This paper intends to investigate punching shear bearing capacity formula of anchorage with embedded steel anchor between transmission tower legs and four-piles-supported footings or spread foundations, subjected to push-in load. At first we made several push-in loading tests about four-piles-supported footings, and studied simplified bearing capacity formula of punching shear. And then we simulated the normal case of these experiments using COM3, which is a three-dimensional finite element program, and we assured that COM3 can simulate ultimate load and failure mode well. At last using COM3, we examined punching shear bearing capacity of anchorage of an anchor in a spread foundation subjected to push-in load.

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In this paper, the characteristics of chemically prestressed members in flexure and the effects of restraint in three directions are experimentally investigated. When sufficiently cured in early ages, chemically prestressed members have large tension stiffening effect, and in flexural members, the stiffness of members near cracking and the behavior of concrete at the tensile end are different from those of normal concrete. The effects of restraint in three directions are observed in flexural behaviors, and the effects are remarkable especially when section size is large. Effects of peculiar characteristics of expansive concrete on the decrease of crack width are discussed.

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In this study, the FEM analysis using discrete crack and bond linkage elements is developed to apply to the reinforced concrete beam without shear reinforcement subjected to bending and shear, and the analytical study was carried out on the occurrence of flexural and diagonal cracks, their developments and the shear bearing capacity of the beam. In this analysis, the characteristics of crack and bond elements are determined individually by plain concrete test and bond test respectively. By using this FEM analysis, it is possible to represent the development of flexural crack and diagonal crack, and the decrease of stiffness of beam after cracking. It is also possible to clarify the shear bearing mechanism of reinforced concrete beam without shear reinforcement by using this FEM analysis.

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This study evaluated how the dimensions of blocks, type of joint material, and method of road surface compaction affect the load transfer efficiency in interlocking block pavement. We also compared the effects of load distribution on pavement with strength of base structures. For these purposes, we measured deflection by lightweight FWD on test pavements and installed on roadway. The measurements revealed a close relationship between block dimensions and the load transfer efficiency, and clarified the effect of joint sand. It was confirmed that, installed on roadway, the load distribution effect varies by base structure and by whether the section is damaged or undamaged.

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Marine aquatic fouling organisms form a dence layer on the surface of concrete structures and enhance durability against corrosion of reinforcement bars. The reason is that a surface layer formed by these organisms restrains penetration of chloride ions and oxygen into concrete and controls corrosion of reinforcement steel. The less OH^- concentration of pore solution is and the more the volume of pore is, the more the layer is. The concept of durability assessment based on prediction of chloride ions penetration and corrosion progress and the metod of utilization of this layer for durability improvement are also shown in this paper.

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Reinforced concrete beams without stirrup using high-strength concrete of compressive strength f′_c ranging from 70MPa to 130MPa were tested. The test results show that for high strength concrete (HSC) beams failed by diagonal tension, the shear strength based on conventional methods is overestimated, and for HSC beams failed by shear compression, the effect of variation of f′_c, a/d, effective depth and main steel ratio on these shear strengths can be evaluated by conventional method. In this study, based on test results including other researcher's ones, the equations of shear strength of HSC beams are proposed and safety factors by taking the the uncertainty of proposed equation into consideartion are also given.

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This research aims at getting the necessary basic data for the proposal of the hysteresis loop of RC members subjected to pure torsion. Pure torsion cyclic loading test was conducted by using the scale model of RC piers. The primary reinforcement and lateral reinforcement, concrete strength and axial forces were set up as parameters. The effect of these parameters on the second slope after yield, a negative slope after the maximum strength, and the ductility factor of torsion are clarfied. Moreover, it was stated that the proposal of the estimation method about the skeleton curve based on the experiment results, and it also was referred that the relations between the torsion rate and the torsion angle, and the characteristics of hysteresis loop.

