The acceleration response spectrum is used as the design earthquake ground motions in specifications for highway brides. The present study clarifies the relation between the design earthquake ground motions determined in accordance with acceleration response spectra and various seismic intensity levels for expressing the degree of shaking in consideration of velocity, displacement, and long-period ground motion. In this paper, an expression of relations of the acceleration response spectra and the various seismic intensity levels is shown by clarifying the effects of the shape of response spectrum and phase characteristic using the simulated earthquake waveforms based on an arbitrary acceleration response spectrum.
The purpose of this research is to clarify the characteristics of corrosion resistance and anti-corrosion performance of overlapping layers between Al-5Mg thermal sprayed coating and heavy duty paint coating in a high corrosive environment. Accelerated exposure test was carried out on specimens with overlapping layer, and the cross-cut defect were introduced into specimens to form a steel based-exposed portion. In addition, the AC impedance measurements, glossiness tests on the coating surface, and the SEM-EDX elemental analyses on the tested specimens were conducted. The results indicate that the deterioration of the overlapping layer at the steel base-exposed portion occurs earlier than that of the single Al-5Mg thermal sprayed coating. Besides, the generation mechanism of precipitate at the steel base-exposed portion is clarified. Moreover, under the conditions of this combined cyclic corrosion test, the upper layer of heavy duty paint coating still has enough anti-corrosion performance even after the deterioration occurred at the thermal spray coating.
Fiber Reinforced Polymer (FRP) provides superior mechanical properties such high strength, high corrosion resistance, light weight etc.. As a volume fraction of fibers of FRP members influences significantly on the mechanical properties, that also depends on manufacturing process, therefore it is necessary to assess the material properties of different volume fraction of fibers to make sure the sectional capability enough with respect to the construction requirement.
This study aims to investigate tensile properties of Glass Fiber Reinforced Polymer (GFRP) manufactured as channel cross section by hand lay-up molding method and pultrusion molding method. Coupon test specimens which was cut from several locations of the GFRP channel members, are used in tensile test. Then, influences of changing the sampling positions of the specimens on the channel section against tensile strength, elastic modulus are discussed. In addition, Monte Carlo simulation is performed by using the statistical model of tested data to evaluate tensile properties in the entire cross sections of FRP member.
Torshear type high strength weathering bolts are widely used to bolted joints in steel bridges. It is known that their bolts vary widely bolt axial force by temperature. However, characteristics of bolt axial force is not clarified. In this paper, we have investigated the 2860 of bolt axial forces on the basis of the mill sheet data and bolt-tightening tests data in order to clarify bolt axial force on torshear type high strength weathering bolts of 22 mm diameter. We also have investigated the mechanical properties of their bolts.