Dissipative devices for seismic-resistant steel frames (Fuseis) : final report

Earthquakes lead frequently to a large amount of damage. Conventional frames (moment resisting, concentric/eccentric braced frames) are not well positioned with regard to reparability. It is therefore advisable to develop structural systems that are simple to repair, i.e. to introduce the reparability as a new property. Two innovative systems of seismic resistant steel frames with dissipative fuses were developed. (1) Fuseis1 consists of two closely spaced strong columns, rigidly connected to multiple beams. The beams run from column to column or alternatively are interrupted and connected by short pins. (2) Fuseis2 devices are seismic fuses for steel and composite steel-concrete moment resisting frames. The fuse is obtained by means of plates bolted/ welded to the web and the flanges of the beam. In case of strong earthquakes damage concentrates only in the fuses, which are exchangeable. Repair work after a strong seismic event, if needed, is limited only to replacing the fuses. The Fuseis system is able to dissipate energy by means of inelastic deformation and combines ductility and architectural transparency with stiffness. Experimental and theoretical investigations were performed to study the response of the fuses and the overall frames to cyclic loading. The investigations conclude with a design guide for practical application, including design examples. The optimal design for the dissipative fuse fulfils the following functional objectives: (a) ease of fabrication of the fuse; (b) maximum energy dissipation in cyclic behaviour; (c) minimum number of exchangeable parts; (d) reduction of the weight, cost and difficulty of replacement of the fuse parts.