By selecting the rigid frame construction for a bridge, the substantial advantages which are, for example, low building and maintenance costs, high earthquake resistance, comfortable driving and so on, could be realized. The Shimotaniike bridge in Hanwa Expressway is under construction as a hybrid frame bridge where the spread foundation was adopted because of a rock ground. To get an economical solution for the connecting method between steel girder and reinforced concrete abutment, a new connection detail by using the PBL (Perfobond Leistung) shear connector was developed and also its loading test using large specimens was carried out. In this paper, first, the outline and design concept of Shimotaniike Bridge system are reported. Next, new connection detail and its design method are proposed and discussed based on the loading test results.

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This paper presents ultimate strength of steel cable-stayed bridges with short tower which are suitable for constructing at the site near an airport in the urban area. The cable-stayed bridges with center span length of both 400-meter and 600-meter whose tower heights were 1/10 and 1/5 of the center span length were designed. Using the designed model, we studied elasto-plastic behavior and ultimate strength of both cable-stayed bridges.
From this comparative study, it is presented, even if the height of tower reduced to about half of economical height (1/5 of center span length), that the cable-stayed bridges have ultimate load factor β_u of 2.07～2.20 for 400m and 600m-spanned models and are expected to be competitive.

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At present safety factors are differently specified for steel cable-stayed bridges and extradosed bridges; 2.5 for steel cable-stayed bridges and 1.67 for extradosed bridges. Parametric studies were conducted for both bridge types with the same center span of 205m using cable safety factors as parameters. Both the ultimate and fatigue strengths of stays were evaluated for different cable safety factors. For steel cable-stayed bridges, the ultimate strength of stays are critical than the fatigue strength, and the safety factor of 2.5 is necessary to satisfy the required ultimate strength. For extradosed bridges, the ultimate strength of stays are also critical than the fatigue strength, and the safety factor of 2.1 to 2.8 is necessary depending on the load factors.

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Experimental tests were performed to investigate the breaking mechanism of reinforcing bars due to ASR. The specimens were produced to simulate ASR expansion using expansive concrete. The experimental results showed that tensile stress occurs at the bottom of reinforcing bars due to expansive pressure of the concrete. Initial cracks occurred during bending process of reinforcing bars, and the cracks progressed by tensile stress, finally resulting in breaking of reinforcing bars.

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As a way of improving the fatigue durability of slab, a waterproof layer is installed at the interface between asphalt pavement and concrete slab. This study focused about vertical and bond shearing stresses, as parameters representing mechanical properties of the waterproof layer, and made additionally an analytical study of horizontal forces due to braking forces. For calculation, a thick plate theory that is able to obtain accurate stress distributions at designated points was employed. As a result of the study, it was found that bond shearing stress exceeded the recommended value in winter when Young's modulus of pavement increased. Under braking loads, bond shearing stress increased further in winter similarly.

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Steel makers have developed a new class of prestressing strands with 15% higher tensile strength than conventional products in terms of both yield strength and tensile strength in 1S21.8. The development of ultra-high strength prestressing strands (USP) increases freedom in the PC cable arrangement, and when used in combination with high strength concrete, USP are expected to result in higher performance in PC structures, and particularly in pretensioned members. In this research, an experimental investigation of the applicability issues is conducted by performing prestressing tests and bending loading tests with PC beams using USP of 1S21.8. As a result, though consideration in design becomes necessary by the computation of the bond-transfer-length and the investigation of the ultimate state, it has been proved that USP of 1S21.8 can be used for pretensioned members.

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To find the effect of various hook shapes of cross tie reinforcement, cyclic horizontal loading tests were performed on 4 types of column specimens. Using the curvature and strain of cross tie reinforcement, deformation of those specimens was also obtained. It was found that the difference of ductility of those specimens was as small as 3% because the difference in ultimate curvature was small.

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The composite slab girders are mainly used for bridges, in which cracking of concrete slab plays an important role.In this study, we developed the slab for through girders that there was in slab more thinly. In development, a loading examination was performed, and it was measured crack of the slab concrete and stress of the steel members. Experiment results are compared with simple calculation results, and basically behavior was confirmed.

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The authors have developed a steel-plate concrete composite deck, which consists of the steel-plate, upper re-bars and concrete. The steel plate is stiffened with steel strips and shear studs are welded on the upper surface of the steel plate. The predominant fatigue damage mode of the composite deck was detected as the shear-off failure of studs, and the authors have already estimated the fatigue durability for the simply supported part of the composite deck. In this study, a wheel trucking test and three-dimensional finite element analyses of the overhanging part of the composite deck were conducted, and the measured values and the analytical values were compared. Furthermore, the fatigue durability for the overhanging part of the composite deck were discussed by the deflection characteristics of the specimen and the fatigue damage of the shear studs.

