Evaluation of the Response of Posttensioned Steel Frames with Energy Dissipators Using Equivalent Single-Degree-of-Freedom Systems

Rivera, Jiménez; Lopez-Barraza, Arturo; Ruiz, Sonia E.; Reyes‐Salazar, Alfredo

doi:10.1155/2014/730324

Cited by 3 publications

(2 citation statements)

References 17 publications

(16 reference statements)

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“…Archer (1965) was one of the first researchers to propose a model for the consistent mass matrix for the case of beams. Rea et al (1971) assesed the amount of damping that exists in special models of steel structures that consist of a flat horizontal platform supported by columns. Wilson and Penzien (1972) proposed two procedures to analytically develop the damping matrix.…”

Section: Literature Review and Objectivesmentioning

confidence: 99%

Evaluating the Effect of Some Commonly Used Idealizations on the Nonlinear Seismic Response of Steel Buildings

Llanes-Tizoc,

Valenzuela-Beltrán,

Baca-Machado

et al. 2024

Preprint

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There have been significant advances concerning seismic analysis and design procedures for steel buildings. Emerging procedures as the performance-based seismic design and the resilient seismic design, are examples of such advances. However, there is a long road ahead before these new concepts can be widely accepted and implemented by structural engineers, government officials and owners. In addition, many simplifications are commonly adopted in seismic analysis, the effects of which on the seismic response, and consequently on the structural performance, are overlooked. Some of these issues are addressed in this paper. Toward this goal, the seismic responses of 3 models of moment-resisting steel frames subject to 20 strong motion records are estimated. Results indicate that the ductility reduction factors for SDOF systems can be up to 95% greater than those of MDOF systems. Bending moments on columns and interstory shears can be underestimated by up to about 30% and 15%, respectively, when using the lumped mass matrix formulation. Underestimates of up to 18% are observed for bending moments on beams if just one element is used to model the beams. Overestimates can be up to 210% for lateral damping forces when using the first two modes of lateral vibration to generate the Rayleigh damping matrix; underestimations of up to 40% are observed for axial loads and flexural moments, while those of lateral shears and drifts can be of up to 20%. The contribution of local rotations and vertical displacements modes to axial loads on columns can be up to 38%, while for bending moments, interstory shears and drifts it can be up to 18%. A damping ratio of 3% to express the yielding effect is very conservative; a value of 7% can be reasonably used. The above results clearly indicate that more accurate structural models (MASM) should be used. One of the justifications for not using more accurate structural models (MDOF systems, consistent mass matrix and the Superposition of the Modal Damping Matrices to derive the damping matrix) has been the high demand on computing time; using modern computers, however, this justification is no longer valid.

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Section: Literature Review and Objectivesmentioning

confidence: 99%

Evaluating the Effect of Some Commonly Used Idealizations on the Nonlinear Seismic Response of Steel Buildings

Llanes-Tizoc,

Valenzuela-Beltrán,

Baca-Machado

et al. 2024

Preprint

Self Cite

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“…Lopez-Barraza et al [38] studied the reduction of the response in terms of inter-story drifts for plane frames with rigid and post-tensioned connections. Rivera et al [39] evaluated the effect of the dissipated energy on the reduction of the seismic response of plane steel frames modeled as MDOF systems and equivalent SDOF systems. Abdollahzadeh and Faghihmaleki [40] studied some methods of seismic rehabilitation of steel structures of medium moment frame with braces considered in the seismic provisions for steel structures (ANSI/AISCF).…”

Section: Literature Reviewmentioning

confidence: 99%

Strength or force reduction factors for steel buildings: MDOF vs SDOF systems

Reyes‐Salazar¹,

Llanes-Tizoc²,

Bojórquez³

et al. 2017

J. vibroeng.

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The nonlinear seismic responses of steel buildings with perimeter moment resisting frames (MRF), modeled as complex 3D MDOF systems, are calculated and the ductility demands, ductility reduction factors and the force reduction factors (), are studied. Equivalent 3D models with spatial MRF, two-dimensional models, and equivalent SDOF systems (SD), are also considered. Results indicate that the global and local force reduction factors significantly vary from one structural representation to another and that they are much larger for the SD models. One of the reasons for this is that, although there is equivalence between the SD and MDOF models, the dissipated energy and the number of incursions in the inelastic range are significantly larger for the SD models. In addition, while for the SD models total plasticization occurs, for the SAC and EQ models, even for significant yielding, plastic hinges are developed only in a relatively small number of structural members; therefore, using the factors of the SD models may be conservative. According to the results obtained in this research for the more realistic representation of the steel building (3D), the value of 8 suggested in many codes for the factor for ductile MRF cannot be justified. It is only justified for the SD systems. The implication of this is that non-conservative designs may be obtained if so large value is used. More transparence is needed in the codes regarding the magnitude and the components involved in the factor.

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Cyclic behavior of hexagonal castellated beams in steel moment-resisting frames with post-tensioned connections

Sarvestani

2017

Structures

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Evaluation of the Response of Posttensioned Steel Frames with Energy Dissipators Using Equivalent Single-Degree-of-Freedom Systems

Cited by 3 publications

References 17 publications

Evaluating the Effect of Some Commonly Used Idealizations on the Nonlinear Seismic Response of Steel Buildings

Evaluating the Effect of Some Commonly Used Idealizations on the Nonlinear Seismic Response of Steel Buildings

Strength or force reduction factors for steel buildings: MDOF vs SDOF systems

Cyclic behavior of hexagonal castellated beams in steel moment-resisting frames with post-tensioned connections

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