بررسی اثر تغییرات مشخصات هندسی، قیودات جانبی و پیش‌فشار بر روی ظرفیت جابجایی دیوارهای برشی بنایی تاریخی ایرانی

نوع مقاله : علمی - پژوهشی

نویسندگان

1 استادیار، دانشکده مهندسی عمران، دانشگاه سمنان، سمنان، ایران

2 دانشجوی دکتری، دانشگاه سمنان، سمنان، ایران

3 استادیار، دانشکده مهندسی عمران و محیط زیست، دانشگاه صنعتی امیرکبیر، تهران، ایران

چکیده

در اکثر آیین‌نامه‌های سازه‌ای، ظرفیت جابجایی در دیوارهای برشی بنایی، تخمینی از عملکرد رفتاری و نسبت ابعادی نمونه‌ها می‌باشد. این تحقیق، به ‌منظور بررسی اثر ظرفیت جابجایی دیوارهای برشی بنایی تاریخی ایرانی و تاثیر وجود پارامترهایی نظیر قیودات جانبی، هندسه و ابعاد، و مقدار پیش‌فشار اعمالی بر ظرفیت جابجایی آن‌ها انجام شده‌است. از‌این‌رو، 64 نمونه مختلف از دیوارهای بنایی تحت بارگذاری برشی درون‌صفحه‌ای، برای چهار حالت مختلف از قیودات جانبی (ناشی از اثرات دیوارهای جانبی و سقف)، چهار نسبت ابعادی (نسبت ارتفاع به طول) متفاوت 0/5 ، 0/75، 1، و 5/1، با سه اندازه مرسوم برای ضخامت دیوار (0/20 ، 0/35، و 0/50 متر)، تحت بار پیش‌فشار 0/1مگاپاسکال (متناظر بار یک سقف) مدل‌سازی گردیدند. ضمناٌ، دیوار با ضخامت 35/0 متر تحت بار پیش‌فشار 0/2 مگاپاسکال (متناظر با بار اعمالی از طرف دو سقف) نیز مدل گردید. تمامی مدل‌ها (64 مدل) تحت تحلیل‌های غیرخطی پوش‌آور، قرار گرفتند. پس از تهیه منحنی-های رفتاری بار - تغییرمکان (منحنی ظرفیت)، به منظور ساده‌سازی پاسخ‌ها، ایده‌آل‌سازی نتایج توسط منحنی‌های معادل دوخطی الاستیک خطی - پلاستیک کامل، انجام گردید. نتایج ناشی از ایده‌آل‌سازی منحنی‌های رفتاری بار - تغییرمکان، مشخص نمود که با افزایش قیودات جانبی، افزایش بار پیش‌فشار و ضخامت دیوارهای بنائی، و نیز کاهش نسبت ابعادی؛ ظرفیت جابجایی دیوارها کاهش می یابد. ضمناً، مشاهده ‌گردید که قید جانبی دیوارهای عرضی - اتصال‌یافته از دو طرف در دو انتهای دیوار برشی - نسبت به مولفه‌ی افقی (سقف تنها) در کاهش ظرفیت جابجایی و مقیدترکردن دیوار برشی موثرتر می‌باشد. در نهایت، بر اساس این مدل‌سازی، مقدار تغییرمکان نسبی برای دیوارهای برشی بنایی تاریخی ایرانی در بازه 1/33 تا 2/63 بدست آمد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Effects of lateral constraints, geometrical characteristics and pre-compression level on the Drift capacity of Persian historical masonry walls

نویسندگان [English]

  • Mohammad Saeed Karimi 1
  • mehrdad ghamari 2
  • Abdulazim Amirshahkarami 3
1 Assistant Professor, Faculty of Civil Engineering, Semnan University, Semnan, Iran
2 PhD student, Faculty of Civil Engineering, Semnan University, Semnan, Iran
3 Assistant Professor, Department of Civil & Environmental Engineering, Amirkabir University of Technology, Tehran, Iran
چکیده [English]