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A steel-FRP-concrete composite deck was developed for replacement of deteriorated slab. The slab is composed of a FRP permanent form installed with steel pipes which can strengthen and lighten the RC deck subjected to fatigue loading or corrosion. Durability of a model deck containing two types of joint was tested with the wheel running machine. In the paper, the load bearing characteristics of each section was observed by monitoring strain distributions. It can be concluded to have enough fatigue durability that the deck must be reinforced for shearing strength the slab is not divided into two layers of the upper RC part above steel tubes and the lower part. Also joints of the bottom plate were examined not to be critical to the deck failure due to omission of the lower distribution reinforcements. It was confirmed the double splice joint has enough function as a FRP panel joint structure.

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This paper aims to investigate the effects of stirrup and bonding configurations of FRP sheets on shear load-carrying capacity of RC beams reinforced with Aramid FRP (AFRP) sheets in shear. Total ten RC beams designed as three series for studying the effects of stirrup, bonding depth of U-shape sheet and anchorage of sheet bonded on the top of beam were used in this study. All the beams were tested with a three-point loading test method. From this study, following results are obtained: shear strength of the beams bonded with U-shape sheet are dependent upon the bonding depth of sheet; a good anchorage can be provided by bonding the sheet up to the top surface of the beams for restraining the debonding behavior, but it can not prevent the debonding of the sheets from the free edge.

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Studied herein is the strength interaction curves for steel tube embedded concrete members subjected to axial force and bending moment, which have become the standard of high-rise piers in the construction of highways recently. Particular emphasis is placed on the optimum arrangement of steel tubes in strength. The exact strength for composite section is obtained by the fiber method and its strength interaction curve is compared each other. The interaction curve by strength superposition suggests the larger distance of steel elemens far from the centroid of the composite cross section; however, it is shown that it depends on the strength ratio of steel sections and RC sections. It is also is validated that the outher steel tube element is very effective to improve the structural performance by the confinement to the filled concrete.

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3-D finite element deformation analyses on the CFT steel columns, which are subjected to constant axial loading and lateral monotonic loading, have been carried out to investigate the post-peak behavior of the CFT steel columns as well as confining effect on concrete from the steel tubular columns.
In order to represent the load-deformation relationship of the CFT columns obtained from the experiment, analytical simulations have been carried out through the parametric study on constitutive models of steel and concrete as well as Young’s modulus ratio. As a result, the condition of confining pressure due to the local buckling of steel tubular column near the column base has been clarified. Also, it has been found that the plate thickness does not affect on the confining pressure, but the high strength concrete brings the higher confining pressure.

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Socket joint between steel pipe of composite pier and steel pile could shorten the term of construction works. A number of experiments were conducted to clarify the ultimate strength of the socket joints. Parameters used in this study were the joint length, specification of steel pile, axial load, concrete strength ...etc. Two types of pier model, Steel-Concrete (SC) and Steel-RC (SRC), are adopted. The experimental results showed that the ultimate capacity obtained from maximum shear stress at annular concrete between inner and outer pipes had a good agreement with CEB-FIP model for shear failure while current design method is applicable to predicting bearing capacity based on concrete compressive strength.

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In rigid connection of the steel-concrete hybrid rigid frame bridge, to improve the integrity between the steel girder and RC pier, the main rebars in the RC pier pass through the bottom flange of the steel girder. Some researches on such rigid connection with rebars are conducted by experiment and numerical analysis employing the reduced scale structures. However, there is little research which focuses on the structural behavior of the element test of the rigid connection with the steel plate and rebar. In this research, a numerical analysis program is developed to simulate the behavior of axially loaded tension tests and beam tests which are investigated experimentally in the past. The numerical analysis results are also compared with experimental results and the structural behavior of the element test is investigated in detail.

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Push-out tests were conducted to clarify the ultimate slip behavior of double-lined perforated rib connector (Perfobond Leisten, called PBL hereafter) which has two-lined parallel perforated ribs. From the tests, the following conclusions were obtained: 1) The slip strength is influenced by the concrete confinements caused by the concrete covering, reinforcing bars set through or near a PBL-hole, and the friction force at the boundary between the test bed and the concrete, which is wholly the same as the case of single-lined PBL, 2) Double slip force (shear force) of single-lined PBL is obtained even if the distance between two PBLs is smaller than that indicated in the Draft of Japanese Standards, which requires three times of PBL-height. 3) The ultimate slip strength of double-lined PBL may be predicted by applying the same concept formulated for single-lined PBL proposed previously.

