Dual high‐strength steel eccentrically braced frames with removable links

Abstract

SUMMARYStructural damage in buildings designed according to the dissipative design philosophy can be significant, even under moderate earthquakes. Repair of damaged members is an expensive operation and may affect building use, which in turn increases the overall economic loss. If damage can be isolated to certain dissipative members realized to be removable following an earthquake, the repair costs and time of interruption of building use can be reduced. Dual structural configurations, composed of a rigid subsystem with removable ductile elements and a flexible subsystem, are shown to be appropriate for the application of removable dissipative element concept. Eccentrically braced frames with removable links connected to the beams using flush end-plate bolted connections are investigated as a practical way of implementing this design concept. High-strength steel is used for members outside links in order to enhance global seismic performance of the structure by constraining plastic deformations to removable links and reducing permanent drifts of the structure.

Design Criteria and Modelling of Re-Centring Dual Eccentrically Braced Frames

“…An experimental program was carried out at UPT, CEMSIG Research Centre, to determine cyclic performance of isolated bolted links [1][2] and another at the European Laboratory for Structural Assessment (ELSA) of the Joint Research Centre (JRC) in Ispra, Italy, to validate the proposed solution through a pseudo-dynamic testing campaign of a full-scale model of a dual EBF structure [3].…”

“…An experimental program was carried out at UPT, CEMSIG Research Centre, to determine cyclic performance of bolted links [1][2], for which the experimental set-up of only isolated link is presented in Figure 2. The removable link was fabricated from IPE240 profile of S235 grade steel, while the rest of the structure -from S355 grade steel.…”

“…Columns should satisfy the "weak beam-strong column" condition: ∑MRc≥1.3∑MRb (2) where: MRc is the sum of upper and lower columns moment resistance and MRb is the moment resistance of the MRF beam. Inter-story drifts were checked from the seismic SLS combination: 1.0·G+0.3·Q+ν·q·S (where ν=0.5).…”

The Art of Application of High-Strength Steel Structures for Buildings in Seismic Zones

“…Consequently, HSS members designed with sufficient over strength will not yield during earthquakes. The other suggested structural system by Dubina et al [32] is called dual steel structures (DSS), as shown in Figure 9. DSS is constituted by several bays of HSS moment-resisting frames and at least one bay of eccentrically braced frame with removable links fabricated from normal strength steel or low yield strength steel.…”

Finite Element Modelling of Detachable Short Links

“…However, in split-K and D configurations of EBFs the concentration of damage into the links can lead to high repair costs due to the interference of the slab and the beam containing the links. In order to overcome this problem, recent studies [12][13][14][15][16][17][18][19][20][21] investigated the possibility to use detachable links for both new and existing structures to allow quick removal of damaged links and easy repair of the structure after earthquake.…”