Earthquake-induced Permanent Ground Deformation (PGD) can affect significantly underground gas or water pipelines. This paper describes large-scale experiments to investigate the effect of PGD on buried steel pipelines with elbows, and to validate and calibrate Finite Element (FE) modeling. There is good agreement between both the magnitude and distribution of measured strains and deformation and those modeled with FE analyses. The analytical models are able to simulate real performance in a reliable way for dry sand, and for partially saturated sand with an adequate correction factor. Using the analytical model, recommendations are proposed for enhancing the earthquake-resistance of buried pipelines with elbows subjected to PGD.

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An optimization procedure for the design seismic coefficient for gravity type quay walls is discussed based on the risk management concept. First, seismic risk evaluation for 280 ports in Japan is conducted to obtain the optimum design seismic coefficient. Second, the variation of the optimum seismic coefficient for the important quay wall or the quay wall with longer service life than usual is examined. Finally, the relationship between peak ground acceleration given by seismic hazard analysis and the optimum design seismic coefficient is examined. The results indicate that the current design seismic coefficient is regarded as reasonable since it is close to or conservative of the optimum design seismic coefficient.

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Analytical parametric study on dynamic characteristics of steel tower of cable-stayed bridges is performed to investigate the individual influence of different design aspects, such as damping mechanism, input ground motion, allowable initial construction imperfections, energy dissipation and tower modal shapes. The results show that the horizontal beam height and length and the low yield energy dissipation system significantly affect tower structural behavior. The initial imperfections within design range have slight detrimental effects on the tower seismic response but these effects grow rapidly beyond the design range. Mass proportional damping leads to overestimate tower axial forces and acceleration response.

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Realistic simulation of the mechanical behavior of concrete and reinforced concrete structures is performed by using a lattice type numerical model. Five different types of lattice members with simple constitutive models are introduced for mortar, coarse aggregate, steel, aggregatemortar interface and steel-concrete interface. The meso-scopic morphology of concrete, which can be realized by the image-based geometry modeling technique, is taken into account. By the incorporation of the accurate meso-scopic morphology into the lattice type numerical modeling, the cracking behavior induced by the meso-scopic heterogeneities has been successfully captured.

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An aluminum deck was fabricated by joining hollow extrusions with the friction stir welding (FSW). The purpose of this study is to make clear the fatigue behavior of the deck. First the material properties of the aluminum alloy used and the FSW region were investigated. Next a fatigue test was carried out for the deck, showing that a fatigue crack was initiated along the FSW-joining line of the top plate just under the load due to the plate-bending stress. Further fatigue tests were conducted for the beam-type specimens, revealing that where the supporting interval of the deck became large, a fatigue crack was caused perpendicularly to the FSW-joining line of the bottom plate by the membrane stress due to the global bending moment.

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Studs are often used as shear connectors or anchors between concrete and steel members at various composite structures. As the studs are welded in a finite range of the steel members and each stud generally has different distance from the edge of structural concrete, it can be expected that they do not show the same pull-out and shear strength. In this paper, therefore, the test data of previous investigations including new data obtained by authors and existing formulae for pull-out and shear strength of the stud are reevaluated, and the strength equations were revised in the case of independent of the edge distance. Then for the studs near the concrete edge, new influence factors were found and composed into the revised equations as coefficients.

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Spatial variation of Q_S-value is estimated using double spectral ratio of strong motion records. Q_S-value in the central part of Aichi Prefecture is higher than that in the eastern and western parts of Aichi Prefecture. Median Tectonic Line passes through the eastern part and Yoro fault zone exists in the western part, which would be the cause of the low Q_S-value. The spatial variation of Q_S-value may reffect the heterogeneity of the crustal structure such as asperity distribution in the crust.

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