بررسی و مقایسه رفتار تک شمع و گروه شمع تحت اثر بار دینامیکی

نوع مقاله: مقاله پژوهشی

نویسندگان

عضو هیأت علمی، گروه عمران، دانشگاه آیت الله العظمی بروجردی، بروجرد، ایران

چکیده

 در سازه­های مهندسی و ساختمان­های بزرگ به دلیل تنش زیاد ناشی از بار سازه و یا ظرفیت باربری ناکافی خاک، استفاده از شمع در زیر پی سطحی توصیه می­گردد. رفتار شمع­ها در بارگذاری­های مختلف به خصوص بارگذاری لرزه­ای یک مسئله مهم است که توسط محققین مختلفی مورد بررسی قرار گرفته است. شمع­ها به صورت تک شمع یا گروه شمع می توانند مورد استفاده قرار گیرند و رفتار آنها در خصوص انتقال نیروی و جابجایی مورد ارزیابی قرار گیرد. از اینرو در این تحقیق به بررسی و مقایسه رفتار تک شمع و گروه شمع معادل آن (به لحاظ میزان آرماتور، حجم بتن­ریزی با تک شمع برابر است) پرداخته شده است. در این بررسی تک شمع و گروه شمع تحت اثر بارگذاری قائم یکسانی قرار گرفته­اند و سپس نیروی دینامیکی سه زلزله طبس، بم و لوماپریتا بر آنها اعمال گردیده است. سپس نشست، جابجایی و نیروهای ایجاد شده در آنها با هم مقایسه شده است. نتایج نشان می­دهد نشست گروه شمع در مقابل تک شمع در حدود 30 درصد کاهش می یابد، اما نسبت نیروی برشی در آنها تقریبا برابر یک می­باشد.

کلیدواژه‌ها


عنوان مقاله [English]

The Investigation and Examination of Single Pile and Pile Group under Seismic Loading

نویسندگان [English]

  • Ahmadreza Mazaheri
  • Shahab Hassanpour
Faculty Member, Department of Civil Engineering, Ayatollah Borujerdi University, Iran.
چکیده [English]

One of the important lateral forces is dynamic loading due to earthquake. The behavior of pile foundations under earthquake loading is an important issue that widely affects the performance of structures. The topic of seismic pile behavior has been covered extensively in the literature over the past few decades. In this paper the behavior of single pile and pile group have been examined. Pile group has four piles and rebar and concrete weight in pile group is equal to single pile in this research. The single pile and pile group are analyzed under Tabas, Bam and Loma-perita earthquakes loading. The finite element software, ABAQUS, is utilized to model pile and piles group. Soil is modeled as an elastic-perfectly plastic model using the Mohr–Coulomb constitutive model. The side boundaries are constrained against horizontal direction and the bottom boundaries are constrained against both horizontal and vertical directions. Maximum shear force, lateral displacement and force along the pile in single pile and pile group, under the earthquake loading that mentioned above, have been measured. The results are shown the settlement in pile group is around 30 percent less than single pile and the lateral displacement in the head of single pile is 0.23 meter but the lateral displacement in group pile is 0.1 meter in Bam earthquake loading. The shear force in the head of single pile is 2084 kN and the shear force in head of the pile in pile group is 334 KN. Taking into account soil condition, the results shown that utilize the pile group (equal rebar and concrete weight by single pile) is better and more economic than single pile.

کلیدواژه‌ها [English]

  • Single pile
  • Pile group
  • Earthquake Loading
  • ABAQUS software
  • seismic behavior
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