Validation of a Design Procedure for Failure Mode Control of EB-Frames: Push-Over and IDA Analyses

Abstract

The paper is devoted to the investigation of the seismic response of eccentrically braced frames characterised by links having different length. In addition, the analysed structures have been designed according to a methodology, already proposed by the authors, aiming to guarantee a collapse mechanism of global type. Therefore, the results of the nonlinear analyses herein presented provide the validation of the proposed design procedure, by testifying that all the designed structures exhibit a global failure mode where all the links are yielded while all the columns remain in elastic range with the exception of the base section of first storey columns, leading to high energy dissipation capacity and global ductility. Furthermore, two different distributions of the link lengths are examined. The first one is characterised by short links with uniform lengths along the height of the structure. The second one is characterised by the use of link elements having different length at the different storeys which are selected to assure the same value of the non-dimensional link length. The seismic response of EB-Frames with such distributions of the link length is investigated by means of both push-over analyses and dynamic non-linear analyses. The comparison of the performances is mainly carried out in terms of plastic hinges distribution, local ductility demand and frame lateral stiffness.

Probabilistic Theory of Plastic Mechanism Control: Design and Seismic Assessment

“…The aim of the non-linear dynamic analyses presented in this section is to check the collapse mechanism developed by the structures designed by P-TPMC [36]- [39]. In fact, it is expected that the percentage of structures exhibiting a collapse mechanism of global type completely developed or compatible with it agrees with the fixed probability given as design achievement of P-TPMC.…”

Design and Analysis of Dual Ebfs Equipped With Prequalified Connections

“…The work herein presented, developed in the contest of the RFCS Project EqualJoints Plus [23], aims at clarifying the role of joints on the design and performance of Dual-Eccentrically Braced Frames (D-EBFs) at the variation of prequalified steel beam-to-column joints typologies. To this scope, several D-EBFs have been designed by the Theory of Plastic Mechanism Control (TPMC) [24]- [35] which always allows the development of a collapse mechanism of global type.…”

The Influence of the Steel Grade on the Probabilistic Theory of Plastic Mechanism Control for Steel Moment Resisting Frames

“…It is important to underline that, within structural reliability analysis and within the contest of failure mode control, the term "failure" denotes the attainment of a collapse mechanism different from the global one. In fact, many experimental investigations made by shaking table test [20]- [22] or Incremental Dynamic Analyses (IDA) [24]- [29] have shown that different failure mode can occur in structures under destructive earthquakes, and the reliability of having a collapse mechanism of global type sometimes is very low. Through the probabilistic procedure, it was possible to define an overstrength factor to apply to the deterministic version of TPMC with a given success probability, taking account the effects of random material variability.…”