In the seismic retrofitting of the existing railway viaduct, not only the improvement of the strength and the ductility but also the improvement in safety of trains running on viaducts was necessary. In this research, to confirm the effect of limiting the response displacement of a viaduct by the brace reinforcement, the shaking table test using a one-fifth scaled specimen of the viaduct was executed. And a series of dynamic interaction analysis between the trains and the structures was conducted to investigate the effect of the brace reinforcement on running safety of the trains in the event of an earthquake. As a result, it was shown that the bridges reinforced with braces better running safety than those without, due to the seismic wave was controlled by the brace reinforcement.

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Steel side blocks are set besides the seismically isolating bearings of a viaduct and are designed as a joint protector against the Level 1 earthquake. The authors suggested the CSB as rapture controllable steel side block with knock-off function and as a trigger to provide isolation effect not only in the direction of the bridge axis but also in the transverse direction against the Level 2 earthquake. In this study, the knock-off effect of the CSB in a vibration system consisting of bridge pier-rubber bearing-mass is investigated through shaking table test. Also the installation effect of the CSB is verified through seismic response analysis of a viaduct with isolating bearings.

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This paper shows the relation of wave velocity and wave height to hydrodynamic force in tsunami act on a bridge. This research conducted hydraulic experiments using bridge models of rectangular and channel form with a width to height ratio of 1, 2 and 4. The experiment measured hydrodynamic force, wave velocity and wave height. As a result, in case of bridge models of rectangular form, hydrodynamic force in vertical direction occured in a downward direction immediately after tsunami acts on a bridge. On the contrary, the channel form model was subjected to weak downward force due to the water flow inside the model. Hydrodynamic force to the bridge in horizontal direction was one to five times larger than the wave force.

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The possibility of reproducing the wind direction fluctuation is studied by a new type wind tunnel, which is called as a fluctuating wind direction tunnel (FWDT). The FWDT consists of eight inflow and eight outflow wind ducts with shutters, which are radiately located around the test section. By opening only one or two sets of inflow and outflow ducts, wind blows in that direction. Now this FWDT is installed with 10 shutters that can be controlled by a computer, and 90 degree wind direction change can be made at most. Wind characteristics in FWDT and the best shutter opening and closing timing with smaller wind speed fluctuations during the wind direction change were studied. Better shutter timings were found to be that with the simultaneous closing and opening of the inflow ducts of the pre- and post- wind direction change.

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In this study, the aerodynamic coefficients of the single and four-bundled conductors were obtained with wind tunnel tests for five kinds of ice and snow accreted shapes. These tests were performed in variation with the wind speed. The results have shown that, because of surface roughness of the wire, aerodynamic coefficients of the ice and snow accreted conductors vary with the wind speed in the range where galloping could occur. Furthermore, to obtain the individual aerodynamic coefficients of each subconductor, surface pressure measurement tests on the individual conductor models were performed. It is clarified that the aerodynamic coefficient of the downstream side conductor decreases due to the wake generated by the upstream conductor.

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Flow patterns around a bluff body are governed by small-scale turbulence and simulation of large-scale turbulence in a wind tunnel is often difficult. An idea of partial simulation of turbulence that simulates the normalized PSD in a high-frequency part was recently suggested. In this study, the idea of the partial simulation of turbulence was experimentally investigated. Base pressure coefficient and Karman vortex intensity of rectangular cylinders with various slenderness ratios were compared for pairs of turbulences partially simulated. The result showed that the base pressure coefficient at and larger than the critical slenderness ratio fairly agrees among the partially-simulated turbulence pairs. However, Karman vortex intensity was not simulated in the partially-simulated turbulence pairs.

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Since the serious corrosions on countermeasures for aerodynamic stability were found on the Tozaki viaduct, which was completed approximately 20 years ago, it is necessary to make the repair plan. In order to reduce the future maintenance cost, the reevaluation on aerodynamic stability of this bridge was conducted. As a result, it was clarified that the half of the original countermeasures have little effect on the aerodynamic stability of this bridge and those members were removed. Furthermore, it was also confirmed that there was no particular change of the dynamic characteristics of the girder before and after the removal of the half of the countermeasure.

