EVALUATION OF DUAL SYSTEMS WITH MOMENT-RESISTING FRAME AND SHEAR LINK FRAME

This paper puts forward a new dual system to dissipate energy and presents its numerical studies. Though moment-resisting frames have a good ductility performance, they suffer low stiffness; as a matter of fact, engineers try to increase the stiffness by reducing the span length of these frames. On the other hand, in order to ensure the formation of plastic hinges at the two ends of the beam, the codes suggest a minimum limit for the clear span-to-depth ratio of such frames. To solve this problem, this paper proposes a new dual system. The proposed dual system includes a moment resting frame and a frame with a replaceable beam with a smaller cross-section than that of the main beam which is placed at the mid-span of the beam designed to act as a shear fuse. This shifts the location of the plastic hinge from the ends of the beam to its middle since the shear fuse yields shear prior to the flexural yielding of the main beam. This dual system eliminates the need to comply with the rigorous limitation on the clear span to depth ratio of beam that is proposed by seismic design codes. Moreover, this system enjoys an increase in the amount of stiffness. It is worth mentioning that this dual system increases the resilience of the building as the shear fuse is readily replaceable after an earthquake. With verification of an experimental model, the finite element numerical models are produced. The ABAQUS numerical models show that the system which includes both moment-resisting frame and shear link frame function much better than the moment-resisting frame system. As a result, by enjoying this dual system as well as using the ductility of moment-resisting frames, the stiffness of the building does not decrease noticeably.