床スラブが梁端ピンディテール接合部およびブレース架構の力学挙動に及ぼす影響

<p> Connection of which the beam web is connected to the gusset plate of column through high strength bolts is considered as a pin connection in structural design. In previous study, fundamental structural behaviors were investigated by conducting experiment of the pin detailed connection. Further, in experiment of tension-only braced frames, it was confirmed that beam-column assemblies which had pin detailed connections at the beam ends hardly resisted in lateral force. On the other hand, in the case of a beam with concrete slab, it is expected that stiffness and strength of the connections increase by restricting a rotation of the pin detailed connections and lateral force of beam-column assembly become larger. However, it is unclear that how much is the influence of the concrete slab on structural behavior of the connection.</p><p> In this study, cyclic loading tests of pin detailed connections which has concrete slab were carried out in order to investigate the effect of concrete slab on structural behavior at the connections. In addition, full-scale frame tests were conducted to clarify the influences of concrete slab on structural behavior of braced frame in which beams were subjected to compressive force.</p><p> In the connection tests, specimens are cantilever beams in length of about 0.8m which are consisted of steel beam and gusset plate. Test parameters are presence or absence of concrete slab and bolt spacing of the connection. As a result, the pin detailed connections with concrete slab exerted a greater rotational stiffness and strength under positive bending. On the other hand, the same behavior as the connection without concrete slab was shown under negative bending. For the rotational stiffness under positive bending, evaluation model is represented by using local spring stiffness around bolt holes and elastic stiffness of concrete slab, and it was confirmed that the model can evaluate the experimental values. For flexural strength under positive bending, evaluation models of yield strength and ultimate strength based on strain distributions are shown, it was found that they can evaluate the test results. Finally, envelope curve model for connection behavior under positive bending is proposed, and it was shown that its model enable to evaluate the test results.</p><p> On the other hands, in the frame tests, specimens are 2 story-1 bay full-scale braced frame which have pin detailed connections at beam-ends. Test parameter is presence or absence of concrete slab on beams. Test results show that horizontal stiffness and strength of specimen with concrete slab was greatly larger to be compared that of a specimen without concrete slab. It indicates that bending moments at beam-end connections increase due to compressive resistances of the concrete slabs, and lateral strength of the beam-column subassemblies increases. Additionally, in the frame test, the maximum strength of connections with concrete slab was about 1.8 times larger than that in connection tests. This is because the concrete slab in braced frame is subjected to compressive force from braces and its force is eccentric to steel beam. At last, using the envelope curve model obtained from connection tests, push-over analysis of a braced frame with concrete slab was conducted. The result represented that the analysis model can evaluate the envelope curve obtained from test result if additional moment due to presence of concrete slab is considered.</p>