calculations, a simple procedure and charts are proposed to evaluate the order-of-magnitude displacement of a quay wall. It demonstrated the capability to evaluate a wide range of displacements, ranging from the displacement in the order of one-tenths of meters to those with one order higher.

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This paper deals with load carrying capacity of corner joints between concrete filled steel columns and beams, with the help of loading tests and FEM analyses. For the loading tests, the model tests were carried out on four specimens by changing the position of stiffeners, the moss-section of beams. In the FEM analysis, six models were compared with each other to supplement the loading tests. As a result, it was found that each filling concrete in the corner hollow section has a constantly strong effect on the ultimate strength of corner joints regardless of whether the ring stiffeners are applied or not. The loading tests also confirmed that filling concrete circular steel pipes used for beam members were expected to two times post-yielding ductility to that of the filling concrete rectangular section member, the hollow circular section one.

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Though it is necessary even for already constructed bridges to improve their antiseismic property according to the Specifications for Highway Bridges 1996, there are many cases in which reinforcement is almost impossible. The tower of cable-stayed bridge responds to transverse great earthquake is one of such cases.
In this study, we made an attempt to reduce the response of tower by means of additional mass to the cables, which changed the interaction among girder, tower and cables. Because there were innumerable combinations of additional mass distributed to the cables, the best decision was made by some optimization techniques. Some numerical examples showed that the response could be reduced to sufficient level.

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Sharing of experimental data on Internet can assist researchers and engineers to conduct their works. Many studies on structural steel experiment database have been undertaken. It was difficult to add data constantly, since conventional databases forced the database manager to collect experiment information. This research aims to develop the system which shares the experiment information from wide range of fields. It allows each institution to release the data under the distributed collaboration environment containing a metadata server following the Dublin Core. Accessing only a metadata server, the users are able to retrieve those data stored at the other servers.

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As bridge is a part of road network and social asset, the asset value of bridge is dealt with in this paper. Degradation of member is considered as the decrease of asset value. To evaluate the asset value of a whole bridge, each asset value of structural member is investigated Taking each structural dimension into account, the initial cost of a whole bridge can be calculated as an asset value. Inspection data given by bridge inspection manual is used as deterioration factor and present remaining asset value is evaluated including deterioration. Taking the ratio between a remaining asset value and initial cost, the ratio is called Bridge Health Index (BHI). And those result of BHI is compared with the result of previous paper and validity of BHI is analyzed.

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This paper proposes a rational and efficient optimal design method for seismic-isolation bridge systems which consists of superstructures, seismic-isolation bearings, piers and pile foundations subject to huge earthquakes. The special characteristic values for dynamic hysteresis of seismic-isolation bearings, piers and pile foundations are dealt with as the design variables, and the estimation formulas of the maximum horizontal displacements are introduced efficiently as the functions of design variables by using the experimental design method. The proposed optimal design method is applied to construction cost minimization problems of five-span continuous steel girder bridge systems and rigorousness, efficiency of the proposed design method are clarified by investigating the optimum solutions.

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It has already been shown that phases defined in time and frequency domain are closely related with nonstationary properties of seismic motions by introducing complex envelope to Fourier analysis of seismic motions. In this paper, descriptions of evolutionary spectrum and time-varying phase based on complex envelope are given so that nonstationary properties of seismic motions simulated by using those are discussed on the basis of above-mentioned relations. Furthermore, such properties of simulated seismic motions modeled on an observed motion are revealed by means of instantaneous frequency, group delay time and strength demanded spectrum. Those of seismic motions simulated by a conventional method are also examined in detail.

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Rocking response of a direct foundation under a strong near-field ground motion may result in the uplift in the foundation, and it often results in the yield of the underlying soils. The rocking response with uplift interacts the nonlinear hysteretic response of a bridge that is supported by the foundation. This paper presents how large uplift is expected in a direct foundation that is designed in accordance with the traditional elastic static seismic method, and the effect of rocking response on the hysteretic response of a bridge pier. It is found that the rocking response result in about 0.1-0.2m uplift in a direct footing, with 6.5m long and 7m wide, that supports a 10m high standard viaduct. It is also found that the rocking response of a direct foundation reduces the nonlinear hysteretic response of a bridge pier.

