The goal of this study is to expand the use of fly ash concrete (FAC). Based on an experimental investigation of the contributions of several FA combinations (k-values) to the strengths of ordinary Portland cement and of Portland blast-furnace slag cement type B, we propose an environmentally friendly formulation for the FAC mix proportion. A method for evaluating the performance of these FA combinations was also proposed. The mix proportion flow for FAC was examined and validated. As a result, basing the mix proportion of FAC on its k-value enables the design of appropriate and environmentally friendly FAC.

The cement-based materials have various void spaces, and water stays inside these spaces. If the structure of void spaces changes as curing progresses, the state of water inside void spaces also changes. Therefore, the state of water will be able to be treated as an index of curing progress. In this work, the dielectric relaxation processes reflecting motion of water molecules in the cement-based materials were observed using broadband dielectric measurements to clarify the state of water. The relationships between the characteristics of the relaxation processes observed and curing progress were examined.

In the previous paper, the authors reported the effects of weld defects focused on groove types and height of weld defects. The difference in beam section size may reduce the deformation capacity due to the scale effects. Test specimens about 1.6 times larger than the previous specimens for full-scale loading tests were prepared for this study. In this paper, the test results and finite element analysis results are reported, and the effects of the scale effects on deformation capacity and crack propagation are discussed.

In seismic risk assessment of building groups, Monte Carlo Simulation (MCS) is used to quantify loss uncertainty. Rather than using MCS results directly, fitting theoretical distributions proves to be practical. While the log-normal distribution has been widely applied, it may not always be suitable due to upper loss limits. This study examines MCS-based loss distributions and proposes using bounded theoretical distributions. A composite Gamma distribution was found to best replicate the MCS results. Sensitivity analysis revealed that both beta and bounded Gamma distributions are less sensitive to MCS sample size, making them suitable candidates for seismic risk evaluation.

We propose fishbone models for high-rise RC buildings with averaged structural properties to evaluate their seismic responses under large-amplitude pulse-like ground motions. The fishbone models, based on design documents, account for overall flexural deformation and demonstrate verified accuracy. By statistically analyzing existing high-rise RC buildings, we refined the generic bending-shear (BS) models from previous studies to improve accuracy. We propose generic fishbone models by integrating the improved BS model with the structural properties of members in existing RC buildings. Generic fishbone models are constructed for buildings with various stories to estimate their responses to large-amplitude pulse-like ground motions.

In the previous study, the author proposed new flare-like structure for the purpose of improving buckling property, and ultimate properties of high-damping rubber bearings with proposed structure were evaluated. In addition, prediction method of buckling property of natural rubber bearings with flare-like structure using machine learning was proposed. In this study, prediction method of break and tensile modulus properties of natural rubber bearings is proposed by the same way of the previous study.

The effect of reinforcement on the strength of embedded parts in pile caps of SC piles was clarified through full-scale lateral loading experiments. The ultimate strength was determined by the crushing of the concrete and the yielding of the reinforcement. Horizontal reinforcement was effective in suppressing extrusion failure, while vertical reinforcement was effective in suppressing bending and shear failure. A formula for estimating the ultimate bending strength of embedded parts using the bearing coefficient was proposed. In addition, the relationship between concrete and reinforcing bars that provides sufficient bearing strength was clarified.

The effects of number and space of steel plates on performance of drift-pinned timber joints with slotted-in steel plates were investigated. The drift-pinned joints with two steel plates showed higher joint performance than that with a steel plate, and that with 80mm steel plate spacing had highest joint performance. The difference between theoretical values based on the beam on elastic foundation and the experimental results varied depending on type of joints, number and space of steel plates. The theoretical values based on the European yield theory were significantly close to the experimental results.

The authors have proposed hysteresis model for timber shear walls considering the strength reduction by repeated cyclic loading. In this paper, the deterioration behavior is related to the characteristics of earthquake motions, and spectral method to predict maximum earthquake response is proposed. The accuracy is confirmed by comparison with numerical analyses. Finally, the index of seismic performance maintenance is proposed. The tendency of the exact solution obtained by time history analysis is discussed, and calculation method of the approximated solution is also presented.

This paper focuses on cases where folded-roof plates are attached to H-shaped steel purlins. The folded plates were joined to the tight frame using a fitting connection, and the tight frame was then attached to the purlins using self-drilling screws. Experiments on flexural-torsional buckling were conducted on H-shaped steel purlins equipped with these folded-roof plates. In conjunction with the results from finite element analysis, which modeled the continuous stiffening effect of the folded-roof plates using horizontal and rotational stiffening rigidities, the study attempted a quantitative evaluation of the continuous stiffening effect of the folded plates on flexural-torsional buckling.

In Japan, structural timber has standard sizes optimized for detached houses, and it is also the most economical for other timber buildings to use these standard sizes. However, because the standard-sized timber has limited cross-sections, it needs special fire prevention method when designing exposed timber. In this study, the concept of “partially exposed timber beam” that protects only the upper part and sacrifices the lower part was proposed, and its effectiveness was verified through fire tests. This paper clarified the factors influencing the load bearing capacity of partially exposed timber beams, and showed a way towards a general design method.