The purpose of this paper is to quantitatively evaluate concrete temperatures during transport and pumping by a truck agitator in a hot environment. In Part 1, a concentrated heat capacity model was developed for the rotating drum of a truck agitator, taking into account solar radiation and hydration heat generation. The analytical results of concrete temperature by the proposed model agreed with the measured results. It was also clarified that the effect of solar radiation was small and the effect of hydration heat generation was large on the increase of concrete temperature during transportation.

The purpose of these studies, including this paper, is to propose the shear design method for the panel-zone at the beam-to-column connections of timber frame. In this paper, experiments were conducted on beam-to-column connections with lag-screw bolts to determine the validity of the theory proposed in the Part 1 and the actual shear strength of the panel-zone. The results showed that the shear strength was 3.0〜4.5N/mm². The same results are obtained in the antisymmetric four-point-bending type shear tests. Based on the previous results, a wire frame model was proposed for use in design. This model agrees well with experimental results.

Vibration characteristics of a two-story timber structure with damage-dispersing and damping elements are discussed based on resonance curves and time history seismic response analysis. Steady-state response of the two-story nonlinear system was obtained by using Caughey’s equivalent linearization technique, then the resonance curves were plotted by solving a sequential quadratic programming problem. Time history response analyses were conducted using 98 ground motion records to evaluate the variation of seismic response. The result shows that the damage-dispersing element stabilizes steady-state response and enhances the robustness on seismic response, and the viscous damping element mitigates jump phenomenon of the resonance curve.

We have focused on the U-shaped device, which has excellent repetitive energy absorption performance, and have been investigating its applicability to steel-based industrialized housings. In the previous papers, we clarified the influence of the shape factor of the U-shaped device on its mechanical performance³⁾ and the cyclic deformation behavior under constant amplitude loading⁵⁾. In fatigue performance evaluation that targets only constant amplitude loading, it is difficult to estimate fatigue characteristics for various amplitudes like actual earthquake motion. Therefore, in this paper, we attempt to estimate the fatigue characteristics at multi-stage amplitude using the formulation results obtained from constant amplitude.

The effects of the horizontal stiffness of a bracing frame on the effective length factors of a long columns in atrium are examined. Evaluation methods for the horizontal stiffness are presented, and the calculated effective lengths are compared with that obtained from a spring model. It is shown that 1) the effective length factor approaches that of the non-sway buckling mode as the horizontal stiffness becomes large, and then, 2) the effective length factor from G factor method is quite large and 3) an evaluation formulas of a flexural stiffness ratio for assuring a specific effective length factor are presented.

This paper targets high-strength steel box-section column to beam moment connections with exterior diaphragms whose depth are smaller than those of conventional ones and investigates the yield strength of beam end connections under axial force of columns by the loading test and the finite element analysis. The evaluation method of the yield strength of connections is proposed by considering column axial force. Furthermore, it is revealed that the evaluation method can correspond to results of the test and the analysis within 20%, and the validity of the evaluation method is confirmed.

It is well known that the bearing capacity of bolted connections subjected to tensile forces is affected by eccentricity. However, the effect of the bending moment caused by the eccentricity on the bearing capacity has not been fully investigated. This study conducted a series of tensile tests and finite element analyses of brace members and examined the stress distribution in the cross-section. Then, a novel method of estimating the bearing capacity determined by the net section fracture in FEA was proposed. Furthermore, design equations for bolted connections that consider the effect of eccentricity in each cross-section were developed.

The ultra low-cycle fatigue fracture of open section steel members undergoing local buckling was experimentally investigated using rectangular clamped-free-clamped-free (CFCF) plates, validating a classic macro model (plastic-hinge-based damage model) and phenomenological micro model (void growth model, or stress-weighted damage model). Finite element models were calibrated to the 3D-DIC experimental data to further analyze the fracture mechanism, and to characterize the stress triaxiality and Load angle parameter during local buckling.

In this paper, shear strength of wide-flange shapes using high-strength steel thin plates at elevated temperatures were examined. The shear-bending experiments using small steel beam specimens were conducted at ambient temperature and 600, 800℃, respectively. Furthermore, the initial elastic-stiffness and shear strength were theoretically evaluated by considering an effect of steel strain rate at elevated temperatures. It was clarified that the shear strength at elevated temperature could be evaluated by shear resistance force using the effective strength of steel.