Dual‐plastic hinge design concept for reducing higher‐mode effects on high‐rise cantilever wall buildings

Abstract

SUMMARYThis paper explores the notion of detailing reinforced concrete structural walls to develop base and midheight plastic hinges to better control the seismic response of tall cantilever wall buildings to strong shaking. This concept, termed here dual-plastic hinge (DPH) concept, is used to reduce the effects of higher modes of response in high-rise buildings. Higher modes can significantly increase the flexural demands in tall cantilever wall buildings. Lumped-mass Euler-Bernoulli cantilevers are used to model the case-study buildings examined in this paper. Buildings with 10, 20 and 40 stories are designed according to three different approaches: ACI-318, Eurocode 8 and the proposed DPH concept. The buildings are designed and subjected to three-specific historical strong near-fault ground motions. The investigation clearly shows the dual-hinge design concept is effective at reducing the effects of the second mode of response. An advantage of the concept is that, when combined with capacity design, it can result in relaxation of special reinforcing detailing in large portions of the walls.

Effect of record scaling on the behavior of reinforced concrete core-wall buildings subjected to near-fault and far-fault earthquakes

“…In the considered systems, beam does not exist and the post-tensioned slab transfers the gravity load to the columns. The insigni cant e ect of the perimeter columns and this kind of slabs subjected to lateral load has been demonstrated by other research studies [1,2,14,21]. Therefore, the RC core-wall undergoes all the seismic lateral loads applied to the building.…”

“…For SPH cases in which the plastic hinge region occurred at the base of the wall, an inelastic shear wall section was used for the lowest 10% of the core-wall height adjacent to the foundation [14]. It was assumed that the upper regions would remain elastic; therefore, in the upper levels, elastic shear wall elements were used.…”

“…There is also the extended plastic hinge approach which allows plasticity to develop anywhere along the height of the wall. This approach is not intended to bring about the development of plasticity concentrated in one distinct region along the height of the wall; thus, plasticity is likely to extend to the upper levels of the walls [14].…”

“…A dual-plastic hinge occurs when one plastic hinge forms at the base and another form at mid-height of the wall. Panagiotou and Restrepo [14] subjected this type of walls to three strong NF ground motions. The results showed that the second plastic hinge in the upper region can reduce the excessive moment.…”

Seismic behavior improvement of reinforced concrete shear wall buildings using multiple rocking systems

“…Previous studies have shown that the effect of higher dynamic modes and their contribution in response to structure are not negligible, particularly in long period structures both in linear and nonlinear behaviors [42][43][44]. The higher mode effects increase the action demands at mid-height of shear walls.…”