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The corrosion durability of steel and concrete structures depend on the amount of airborne salt, and the observation of airborne salt is important to estimate corrosion durability. Airborne salt is observed by accumulation apparatus such as dry gauze type apparatus established by JIS or Doken type apparatus proposed by PWRI. However, the amount of airborne salt is influenced by setting direction of these apparatuses. In this paper, relation between airborne salt and setting direction of airborne salt accumulator is discussed by the observed results of airborne salt and wind velocity and direction.

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Fiber reinforced polymer (FRP) composites have been widely used as externally bonded reinforcements to strengthen or rehabilitate different kinds of deteriorated concrete structures. However, premature debonding failure due to the limitation of bond at the FRP-concrete interface are often encountered under utilizing FRP material potential for strength increase. To minimize debonding failures due to environmental factors such as water intrusion, etc. and other mechanical damage such as vehicular traffic and impact, etc., near surface mounted (NSM) FRP technology has emerged as another structural strengthening method. This study aims at developing a new strengthening system for the rehabilitation of deteriorated concrete structures using prestressed NSM carbon fiber reinforced polymer (CFRP) tendons.

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A port steel structure under marine environments often shows structural performance degradation due to loss in steel cross section caused by corrosion. Therefore, repair and strengthening methods that have high potential for use in the sea are needed. In this paper, a conventional FRP bonding method was focused on to investigate its applicability to port steel structures. CFRP strand sheet was bonded with epoxy lining material that is hardened in the water on a steel pile having a purposely decreased section to simulate the real corrosion status. Bond tests on steel plates and bending tests on corroded steel pipes strengthened by CFRP strand sheet were carried out. As a result, it was proved that the bonded CFRP strand sheet through the particular epoxy lining material can reduce the stresses efficiently in corroded steel piles. The effectiveness of the proposed strengthening method was demonstrated.

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Tokaido Shinkansen has more than 4000 RC rigid frame viaducts on its line. Some piles for these viaducts are end-born by layers with substantial bearing capacities above lower soft soils. Vertical acceleration of these viaducts under train loads is comparatively higher than that of other viaducts. There is no matter of structural durability in present. However, they might deteriorate their durability with aging due to their vibration. Then, we have conducted additional steel piles and RC underground beams which connect the steel piles and the bottom of columns of the viaduct in order to reduce their vertical acceleratin. And we evaluated the effect of its structural reinforcement.

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Deterioration of a pipeline system is normally realized by an accident of water-leakage due to damage accumulation of pipe materials. For effective maintenance and management of pipeline system, it is necessary to evaluate not only the degree of damage but also the water-flow conditions (i.e. gas-liquid flow). In this study, acoustic emission (AE) method was applied to be detecting a gas-liquid flow in open type pipeline system. Two experiments were conducted in laboratory model and open type pipeline systems in service. The results show that a gas-liquid flow conditions could be quantitatively evaluated by using AE parameters, such as generation behavior, average frequency and AE energy. It becomes clear that the situation of gas-liquid flow in the pipeline system can be clearly identified through AE monitoring. Thus, it is demonstrated that AE monitoring is effective for qualifying the gas-liquid flow conditions in an open type pipeline system.

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In order to guess the behavior of member causing fatigue damage at joint part in a railway truss bridge, experimental measurements in actual bridge was conducted by using wireless acceleration sensor devices and strain gauge. The grobal behavior of member, causing the fatigue damage when train passed through the target panel point, was verified based on the local strain data from strain gauges and acceleration data from wireless sensors. Finally, from the measurements, a countermeasure for the prospective fatigue crack was suggested.

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Steel-concrete composite slab seems to be preferable one to satisfy required performance on easy management in the specification of highway bridges. In this study, concrete replacement of the locally damaged steel-concrete composite slab was focused. In order to verify the continuity on fatigue durability after replacement as before, an experimental investigation was carried out with the wheel road running machine. As the result of tests, any abnormal degradation was not found and the replacement was improved to have a beneficial effect on fatigue durability of steel-concrete composite slabs.

