Seismic performance of chevron braced frames with shape memory alloy vertical shear link

This paper presents a new approach to the project of steel buildings, mainly focused on the architectural, structural, and seismic design of stairs. The objective is to design a structural stair system capable of controlling seismic damage and contributing to the bracing system of the building. The article begins with a review of the seismic standard (ATC, FEMA, and EC8) on which the current design criteria for new buildings with stairs are based. The research is based on two spatial building models (A-B) with the same bracing elements but placed differently. Reference Model A follows classical design approaches. It means, stairs are considered nonstructural elements that do not influence the seismic behavior of the building. This structure corresponds to typical braced frames (IV-CBF and EBF) according to EC8. Model B includes a stair system designed to help control the effects of inter-story drifts and inertia forces. In this case, the same bracing elements of Model A were integrated into the stair structure of Model B. A comparative seismic behavior analysis of typically braced frames (A) versus specially braced stairs (B) is presented. The research was based on the static nonlinear (pushover) analysis and the capacity spectrum method (ATC-40) according to the seismic performance levels (FEMA) and damage limitation (EC8).Finally, the braced stairs was verified via nonlinear time-history analysis in order to better capture the structural safety of the evacuation routes and their influence on the behavior of the building. This deterministic analysis of the braced stairs verified satisfactory results compared to reference bracing systems.

Section: Plastic Hinge In Seismic Links (Ebf)mentioning

confidence: 99%

Special braced stairs versus typical braced frames. New architectural‐structural‐seismic approach to stair design

Turon

Alzate

2023

“…Since then, the idea of link beams was used as a structural fuse element in different structures that yields and dissipates energy during major earthquake events. [ 27–29 ] The lateral load‐resisting behavior of the CDS is identical to the concentrically braced frames, and by dislocating the joints, an eccentric diagrid system (EDS) can be generated, which behaves similar to EBF. The eccentricity of the diagonals allows the link to rotate under a lateral load, and this rotation imposes significant shear and bending moment in horizontal elements, unlike CDS.…”

Section: Introductionmentioning

confidence: 99%

Comparison of seismic behavior of the eccentric and conventional diagrid systems

Dabbaghchian

Mirghaderi

Sayadi

2020

SummaryDiagrid system is known for its efficient structural behavior besides its outstanding aesthetic characteristics and architectural flexibility. However, a brief existing study on the nonlinear performance of the diagrid system has reported an inefficient nonlinear behavior. Diagrid with fused‐shear link is a newly introduced system that can solve this flaw in the conventional diagrids and keep the advantages as well. In this paper, this newly introduced system is called eccentric diagrid system (EDS). Benefits of the EDS are presented, and a series of nonlinear pushover and time history analyses are conducted to compare EDS with the conventional diagrid system (CDS). In this manner, three different configurations for both EDS and CDS with diagrid angles of 45°, 63.4°, and 71.6° are chosen for two different 12‐ and 18‐story buildings. The models are designed based on an R‐factor equal to 3.6 and 5 for CDS and EDS frames, respectively. Then, the assumed R‐factor for EDS is verified according to Federal Emergency Management Agency P695, and the priority of members yielding is spotted. The results show that EDS can effectively enhance the post‐yield performance and seismic characteristics of the structure relative to CDS, including ductility and overstrength ratio more than 2.5 and 1.3 times, respectively.

“…The results show that the proposed viscous damped system can perform more effectively in reducing high‐rise structural responses. Fahiminia et al [ 20 ] described the seismic performance of chevron‐braced frames with shape memory alloy vertical shear link which had reliable displacement dependent dampers with sufficient strength and ductility to dissipate energy of strong earthquakes through inelastic mechanisms. Martinez‐Paneda and Elghazouli [ 21 ] proposed an integrated damping system that aimed at providing relatively high damping levels through the mobilization of a proportion of the structure's own mass.…”

Section: Introductionmentioning

confidence: 99%

Seismic performance enhancement of buildings using multi‐limb brace damper systems

Feng

Zhou

et al. 2020

SummaryA novel brace system with a displacement amplification mechanism for damper energy dissipation is proposed in this paper. Theoretical mechanism of the multi‐limb brace damper system (MLBDS) is established. Finite element models are established to confirm the effectiveness of the proposed system. The seismic performance of the MLBDS is compared with those of traditional brace damper systems. Comparison results show that MLBDS has an excellent energy dissipation performance. In addition, the dynamic responses of a high‐rise building with the MLBDS installed to seismic excitations are evaluated. The results show that the MLBDS can significantly reduce the dynamic responses of the high‐rise building under strong earthquakes.