The high-frequency (3–10 Hz) motion generation areas (HMGAs) of the 2023 Mw7.8 Turkey-Syria earthquake were estimated using the empirical Green’s function method. One of the HMGAs was located near the end of the southwestern segment, where the off-fault deformation was large. The other HMGA was located near the stepover. The edges of strong motion generation areas revised from Satoh (2023) were near the stepover, the bend, and the junction. These results show that off-fault damage and discontinuity in fault geometry generated high-frequency motion. This is identical to the features shown by numerical simulations for strike-slip earthquakes in previous studies.

This paper evaluated the relationship between load-carrying capacity and maximum displacement response of buildings by response analysis using typical Japanese strong motion observation data. The analytical results revealed that the maximum response displacement was almost constant regardless of the base shear coefficient in areas where the acceleration response spectrum decreases rapidly after the predominant period. The paper named these areas “Concentrated Areas of Response Displacement (CARD)” and theoretically proves that such phenomena were inevitable for buildings on the ground with a pronounced predominant period. Finally, the outstanding findings for seismic design were concluded based on CARD.

This paper discusses a method for uniformizing the maximum inter-story drift angle of multiple seismic responses in elastic equivalent shear-spring models with untuned inertial mass dampers. First, the author proposes using pseudo-equivalent stiffness to assess the effect of untuned inertial mass dampers. Then, this pseudo-equivalent stiffness is applied to the method using closed-form representations of the primary mode, confirming the effectiveness of the control strategy for untuned inertial mass dampers. This allows for comparison with the damping effects of viscous dampers and demonstrates the potential for a wide range of applications of untuned inertial mass dampers.

A room damage rank was built using shake table test results for assisting the seismic design of medical facilities with enhanced functional continuity. The proposed rank, categorized into four levels based on the communication with medical staffs, prognosis the medical service after seismic events using floor responses as engineering demand parameters (EDPs). To classify the rank, the maximum floor acceleration, maximum floor velocity, arias intensity and the integration of bracketed acceleration are considered as EDPs. The proposed rank was verified with past survey results. Then, the relationship between the structural properties and room damage were investigated by parametric analysis.

Existing machine learning methods are difficult to apply to complex and large buildings with many design variables, and the design conditions are simplified in the formulation of optimal design problem. This paper presents a method using reinforcement learning of multi-agent for the problem of minimizing material volume of 3D-steel frames. In the learning process, two agents select the member and its cross-sectional dimension, respectively, with simple neural networks with small number of input features of local information. The numerical examples show that the method exploiting the two agents can optimize cross-sectional dimensions more efficiently than simulated annealing and local search.

This study presents a formulation method for implementing a material constitutive model using a memory surface in finite element analysis, capable of accurately reproducing the cyclic hardening and softening behavior of SN490B structural steel under constant strain amplitude. The formulation employs an implicit discretization method, specifically the backward Euler method. For solving plastic multipliers, elastic predictors and plastic correctors are used. Additionally, to ensure the convergence and stability of the nonlinear analysis, the derivation of the consistent tangent modulus tensor is demonstrated. The validity of the modeling method was verified through finite element analysis.

The vertical bearing capacity determined from the wall strength of soil-cement retaining walls may be subject to the confined effect by the ground. In this study, vertical loading tests of a model pile were conducted using a pressure chamber, and increased vertical bearing capacity by the confined effect was confirmed. The increased vertical bearing capacity due to the confined effect is caused by increases in shear and bearing strength of soil-cement. Furthermore, it was confirmed that the vertical bearing capacity can be evaluated as the sum of the bond, shear and bearing capacity of the pile without the confined effect.

This study conducted a static horizontal loading experiment on CLT rocking wall columns by introducing pre-stress. We understood the mechanical behavior in the case of changing the pre-stress amount and the PC bar’s cross-section.

We proposed a method for evaluating the relationship between the bending moment and the rotation angle of column base. The characteristics of the evaluation method are (i) Analyzed stress distribution cases at column bases and (ii) The uplifting of the column base was modelled using a spring model. The evaluation results could roughly reproduce the experimental values, although there were some improvements.

The evaluation of the skeletal curve of RC beams with partially debonded longitudinal rebars was examined. Based on previous study, the skeletal curve model for RC beams with partially debonded rebars was assumed, and the evaluation formula for each characteristic point was proposed. It was confirmed that the calculated skeletal curve roughly corresponds to the experiment results.

In addition, a finite element analysis was conducted using the debonding length as a variable, and it was confirmed that the proposed evaluation formula can evaluate the change in the yielding deformation angle of the rebars due to differences in the debonding length.

The maximum experienced bending moment and drift angle were estimated from the maximum residual crack width at the tip of the widened section, and the degree of damage of the member was determined. As a result, the residual crack width in the case of hinge relocation and the yielding of the PC steel bar in the case of beam-end yielding type determined the degree of damage to the member. The decrease factor of seismic performance used in the damage classification was also able to determine the degree of damage of beam members in the hinge relocation type.

In this paper, a method for evaluating the buckling length of atrium columns in the slide-sway buckling mode using the lateral stiffness of the frame and the story height is proposed. The proposed method, by treating slide-sway buckling as a story phenomenon, enables the consideration of the effect of other members in the story acting as buckling-restrained elements for atrium column. Consequently, it allows for a more accurate evaluation of atrium column buckling length factors in slide-sway mode compared to the conventional monograph that calculate the buckling length factor for isolated columns.

Seismic retrofitting for factories or warehouses with inadequate seismic performance can be hindered by operational disruptions and fire risks. This study introduces a novel method that involves attaching strengthening members to existing structures using high-strength bolts. Cyclic loading tests were conducted on braced frames with varying eccentricities to investigate the influence of the eccentricity and bolted connections. The test results indicate that an increase in brace eccentricity leads to a reduction in stiffness and strength of braced frame. Furthermore, the proposed structural model accurately evaluates the stiffness and strength of braced frames with eccentric braces.