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For the purpose of noise reduction, the non-composite girders are frequently used for railway bridges. In this study, the real behavior is investigated by measuring the live load and dead load responses.The girder of the measurement is an actual girder made in Tukuba-express. The measured results of displacement, strain are compared with design calculations.As for the measurement result; it was examined influence of a composition effect.

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At present, the performance for fire resistance of the bridges is not generally required in its design. However, many damaged examples by the fire due to the traffic accident under the bridge, doubt fire, incendiary fire and so on, have been reported. Therefore, the evaluation of the fire resistance for the bridges is becoming important. First, the evaluation method of the fire resistance for the the steel-concrete composite girder bridge is discussed. Next, in order to verify the validity of the heat transfer analysis, the analytical and test results of the heating test of the reinforced concrete srab are reported. Finaly, as the results of the numerical analysis, the distribution of the temperature and the ultimate strength of the composite girder are reported and discussed herein.

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Composite members made of steel and concrete are adopted for tunnels. Since steel plates are exposed to the internal side of the road, vehicle fire countermeasures are required. After fire tests, concrete cracks were observed and strains of the steel plate were fairly large beyond design values due to high temperature and vapor pressure. To be aimed at clarifying these phenomena, heat analysis considering the air and stress analysis considering the sectional forces of tunnel were performed.

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In this study, the effect of ground irregularity on the seismic response of a superstructure-pile-ground system was investigated. The seismic response of a superstructure did not changed largely due to the ground irregularity. However, the section forces of piles were changed due to the ground irregularity. The amplification rates of seismic responses were also calculated with regard to the inclination of basin layer. Finally, the seismic analysis during the 2005 Fukuoka-ken Seihooki earthquake was analyzed to investigate the effect of irregularity. Considering the interaction of soil-pile-structure system was found to be important.

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The seismic bearing capacity factors of spread foundations on sloping ground have been theoretically investigated. The pseudo-static approach was used, and the seismic forces consisted of a horizontal load applied to the foundation and the inertia of the soil mass. The upper-bound method of limit analysis was also used. A non-symmetrical failure mechanism was proposed. The mechanism was composed of a triangular active wedge, a logarithmic spiral shear zone and a passive wedge. The case of embedded foundations on sloping ground was considered. The shear transfer coefficient was introduced to calculate the seismic bearing capacity of spread foundations with variable shear transfer. The validity of the results from the present analysis was confirmed by comparing with other investigators’ results. Finally, the lowest upper-bound solutions of the seismic bearing capacity factors were presented in the form of design charts for practical use. The seismic bearing factors reduce considerably with the increase of horizontal seismic coefficient. In addition, the magnitudes of bearing capacity factors decrease further with the increase of ground inclination.

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A design method, in which ground improvement is made around the heads of pile foundations constructed in soft ground and ground subject to liquefaction and the increased shear strength is reflected in the horizontal resistance of piles, was put to practical use. In this design method, the range of influence of the horizontal resistance of piles, or the necessary range of ground improvement, is supposed to be a three-dimensional domain formed with the gradient of passive earth pressure θ = (45° + φ/2) from the depth of the characteristic length of piles, 1/β. Horizontal subgrade reaction of piles is determined by converting the shear strength S of improved ground to the modulus of deformation E. In this study, earthquake resistance, such as reductions in the displacement and bending moment of piles caused by earthquake motions, achieved from ground improvements around the pile heads was confirmed through a series of centrifuge shaking tests. The influence of the difference in strength between the original and improved grounds on piles during an earthquake was studied through numerical analysis using the dynamic elastic finite element method, and the potential practical applicability of the design method was essentially verified.

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A practical estimation method with fundamental statistics is discussed in this paper, where First Order 2nd Moment Method (FOSM) is applied to estimation for probability distribution of seismic fragility of the in-ground structures. First, As a case study, accurate earthquake response analysis is carried out for Daikai Station severely damaged during the Great Hanshin Earthquake (1995), which is able to consider interaction effect and non-linear behavior of Soil-Structure Interaction-system. Monte Carlo simulation (MCS) is carried out in the same way as numerical experiments. Several estimation techniques are tried to approximate the result of MSC. As a result, it is found that a practical method is useful to estimate the variation of seismic response of in-ground RC structure, even if non-linear response of it was considered.

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This study discusses how seismic isolation devices for center pillars of tunnels affect the moment and shear force distributions along side walls and upper/lower slabs as well as center pillars. The effects of seismic isolation are simply incorporated as flexible springs at the top end of the center pillars so that possible isolation effects can be taken into account in a simplified and comprehensive manner for the convenience of parametric study. The obtained results are useful for those who would like to choose appropriate devices for the seismic isolation of tunnels.

