Damage Avoidance Design of Special Truss Girder Frames with Energy Dissipation Devices
Civil and Environmental Engineering
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An innovative detail that facilitates the use of energy dissipating devices, such as Buckling Restrained Braces (BRBs), is proposed for Special Truss Moment Frames (STMFs). The configuration of the proposed Special Truss Girder Frame (STGF) consists of pins introduced at the ends of the top and bottom chord elements of the special segments. Subsequently, energy dissipating devices (EDDs) are used in the form of diagonal BRBs and re-centering devices respectively inside the special segments. An energy-based design methodology is adopted such that the EDDs are designed to provide sufficient energy dissipation capacity with respect to the seismic input energy demand on the structure. The energy based methodology is demonstrated to be accurate by means of a series of nonlinear time-history analyses. The overall seismic response of the proposed system incorporating BRBs is contrasted with the conventional STMF in terms of story displacement, interstory drifts, story shears, and overturning moments, as well as observed damage to the structural elements. The proposed system leads to more predictable seismic response and would potentially allow lighter construction and significant cost savings, due to reduced member forces (up to 50% compared to the conventional design). Furthermore, damage to structural elements is largely mitigated, hence allowing damage avoidance design of STGFs. Additionally, the efficiency of the proposed STGF is investigated with of re-centering devices. The results confirm a better seismic performance of the structure since residual displacements can be mitigated through the use of re-centering devices.