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The equivalent shear stiffness of a rubber bridge bearing increases over time due to the deterioration of rubber. It was assumed in the past aging estimation that rubber in the bearing and at the surface had the same temperature as its surrounding ambient temperature because rubber bearings were thought to be usually in the shadow as they are installed between the superstructure and the substructure. However, in the actual environment, there are many bearings that are exposed to solar radiation that causes bearing temperature to increase. To evaluate the effect of solar radiation on the bearing temperature, bearing surface temperatures were measured for a bearing installed on an elevated highway in Nagoya, Japan. In addition, to understand a temperature variation in a bearing, a bearing model was manufactured, and a temperature measurement of internal temperature was carried out. Long-term performance of rubber bearing by considering solar radiation effect on bearing temperature was investigated.

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The decrease of the support function causes the fatigue crack to occur in the sole plate weld. We are concerned about the decrease of the support function having bad influence on superstructure. However, the concrete influence level is hardly examined.
In this study, the loading test is performed in bridges where the support function is normal and deteriorates. We identify consistency with FEM analysis values as these test results. FEM analysis is carried out about the state that design live load and temperature load acted on in the existing steel composite I girder bridge where the support function deteriorated.
We examined an influence degree of the decrease of the support function from the result.

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In order to investigate the structural behavior of an old continuous non-composite steel I-girder bridge with deck joints, which had been in service for five decades in cold region of Hokkaido, Japan, visual inspection and static/dynamic loading tests were conducted. In addition, analytical study using frame analysis and FE analysis were carried out. It is found that composite action between concrete deck and steel girders is clearly shown through comparison between analytical values and measurement values, and that there is a little difference between FEA and measurement values.

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In this paper, the ultimate strength of the girder end with corrosion of a plate girder for Highway Bridges is studied by FEM analysis. We have dealt with the stiffener or web on the support, whose effective sectional area is lost by corrosion at the end of the bottom portion. The vertical stiffener on the support is designed as a column subjected to compression. But in the case that the thickness of the plate at the bottom end is decreased by the corrosion, it is considered that the limit state of the bottom-end is dominant. Finally, the design concept of the stiffener is also discussed.

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A reliability-based durability design for reinforced concrete (RC) structures in a marine environment based on the partial factors format is proposed. In the proposed method, RC structures are designed so that the time to the occurrence of the specified amount of steel corrosion provided by the partial factor and design criterion is longer than the design lifetime. By using the proposed method, RC structures satisfy the target durability reliability level without any probabilistic calculations. Also, the effects of uncertainties involved in the evaluation of the amount of steel corrosion in durability design of RC structures are discussed based on the sensitivity analysis.

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This paper presents a series of experiments on fourteen different assemblies of fillet weld joints produced by both underwater and in-air welding. Mechanical properties of underwater fillet welds in terms of strength, ductility, and failure modes are investigated in this study. Weld profiles, hardness distributions, and metallographic features of underwater welds are also examined. The study indicates that underwater fillet weld joints have larger strength but smaller ductility when compared with their counterpart in-air ones. The increase in strength ranges from 6.9% to 41.0%, and the decrease in ductility is about 50% for most of weld assembly types. Underwater fillet weld joints on corroded SY295 steel exhibit inferior ductility due to underbead cracks. Based on the test results, the paper proposes a practical method to model underwater welds in finite element analysis.

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In this study, in order to clarify the mechanical behavior, and the relationship between corrosion and residual strength of single-riveted joint damaged by corrosion, experimental and analytical studies are carried out. In the experiment, are used the specimens, which cut from the demolished steel bridge members. Two types of the specimens, light and the heavy corroded joints, are prepared and tensile tests are excuted. In FE analysis, corroded condition of rivet head is varied and parametric analysis is carried out. From the result, it is found that there is the influence to strength when a rivet head is corroded heavy, in case of the single rivted joint.

