ASSESSMENT OF DUCTILITY REDUCTION FACTOR FOR OPTIMUM SEISMIC DESIGNED STEEL MOMENT-RESISTING FRAMES

Authors

  • B. Ganjavi
  • G. Ghodrati Amiri
Abstract:

In the present study, ten steel-moment resisting frames (SMRFs) having different numbers of stories ranging from 3 to 20 stories and fundamental periods of vibration ranging from 0.3 to 3.0 second were optimized subjected to a set of earthquake ground motions using the concept of uniform damage distribution along the height of the structures. Based on the step-by-step optimization algorithm developed for uniform damage distribution, ductility-dependent strength reduction factor spectra were computed subjected to a given far-fault earthquake ground motion. Then, the mean ductility reduction factors subjected to 20 strong ground motions were computed and compared with those designed based on load pattern of ASCE-7-16 (similar to standard No. 2800) code provision. Results obtained from parametric studies indicate that, except in short-period structures, for moderate and high levels of inelastic demand the structures designed based on optimum load pattern with uniform damage distribution along the height require larger seismic design base shear strength when compared to the frames designed based on the code provisions, which is more pronounced for long-period structures i.e., the structural system becomes more flexible. This phenomenon can be associated to the P-delta effect tending to increase the story drift ratios of flexible structures, especially at the bottom stories. For practical purpose, a simplified expression which is a function of fundamental period and ductility demand to estimate ductility-dependent strength reduction factors of designed SMRFs according to code-based lateral load pattern is proposed.

Upgrade to premium to download articles

Sign up to access the full text

Already have an account?login

similar resources

Robustness Assessment of Steel Moment Resisting Frames

Nowadays, many buildings with steel Moment Resisting Frames (MRF) are built in seismic zones when seismic codes are at its early stages of development, and as such, these structures are often designed solely to resist lateral wind loads without providing an overall ductile mechanism. On the other hand, current seismic design criteria based on hierarchy of resistance allow enhancing the structur...

full text

assessment of the park- ang damage index for performance levels of rc moment resisting frames

چکیده هدف اصلی از طراحی لرزه ای تامین ایمنی جانی در هنگام وقوع زلزله و تعمیر پذیر بودن سازه خسارت دیده، پس از وقوع زلزله است. تجربه زلزله های اخیر نشان داده است که ساختمان های طراحی شده با آیین نامه های مبتنی بر نیرو از نظر محدود نمودن خسارت وارده بر سازه دقت لازم را ندارند. این امر سبب پیدایش نسل جدید آیین نامه های مبتنی بر عملکرد شده است. در این آیین نامه ها بر اساس تغییرشکل های غیرارتجاعی ...

15 صفحه اول

A Technique for Seismic Rehabilitation of Damaged Steel Moment Resisting Frames

Moment resisting frames as one of the conventional lateral load resisting systems in buildings suffer from some limitations including code limitations on minimum span-to-depth ratio to ensure the formation of plastic hinges with adequate length at beam ends. According to seismic codes, in ordinary steel moment resisting frames the minimum span-to-depth ratios should be limited to 5 and in speci...

full text

A COMPARATIVE STUDY OF OPTIMUM AND IRANIAN SEISMIC DESIGN FORCE DISTRIBUTIONS FOR STEEL MOMENT RESISTING BUILDINGS

In this study, constant-ductility optimization algorithm under a family of earthquake ground motions is utilized to achieve uniform damage distribution over the height of steel moment resisting frames (SMRFs). SMRF structures with stiffness-degrading hysteric behavior are modeled as single-bay generic frame in which the plastic hinge is confined only at the beam ends and the bottom of the first...

full text

SEISMIC RELIABILITY ASSESSMENT OF OPTIMALLY DESIGNED STEEL CONCENTIRCALLY BRACED FRAMES

The main aim of this study, is to evaluate the seismic reliability of steel concentrically braced frame (SCBF) structures optimally designed in the context of performance-based design. The Monte Carlo simulation (MCS) method and neural network (NN) techniques were utilized to conduct the reliability analysis of the optimally designed SCBFs. Multi-layer perceptron (MLP) trained by back propagati...

full text

Seismic fragility assessment of RC moment resisting frame buildings designed for different editions of Iranian seismic design code

Background and objective: Developing fragility and vulnerability functions are important tools in seismic reliability assessment of buildings and are widely used in regional seismic risk studies. To date sufficient studies for developing analytical fragility functions for Iranian code-conforming buildings have not been carried out. Performing such studies are necessary to assess the adequacy of...

full text

My Resources

Save resource for easier access later

Save to my library Already added to my library

{@ msg_add @}


Journal title

volume 9  issue 1

pages  1- 18

publication date 2019-01

By following a journal you will be notified via email when a new issue of this journal is published.

Keywords

Hosted on Doprax cloud platform doprax.com

copyright © 2015-2023