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Recently large external prestressing tendons anchored at the middle of girders have been often employed for concrete bridges, for such purposes as span extension or cost saving. However, the general design method and detailing practices have not been established for such internal anchorage zones basically consisting of a concrete blister and surrounding thin slab and web, although their stress field may be severe as well as complicated. In this context, full scale model tests were conducted in order to confirm the safety of the internal anchorages for two unique bridges. This paper outlines the test results, comparing with the estimated performances in the design. Then, with supplemental studies to understand the observed behavior, a few ideas for appropriate design of internal anchorages are discussed.

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In this study, a triangular plane element with 12 degrees of freedom based on hybrid stress element is applied to fracture analysis of concrete. This element is useful for treating non-linear problem including discrete crack because it has a node at midpoint of the each boundary side. In numerical analysis by which the tension softening is considered, the unstable phenomenon such as snap-back is often appeared. Therefore, authors developed the algorithm which can apply the analysis for an unstable phenomenon. To clarify the validity of this method, the fracture of the CT specimen and notched concrete beam were simulated by proposed method. The analytical results are in good agreement with the experimental ones.

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This paper shows the analytical method for strain softening using a one-dimensional element (the truss element and beam element). In numerical analysis considered the tension softening, we can obtain excellent results by using the plane element, when the bending moment or the axis force acts on the beam member. However, if the one-dimensional element can be used instead of the plane element, the cost of calculation or making data is reduced. Therefore, we proposed the analytical method, and showed the simulation of the fracture of the plain concrete and lightly reinforced concrete beams. Their results are in good agreement with the experimental ones.

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Upper slabs of caisson foundation are RC planar members with small shear span ratio to which all surroundings under the outside edge are supported. However, neither consideration method as the planar member nor the influence of eccentricity of the load is clarified in the shear design of upper slabs. Moreover, the shear strength of slabs with very small shear span ratio is not clarified though there is a tendency that the shear span ratio of upper slabs is reduced by the revision of seismic design. Then, the method of calculating the shear strength based on the load testing result of the model of upper slabs of caisson foundation was examined. As a result, it was concluded that the shear strength of upper slabs can be calculated by considering the peripheral length of shearing fracture area.

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Non-linear 3-dimensional dynamic analyses of total bridge system under earthquake loading were carried out and the effects of 3-dimensional response on the behavior of the bridge pier were discussed. As the results of these considerations, in case 3-dimensional earthquake loading was input, the resisting capacities of sections of RC bridge pier degrade remarkably due to bi-axial bending. And because of the vertical vibration of superstructure, noteworthy additional bending moment generates at the top of the pier by considering 3-dimensional total bridge system. Furthermore, it becomes clear that the magnitude of 3-dimensional effects depends upon the configuration of bridge pier.

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In this study, elastic wave methods are applied to estimate mechanical properties of polymer concrete with liquid resin mainly composed of methyl methacrylate (MMA). In order to investigate hardening processes of MMA polymer concrete, acoustic emission (AE) and ultrasonic testing (UT) are applied. Obtained results demonstrate that elastic waves propagate through the polymer concrete under the hardening process from the fresh state to the hardened state. Propagation characteristics of elastic waves through the polymer concrete reflect remarkably the reaction of MMA, and thus it is shown that the elastic wave methods were effective to estimate the variation of those mechanical properties.

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The mechanism of diagonal tension failure of RC linear members without shear reinforcement, which is difficult to be clarified by means of both experimental and analytical approach, is presented. In this study, the close relationship between the failure modes and the transferred stresses along a diagonal crack is disclosed. The experimental results on diagonal tension failure are verified by finite element method in which the influence of a splitting crack and dowel action are considered. In RC linear members without shear reinforcement, diagonal crack width increases owing to occurrence of a splitting crack along tension reinforcement. As a result, the transferred stresses along the diagonal crack decrease, and the diagonal crack grows rapidly. Finally diagonal tension failure is caused by compressive failure at the tip of the diagonal crack.

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The resilient modulus Mr of hydraulic mechanically stabilized slag base-course material was evaluated by carrying out a repeated loading triaxial compression test with improved measurement techniques of axial strain and applied load. The repeated loading was imposed following the method suggested by AASHTO and also the one used by Nishi et al. for comparison. From the results, Mr depended on both applied mean principal stress and applied deviator stress and increased with curing time. Use of axial strain measured by LVDT outside the triaxial cell underestimated Mr and the hydraulic nature. Two loading methods gave little difference in the estimated Mr for the stress level applied in this study.