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Significent increases in traffic intensity and wheel loads are causing fatigue cracks in orthotropic steel decks. Under traffic loading, in particular the local effect of wheel loads, longitudinal welds between deck plate and trough rib are subjected to local transverse bending moments and are susceptible to fatigue cracks. For the purpose of evaluation of crack originating from root of weld, FEM analysis modeling the full-scale orthotropic steel deck of two span continuous box girder bridge is carried out. The stress of welds which originates in a deformation of large range in deck plate is calculated. From these analytical results, it became clear that the state of the stress under different loading location affects fatigue cracks.

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Recently, with a series of accidents of steel truss bridge failures, the structural redundancy has become important in maintenance management. And the redundancy analysis has been receiving much attention. However, the exact redundancy analysis has not been investigated as yet. Therefore the purpose of this study is to develop and evaluate redundancy analysis program capable of estimating structural redundancy and fracture critical members of truss bridges including progressive member failures. Moreover, this program is applied to an actual three-span continuous steel truss bridge.

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Two types of impacts occur due to a sudden failure in a diagonal tension member of truss bridges. One is the primary impact caused by the longitudinal strain wave propagation from the failure point. The other is the secondary impact resulting from the dynamic transition of the overall equilibrium from the pre-failure state to the post-failure state. It is shown by a precise dynamic analysis that the secondary impact is much larger that the primary impact. Thus, the properties of the secondary impacts are investigated for two types of Warren truss bridges in view of the application to the redundancy analysis as an impact factor. This impact factor takes almost a constant value for the important members where large stress increment occurs by the member failure. For practical application, an approximate method is proposed to predict the secondary impact without carrying out dynamic analysis.

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Adequate maintenance is needed to life extension of steel bridges in Tokaido Shinkansen line because it is the vital infrastructure for transportation in Japan. It was reported that the heavy wheel load, which was over 130% of static one, occurred on long span truss bridges. Thus, the distribution of the heavy wheel load was identified and its effects on struncturs were evaluated by measurement and 3D dynamic analysis. As a result, heavy wheel load concentrated at particular location where specific track structure existed and the maximum stress range did not exceed fatigue limit. The analysis revealed that stress ranges were related to train speed because of resonance vibration of stringers. Based on these findings, retrofit procedure triggered by wheel load is proposed as a countermeasure.

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At present, it has been reported that the limit span of a suspension bridge will be around 4000m. In order to realize such super long-span bridge, the development of new construction techniques is necessary. Furthermore, in Japan, the economy and durability by the rational design is strongly demanded. This paper clarifies the elasto-plastic behavior and the ultimate strength of continuous suspension bridge with 4 super long spans. In particular, we examine the effectiveness of applying two boxes and grating cross-section to a main stiffening girder and 2000 MPa high strength cable to the main cable.

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Application of high-strength steel bolts to friction joints for aluminum alloy plates demands to make clear the problems arising from the difference between aluminum alloy and steel in strength, Young's modulus and coefficient of linear expansion. In this study, on friction joints for aluminum alloy plates fastened by high-strength steel bolts, the relation between the reduction in bolt axial force due to creep of aluminum alloy and the time elapsed, and the one between the change of the bolt axial force and the temperature change are provided. The relation between the bolt axial force and the deformation of the surface of aluminum alloy plates is revealed.

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Recently, thousands of fatigue cracks have been detected in orthotropic steel decks in Japan. Among them, fatigue cracking in welded joints between bulb ribs and lateral ribs is the most frequent type. In this study, we tried to grasp fatigue behaviour in the welded joints between the bulb rib and the lateral rib through fatigue tests of the orthotropic steel deck specimen which is same structural detail as A-type bridge. Fatigue cracks were initiated at the weld toe of the upper part of the slit and propagated through the weldment into the deck plate. We confirmed that the fatigue crack detection life of the welded joint between the bulb rib and the lateral rib was improved more than eight times by applying angle steel reinforcement.