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The authors have investigated shear destruction of PC beams by impact given near support point, and this time we intend to study contribution of concrete itself to the phenomena. The PC beams used in this study have various shear-span ratios (1.5, 3.0 and 4.8), but have no stirrups, and both specimens were made regarding to presence or absence of prestress. Contents of the experiment were static-loading tests, impact-loading test and static loading test of damaged beams by the impact, and these tests lead understanding of the influence of shear-span ratio and effect of prestress on shear destruction of PC beams by impact.

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In order to investigate the impact resistant behavior of an arch-type structure, static and falling-weight impact tests for a small scale RC arch-type model were conducted taking arch width as variable. Total eight specimens were used for this study, in which four specimens are for 200 mm width and the other four specimens are for 800 mm width. Here, impact load was surcharged using a 300 kg falling heavy weight. The results obtained from this study are as follows: 1) in spite of loading way, specimens with a 200 mm width were failed with a flexural failure mode and specimens with a 800 mm width were failed with a punching shear failure mode; 2) it was confirmed that arch effects were not remarkable in case accompanying with punching shear failure.

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In order to establish a rational impact response analysis method for arch shape RC structures, conducting static and falling-weight impact loadings of small scale and arch shape RC beams, and three-dimensional elasto-plastic finite element analysis for those was performed and its applicability was discussed by comparing with experimental results. From this study, the following results were obtained: (1) impact force wave and maximum displacement at the loading point and the crack patterns occurred on the side-surface of the arch beams can be simulated in a good agreement with the experimental results; and however, (2) the damped free vibration after unloading and residual displacement cannot be better simulated.

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Check dam structures had been constructed in the upriver distinct in order to prevent the disaster by debris flow. Steel frame dam is one of these protective structures, and it is considered as the rational and economic due to its unique structural system. Steel frame dam is composed of the comparatively thin frame members and a number of local small gravels that filled in the frame casing. Although, these gravels and steel frames are expected to reinforce each other against the impact load, their impact behavior and dynamic strength have not been investigated. Thus, this paper presents an analytical approach on the dynamic strength of steel frame dam by one’s own improved 3-dimensional distinct element method.

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When a massive earthquake occurs, displacement response of superstructure exceeds expansion gap and there is a possibility of pounding between bridge girder and abutment. Many studies have been made on seismic response characteristics of the bridge by considering the pounding effect. But most of them are based on nonlinear seismic analysis by using frame model. To evaluate the damage condition of girder and abutment, it is necessary to conduct an impact response analysis. In this study, impact response analyses of pounding effect were conducted by using 3-dimensional FEM, so the damage of abutment was estimated. Furthermore, the decision method of the characteristic of impact resistance between girder and abutment was proposed by using rheologic technique.

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In order to establish a rational verification method for each limit state for impact resistant RC structures, not only experimental study but also numerical analysis study should be conducted. However, it is not easy to numerically analyze large scale RC structures under impact loading. Here, in order to establish a modification method for material properties of concrete so as to rationally analyze using coarse mesh, an equivalent fracture energy concept for concrete elements was proposed and the applicability was conducted comparing numerical analysis results and experimental results. From this study, it was confirmed that even though coarse mesh was used for prototype RC girder, similar results with those obtained using fine mesh can be assured and those results were in good agreements with the experimental ones.

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In order to investigate the impact resistant behavior of lightweight aggregate RC slab (LA RC slab) mixed with Poly-vinyl Alcohol (PVA) short-fibre, falling-weight impact tests were conducted taking fibre mixing volume ratio V_f as variable. In this paper, to evaluate the impact load carrying capacity of each LA RC slab, single impact loading tests were conducted, referring to the former experimental results of static and iterative impact loading test conducted by authors. The results obtained from this study are as follows; 1) static and impact resistant capacity of the LA RC slabs can be increased with an increment of fibre volume mixing ratio; 2) evaluating input impact energy in terms of impact resistant capacity, that of the LA RC slabs mixed with V_f = 0.5 and 1.0 % PVA short-fibre can be upgraded by 3 and 4 times than that of the RC slab without short-fibre, respectively; 3) maximum input impact energy of each RC slab increases linearly corresponding to the static load-carrying capacity, and the increment ratio of the RC slab mixed with PVA short-fibre is larger than that of the RC slab without PVA short-fibre.

