مطالعه عددی تاثیرات اندرکنش سازه-خاک-سازه بر ضریب بزرگنمایی تغییرمکان و اصلاح آن برای قاب خمشی فولادی ویژه

نوع مقاله : علمی - پژوهشی

نویسندگان

1 گروه مهندسی عمران، دانشکده مهندسی، دانشگاه فردوسی، مشهد، ایران

2 استادیار، دانشکده مهندسی، دانشگاه فردوسی مشهد، مشهد، ایران

چکیده

با توجه به اهمیت ضریب بزرگنمایی تغییرمکان Cd در طراحی سازه‌ها و عدم درنظر گرفتن اثرات اندرکنش سازه-خاک-سازه در پاسخ سازه‌ها، این مقاله اثرات مهم‌ترین پارامترهای تأثیرگذار بر این ضریب، در سامانه سازه-خاک-سازه را بررسی کرده است. پارامترهای کلیدی شامل دوره تناوب سازه اصلی (T1) و مجاور (T2)، فاصله سازه‌ها (d) و نوع خاک هستند. هدف از این پژوهش، اصلاح ضریب Cd در قاب‌های فولادی ویژه تحت اثر اندرکنش سازه-خاک-سازه، بدون مدل‌سازی سازه مجاور است. برای این منظور 6 سازه 2 تا 15طبقه واقع بر دو نوع خاک رسی به صورت دوتایی در سه فاصله صفر، 10 و 25 متری با استفاده از روش مستقیم به‌صورت غیرخطی مدل و با استفاده از روش تاریخچه زمانی غیرخطی تحلیل شده‌اند. بر اساس نتایج این کار، تکیه‌گاه نرم منجر به ایجاد طبقه نرم به‌دلیل افزایش شدید دریفت طبقه اول نسبت به حالت تکیه‌گاه ثابت می‌شود که حداقل این نسبت 1/1 و حداکثر آن 61/3 است؛ به‌طوری که با افزایش T1 و T2 مقدار این نسبت بیشتر می‌گردد. از طرفی برای سازه‌های اصلی با T1 در محدوده 7/0 تا 5/1 برابر دوره تناوب خاک، دریفت سازه دچار تشدید می‌شود. در نهایت با استفاده از نتایج کار و تحلیل رگرسیون، بر مبنای طیف پاسخ دریفت سازه‌ها روابطی جهت اصلاح ضریب Cd ارائه شده است. بر اساس رابطه به‌دست‌آمده، برای طراحی سازه بایستی مقادیر دریفت به‌خصوص دریفت طبقه اول افزایش یابد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Numerical Study of Structure-Soil-Structure Interaction Effects on Deflection Amplification Factor and Correction for Special Steel Moment Frames

نویسندگان [English]

  • Reza Esmailzadeh Shahri 1
  • Abbas Karamodin 2
1 Department of Civil Engineering, Faculty of Engineering, Ferdowsi University, Mashhad, Iran
2 Assistant Professor, Department of Civil Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
چکیده [English]

Considering the importance of the deflection amplification factor ,Cd, in the structural design and the lack of consideration of the structure-soil-structure interaction effects on structural response, this paper has investigated the effects of the most important parameters affecting this factor in the structure-soil-structure systems. Key parameters are period of main (T1) and adjacent (T2) structures, distance between the structures (d) and type of soil. The purpose of this study is to correct the Cd coefficient in steel moment frames under the influence of structural-soil-structure interaction effect. For this aim, 6 structures of 2 to 15 story based on two types of clay soil in a three distances of zero, 10 and 25 meters using direct method is modelled and analyzed with nonlinear time history method. According to the results, most of the story drifts is concentrated at the first story due to soft base. The minimum ratio of first story drift with respect to the fix-base, is 1. 1 and the maximum is 3.61. Increasing T1 And T2, the value of this ratio is increased. For the main structures with T1 in the range of 0.7 to 1.5 times the soil period, the structural drift is intensified. Finally, using the results of this study and regression analysis, a correlation coefficient for the Cd is presented based on the spectral response of the structural drift. Based on the obtained relationship, story drifts, especially at first story, should be increased for the design of the structures .

کلیدواژه‌ها [English]

  • Structure-soil-structure interaction
  • Soil-structure interaction
  • Deflection amplification factor
  • Structural drift
  • Soft story
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