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In a timber bridge, resin is filled up into bolt-hole clearances to prevent backlash. However, the effect of resin on the mechanical properties of bolted connections has not been sufficiently clarified. The authors carried out static tensile tests to clarify the effects of filled up resin on the pull-out properties of a bolted connection. As a result, it was cleared that filled up resin in bolt-hole clearance increases not only the pull-out capacity but also the stiffness of a bolted connection. It was also indicated that filling up resin into a bolt-hole clearance has the same effect as increasing the bolt diameter to the size of a bolt-hole from the viewpoint of strength, and remarkably improves the toughness of a bolted connection.

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In recent years, the concern of environmental problem is globally rising. Since amount of carbon dioxide exhaust at construct of timber bridge is much smaller than that of steel or concrete bridge, attention of timber bridge increases. It is more effective to utilize timber for railing in visual effects and decreasing amount of carbon dioxide exhaust. Although the design standard for road bridge cannot be filled with current technology to make timber railing, the standard for pedestrian bridge can be filled with it. In this study, we make prototype of timber railing for the pedestrian bridge, experimentally investigate the performance and compare FEM analysis with experimental results.

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A lot of wooden bridges naturally match, and are used from excellent on the spectacle for the pedestrian bridge in the park. However, longevity of life in the wooden bridge is shorter than the steel bridge, the RC bridge, and the PC bridge, etc. It is necessary to establish the deterioration diagnosis technique to manage the wooden bridge maintaining. The object bridges in the present study are wooden pedestrian bridge of two different arch types. Because both bridges pass 15 years that are the management periods in the wooden bridge, deterioration is remarkable. In the present study, static and dynamic loading tests are examined using the human power load. The deterioration diagnosis of the object bridge is tried by comparing it with the test results when those test results are constructed.

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This research studied the flexural strength of the members where bond loss occurred in tensile reinforcing steel. The implementation of the tests on member specimens and analytical study was conducted with length of bond loss, reinforcement ratio, and existence of the concrete cover as parameters. For the members where the concrete cover had flaked off, and the members where the reinforcing steel was gouged out due to repair work, from the result, it was clear that the longer the length of bond loss and the higher the reinforcement ratio, the more remarkable the decrease in the strength if compared to non-deteriorated members.

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Using the expansive concrete, experimental tests were performed to investigate the failure mechanism of reinforcing bars due to ASR. As a result of the experiment, the cross section deformed roundly by the expansive concrete, and the angle of bending bars increased 2 degrees at the corner. The most progressed crack of reinforcing bars was 7.42% of the diameter of the reinforcing bars. There have a clear relationship between the increment of angle at the corner and the progress of crack of reinforcing bars.

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In reinforced concrete structures, mechanical anchors are increasingly being used in place of hooks to improve the bar arrangement of these structures. However, the use of mechanical anchors involves higher expenses than that of hooks. Therefore, the mechanical anchor method fixed in reinforced bar with thread was developed for cost cut and to make that method that can apply to various ribs. From test results, it was confirmed that the thread strength is equal to the base material strength for diameters D16-D35, strengths SD295-SD490, and ribs (standard steel bar and steel bar with threaded rib). The results of a load test on a beam and wall confirm that the performance achieved using the mechanical anchor is identical to that achieved using existing hook anchors.

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The failure mechanism of loop-shaped re-bar joint under bending moment is investigated from analytical point in this paper. In the analysis, RBSM is applied to describe the failure behavior of RC member with the loop-shaped re-bar joint. Validity of the numerical model is verified by comparison of a loading examination, and the failure process and the stress transfer mechanism are discussed.

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In RC high piers, there are problems of high axial compressive stress and congested reinforcement arrangement. In this study, in order to put the high strength material into practical use for RC high pier, seismic performance of RC high pier using SD490 reinforcement and concrete which has compressive strength of 30N/mm² or 40N/mm² under high axial compressive stress was evaluated experimentally. Experimental results satisfied load capacity and ultimate displacement calculated by Specification for Highway Bridges. It is noted that the combination of SD490 and 30N/mm² or 40N/mm² concrete has a small effect on ultimate state, and possibility of reducing amount of reinforcement by the use of SD490 was indicated.