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Autogenous and drying shrinkage of mortar using fly ash were investigated in this paper. The water cement ratio was set 25% and 45%, and the rate of fly ash of these mix proportion was changed. The specimens were cured at the temperature of 10°C or 20°C, and 57±5% of relative humidity. When the rate of fly ash was gathered, autogenous and drying shrinkage strain decreased. However, compared with the mortar of only cement, the strain did not necessarily decrease. It appears that the factor of autogenous and drying shrinkage are not only the capillary tube tension and hydration action but also the adsorption and desorption of inner water of pore. When the rate of fly ash was gathered, free water increases in pore. Therefore, since change of the chemistry potential energy by hydration action and diffusion of water is decreased, autogenous and drying shrinkage strain is decreased.

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A prediction method for ductility of reinforced concrete columns retrofitted with externally-bonded continuous fiber sheet is related in this paper. The method is based on the mechanical model that represents experimentally observed deformation and failure behavior of RC column with CF sheet observed: generation and propagation of diagonal sheer crack in the member and delaminating of the CF sheet from concrete over the sheer crack. It was verified that ductility of the RC columns with CF sheet is well predicted by the proposed method in terms of their deformation and failure mechanisms. It was also clarified from sensitivity analysis using the prediction model that the ductility of the RC columns with CF sheet does not much depend on bonding characteristics of CF sheet from concrete but on the ultimate tensile strain of CF sheet.

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In this study, the compatibility of cement and reactive aggregate with respect to the expansion behavior of mortar due to alkali-silica reaction (ASR) was studied. Two types of the mortar bar expansion test were used to clarify the expansion behavior of mortars made with the cement and the reactive aggregate. The influence of a combination of the chemical and mineralogical compositions of cement and the reactive components of aggregate on both the amount of ASR-gel and the expansion rate of the mortar was also investigated. From the results, it was found that the expansion behavior of mortars due to ASR varied significantly depending on a combination of the mineralogical compositions of cement and the reactive components of aggregate.

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The box rigid-frame is mostly applied to underground structures. The leakage is one of the problems resulting from temperature cracks in side wall segment of the box rigid-frame. This paper/research shows the survey and analysis of conditions causing temperature cracks and installation of temperature crack inducement joints. As a result, we obtained several factors that control temperature cracks of the box rigid-frame effectively.

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This paper describes an experimental study on uniaxial tensile test of concrete, in which concrete failures within the testing zone in specimen at high possibilities, specimen can be easily prepared and tested, and the testing zone of specimen has enough length for measurement of strain. After the trial of the dog-bone shape specimen and the conventional prismatic specimen, the authors developed the prismatic specimen, which was externally strengthened with continuous fiber sheet. It was verified that this specimen ensured failure of concrete in the testing zone instead of failure in the end caused by embedded anchor bolts. Strain of concrete at elastic stage can be successfully measured. The preparation of this specimen can be easier than that of the dog-bone shape specimen.

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The purpose of the present study is to obtain the higher Young's modulus of lightweight concrete by mixing various aggregates. Two different mixes of concrete were here in tested. The test results indicate that the Young's modules were almost proportional to the weight of concrete. In addition, composite structural models applied to determine the Young's modules of lightweight concrete with various aggregates, and applicability of the models was confirmed in the present study

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Static loading tests on steel columns and composite columns were carried out in order to investigate basic properties of torsion. Moreover, the results of loading test were compared with theoretical analysis and F.E.M. (Finite Element Method) analysis, considering nonlinear material properties. From the comparative works, following conclusions were obtained. At the test, the failure of steel columns was determined by local buckling. Composite columns had much higher bearing capacity than steel columns because local buckling of steel column was prevented by filled concrete. Torsional moment on yield point and torsional rigidity in the theoretical analysis and the results of F. E. M. analysis had almost corresponded to those of loading tests.

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