Tile peeling diagnostic method for the external tile finishing wall by impact sound analysis for wall contact type UAV was investigated using FEM. The focus is on the fundamental peak frequency. Time history response analysis revealed tile wall displacement during impact and sound wave characteristics. Relationship between floating plate thickness and fundamental peak frequency was revealed.

Natural frequency analysis of the floating model revealed how floating plate shape influences natural frequencies, determining impact sound. Considering UAV's wind noise and using fundamental peak frequency of impact sound, tile peeling diagnostic for external tile finishing wall with wall contact type UAV becomes feasible.

In this study, a shear test was performed on the joints of an existing brick building constructed in Meiji period. The distribution of joint mixing proportion, width of joint, filling ratio, and distribution of porous, which are thought to affect shear strength, were analyzed. The possibility of influence of these factors on shear strength was clarified. Based on the knowledge obtained from these studies, points to be noted when evaluating the shear strength of joints in existing brick buildings were clarified.

A mortar using electric arc furnace oxidizing slags and styrofoam beads (“beads”) as aggregate (“beads slag mortar”) becomes a broadband electromagnetic wave absorber by vibrating before curing. In this study, the effect of varying the particle diameter and expansion ratio of the beads used as aggregate in beads slag mortar on the electromagnetic wave absorption was investigated. The larger the particle diameter of the beads, the smaller the water cement ratio and vibration time required to design a broadband electromagnetic wave absorber. On the other hand, effect of the expansion ratio of the beads is little.

Window glass is an important material for finishing building exterior. However, it is prone to breakage by colliding objects and posing a risk of harm to humans. Therefore, it is crucial to consider the damage characteristics of window glass in building design. In this study, window glass damage behaviors collided by flying objects were observed in the impact tests. FEM analysis was performed to reproduce the experimental results and the sensitivity of the glass model was estimated through parametric studies. The analysis results were compared to the experimental ones to determine the applicability of the FEM model.

It is known that the topology optimization problem of frame structures can be formulated as mixed-integer second-order cone programming problem (MISOCP). Although MISOCP can obtain the global optimal solution, it is difficult to apply to large-scale frame structures due to its high computational cost. In this paper, such topology optimization problem is solved as a DC (Difference of Convex Functions) programming problem to reduce computational cost. The effectiveness of proposed approach is confirmed thorough numerical examples while comparing with the global optimal solution obtained by solving MISOCP.

Unidirectional suspended roof structure is a system that is easier to construct than two-way system. On the other hand, compared to two-way suspended roof structure, it is less stable against asymmetric loads and is prone to large deformations due to dynamic load like earthquakes. In order to understand the dynamic behavior of such structures, it is most important to evaluate their natural frequencies precisely. This paper proposes a method for theoretically estimating the natural frequencies of such structures. Several numerical examples are conducted and the results are compared with the proposed theoretical values to prove its effectiveness.

Experiments were conducted to investigate the screw withdrawal performance of CLT that surface was wetted with water. Water wetting time and the location of the screw (surface or edge joint of lamina) were the experimental variables. Experimental results showed that the withdrawal force decreased as the time of water retention increased, and that the withdrawal force was significantly lower when screw was placed at edge joint of lamina. Furthermore, we proposed a formula for calculating the rate of reduction of the withdrawal force and confirmed the validity of the proposed formula.

Bending stiffness, yield moment, and bending capacity of steel bar-timber composite beam under high-temperature environment with uncontrolled humidity were revealed by heating and loading tests, and methods for estimating those were proposed. Internal stresses of rebar and glulam timber within the beam, derived from temperature rising, did not affect the stiffness and capacity, but only the yield moment. The stiffness and capacity could be estimated by considering only deterioration of wood and rebar owing to temperature rising. The internal stresses were appropriately estimated using the previously proposed equations, and the yield moment could be estimated using values of the stress.

Considering RC high-rise buildings higher than 200m have been constructed in recent years, it is necessary to develop structural design method by severe wind force which is repeated thousands of times. Main conclusions are as follows.

1. The stiffness of beams gradually decreases under repeated loads less than yield of longitudinal reinforcement, and the ultimate bending strength is maintained. However, one of tests fails at about 150 repeated loads greater than yield of longitudinal reinforcement.

2. Hysteresis energy absorption before yield of longitudinal reinforcement is about 1 to 2% in the range of over 10 repeated loads.

It has become a important issue to establish a rational reinforcement method for transmission towers, since the increase of assumed loads resulting from revision of design standards. The authors have conducted buckling tests and FEM analyses of reinforcement and proposed a buckling strength equation, but the performance for different-size reinforcement was not clear. In this study, the buckling strength equation for different size reinforcement is constructed by considering the end-bending moment ratio in the buckling strength equation for same size reinforcement. Finally, the results are compared with the FEM analysis results to confirm the usefulness of buckling strength equation.

Built-up section members are frequently used to increase the strength of cold-formed steel members. Many kinds of cross-sections exist on the built-up members, but the current design specifications can be applied only to limited cross-sections; hence, an innovative design approach is required to apply to various cross-section types. This paper proposed a new design equation for the built-up members by modeling the screws as elastic shear springs. Four different section types were investigated in terms of their flexural buckling. Through the analytical investigations, it was found that the proposed method could provide accurate evaluation results.

In this study, axially loaded compression experiments at elevated temperatures for steel column specimens with high-strength bolted connections providing clearance-gaps between column faces were conducted to clarify the fire resistance performance and the surface-touch behavior of the column cross-sections in the connection after the slip-behavior. The steady state, transient state, and thermal stress experiments at the elevated temperatures were conducted. Experimental results show that the slipped column connection at elevated temperature exhibited the stable load-bearing capacity because the column cross-section surfaces in the connection were wholly touched and the axial load was transmitted by the surface-touch without the bolt shear-fractures.

Estimation of natural period is indispensable for evaluating dynamic behavior such as wind induced vibration and earthquakes. However, it is complicated to estimation of natural period of truss tower supported steel chimney. Because there are many members that making up truss tower, it is impossible to uniquely determine the weight and stiffness of truss tower, and also chimney body weight concentrating on the tower support point height depends on the number of parts to support and the height. This paper presents estimation formula of natural period truss tower supported steel chimney except such kind of complicate process.