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In order to establish a verification method for performance-based impact resistant design method for flexural-failure type RC beams, experimental data of total thirty-six RC beams under single impact loading whose dimensions of cross-section, main rebar ratio and clear span were varied and bending-shear capacity ratio is more than 1.5, were accumulated. In order to verify the load-carrying capacity of the RC beams from service limit sate to ultimate limit state, data for wide range of each parameter were considered as: 2.4 to 14.7 kJ input impact energy; 300 to 500 kg mass of heavy weight for falling-weight impact loading; and 4 to 7.7 m/s impact velocity. From this study, it is confirmed that: input impact energy is proportional to residual displacement of RC beams; and static load-carrying capacity for verifying impact resistant capacity of the RC beam for required limit state can be evaluated using that relationship.

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In this study, to investigate effects of material models of concrete on responses of RC beams under blast loadings, 3-D blast response analyses are carried out for reinforced concrete (RC) beams with two kinds of cross sectional dimensions. Here, the effects of following items are numerically investigated: modeling methods of pressure - bulk strain relation and material constitutive law of concrete, and values of yield stress and tensile failure pressure of concrete. These analytical results are compared with the corresponding experimental ones, which are time histories of reaction force and strain of a longitudinal bar, and crack patterns of a side surface of RC beam. From this study, it is seen that by assuming a proper value of tensile failure pressure of concrete, responses of RC beams subjected to blast loadings may be relatively simulated well with a simple analysis method based on static material properties.

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This study is to find the local damage and failure of concrete plate due to the contact and close-in explosion by C4 explosive. First, to examine the blast effects by C4 explosive, basic explosion tests were done. Then, the relation between the maximum overpressure and distance from an explosive source is formulated. Next, to examine the local damage and failure of concrete plate due to the contact and close-in explosion by C4 explosive, the small scale explosion tests were carried out. In tests, the concrete plates (50cm x 50cm square) were employed. And, to know the material model and parameter to be used for the hydro code AUTODYN, some of test cases were numerically simulated.

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To build a protective design of buried structures, the ground shock loading should be predicted. However, ground shock propagation in earth media may be a complex function of the dynamic properties of the soil. In this study, small-scale indoor tests of underground explosion were conducted with the different degree of saturation of soil. And, shock pressure due to explosion in soil was measured at the distances of 40cm, 65cm and 80cm, respectively, by a subminiature pressure transducer. The results showed that the pressure became higher with the increase of soil saturation and the attenuation of ground shock depends on the distance from charge. Based on test results, the approximation methods of estimating the ground shock properties (e.g., the peak pressure, the duration time of positive phase and the impulse) were formulated.

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This study presents mechanism of the local damage of concrete plate subjected to high velocity impact by rigid projectile. First, characteristics of the local damage of concrete plate subjected to collision by rigid projectile were explained. Then, a numerical model which can describe dynamic behavior of concrete was investigated in terms of combination of failure model and strain rate effect of concrete. Based on the proposed numerical model, mechanism of the local damage of concrete plate was illustrated. Finally, energy transition of initial kinetic energy of projectile and energy consumption in eroded area were discussed

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In order to examine the slip resistance of the friction type of high strength bolted connections with rusted contact surfaces, tensile tests on the model specimens and observation on the rust have been performed. The steel used is SM490Y. Their surfaces have been treated by grid blast or disk grinder. Then they are exposed near or far from seashore in a period of 0, 2, 4 or 6 months. Test results indicate that quantity of rust is gained with increase in exposure period, significant in the location near seashore and does not depend on the ground treatment for steel. The slip factor is independent of the amount of rust if some quantity of rust covers the steel. The value of the slip factor for the connection with rust surface is over 0.73 in average though the slip factor of the connections without rust is 0.46 or 0.28 when the steel surface is treated by grid blast or disk grinder.

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Recently, research reports on application of CFRP plates to repair of fatigue cracks initiated in steel structures are published. CFRP plates are often separated from steel plates, due to high shear stress produced in the adhesive at the end of CFRP plates and at the edge of fatigue cracks. The debonding behavior of CFRP plates from the steel plate which is divided into two by a fatigue crack can be given by that for butted steel plates. In this research, the debonding behavior of CFRP plates adhered to butted steel plates is theoretically investigated. Then, the debonding behavior is also analyzed for the case that a fiber sheet is inserted between steel and CFRP plates.

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In this study, the model experiments were conducted in order to confirm that the pier-to-foundation connection in the rapid construction method of overpasses, ”YS-Quick Bridge”, could be applied in practice. The gradually increasing and cyclic loading test was carried out in order to investigate the mechanism of the load distribution in the region of connection of the models with perfobond leistens. This paper presents the experiment result of 8 cases, which consists of influence parameters (the number of perfobond leisten, depth of pier, thickness of steel pipe).

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