Crack initiation at the strain concentration point of beam-to-column connection is one of the major factor which determines the plastic deformation capacity of the beam. However, the influence of the strength ratio between base metal (beam flange or diaphragm) and weld metal on the crack initiation is not clear. In this paper, FEA is performed to clarify when and where cracks at the strain concentration points. As a results, when the strength of the weld metal is larger than that of base metal crack occurs at the base metal of the beam flange, and when the strength of the base metal is larger than that of the weld metal the crack occurs at the weld metal of the diaphragm. And the premature failure is determined by the crack at the weld metal of near the diaphragm.

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Concrete filled tube is efficient structure, which confined concrete mainly resist to the compression force, and steel pipe is expected mainly resist to horizontal restriction force and tensile force due to bending moment. In this paper, we propose the application of the reinforced concrete filled tube (RCFT) to "Bow String Arch" that Rise is shallow, as the structure which used the feature of RCFT structure. In this paper, the economical efficiency of shallow rise arch applying a concrete filled tube is examined based on a trial design.

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The present paper investigates the nonlinear behavior of a new type of two-way single layer lattice dome with nodal eccentricity using T-joint struts. First, the paper presents a T-joint system for the dome using a connection for orthogonally crossing arch members, and performs an analysis to find the rigidity and strength of the T-joints using 3D solid finite elements. Next, using the rigidity and strength, a geometrically and materially nonlinear analysis is performed to investigate the nonlinear behavior of the two-way single layer lattice dome with the present nodal eccentricity. The results of analysis show that the domes with this nodal eccentricity, which can be classified as a semi-rigid joint, are feasible as one of single layer spatial structures and well enough to be applied in construction of large two-way single layer lattice domes.

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This paper presents a feasibility investigation for bridge health monitoring (BHM) using bridge vibration data induced by a single moving vehicle. An inverse problem taken from a linear equation of the element stiffness index (ESI) which provides the location and severity of damages in bridges is solved using the ordinary least-squares and regularized least-squares methods. The numerical example demonstrates feasibility of the method to bridge condition screening, even though there remain many tasks to make the procedure practically applicable.

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The studies for the buckling behavior of H-shaped compression members with eccentric braces have not been investigated. Our previous papers clarified the influence of web deformation on buckling load for these members with eccentric braces. However, it was shown that the buckling stress for the members of wide flange shapes is higher than that of plate girder, even though their values of rotational rigidity ratio are equal. In addition, the reduction ratio of the buckling stress with web deformation in inelastic range may be different from that in elastic range. This paper suggests the evaluation method of the buckling stress for eccentrically braced members in inelastic range by the energy method and elasto-plastic large deformation analyses.

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This paper describes maximum deformation of composite beams. Numerical response analysis was carried out for 15 frames against a variety of ground motions. The prediction method of maximum plastic rotation proposed by authors was studied by comparing maximum strain of earthquake response analyses and static analyses. As the result, it was found that the prediction method of maximum plastic rotation introduced into beam-ends could be applied to composite beams.

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This paper deals with the base anchor structures with high fatigue resistance for additional column members such as poles for lighting and information on elevated highway bridges. The lower part of the steel column and the bottom flange plate of an additional column member are generally strengthened with triangular rib plates in order to set tightly the additional column member on the highway bridge. However, unfavorable stress concentration is often observed around the welded zone at the tops of the triangular rib plates. These welded zones are also one of the locations where welding defect tend to occur because of the difficulty of welding. For these reasons, two new types of base anchor structures without triangular rib plates are proposed in this paper. These are the flare type and the increased thickness type of base anchor structures. It is concluded through the fatigue test that these new type base anchor structures can have high fatigue resistance compared with the ordinary base anchor structure using triangular rib plates. It is also observed from the fatigue test that the fatigue strength of the ordinary base anchor structure using triangular rib plates can be improved substantially by finishing smoothly the welding beads at the tops of the triangular rib plates.

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Recently, the fatigue cracks which penetrated through the deck plate of orthotropic steel decks have been found. The cause of the fatigue cracks is the local bending of deck plate. Therefore, reinforcement of deck plate is effective. This study addressed the stress reduction by attaching UFC (Ultra-high-strength Fiber-reinforced Concrete) panels onto deck plate. We evaluated its effectiveness by FEM and static load test. As a result, the method could reduce stress at scallop of transverse rib up to 30%, and still had enough stress reduction effect, even if UFC panels detached from deck plates.

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In this paper, the results of experiments on the part demolition of high strength bolted connections by shaped charge are described. With the part demolition of high strength bolted connections, the demolition methods from both bolt head side and nut side will be important and necessary indeed. Firstly the results of experiments on the part demolition from nut side are described in this paper. And also the conditions of shaped charge which can demolish the nut perfectly are proposed.

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