ارزیابی ظرفیت شکل‌پذیری ساختمان فولادی تحت نشست غیریکنواخت

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده مهندسی عمران، آب و محیط‌زیست، دانشگاه شهید بهشتی، تهران، ایران.

10.22091/cer.2024.10947.1562

چکیده

نشست فراتر از حد مجاز در سازه‌ها، تحت اثر عوامل مختلف، یکی از مهمترین مواردی است که ظرفیت شکل‌پذیری سازه‌ها را تغییر می‌دهد. هدف از پژوهش حاضر، ارزیابی لرزه‌ای سازه‌ها تحت شرایط مختلف نشست غیریکنواخت و بررسی میزان اثرگذاری نشست بر شکل‌پذیری سازه می‌باشد. در این تحقیق، شش قاب خمشی فولادی با شکل‌پذیری متوسط با ارتفاع و دهانه‌های متفاوت طراحی شده و بعد از اعمال نشست‌های غیریکنواخت در سه حالت کلی نشست تک ستون، نشست دو ستون و پروفیل واقعی نشست، رفتار لرزه‌ای آنها با تحلیل غیرخطی مورد بررسی قرار گرفته ‌است. نتایج نشان می‌دهد که نشست غیریکنواخت ظرفیت شکل‌پذیری سازه را کاهش می‌دهد، اما ظرفیت نهایی سازه را تغییر نمی‌دهد. همچنین نشست غیریکنواخت، ممکن است با در نظرگیری اثر رفت‌وبرگشتی زلزله، در یک جهت باعث کاهش سختی سازه شود که با آنالیز حساسیت طبقات و دهانه‌ها، مشاهده شد که این اثر با کاهش تعداد دهانه و افزایش تعداد طبقات در سازه‌ها بیشتر می‌شود. بررسی‌های دیگر نشان می‌دهد که وضعیت مفاصل پلاستیک سازه به صورت کلی در حضور نشست بحرانی‌تر می‌شود که شرایط در قسمت‌های میانی سازه بدتر است. وضعیت مفاصل پلاستیک سازه تحت بارهای ثقلی و بارهای نشست در حالت‌های نشست یک و دو ستون، بحرانی‌تر از پروفیل واقعی نشست مورد مطالعه می‌شود که علت آن به وجود چرخش صلب سازه ارتباط داده می‌شود. همچنین نتایج نشان می‌دهد که در ساختمان‌های دارای نشست، پاسخ سازه به تحلیل پوش‌آور در راستای رفت‌وبرگشت می‌تواند کاملا متفاوت است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Evaluation of the Ductility of Steel Buildings under Non-uniform Settlement

نویسندگان [English]

  • Mojtaba Amirabadi
  • Hamid Bayesteh
  • Reza Rasti Ardakani
Department of Civil, Water & Environmental Engineering, Shahid Beheshti University, Tehran, Iran.
چکیده [English]

Non-uniform settlements beyond allowable limits in structures, is one of the common items that reduces the seismic ductility of the structure. The aim of this study is to investigate the seismic performance of structures under non-uniform settlement and its effect on ductility of the structure. In this research, six models of steel moment frames with different heights and spans are considered. They have evaluated under seismic condition after applying non-uniform settlements in three cases of single column settlement, double column settlement, and real profile of settlement. The results show that non-uniform settlement reduces the ductility of the structure, however it has no effect on ultimate capacity beyond target displacement. Also, considering both direction of seismic motion, the stiffness of the structure can be reduced in one direction and the structure will become unsymmetric. This is more sensitive to number of stories and spans. Additionally, investigations indicate that the condition of the plastic hinges in the structure becomes generally more critical in the presence of settlement. The condition of the plastic hinges in single and double column settlement scenarios are more critical than the real settlement profile, which is attributed to the presence of rigid body rotation of the structure. Furthermore, the results show that in buildings under settlement, the response of the structure to the pushover analysis is completely different in forward and backward directions.

