In this study, several physical properties of cementitious materials including synthetic calcium carbonate (SCC) by gas-solid reaction as minor additional constituents were investigated. The results suggested that SCC may affect the fresh properties of concrete and adiabatic temperature rises, but the effect of replacement ratio and curing temperature on compressive strength is similar to that of limestone powder (LSP). The durability of concrete including either of minor additional constituents were equivalent.

The final goal of this study is establishment of evaluation method of floor hardness in terms of physical fatigue caused by long standing work. First, sample floors which have different hardness were selected, and performance values representing hardness were measured. Next, sensory tests that users were asked to degree of fatigue by continuing simulated standing work on walking path made with the sample floors was conducted, and psychological scales were constructed. Finally, the relationships between the psychological scales and the performance values were examined, and a performance value that can evaluate hardness in terms of physical fatigue has been discovered.

Composite structural wind turbine support structures are one useful means of increasing the size of wind turbine installations. However, there are still no examples in Japan, and it is unclear to what extent each design variable affects the seismic response. Therefore, this study attempts to quantitatively evaluate the influence of each design variable on the seismic response using the response spectrum method through multi-objective optimization and through sensitivity analysis. Furthermore, a method is proposed to apply the obtained results to actual design.

Vibration control technology in Japan has advanced and widely developed, and engineers have showed its efficacy in various evaluation indicators. However, the issue is that it’s difficult for non-engineers, such as building owners, to understand its efficacy. In this study, we clarify that the indicators recognized by engineers and non-engineers are investigated through literature and questionnaire-based research, and differences. It also proposes a seismic intensity conversion formula that links the maximum interlaminar deformation angle to the seismic intensity based on three-dimensional seismic response analysis. Furthermore, a method is proposed to comprehensively assess the effectiveness of vibration control for non-engineers.

This paper proposes a hybrid method using the SIMP (Solid Isotropic Material with Penalization) and IESO (Improved Evolutionary Structural Optimization) methods. In this method, the SIMP method adds to the IESO method’s solution that it is locally optimal. On the other hand, the IESO method adds solution diversity to the SIMP method. The effectiveness of the proposed method is demonstrated by comparing it with the SIMP method using density filtering and the IESO method using sensitivity filtering.

The present study presents a new FEM element for buckling analysis of open section members of mono-symmetry such as T and H-sections and its application to structures. The element is composed, fundamentally, of parallel three beams together with four struts normal to the three elements, enabling a consideration of lateral-torsional buckling. The present study first investigates the capability to analyze buckling strength of beams of T-sections and H-sections, followed by buckling analysis to simple lattice frames. Through the analyses, the effectiveness of the proposed element for buckling analysis is confirmed.

Column base joints of mid-to high-rise wooden buildings are subjected to large bending moment and axial force, and they should be designed to prevent brittle failure mode. In this research, tensile-bolted glulam column base joints are tested, and the strength of the cross-section with rectangular notched holes for anchorage is evaluated. The effect of repeated compression and tension stress history is particularly focused on. It is found that the tension strength might be decreased if 80-90% of compression strength was applied to the material.

In-plane cyclic loading tests were performed to examine the flexural properties of SFRC walls. The test results revealed that steel fiber reinforcement mitigated damage to the walls and enhanced deformation performance. Steel fibers also increase both flexural and shear capacities and suppress shear stiffness degradation after shear cracking. By taking these factors into account, skeleton curves that fit experimental results were obtained. SFRC specimen with 0.30% wall reinforcement and shear to flexural capacity ratio of 1.00 showed superior deformation performance than RC specimen with 1.13% reinforcement and the ratio of 1.14. SFRC increases the toughness performance of walls.

The purpose of this paper proposes a design and evaluate method for stiffened beams with stiffener plates at the beam ends with the aim of increasing the plastic deformation capacity. For this purpose, the scope of application of the width-to-thickness ratio indicator W_F was extended and a design formula for the stiffening length was proposed. In addition, cyclic loading tests and FE analyses were conducted to validate the proposed design and evaluate method for stiffened beams.

In order to realize the buckling-restrained brace (BRB) with high energy dissipation performance, it is important to prevent early local bulging failure of the restraining part. In this study, local bulging failure in the strong axial direction of the core plate of the BRB with steel mortar planks is examined. Based on the experimental results and the discussion of previous studies, the strength of the restraining part against local bulging failure considering the effect of spacers was calculated and verified.

A method is proposed to evaluate the required bracing stiffness for a one-story, multi-span 3D frame with non-uniform column axial force distribution and column bending stiffness distribution to achieve the specified buckling load without torsion. Stability analyses were conducted using the finite element method for a 3D frame with braces satisfying the required bracing stiffness obtained by the proposed method. As a result, it was confirmed that the specified buckling load corresponded well with the buckling load obtained by the finite element method, and the validity of the proposed method was shown.

This study proposes a material constitutive model using a memory surface concept to accurately replicate the cyclic hardening and softening behaviors of SN490B structural steel under constant strain amplitude loading. The model combines isotropic and kinematic hardening rules, accounting for strain amplitude dependency in both hardening rules. The isotropic hardening rule includes hardening and softening mechanisms, enabling the accurate reproduction of cyclic hardening and softening behaviors dependent on strain amplitude. This approach successfully replicates the stress–strain relationship of the tested material.

The influences of the number of stories and spans of a bracing frame on the effective length factor of a long column in atrium are examined by analysis using the buckling slope deflection method, and the calculated effective lengths are compared with that of obtained from simplified method. We call the simplified method as “Extended Sakamoto-Mitani method”. It is shown that 1) the number of stories affect significantly on the effective length factor, however, that of spans is small. 2) The effective length factors obtained from “Extended Sakamoto-Mitani method” agree with the correct values about within 5% error.

An evaluation method of seaquake response of pontoon-type offshore wind turbines using stationary random vibration theory is presented. Seabed motion in the vertical direction due to an earthquake is modeled as a stationary random process. A BE-FE hybrid model is used for the response analysis. The excitation surface on the seabed is discretized by boundary elements. The response results are used to structural failure probability and the probability is analyzed using a first-order reliability method. Numerical examples show the variety of the responses and the failure probability of structures for class of soil, seismic acceleration and epicentral distance.