The purpose of this paper is an analysis in assessing the damage of a building when the durability of the structure changes. The target structure is a steel-framed medium and low-rise office building. In this paper, Qu/Qun (the horizontal load bearing capacity Qu / the required held horizontal yield strength Qun) and phase characteristics of seismic motion σtgr are set as analysis parameters. In this study, the response values are evaluated by seismic response analysis, and the calculated maximum response values are analyzed. Building criteria were set for the interlaminar deformation angle, residual deformation angle, and member rupture of the building, and a seismic performance evaluation method was proposed.
In this study, bolt axial tension force and slip strength for high-strength bolted connections after heating and cooling processes were investigated by using an ultrasonic measuring unit and the tensile tests of the connection specimens, respectively. The measuring results on axial tension force of JIS F10T and slip strength of the connection subjected to the heat-damages were accumulated, it was, furthermore, clarified that the secondary tightening for the damaged connections was an effective repair work to recover the bolt axial tension force and the slip strength after fires.
It is not clear how to take measures other than replacing when the cable covered with polyethylene is damaged for some reason and the inside of cable is in a corrosive environment. In this paper, we examine the effect of various methods for improving the corrosive environment using an actual cable with high humidity inside the cable. As a result, it is found that it is necessary to induce clear air flow in order to dehumidify inside the cable which consists of a large number of wires. And if the polyethylene is not damaged and sealed,there is a high possibility that the entire inside the cable can be dehumidified by air supply drying using the air supply holes and the exhaust holes provided at the bottom of the cable.
This study investigated a seismic retrofitting design method using carbon fiber reinforced plastics for steel truss bridge members. A series of compression loading tests were conducted on H-section steel members reinforced with carbon fiber reinforced plastic in order to clarify buckling behavior and reinforcing effects on the load carrying capacity after buckling. Test results showed increase in the buckling strength and effects on the post buckling behavior. Lastly, evaluation methods for the buckling strength for CFRP reinforced steel members were proposed.
The purpose of this study is to clarify the effect of CFRP bonding on the elastic buckling load of steel plates when the elastic putty is inserted. First, uniaxial compression tests were conducted on CFRP-bonded steel plates with elastic putty inserted between the steel plate and CFRP, and the difference in buckling load between steel plates with/without elastic putty was confirmed. Then, the buckling eigenvalues of the CFRP-bonded steel plates are calculated using the finite element method, and the difference in the elastic buckling load improvement effect with/without elastic putty is evaluated. Finally, a method is proposed for estimating elastic buckling load with the effects of adhesive and elastic putty.
Recently, there has been an increase in the number of studies on high-strength bolt tension joints using FE analysis, and it is important to create guidance on how to create an analytical model that can guarantee uniform analytical results. In this study, the effects of element conditions, contact conditions, and modeling of welds and bolts on the analysis results were investigated by FE analysis to propose a benchmark model for three-dimensional FE analysis that can simulate the mechanical behavior of split tee joints in yield and ultimate state. By comparing the experimental results with the analytical results, the analytical parameters that can simulate the experimental behaviors are identified.
In this study, in order to clarify the composite action between main girder and precast slab with thin mortar layer, positive bending experiment was carried out with headed stud spacing as a parameter. As the result, it was proven that it had the same composite action as the composite girder with full interaction, even if the headed stud maximum interval was expanded to 1000 mm, if it is to the slip limit. In the future, this paper carries out analytical examination taking the thickness of thin mortar layer, headed stud spacing, headed stud design as parameters, and establishes a composite girder design method considering the composite action between main girder and floor slab in the precast floor slab with thin mortar layer.