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No matter how the plastic hinge region is confined by ties, a reinforced concrete pier that suffered flexural damage in an extreme earthquake has to be repaired after the earthquake. Since failure of core concrete occurs only at the plastic hinge region, if a stable material under cyclic load excursions could replace the concrete at this region, the pier could perform satisfactorily without failure of concrete. Thus, repair after an earthquake could be eliminated. Based on such a concept, this paper proposes a new pier with a rubber layer at the bottom. Cyclic loading tests for 5 specimens with a 400mm×400mm section was conducted to clarify the performance. Various factors including the effect of confinement of rubber by steel plates and shear key were studied. Fiber element analysis was also conducted to reveal the performance of the new pier. It was found that it is feasible to construct a reinforced concrete pier that has stable hysteresis up to 4% drift without significant damage in the core concrete.

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This study is aimed at offering fundamental data needed for development of an ultimate earthquake-resistant design method for steel frame structures. For this purpose, the shear strength and ductility of unstiffened box section members are evaluated from the results of large-deformation elasto-plastic FEM analysis for web plates including the effect of flange plates. As a result, it is obtained that the strength calculated in this analytical model is almost the same as the results excluding flange plates, and the ductility is slightly larger than the previous results. Furthermore, the required flange thickness is discussed from the viewpoint of strength and ductility through parametric study on flange thickness to web thickness ratio. Finally, the formula estimating the ductility capacity of web plates is proposed.

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The extended Kalman filter is applied to the simultanious identification of tension and flexual rigidity of cables which diameters are comparative large with the length. The one degree of freedom model reduced to low order natural frequency mode is used as the mathmatical model of cables. on the extended Kalman filter. The experiments are carried out by using the twisted wire which diameter is 0.0287m and length is 1.990m. Impact hammering and an attached type excitation machine are used as excitation methods. Because the mass of the attached type excitation machine was not able to be disregarded compared with the mass of the cable, the frequency equation of the cable which had the additional mass at an arbitrary position was led, and was introduced into the extended Kalman filter. It was confirmed that the tension and the flexural rigidity of the wire were identified accurately by the experiment in the area where the tension was small.

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Railway elevated bridges in urban areas are often constructed under many spatial restrictions in a limited time. Moreover, railway structures are demanded to show the high seismic resistance. A hybrid railway elevated bridge may be a structure to meet above-mentioned requirements. Authors have already proposed a method of evaluating performances for concrete-filled tubular steel pipes and concrete encased steels, which are used as column and beam members in hybrid railway rigid frame elevated bridges respectively. On the other hand, a design method of beam-to-column joint panels of hybrid railway elevated bridges is not enough clarified.
This paper describes a design method of a newly developed beam-to-column insert joint, where steel frame and rebars are inserted into concrete filled tubular steel columns, based on the experimental study.

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This paper presents both an application of the distinct element method of debris flow passing through the open type steel made check dam structure and a stochastic evaluation method for the damming up performance of the structure hit by the debris flow which includes huge rocks or large gravels.
The simulation by the distinct element method shows very well the plugging mechanism observed at the open space of the check dam by the rocks or gravels and its randomness induced by the randomness of gravel size and gravel arrangement contained in the debris flow. The proposed stochastic evaluation method can estimate very well the expected value and/or its variation for the simulation results by the distinct element method.

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Measuring the stress and checking the welded sections are carried out as the investigation of the fatigue cracks at the frame connections of steel bridge piers. The measured stress was found to be much larger than that of considered in the design. Also, large lack of fusion was found in the double bevel groove type welded sections. Because of these large stress and defeats, the fatigue cracks were developed. As the temporally-repair, bolted splice plates were installed on the box webs of the connections. This repairing decreased the measured stress by about 50%, so that these piers can be used safely temporally. But still, it is needed to remove all the fatigue cracks as the final repair. Further studies on the method of this removing are necessary.