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This paper represents a tension stiffening effect on a High Performance Fiber Reinforced Mortar (HPFRM), which has a compressive strength of 130 N/mm² and high tensile ductility by the addition of short steel fibers. Uni-axial tensile tests on the reinforced HPFRM with various fiber content and fiber orientation were conducted. On basis of the experimental results and the analytical simulations using Rigid Body Spring Model (RBSM), a simplified equation to determine the tension stiffening effect on the HPFRM was proposed. The accuracy of the model was verified through simulations with non-liner FEM analyses on reinforced HPFRM members.

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Concrete deterioration exerts a large influence on the endurance performance of a concrete structure. The present study inspects safety with respect to maintenance and management by conducting the deterioration progress forecast of alkali aggregate reaction that is one of the concrete deterioration factors. The target of the forecast is a real structure where alkali aggregate reaction ASR has been progressed. To evaluate the current and future situation of ASR the analytical method by which ASR is reproduced is employed. As a result of the analysis, it turned out that the targeted real structure was not in a serious condition not only for the current but also future situation.

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In order to establish a numerical analysis method for evaluation of the flexural reinforcing effects of fiber reinforced polymer (FRP) sheet for the damaged RC beams, a 3D nonlinear FE analysis method is proposed. In this paper, both smeared and discrete cracking models for concrete are applied. For numerical simulations, two damaged beams are prepared which are pre-loaded up to point of: 1) the rebar yield point; and 2) the residual displacement reaching 0.4 % of the clear span length. Those are reinforced by bonding Aramid FRP (AFRP) sheet and statically reloaded up to reaching the ultimate state. The numerical results are compared with the experimental ones. From this study, it is confirmed that applying the proposed numerical analysis method, flexural reinforcing behavior of the damaged RC beams due to bonding AFRP sheet can be better simulated.

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The purpose of the present study is to investigate an effect of the rubber-latex mortar which is sprayed on the surface of steel of the continuous composite girders. There are few examples that rubber-latex mortar is sprayed on all over the steel. In order to investigate the effect of the rubber-latex mortar, the results of static load tests for the models with the rubber-latex mortar coating are compared with those of the models without the rubber-latex mortar coating. From this study, it is concluded that the rubber-latex mortar coating improves the slip resistance between steel and concrete.

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This study deals with the deformation and failure behavior of concrete-filled CFRP box beams under four point bending and axial load. Various parameters such as fiber volume proportion, concrete strength and ratio of bending moment to axial load were examined in the past experiment. A finite element analysis is carried out to confirm the deformation and failure behavior. It is shown that the deformation is affected by the interface and confined effect of CFRP, and the failure is caused by a combination stress. Based on the results of the analysis, a deformation and a failure load caluculation method are developed. Finally, the results of the methods are compared with the experimental results.

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Recently, actual steel members have been repaired by bonding CFRP strips. However, in the current repair method, the CFRP strips, despite their excellent mechanical properties, were not optimally utilized. It is because the stress induced in CFRP strips by live load is relatively small. In order to distribute the stress induced in steel members by dead load to CFRP strips, pre-stress inducing method is effective. However, bending moment when CFRP strips peel off from steel members at the ends of CFRP strips becomes small by inducing the pre-stress. In this study, debonding behavior of pre-stressed CFRP bonded steel members under bending condition is theoretically analysed, and the debonding bending moment of CFRP strips is given.

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Composite slab bridges have been widely adopted and have growing needs for continuous bridges because of their low girder height. The supports of continuous composite slab bridges should have more complicated structures and require wider space, compared to those of simply supported bridges. Thus, it is difficult to place a bearing under each main girder, as in constructing a simply supported bridge, when it has relatively short intervals between girders. In this study, the possibility of reducing number of bearings is evaluated by a series of three-dimensional finite element analyses.

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The steel-concrete double composite twin I-girder bridge, which has two concrete slabs at upper and lower surfaces in the region of the intermediate supports, was proposed for long span range. However, when the eccentric load was applied, the torsional behavior of this type of the bridge is not clarified perfectly. To increase the torsional rigidity, it seems that the adopting of the lower concrete slab of the whole length is effective. Therefore, the authors selected a three span continuous double composite twin I-girder bridge as analytical model and carried out the torsional analysis. In this paper, the results of the torsional moment and angle, shear stress of the steel web plate due to eccentric loading are reported and discussed.

