The cementing efficiency factor (k-value) of concrete containing thermally modified fly ash (TMFA) was calculated according to the CEN method based on the concept of the equivalent water-cement ratio, and the estimation equation for the k-value was expressed as a function of the age and water-to-powder ratio of the concrete, the TMFA replacement ratio and the specific surface area. This estimation equation was applied to the k-value of domestic and foreign FA concretes and was found to be valid for domestic FA concrete. The strength of TMFA and domestic FA concrete was also adequately expressed by the estimated k-value.

We investigated reduction effects of effective input motions on actual buildings by analyzing strong-motion records obtained from 17 buildings with various ground conditions. Based on the records observed at the base and nearby ground surface of those buildings, the peak amplitude ratio of the base to the ground surface was evaluated. Furthermore, numerical analyses using axisymmetric hyperelements were conducted to identify foundation and soil parameters influencing the reduction effects of effective input motions to structures. It was found that the peak amplitude ratio of the base to the ground surface is highly dependent on the shear wave propagation time.

Expansion joints in seismically isolated buildings are intended to remain undamaged following earthquakes. However, numer-ous reports from past earthquakes indicates significant damage to these joints or adjacent structures resulting from collisions. This study quantifies the impact force generated when the main panel of a rising-type expansion joint collides with the slope of the joint through collision tests. The results demonstrate that the impact force increases proportionally with the velocity and effective mass of the main panel, and it intensifies further with an increase in the slope angle.

This study proposes a time-domain method for evaluating the variance and covariance of the response of an elasto-plastic SDOF system subjected to nonstationary input ground motion modeled using an evolutionary spectrum. The Bouc-Wen model is employed to describe the restoring force, and the central difference method is applied to derive difference equations for the variance-covariance matrix, which are solved without equivalent linearization. The results are then utilized to estimate the maximum response distribution based on the level crossing statistics of the envelope process. The effectiveness of the proposed method is demonstrated through comparisons with Monte Carlo simulations.

As seismic isolation buildings have become higher in recent years, seismic isolation members have become larger in size. However, the seismic behavior of large seismic isolation members and the differences in behaviors between full-scale and reduced-scale specimens due to scale effects have not been clarified. In this paper, dynamic experiments were conducted using E-Isolation, which is the testing facility to conduct dynamic tests on full-scale seismic isolator, and investigate the scale effects on the fundamental and ultimate characteristics of natural rubber bearings with rubber diameters of 300, 600, and 1100 mm.

During major earthquakes, many damages were reported to RC gymnasiums with steel roofs. Previous studies have proposed methods to control the out-of-plane response, which is the main cause of damage. However, a method for calculating the design seismic loads that considers the vibration characteristics of the entire structure, including the out-of-plane response, has not yet been proposed. Therefore, in this paper, we propose a method to calculate the design seismic loads for RC gymnasiums with steel roofs by the response spectrum analysis using ground acceleration.

In this study, which focuses on thin-walled members subjected to axial compressive forces, column tests and finite element analysis are conducted to elucidate the effects of boundary conditions at plate end edges and member geometry on the ultimate (i.e., post-buckling) strength of thin-walled members. It is found that the boundary conditions at the plate end edges do not influence the ultimate strength of the thin-walled members; however, the rate of increase from the elastic buckling strength to the ultimate strength varies depending on the member geometry.

The design algorithm to obtain superior design solutions (SDSs) of steel office buildings associated with the different-type damping devices such as buckling restrained braces (BRBs) and oil dampers (ODs) is proposed. The SDSs are rational design solutions satisfying practical design constraints with the locally minimized structural cost. The design variables are the section sizes of columns and beams as well as locations and properties of the damping devices. The response history analyses are conducted during the optimization process directly evaluating the damping effect of ODs. The SDSs of 10 and 16-story buildings are derived and the structural properties are evaluated.

This paper proposed a novel damped outrigger system with tuned viscous mass dampers (TVMDs) for a Japanese tall building where the outrigger span was relatively larger than that of a typical tall building in the world. A series of generalized response spectrum analysis and nonlinear response history analysis for a typical Japanese tall building with a center core was performed to investigate the seismic response reduction effect. Moreover, the structural detail was designed to estimate the cost and cost performance index, and the feasibility of the TVMD damped outrigger system was strictly discussed.