DUAREM: Full-scale experimental validation of a dual eccentrically braced frame with removable links

Conventional seismic design philosophy is based on dissipative structural response, which implicitly accepts structural damage under the design earthquake load. Different strategies can be employed in order to reduce damage to structures. One of these options is to adopt a conventional design with replaceable dissipative members, easy to substitute even after strong earthquake, thus reducing the repair costs. In such systems, the inelastic deformations should occur in removable elements only, and the damaged dissipative elements must be replaceable. Replacing the elements is more efficient if the structure does not have large permanent deformations. These two concepts were implemented in a dual structure, obtained by combining steel eccentrically braced frames (with removable bolted links) and moment resisting frames. The bolted links provide the energy dissipation capacity, while the moment resisting frames provide the necessary recentering capability. The dataset gathers the signals recorded during the pseudo-dynamic testing campaign performed at JRC-ELSA. The considered complete prototype building is a steel-concrete composite structure with three 6 m bays in the transverse direction, five 6 m bays in the longitudinal direction, and three 3.5 m high storeys. In the transverse direction, i.e. the testing direction, the main lateral load resisting system is composed of eccentrically braced frames (EBF). These are working in parallel with four moment resisting frames (MRF), 2 on each side of the prototype. The bracings are attached to the rest of the structure through removable links representing the principal source of energy dissipation when undergoing significant seismic loading. The test structure in the lab was limited to the two external frame of the prototype building in the transversal direction. The specimen is therefore a three 3.5 m high storeys structure with three 6 m long bays in the loading direction and one 6 m bay in the perpendicular direction. The lateral force resisting system is equal to the one of the prototype building, featuring two dual steel frames (EBF and MRF).

The specimen layout allowed the investigation of two alternative construction details. On one side, the beam of the EBFs was connected to the reinforced concrete slab, expecting to damage the reinforced concrete slab at the interface with the removable link, hence calling for local repair after a strong earthquake. The restoring force of side of the specimen was actually fed-back to the pseudo-dynamic algorithm driving the majority of the tests. On the other side, the beam connected to the dissipative link on top of the EBFs was completely disconnected by the reinforced concrete slab, preventing damages to occur in this latter element. For this side of the specimen, the performed experiments must be considered as cyclic tests