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The rigid connection parts of the steel concrete hybrid bridge are important parts in order to improve the seismic performance of the bridge. We adopted steel frame structure with deformed flange H-shape to the rigid connection parts.
In this study, the failure mechanism of steel frame structure was examined using the pull-test and FEM analysis. Also, the design method of pull-out load of H-shape was proposed by utilizing the split crack occurrence load of the test and the analysis.

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The construction of the continuous composite girder bridge with two or three I-girder has been increasing in expressway due to its economical advantage. In the design of continuous composite girder bridges, one of important design issues is preventing the cracking in the concrete slab subjected to tensile force at intermediate supports. The crack width control design has been employed, and cast-in concrete with transversely pre-stressing slab has been preferably used. By employing pre-cast concrete slab, it is expected to shorten the construction period, obtain higher quality and durability. However, the crack width control design method of this type of slab has not been established. In this paper, through the experiment, cracking behaviors of the pre-cast slab are clarified.

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The integrated column by multiple steel pipes has been proposed based on damage control design in the previous research. This structure intends to lead seismic damage into shear panels that connect each steel pipe. Shear panels are built up by low yield stress steel which has hysteretic energy dissipation property. They work to reduce the acceleration and displacement response of the column. In this paper, an innovative steel pipe pile foundation, in which each steel pipe of the column is supported by a connected steel pipe pile without a footing, is proposed as the rational foundation for the column. The static lateral resistance characteristics are investigated by three-dimensional finite element analysis considering superstructure-foundation-ground interaction.

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In the urban area in Japan, infrastructure development has been constrained to limited space due to the excessive concentration of population and business. Under these circumstances, utilization of underground space with large excavation for transport facilities, public utility conduit, underground mall etc. advances actively nowadays. Therefore, rise of artesian head, which influences the stability of ground, is generally-cited as a major disadvantage in recent years. As a result ,the excavation work becomes important to check the stability for heaving when an earth retaining wall is executed in ground with high artesian head. In this paper, evaluation methods for stability of heaving are reviewed, followed by examining existing in-situ measurement management and sorting out the reference values for control criterion, as an attempt to identify current issues that requires appropriate improved solutions. Next, the applications of two separate new measurement methods for evaluating the stability of heaving behavior during excavation for earth retaining wall are discussed based on the unique measurement results.

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The hammer pile driving method is popular for installing steel pipe piles in port and harbor areas. It is, however, getting harder to apply this method, because of noise and vibration problems to surrounding areas. Therefore a new pile driving method such as to perform high bearing capacity with low noise and low vibration when installing piles was studied. In this method, a pile is penetrated into the ground with water jetting and vibration hammer to reduce noise and vibration. And soil cement block is constructed at around pile tip with cement milk during installation for performing high bearing capacity. In this method, noise and vibration will be decreased when installing piles, and high bearing capacity of piles will be performed. A series of model pile loading experiments was conducted in the laboratory to investigate the axial resistance of the pile tip. Three cases of full-scale pile installations and static loading tests were conducted to verify the performance of the piles installed in this method. Depending on these research works, design method and installation procedure of new method were proposed.

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An earthquake resistance reinforcement method for existing pile foundation, which is based on ground solidification techniques a portion of ground surrounding the pile foundation to confine the deformation of pile foundation and thus enhance their lateral resistance, has been put into practical application on the site. In detailed investigation of stress and deformation behaviors of this method, 3-D statically non-linear FEM analyses were carried for the full-scale loading test paying attention to the interaction between piles, reinforcement body and ground, from that reinforcement mechanism was evaluated. Moreover, 3-D dynamic non-linear FEM analyses were also carried out in order to clarify influences such as different input motion and reinforcement body arrangement on the foundation behaviors under dynamic loading conditions and reinforcing effectiveness.

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