مطالعه آزمایشگاهی مدول الاستیسیته ستون‌های کوتاه فولادی محصورشده در بتن مسلح حاوی الیاف فولادی

نوع مقاله : علمی - پژوهشی

نویسندگان

1 گروه مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه مازندران، بابلسر، ایران

2 گروه عمران، دانشکده فنی و مهندسی، دانشگاه مازندران، بابلسر، ایران

چکیده

امروزه استفاده از ستون های مرکب بتن و فولاد به‌ سرعت در حال گسترش می باشد. از این رو اهمیت مطالعه بر روی این نوع ستون ها، عوامل مؤثر بر آن ها و ارائه راهکارهایی به منظور ارتقاء عمکرد این ستون ها، بسیار مهم تلقی می شود. مدول الاستیسیته یک عامل کلیدی برای تخمین تغییر شکل ساختمان ها و اعضای سازه ای است. شناخت مدول الاستیسیته ستون‌های فولادی تقویت ‌شده بتنی حاوی الیاف فولادی و علی الخصوص تغییرات رفتاری آن ها در طی اعمال بار محوری از موضوعات مهم و قابل بررسی می باشد. این مقاله سعی دارد مدول الاستیسیته چهارگانه ستون‌های فولادی تقویت ‌شده بتنی حاوی الیاف فولادی را مورد ارزیابی قرار دهد. برای نیل به این هدف، تعداد 36 نمونه ساخته شد و انواع مختلف مدول الاستیسیته شامل مدول الاستیسیته اولیه، مدول الاستیسیته سکانتی، مدول الاستیسیته نقطه تسلیم و مدول الاستیسیته نقطه اوج مورد بررسی قرار گرفتند. متغیرهای تحقیق شامل نوع شکل نیمرخ فولادی (اعم از H شکل و C شکل)، کسر حجمی الیاف فولادی (0%، 75/0% و 25/1%) و فاصله خاموت ها (40، 65 و 130 میلی‌متر) می باشد. نتایج نشان داد که مدول الاستیسیته ستون های فولادی محاط شده در بتن از شکل فولاد داخل آن تاثیر می پذیرد. بدین صورت که مدول الاستیسیته ستون‌ها با مقطع H شکل بیشتر از ستون‌ها با مقطع C شکل بود که علت آن محصورشدگی بیشتر در این نوع مقاطع می‌باشد. همچنین، افزایش درصد الیاف فولادی در بتن این نوع ستون‌ها می‌تواند علاوه بر افزایش شکل‌پذیری، مدول الاستیسیته ستون را به طور متوسط تا 6 درصد افزایش دهد. علاوه بر این، فاصله خاموت ها تاثیر بسیار چشم گیری بر روی مدول الاستیسیته این نوع ستون‌ها دارد به طوری که با افزایش فاصله خاموت ها مدول الاستیسیته ستون‌ها به ‌شدت کاهش (در حدود 35 درصد) می یابد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Experimental Study on Elastic Modulus of Steel Stub Columns Encased in RC Containing Steel Fibers

نویسندگان [English]

  • Armin Memarzadeh 1
  • mehdi nematzadeh 2
  • Hamed Jafarzadeh 1
1 Department of Civil Engineering, Faculty of Engineering and Technology, University of Mazandaran, Babolsar, Iran
2 Department of Civil Engineering, University of Mazandaran, Babolsar, Iran
چکیده [English]

Today the use of concrete and steel columns is expanding rapidly. Therefore, the importance of studying these types of columns and providing solutions to improve the performance of these columns, is considered very important. Elastic modulus is a key parameter employed to estimate the deformation of structures and structural members and is typically expressed in terms of the compressive strength. Understanding the modulus of elasticity of reinforced concrete steel columns (SRCs) containing steel fibers and especially their behavioral changes during axial load application is an important issue. This paper tries to evaluate four moduli of elasticity of reinforced concrete columns containing steel fibers (SRFC). To achieve this goal, 36 SRFC specimens were constructed and various types of modulus of elasticity including the initial modulus, the sequential modulus, the yield point modulus, and the peak point modulus were examined. The research variables include the shape of steel section (H-shaped and C-shaped volume ratio of steel fibers (0, 0.75, and 1.25%), and stirrup spacing (40, 65, and 130 mm). The results showed that the modulus of elasticity of the SRFC columns was affected by the shape. Thus, the modulus of elasticity of columns with H-shaped cross-section was higher than columns with C-shaped cross-section due to more confinement in this type of cross-section. Also, increasing the percentage of steel fibers in the concrete of these types of columns can, in addition to increasing the ductility, increase the modulus of elasticity of the column by an average of up to 6%. In addition, the distance of the arches has a very significant effect on the modulus of elasticity of this type of columns, so that with increasing the distance of the arches, the modulus of elasticity of the columns decreases (about 35%) sharply.

کلیدواژه‌ها [English]

  • Steel-Concrete Composite Column
  • Stress-strain Curve
  • Elastic modulus
  • stirrup ratio
  • Steel fiber reinforced concrete
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