In most structural codes, the drift capacity of masonry walls is an estimated of the structural behavior and the aspect ratio. In this paper, the determination of the drift capacity considering the effect of parameters such as lateral constraints, geometries, dimensions, and pre-compression for the Persian historic brick masonry was studied. Hence, the behavior of 64 different specimens of masonry walls under in-plane loading with four different modes of lateral constraints (under the effect of lateral walls and ceiling), four different aspect ratios (height to length) and six different boundary conditions (under the effect of lateral walls and ceiling), three values for the wall thickness and two values for the pre-compression (According to the load applied by one or two ceilings) were studied by nonlinear numerical analysis. After preparing the force-displacement curves, in order to obtain simplified parameters that are easily comparable and usable for design purposes, bilinear behaviors were idealized (linear elastic, perfectly plastic). The results showed that by increasing the lateral constraints, wall thickness and pre-compression, the drift capacity of the walls decreased, whilst the drift capacity increases by increasing the height-to-length aspect ratio. In addition, it was observed that the lateral walls (vertical components) were more effective in reducing the displacement capacity than the ceiling (horizontal component). In conclusion, according to numerical calculations, the value of drift capacity for the Persian historic brick masonry was found to be 1.33% to 2.63%.

کلیدواژه‌ها [English]

  • Persian historical masonry walls
  • Lateral constraints
  • Nonlinear pushover analysis
  • Lateral load-bearing capacity
  • Drift capacity