کلیدواژه‌ها [English]

  • Steel frame
  • و Non-uniform settlement
  • و Seismic evaluation
  • و Nonlinear analysis
[1] Elsharawy M. The Effect of 3D Interference of Shallow Foundation on Settlement and Its Impacts on Building Structures. Civil Engineering and Architecture. 2024; 12(3A): 2074-2090. doi: 10.13189/cea.2024.121311
[2] Mirnaghizadeh MH, Hajiazizi M. Numerical Study of Tabriz Urban Railway Line 2 Tunnel Settlement. Civil Infrastructure Researches. 2018; 3(2): 25-32. doi: 10.22091/cer.2017.1475.1059. [In Persian]
[3] U.S. Army Corps of Engineers. Design of Buildings to Resist Progressive Collapse (UFC 4-023-03). 2005.
[4] Abdizadeh kalkhoran E, Shakri K, Raman Shokrgozar H, Gholizad A. Investigation of progrssive collapse in steel moment and bracing frames due to support settlement. MSc Thesis, Faculty of Engineering, University of Mohaghegh Ardabili, 2016. [In Persian]
[5] Mehrpour M, Memarpour M. Evaluation of Seismic Capacity of Reinforced Concrete Buildings with Dual System affected by Unequal Settelment in foundation. MSc Thesis, Faculty of Engineering, Imam Khomeini International University, 2019. [In Persian]
[6] American Society of Civil Engineers, Reston, Virginia. Federal Emergency Management Agency (FEMA-356). Washington, D.C, 2000.
[7] Kulivand Salooki A, Bagherieh A. An analysis on allowable differential settlement of concrete buildings. MSc Thesis, Faculty of Engineering, Malayer University, 2016. [In Persian]
[8] Ministry of Housing and Urban-Rural Development of the People's Republic of China, Code for seismic design of building (Chinese Standard GB 50011), 2010.
[9] Bao C, Ma X, Lim KS, Chen G, Xu F, Tan F, Abd Hamid NH. Seismic fragility analysis of steel moment-resisting frame structure with differential settlement. Soil Dynamics and Earthquake Engineering. 2021 Feb 1;141:106526. doi: 10.1016/j.soildyn.2020.106526
[10] Pereira WM, Moraes MH, Beck AT, Araújo DL, Sarmento AP, Sousa MA. Reliability analysis of reinforced concrete frames subjected to post-construction settlements. Revista IBRACON de Estruturas e Materiais. 2023 Jan 16; 16(5): e16503. doi: 10.1590/S1983-41952023000500003 
[11] National Research Council of Canada. National Building Code of Canada, Ottawa, 2005. 
[12] National Research Council of Canada. National Building Code of Canada, Ottawa, 2010.
[13] American Society of Civil Engineers. Minimum Design Loads for Buildings and Other Structures (ASCE/SEI 7-05), 2006.
[14] Lin L, Hanna A, Sinha A, Tirca L. Structural response to differential settlement of its foundations. Journal of Civil Engineering Research. 2015; 5(3): 59-66. doi: 10.5923/j.jce.20150503.02
[15] Esteban Desbrousses R. Enhancing Building Resistance to Differential Settlement with Canadian Seismic Design Provisions, MSc Thesis, The Department of Building, Civil and Environmental Engineer-ing, Concordia University, 2020.
[16] Lahri A, Garg V. Effect of differential settlement on frame forces-A parametric study. International Journal of Research in Engineering and Technology. 2015; 4(9):453-464. doi: 10.15623/IJRET.2015.0409083
[17] Hanna A, Chen W. Response of multistory steel structure subjected to differential settlements of its foundation. International Journal of Structural Integrity. 2022 Jul 25; 13(4):594-610. doi: 10.1108/IJSI-08-2021-0083  
[18] Sarkar R, Dutta SC, Saw R, Singh JP. Effect of differential settlement on seismic response of building structures. InProceedings of the Institution of Civil Engineers-Municipal Engineer. 2020 Sep; 173(3): 136-145. doi: 10.1680/jmuen.18.00032
[21] Standing Committee for Revision of Building Regulations Against Earthquakes. Regulations for the de-sign of buildings against earthquakes-2800 standard. Fourth edition, Road, Housing and Urban Devel-opment Research Center. 2014. [In Persian]
[22] Deputy for Strategic Supervision of Technical System Affairs. Guidelines for Seismic Improvement of Existing Buildings, Publication No. 360, First edition, 2013. [In Persian]
CAPTCHA Image