مطالعه ضریب رفتار و تغییر مکان های نسبی ماندگار ساختمان بتنی مسلح شده با آلیاژ حافظه دار سوپر الاستیک

نوع مقاله : علمی - پژوهشی

نویسندگان

1 دانشیار، گروه عمران، دانشگاه صنعتی خواجه نصیرالدین طوسی، تهران،ایران

2 کارشناس ارشد مهندسی عمران ، دانشگاه صنعتی خواجه نصیرالدین طوسی، تهران،ایران

3 دانشجوی دکتری، دانشگاه صنعتی خواجه نصیرالدین طوسی، تهران،ایران

4 کارشناس ارشد مهندسی عمران ، دانشگاه صنعتی شریف، تهران،ایران

چکیده

استفاده از آلیاژهای حافظه دار سوپرالاستیک (SMAs) به عنوان میلگرد در سازه های بتنی در میان پژوهشگران به تدریج در حال افزایش است. به دلیل تفاوت خواص مکانیکی SMA در مقایسه با فولاد معمولی، استفاده از میلگرد SMA در بتن ممکن است تغییراتی در پاسخ سازه، تحت بارهای لرزه ای به وجود آورد. در این مطالعه، تأثیر استفاده از میلگرد های SMA در سازه های بتنی بر روی ساختمان های بتن مسلح با طبقات 3، 6 و 8 به روش تحلیلی مورد بررسی قرار گرفته است. برای هر ساختمان سه نحوه متفاوت میلگرد گذاری در نظر گرفته شده است: 1- تمام میلگرد ها از جنس فولاد معمولی ، 2- در ناحیه مفاصل پلاستیک تیر، میلگرد ها از جنس SMA و در سایر قسمت ها از جنس فولاد معمولی و 3- میلگرد SMA در تمام طول تیر و میلگرد فولادی در دیگر قسمت ها. به منظور بدست آوردن پاسخ لرزه ای سازه های مجهز به میلگرد SMA، تحلیل دینامیکی افزایشی (IDA) با استفاده از ده رکورد معروف زمین لرزه، برای هر سه نحوه آرماتور گذاری توسط برنامه Opensees انجام شده است. نتایج بدست آمده نشان می دهد، در قاب های سه طبقه ظرفیت فروریزش قاب ها تقریبا یکسان است، اما در مورد قاب های 6 و 8 طبقه ظرفیت فروریزش قاب های Steel بیشتر می باشد، ضریب رفتار 3 و 6 طبقه در حالات متفاوت آرماتور گذاری تغییر زیادی ندارد ولی در قاب 8 طبقه این تغییر محسوس است. در مورد تغییر مکان های نسبی ماندگار هم در همه قاب ها استفاده از آلیاژهای حافظه دار، این تغییر مکان ها را کاهش داده است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Study Of structural Behaviour And Residual Drift Of Concrete frames Reinforced With Shape Memory Alloy Rebar

نویسندگان [English]

  • Masoud Mirtaheri 1
  • Mohammadreza rajabi 2
  • hamid mirzaeefard 3
  • Meysam Nazerian 4
1 Associate Professor, Department of Civil Engineering, K.N. Toosi University of Technology,Tehran, Iran
2 M.Sc. of Earthquake Engineering
3 K.N.toosi department of civil engineering
4 MSc
چکیده [English]

Buildings in high seismic regions are prone to severe damage and collapse during earthquakes due to large lateral deformations. The use of superelastic shape memory alloys (SMAs) as reinforcements in concrete structures is gradually gaining interest among researchers. the effect of SMAs as reinforcement in concrete structures is analytically investigated for 3, 6 and 8-story reinforced concrete (RC) buildings. Each building has five bays in both directions with the same bay length of 5m. For each concrete building, three different reinforcement details are considered: (1) steel reinforcement (Steel), (2) SMA bar used in the plastic hinge region of the beams and steel bar in other regions (Steel-SMA), and (3), beams fully reinforced with SMA bar (SMA) and steel bar in other regions. For each case, columns are reinforced with steel bar. Results obtained from the analyses indicate that the value of Sa in Steel-SMA frames are higher than SMA frames, and its recovery capacity is almost similar with SMA frames. the SMAs materials are expensive, and the use of Steel-SMA frames can be reasonably effective in seismic zones. The comparison between frames with various reinforcements details shows that Sa of 3-story frames with various reinforcements are almost identical. but, in 6- and 8-story frames, Sa of Steel frames are higher than others. frames with SMA bars in the all length or plastic hinge region of the beam have reached a same level of seismic demand under lower spectral acceleration which can be resulted from the decreased stiffness caused by SMA bars. results indicate that structural behaviour factor in 3 and 6 story buildings with different types of reinforcement is not much change, but this change is perceptible in the 8-story frame. In the case of residual drift in all cases, the use of shape memory alloys will reduce this drifts.

کلیدواژه‌ها [English]

  • Concrete Structures
  • Superelastic Shape Memory Alloys
  • IDA
  • Residual Drift
  • structural behavior factor
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