When end tabs made of conventional ceramic are used for full penetration weld of beam-to-column connections, weld defects are ready to occur at the start point in the weld first pass. The defects are located at the inner surface of beam flanges for shop-welding types. On the other hand, at the outer surface of lower beam flanges for field-welding types. Therefore, weld defects of lower flanges for field-welding types result in poor plastic deformation capacity of the beam. In this paper, test results and finite element analysis results focused on groove types and height of weld defects are reported.

In this study, experiments were conducted in which tile walls were tapped by a pendulum and FEM analysis of the response deformation behavior of impact loads on tile walls was conducted. Local deformation at the load location occurs in the normal area, and in the detached area, in addition, the deformation around impact position also occurs. This is applicable even when the detached plate is thin. Closer than 20 mm from the detached boundary, the coefficient of resilience approaches the value of the normal area, and farther than 20 mm, there is almost no change.

In this paper, we propose a simple method to estimate the cumulative plastic deformation, η, of hysteretic dampers installed to a response control structure using multi-spring models equivalent to each mode of the structure. It is found that the ratio of η’s among the inelastic springs in the models, each of which corresponds to the dampers in each story, can be expressed by a simple function. The hysteresis energy of each spring can be estimated using the ratio, and the hysteresis energy of the dampers in each story can be estimated as the sum of those of the corresponding springs.

A viscoelastic damper is a vibration-damping device that effectively absorbs energy against vibrations of various amplitudes. Viscoelastic materials convert absorbed energy into heat, which increases internal temperature and reduces performance. It is necessary to consider the performance degradation of viscoelastic materials to reduce the response of high-rise buildings due to long-period earthquakes. This paper presents a seismic response prediction method for high-rise buildings that considers the performance degradation of stud-type nonlinear viscoelastic dampers.

This paper presents elasto-plastic seismic response analytical method of high-rise building in consideration of fluctuation of axial force on concrete-filled steel tubular (CFT) columns and its application to structural tests of square CFT columns. In this analytical method, two strength curves named crack curve and yield curve are set on the stress plane of bending moment and axial force to judge the elasto-plastic behavior of the column ends. From the results of the experimental simulation analyses, the adequacy of this analytical method is verified.

Analytical investigations of steel roof structures with supporting substructures have shown that the roof response, including vertical vibration, is coupled with the response of the supporting substructure. However, the seismic response of roof structures including energy-dissipation members has not yet been verified by full-scale shaking table experiments. In this study, shaking table tests of a complete near-real scaled roof model with energy-dissipation members at the supporting substructure are conducted to clarify the actual response characteristics, the response reduction effects, and the collapse behavior of the roof structure.

A series of the proposed GRSA-based computational morphogenesis subjected to dead load and seismic load was performed for metal gridshell with square plane to investigate the effect of the level of seismic load, the period ratio between the roof and the supporting structure and the seismic-energy dissipation by the supporting structures with buckling-restrained braces on the form-found roof shape of the pareto solutions. Furthermore, the dynamic characteristic, seismic performance and buckling load were analyzed by linear static analysis, non-linear response history analysis, linear buckling analysis, non-linear buckling analysis.

Timber structural joints should be modeled as semi-rigid joints reflecting local deformation. Therefore, this study aims to contribute to a theoretical formulation of its behavior, and deals with one of its dominant factors, embedded behavior, especially elastic embedded behavior due to equally displacement. Currently, the Inayama model is often used to evaluate a stiffness of the behavior, but the model approaches only geometrically and lacks mechanical knowledge of the behavior. So, this study uses 3D FEM analysis to clarify the mechanical mechanism, and makes a mechanical model. However, for simplicity, this paper deals with the case on one-way extra length.

This study concerned placement of the beam joints in frame design of conventional wooden houses. It clarified effect of beam joints placed near the angle tie on the strength performance and fracture properties of the horizontal structure with angle ties. The results of in-plane shear tests and structural analysis showed when the beam joint is placed near the angle tie, beam joint break before the angle tie. Furthermore, maximum load was reduced depending on how beam joints were reinforced. Besides, an analytical model of horizontal structure with angle ties with beam joint is proposed, which agrees well with experimental results.

To develop fire-resistant design for 60-minute semi-fireproofing of steel bar-timber composite beam, burning tests were conducted and the followings were identified.

1.　By gluing lamina of 90 mm in thickness at the lower surface of beam, the beam maintained bending and shear capacities calculated using the proposed resisting portion model.

2.　When the area was divided into three equal portions in the beam width direction, the central portion was still below 70℃ even after 60 minutes of burning, and the rebar within that area was also below 30℃, a temperature situation that would provide resistance as the composite beam.

Referring to a previous experimental study of RC exterior beam-column joint structures subjected to high varying axial forces, a 3D nonlinear FEM analysis was conducted. The main parameters were the strength reduction ratio β_j, the joint reinforcement ratio, and the varying axial force ratio. Based on the strain transverse to the direction of compressive strut, the damage level of the joint panel and the effective strength coefficient could be estimated. A change of the effective strength coefficient with respect to the experienced story deformation angle was quantitatively presented. The design factors that correlate with the effective strength coefficient were organized.

A series of quasi-static cyclic tests of cold-formed circular hollow section members (which is used in steel tower structures) with 20 or 40 of the slenderness ratio and 60 to 80 of the diameter-to-thickness ratio was performed to investigate the buckling behavior and the cumulative deformation capacity. A modified Shibata-Wakabayashi hysteresis model was proposed based on the experimental result. Moreover, finite element analysis was performed to analyze the local strain and to validate the existing simple evaluation method of fracture initiation on the local buckling part of cold-formed circular hollow section members.

This paper aims to clarify effects of beams on full plastic strength of circular hollow section panel zones in beam-column subassemblies. We categorized the effects as following two factors; [a] reduction of shear force at both ends of panel zone due to resistance of beams, and [b] restraint of out-of-plane deformation and reduction of axial force of panel zone by beams. The contributing ratios of the individual effects were evaluated quantitatively based on finite element analysis of cruciform subassemblies and simple panel zones varying panel aspect ratio, axial force ratio of the column, input direction, and so on.

This paper discusses usefulness of evaluating relationships between the seismic demand and optimized steel weight. The influences of structural design conditions to the structural properties of the buildings are numerically investigated by comparative evaluation of superior design solutions (SDSs). SDSs are rational structural design solutions, which satisfy practical structural design constraints with minimized steel weight using the multiple start local search method. The steel weight in SDSs was quantitatively evaluated for different building sizes, occupancies, structural systems and the seismic demand. Major findings include the fact that steel weight in higher buildings is less influenced by the seismic demand.

To contribute to the development of a blast-resistant strengthening method of reinforced concrete (RC) slabs using slurry infiltrated fiber concrete (SIFCON), experimental investigations were conducted regarding blast resistance of RC slabs with backsides strengthened with SIFCON panels under contact detonation. The results showed that SIFCON panel on the backside of RC slab had a good detached spall-suppressing effect equivalent to that of normal concrete with a thickness of 10.8 times. However, it should be noted that even if detached spall is suppressed by this method, damage inside RC slab progresses in the same manner as in case of no reinforcement.

This paper describes influence of laps of welded wire mesh on bending resistance and failures of RC slabs at high temperatures by carrying out high temperature loading tests for one way RC slabs, varying the lap length and the temperature of the lap. The test result indicated that RC slabs for the lap length of the mesh interval plus 50 mm transfer sufficient tensile stress at the lap up to 550 °C and prevent brittle failure of the lap. Test result of the bending resistance is more than the calculation result determined by the yield stress of welded wire mesh.