مراجع

[1] Magenes, G. and Calvi, G M J. (1997). In‐plane Seismic Response of Brick Masonry Walls. Earthquake Engineering and Structural Dynamics, 26(11), 1091-1112.
[2] Lourenco, P. Milani, G. Tralli, A. and Zucchini, A J. (2007). Analysis of Masonry Structures: Review of and Recent Trends in Homogenization Techniques. Canadian Journal of Civil Engineering, 34(11), 1443-1457.
[3] Abrams, D. (1996). Effects of Scale and Loading Rate with Tests of Concrete and Masonry Structures. Earthquake Spectra; 12(1), 13–28.
[4] Salmanpour, A. Mojsilović, N. and Schwartz, J. (2015). Displacement Capacity of Contemporary Unreinforced Masonry Walls: An Experimental Study. Engineering Structures, 89, 1-16.
[5] Ganju, T. (1997). Nonlinear finite Element Analysis of Clay Brick Masonry, 6th Australasian Conf. on Mech. of Structures and Materials, 59-65.
[6] Samarasinghe, W. Page, A. and Hendry, A. (1982). A Finite Element Model for the In-Plane Behavior of Brickwork, Proceedings of the Institution of Civil Engineers, 73, 171-178.
[7] Dhanasekar, M. Page, A. and Kleeman, P. (1984). A Finite Element Model for the In-Plane Behavior of Brick Masonry, Proceedings of the Institution of Civil Engineers, 79(2), 262-267.
[8] Laurenco, P. Rots, J G. and Blaauwendraad, J J. (1995). Two Approaches for the Analysis of Masonry Structures: Micro and Macro Modeling. HERON, [online] 40 (4), Available at: http://resolver.tudelft.nl/uuid:c39b29ab-3c75-47db-9cb5-bf2b1c678f1f [Accessed 01. 01. 1995].
[9] Page, A. (1978). Finite Element Model for Masonry. Journal of the Structural Division, 104, 1267-1285.
[10] Standard, B. (2005). Eurocode 8 (Design of structures for earthquake resistance – Part 3: General rules, seismic actions and rules for buildings, Design Code EN 1998-3, European Comittee for Standardisation (CEN)). Brussels, Belgium.
[11] Najafgholipour, M. Maheri, M. and Lourenço, P. (2013). Capacity Interaction in Brick Masonry under Simultaneous In plane and Out-of-plane Loads. Construction and Building Materials, 38, 619-626.
[12] Calderini, C. Cattari, S. and Lagomarsino, S. (2010). In-plane Strength of Unreinforced Masonry Piers. Earthquake Engineering and Structural Dynamics, 38, 243-267.
[13] Bosiljkov, V. Page, A. Bosiljkov, V B. and Zarnic, R. (2008). Evaluation of the Seismic Performance of Brick Masonry Walls. Structural Control and Health Monitoring, 32, 124-135.
[14] Roca, P. (2006). Assessment of Masonry Shear-Walls by Simple Equilibrium Models. Construction and Building Materials, 20, 229-238.
[15] Giordano, A. De Luca, A. Mele, E. and Romano, A. (2007). A Simple Formula for Predicting the Horizontal Capacity of Masonry Portal Frames. Engineering structures, 29, 2109-2123.
[16] Benedetti, A. and Steli, E. (2008). Analytical Models for Shear – Displacement Curves of Unreinforced and FRP Reinforced Masonry Panels. Construction and Building Materials, 22, 175-185.
[17] Russell, A P. (2010). Characterisation and Seismic Assessment of Unreinforced Masonry Buildings. Ph.D. thesis. University of Auckland.
[18] Magenes, G. and Penna, A. (2011). Seismic Design and Assessment of Masonry Buildings in Europe: Recent Research and Code Development Issues. Nine Th Australasian Masonry Conference. Queenstown, New Zealand, 583–603.
[19] Moon, F L. (2003). Seismic strengthening of low-rise unreinforced masonry structures with flexible diaphragms. Ph.D. thesis. Georgia Institute of Technology.
[20] Petry, S. and Beyer, K. (2014). Influence of Boundary Conditions and Size Effect on the Drift Capacity of URM Walls. Engineering Structures, 65, 76–88.
[21] FEMA 306. (1998). Evaluation of Earthquake Damaged Concrete and Masonry Wall Buildings. Washington, D.C: Federal Emergency Management Agency, 250.
[22] FEMA 356. (2000). Prestandard and Commentary for the Seismic Rehabilitation of Buildings. Washington, D.C: Federal Emergency Management Agency, 519.
[23] Iranian national building regulations (2014). Design Loads for Buildings (in Farsi), Tehran, Ministry of Roads and Urban Development.
[24] Binda, L. Fontana, A. and Frigerio, G. (1988). Mechanical Behaviour of Brick Masonries Derived from Unit and Mortar Characteristics. Proc. of the 8th Int. Brick and Block Masonry Conf. London: Elsevier Applied Science, 205-216.
[25] Korany, Y. and EL-Haggar, S J. (2003). Mechanics and modeling of URM structures. Proc. Int. Short Course onInternational short course on architectural structural design of masonry, Dresden: Dresden University of Technology.
[26] Willam, K J. and Warnke, E P. (1975). Constitutive Model for the Triaxial Behaviour of Concrete. Proc. of the Int. Assoc. for Bridge and Struct. Eng, 19, 1-30.
[27] Basic Analysis Guide for ANSYS 14. (2011). New York, SAS IP Inc.
[28] Chen, W F. and Han, D J. (2007). Plasticity for Structural Engineers. New York: J. Ross Publishing, 606.
[29] Betti, M. Orlando, M. and Vignoli, A. (2011). Static Behaviour of an Italian Medieval Castle: Damage Assessment by Numerical Modelling. Computers and Structures, 89(21-22), 1956-1970.
[30] Betti, M. and Vignoli, A. (2008). Modelling and Analysis of a Romanesque Church under Earthquake Loading: Assessment of Seismic Resistance. Engineering Structures, 30(2), 352-367.
[31] Pineda, P. GilMarti, M A. and González, M D. (2011). Seismic Damage Propagation Prediction in Ancient Masonry Structures: an Application in the Non-Linear Range via Numerical Models. Open Construction Building Technology Journal, 16(5), 71-79.
[32] Araújo, A. (2014). Modelling of the Seismic Performance of Connections and Walls in Ancient Masonry Buildings. Ph.D. thesis. University of Minho.
[33] Tomazevic, M. (1999). Earthquake-Resistant Design of Masonry Buildings. London: Imperial College Press World Scientific, 268.

فایل ها

سابقه مقاله

  • تاریخ دریافت: 10 آذر 1398
  • تاریخ بازنگری: 12 اسفند 1398
  • تاریخ پذیرش: 17 اسفند 1398

هم رسانی

ارجاع به این مقاله

آمار