This paper proposes a probability density function model of wind-induced ”rainflow range” in elastic structures for evaluating fatigue damage without time-history response analysis and shows the analytical derivation of the model and its validity using time history response analysis. The proposed model is applicable for not only wind-induced narrow-band responses but also broadband responses. The wind-induced fatigue of elastic structures has been studied based on narrow-band vibration following Rayleigh distribution. However, the number of buildings with vibration-damping system or seismic isolation structures which have large damping increased, and a method for evaluating ”rainflow range” of wide-band vibration is needed.

In this paper, an improved ESO (Evolutionary Structural Optimization) method for topology optimization of frame structures is proposed. In this method, in the optimization process, the elements with low strain energy are deleted based on ESO method until the target total member mass is reached. Next, when the target total member mass is reached, the elements around the element with high strain energy are added. The above two processes are repeated to find the optimal solution. The effectiveness of the proposed method is shown by comparing the solution of this method with the solutions of mathematical programing method.

This paper proposes a data-driven modeling method to predict the displacement of beam string structures through the steel erection process. A data assimilation framework is employed to create an as-built simulation model that represents the uncertainties in the real-world structure. Weld shrinkage of the beam and stiffness of the temporary support system are major sources of the model uncertainty, and these parameters are calibrated. The observation data acquired during the erection work are assimilated to update the displacement prediction model. The obtained model can predict the future displacement behavior with less error than the model without data assimilation.

This paper investigated the highly nonlinear behavior of soil–pile interaction system. 1:50 scale reinforced concrete (RC) piles were used for the centrifuge tests. Six models with soil density, pile diameter, reinforcement ratio, and axial force ratio of the piles as variables were tested by static horizontal loading. The ultimate state of the interaction system was brought about by the flexural or shear failure of the RC pile. The maximum strength could be estimated using existing design formulas. The proposed simple analytical model using beam and spring elements reproduced the test results with good accuracy.

To propose a method to detect pile damage, the relationships between pile cap vertical displacement and pile curvature were investigated by E-Defense shaking table tests and 3D FEM analysis. The following findings were obtained.

The pile damage causes dynamic upward displacement at the bottom center of structure with rocking motion. Therefore, the pile damage can be detected from a significant increase of the upward displacement against the overturning moment, and the degree of the damage can be estimated from the amount of the upward displacement.

Lattice shells have various forms, mesh patterns of member arrangement and boundary conditions. The buckling behavior is different depending on these parameters. As considered, reliability indexes for lattice shells under vertical loads are determined by these parameters. Therefore, it is important to accumulate the results with reliability analyses for various lattice shells. In this study, reliability analyses are performed for the cylindrical lattice shell roofs under dead load and uniform snow load using member slenderness ratios, boundary conditions and half open angles as parameters. The relationships between load factors for snow depth of 0.5 m and reliability indexes are clarified.

This research aims to install a panel with solid wood board fitted to timber grid into a frame and apply it as a bearing wall. In this paper, shear loading tests of the frame are conducted. A new mechanical model of the frame and an equation for calculating shear strain of solid wood board are proposed by extending the results of Part 1. The important factors here were the gapping between the each element of the mechanical model and the dispersion of the shear strain. The newly proposed model accurately calculated the restoring force characteristics of the frame experiments.

The shaking table tests of a three-storey CLT building with two types of continuous shear walls were conducted to verify the seismic design. One was the post-tensioned shear wall system and the other was the shear wall fixed at the base with drift pins. In addition, dampers were installed between the walls and side-columns in both shear wall system. Seismic design was applied based on the Japanese Building Standard Law. Safety against extremely severe earthquakes and no structural damage against moderate earthquakes were confirmed during the tests. The results verified the proposed seismic design procedure.

This paper introduces a method for evaluating the horizontal stiffness of CLT seismic panels within steel frame, along with the bearing capacity of compression struts and the easy-to-use stress analysis model. The summary of this paper is as follows:

・The equation for the intrinsic horizontal stiffness of CLT, derived from the simple stress model, has been validated.

・The width and bearing capacity of compression struts of CLT have been quantified.

・The simplified stress analysis model, substituted with the diagonal linear elements, has shown good alignment with the experimental results, as well as the detailed analysis model.

To reinforce the connections of angle diagonal braces of power transmission towers, retrofit methods attaching the additional steel plates including adhesive bonding are proposed. Comparing to the bolt attachment, adhesive bonding attachment can add the additional plates without the loss of sectional area. In this paper, real-size mock-up tests and finite element analysis for the reinforced connections are carried out and it is confirmed that adhesive reinforcement reduces the damage concentration around the existing bolt holes of angle member and improves deformation performance of brace and ultimate strength of connections.

Design method of building steel structures for reuse consists of three types which are elastic design method, elastoplastic design method, and design method considering damages of structural members, and they are used in accordance with structural performances. Tensile tests on specimens obtained by reused steels and newly manufactured steels, which are subjected to bending and unbending with parameters such as bending radius, thickness, and number of bending cycles are conducted and the mechanical properties of structural steels are shown. Furthermore, the feasibility of nondestructive test is shown to evaluate the mechanical properties of structural steels subjected to bending damage and repair.