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The dynamic response of the human body exposed to vertical whole-body vibration has been investigated in an experiment involving human subjects. The apparent mass showed a principal resonance at a frequency around 5 and 6Hz for standing and seated subjects. Bending of the lumber spine at the principal resonance frequency has been illustrated based on the measurement of the transmissibilities. An investigation of mathematical models showed a possible major contribution of the vertical motion of the viscera to the principal resonance of the apparent mass for standing and seated subjects. For the seated body, deformation of the tissue beneath the pelvis may also make a major contribution to the resonance.

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In this paper, a method of optimization of risk transfer due to earthquake insurance is proposed, which is aimed to be used for a countermeasure of disaster prevention. In this method, a risk is defined by annual expected loss considering a coverage of insurance and an acceptable premium. The coverage of insurance is determined by deductible and limit, and the loss of insured and insurance company can be evaluated in probability mass function with its coverage. Also the acceptable premium can be provided by the function of loss considering subjectivity of decision-makers. The optimal risk transfer is showed by deductible and limit which minimize the risk of insured. The effectiveness of risk transfer and the validity of the proposed method is demonstrated through the numerical example.

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In order to investigate fatigue behavior of welded joints under the combined stresses, which consist of normal and out-of-plane shear stress, fatigue tests of butt-welded joints containing lack-of-penetration inclined to applied stresses are carried out. The inclined angles are 0, 15, 30 or 45 degrees for transverse direction which is perpendicular to applied stresses and a gap of 0 or 1.5mm wide is introduced in each specimen. The test results show that the inclined angles and applied stress ranges influence the pattern of fatigue crack propagation, which can be divided into two types. The test results arranged for 0, 15 and 30 degrees show almost the same fatigue life when the data are plotted for nominal stress ranges at throat section. The test results for 45 degrees show the longer fatigue life than the other specimens.

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This paper presents a series of shaking table tests of a model bridge to identify the effect of pounding and restrainers. The model bridge was of two span steel decks supported by steel columns. Rubber shock absorbers and cable restrainers were provided at the ends of decks to mitigate the pounding effect. The decks were excited by a shaking table. The test result that presents the effect of poundings between the decks and cable restrainers was analyzed by a nonlinear dynamic response analysis. The impact spring was used to idealize the pounding effect. It was found that good agreement was obtained by the analytical simulation.

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A generalized inversion scheme to separate the effects of source, propagation path and local site from S-wave spectra was applied to “Small-Titan” records obtained in the Sendai region, North East Japan. Site amplification factors estimated from the generalized inversion scheme vary significantly, reflects the effects of soil characteristics at each site: strong site-dependency was found in the site amplification factors. Results from the generalized inversion scheme are compared with those obtained by the direct spectral ratio scheme, the H/V method and the bootstrap inversion. There is a good agreement in the amplification factors between them. The H/V method for estimating site amplification is found to extract the same predominant periods as the other methods. This paper especially emphasizes a good agreement in not only predominant periods but also amplification factors. Estimated source spectra and Qs-value were also in an agreement with results of previous studies by others.

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An aluminum deck is fabricated by joining hollow extrusions with the friction stir welding (FSW). The purpose of this study is to understand the fatigue behavior of the deck. The material properties of the FSW region are investigated. A fatigue test is carried out for the deck, to show that a fatigue crack is initiated along the FSW-joining line of the top plate just under the load. The plate-bending stress produced by the local deformation of the top plate causes it. More fatigue tests are done for the beam-type specimens provided by cutting the deck in the transverse direction. The tests reveal that where the supporting interval of the deck becomes large, a fatigue crack is caused at the FSW of the bottom plate by the membrane stress due to the global bending moment, and that it propagates in the transverse direction to the FSW-joining line.

