This research aims to determine the effect of loading pattern on the damage of a reinforced concrete bridge column. Five specimens were tested with uni-directional or bi-directional cyclic loading patterns combined with a constant axial load. In this report, a simple procedure to predict the damage and failure of a reinforced concrete column, that is subjected to an arbitrary seismic loading pattern, is proposed using the fatigue based damage model combined with the energy dissipation.

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It is known that iterative procedures are always needed when the capacity spectrum methods based on the equivalent linear systems are employed to estimate the maximum deformation of existing structures. In addition to inefficiency, it has been shown that the existing method sometimes leads to the lack of convergence and accuracy. Besides, the problem of multiple solutions is encountered in many cases, and it is hard to decide which one is the best. To overcome these problems, this paper presents a non-iterative capacity spectrum method using a varied version of the equivalent linear methods for determining the maximum displacement demands of existing structures. A trustworthy single value will always be obtained by the procedure.

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The functionalities and energy dissipation capability of Displacement dependent semi-active hydraulic damper, DSHD are analyzed and discussed with complete experiment which involves the factors to affect time-delay of DSHD, and the reasons to cause sliding of the oil cylinder under the dynamic state. The test results show that 1) Time-delay occurs in unloading period because of the hysteresis phenomenon. Herein, Kelvin solid is approved to simulate this process and shows that stiffness of the brace and damping coefficient of oil will lead time-delay; 2) It's important to avoid sliding of the cylinder, caused by insufficient oil pressure and residual air in the oil cylinder and pipe, for achieving excellent performance of DSHD. These phenomena can be improved by applying appropriate pre-pressure to the oil tank.

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An elastic beam bending theory for analysis of prestressed concrete girders with corrugated steel web is derivedbythe application of the variational principle. The theory is a shear deformable beam theory which is based on three displacement fields and is similar to the classical Timoshenko beam theory. A two-node linear finite element with full and reduced integration of the theory is provided. It is then used to analyze simply supported and continuous I-and box-girders. Their predicted results are found in good agreement with those by the 3D finite element analysis. A simplified theory which is similar to the proposed theory by Kato et al. (2002) is also discussed and included in appendix.

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Wave scattering in the Biot's poroelastic media is investigated using a numerical method based on the boundary integral formulation. The formulation adopts the fundamental solution derived with a direct manner and traction operators for physically meaningful boundary conditions. Some numerical examples for wave incidence on a spherical scatterer is presented. In the examples, coupling effects of solid and .uid are parameterized with coupling parameters and the boundary conditions. The results show that scattered fields, especially pore pressure, are highly infiuenced by the coupling e.ects with the conversion of the fast longitudinal wave to the slow one.

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As a fundamental study to develop a force-displacement-based seismic design of RC piers, the acceleration-displacement response spectrum (ADRS) of SDOF systems with elastic-plastic bilinear restoring force characteristics is obtained by inelastic response analysis, provided that the value of modified Park-Ang damage index D of a SDOF system equals the required value D_r=0.4 that almost correspond to the repairable limit of the system. The regression equation of ADRS is derived and applied to a force-displacement-based seismic design of a single-column RC pier. The design results by the proposed method are compared with the ones by the ductility design method of Japanese Specifications.

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The design of connecting devices for preventing bridge girders from becoming unseated during strong seismic motion is extended to include consideration of the velocity response of the bridge. The necessary strength and cross-sectional area of the connecting cable are derived based on conservation of energy considerations, and the shock stress arising when the device becomes active is calculated. The installation of a shock absorber with optimum stiffness based on its deformation limit and the cable stiffness is found to reduce both the impact stress on the cable and the required cross-sectional area. The effectiveness of the proposed design is then verified through numerical simulations.

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In the design of railway bridges crossing over roads or rivers, bridge height from the lowest point to railway level is sometimes restricted by the height of the road or the high-water level of the river. In order to satisfy these conditions, the authors propose the application of steel-reinforced-concrete (SRC) slab structures to floor systems of through-truss bridges. Since the behavior of this type of bridge had never been verified, this study conducts pull-load and dry-shrinkage experiments on concrete slab structures. These experiments demonstrates the location of cracks in the slab concrete, their developing patterns, and the axial assignment-force of lower chord members.

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A developed form of the PC box girders using corrugated steel web are flourishingly under construction. The form has been used for the continuous girders and the usage to be developed even for the cable stayed bridges. Since the corrugated web does not possess rigidity along the span axis, the influence due to shear deformation strongly appears. The authors have developed an elastic equation extending beam-bending theory considering shear deformation. The dual three-moment method and the CWB (Corrugated Web Beam) matrix displacements-method are formularized. The obtained knowledge is so important that the practical bridge engineers should take it into their consideration.

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