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The characteristics of severely damaged buildings were examined by image processing of aerial television images taken after the 1999 Kocaeli, Turkey, the 1999 Chi-Chi, Taiwan and the 2001 Gujarat, India earthquakes. In image processing, color indices and edge elements calculated from the post event images were used. After pixels indicating damaged buildings were detected, the texture analysis of the image was attempted to identify the areas corresponding to the size of buildings. The extracted areas almost corresponded to the results of visual inspection. We found that the threshold values to judge damaged buildings should be determined for each image or for the images having similar built environment and damage pattern.

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Studs are often used as shear connectors or anchors between concrete and steel members at various composite structures. Generally as each stud has different edges distance from the edges of structural concrete, it is not expected that they have same pull-out and shearing strength as the studs located enough inside, even if all studs were arranged in a group to be subjected same displacement.
In this paper, the authors evaluated again test data of previous investigation including their new test results and strength equations for pull-out and shearing capacities were revised in the case of free to consider the edge distance. Then in the case of the studs to be considered the edge distance, new influence factors were found and composed into the revised equations as coefficients.

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To cross deep valley PC box girders have been adopted. Recently, a developed form of the girders with corrugated web begins to be used to satisfy the severe request of the reduction for the cost and time during construction. However, the corrugated web does not possess rigidity along the span axis, and influence due to shear deformation strongly appears under bending. This report introduces an elastic equation extending beam-bending theory considering shear deformation. To respond to the demand from bridge engineers who require rational design method, a series of analyses varying structural dimensions were achieved and the effect of the shear deformation is investigated for the actual structure.

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The interaction between a stiffening girder and a floor system always make some problems in the design of through-type arch bridges. The purpose of this paper is to investigate the relation between rigidity of floor system and additional stress, and to propose a design method for floor system. In order to study the interaction behavior in actual structure, a typical through-type arch bridge was analyzed using 3-D frame model. And, in order to explain the interaction behavior qualitatively, a new approximate formula was proposed by improving Bleich's formula. As the result, this study indicates the rigid design method using a box-type girder as an end floor beam excels what is called as the flexible design method.

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An application of concrete-filled steel tubes to main arch ribs is discussed based on 3-dimensional static and dynamic analyses of a prototype half through braced-rib arch bridge. The method for nonlinear characteristic assessment of a concrete-filled tube considering the composite action of steel pipe and concrete is proposed. Difference of the dead load stress in steel pipe arch ribs due to the different concrete-filling sequence is considered, and the safety evaluation of arch ribs is performed using both the allowable stress and the ultimate strength design method. The bridge performance during strong earthquake motions comparable to the Great Hanshin Earthquake is assessed in detail through a nonlinear time-history analysis.

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Liquefaction array observation has been conducted since 1990 at two adjacent sites on soft soil in Tomakomai, Hokkaido. Several records during earthquakes including the 1993 Kushiro-oki earthquake were successfully obtained. This paper shows that the orientation errors of accelerometers varied between -9 and +64 degrees. And it illustrates that excess pore water pressure starts to be built up more than 20cm/s² in acceleration at the ground surface and suddenly increase over 100cm/s² as part of conclusions.

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The relationship between surface ground strain records and ground motion velocity records is examined. More records than observed in this study are needed to obtain a credible relationship between strain amplitude and velocity. As for the relationship between time history of strain and that of velocity, the time variation of two strain invariants and that of resultant velocity are compared at interval of 1/100 second. When the absolute value of strain invariant showed a peak value in time history, the resultant velocity showed a minimum during sinusoidal vibration and showed a peak value during wave propagation. According to the analysis, the state of sinusoidal vibration and wave propagation appeared respectively in about half of the measurement. Therefore, the relationship between time history of strain and that of velocity was not clalified.

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We present a simple method to estimate the horizontal incident direction of earthquake ground motion, which gives most severe response of a curved girder bridges: we call it “critical direction.” To find the critical direction, most of designers have to calculate dynamic responses of a structure for incident waves from various azimuth. Thus, the many resources are required for calculation. To diminish such the difficulty in numerical calculation, we improve a method proposed by Okano. He has developed a method to estimate the principal axis of the ground using coherence functions among the observed time traces of earthquake ground motion. It is concluded that the proposed method can reduce the cost for numerical calculation without a lack of accuracy.

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