بررسی تأثیر سربار قائم بر رفتار دیوارهای خشتی تحت بار جانبی چرخه‌ای

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشکده عمران،دانشگاه یزد

2 عضو هیئت علمی / دانشگاه یزد

3 دانشگاه یزد/دانشکده عمران

چکیده

ساختمان‌های خشتی از بناهای آسیب‌پذیر در برابر بارهای جانبی محسوب می‌شوند، به طوری که خرابی آنها در زلزله‌های گذشته با خسارت و تلفات جانی زیادی همراه بوده است. با این وجود، هنوز ساختمان‌های خشتی زیادی در مناطق لرزه‌خیز جهان از جمله در کشور ایران در حال استفاده است که بسیاری از آنها دارای ارزش تاریخی نیز هستند. لذا، شناخت رفتار این گونه ساختمان‌ها در برابر بارهای جانبی از اهمیت به سزایی برخوردار بوده و منجر به اتخاذ تصمیم مناسب در چگونگی حفظ بنا خواهد شد. در تحقیق حاضر رفتار جانبی دیوارهای ساخته شده از خشت و ملات گل که تحت اثر بار محوری ثابت قرار داشتند، تحت بارگذاری جانبی چرخه‌ای مورد ارزیابی قرار گرفت. نمونه‌های آزمایشگاهی شامل 4 دیوار خشتی به طول 1000 میلی‌متر، ارتفاع 900 میلی‌متر و ضخامت 200 میلی‌متر بودند. متغیر اصلی آزمایشگاهی، تنش محوری قائم روی نمونه‌های دیوار بود. نتایج آزمایشگاهی به صورت منحنی‌های چرخه‌ای بار-جابجایی، الگوی ترک‌خوردگی، مد شکست، افت سختی، اتلاف انرژی تجمعی و میرایی چرخه‌ای با یکدیگر مقایسه گردیدند. بر اساس نتایج تحقیق، میزان تنش محوری دیوار تاثیر زیادی روی نحوه شکست و رفتار دیوار خشتی تحت بارهای جانبی و در نتیجه اتخاذ روش مناسب مقاوم سازی دارد. با افزایش تنش محوری از 0/1به 0/7 مگاپاسکال مد شکست از گهواره ای-برشی به برشی - فشاری تغییر کرد. همچنین با افزایش تنش محوری مقاومت جانبی افزایش اما جابجایی متناظر شکست کاهش یافت.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Investigating the effect of vertical load on the behavior of adobe walls under cyclic lateral loading

نویسندگان [English]

  • ali mirjalili 1
  • reza morshed 2
  • Abolfazl Eslami 3
1 Civil Eng. Dept., Yazd University
2 Yazd University / member of Scientific Board
3 Civil Eng. Dept., Yazd University
چکیده [English]

Adobe constructions are vulnerable to lateral loading and their failure in the past earthquakes has caused severe casualties and structural damages. Nonetheless, numerous adobe buildings are still being used in seismic-prone regions worldwide, including Iran, many are of historical background. Therefore, evaluation of their lateral behavior and retrofitting stands of high priority and can lead to preserving these national assets. In this study, the cyclic lateral behavior of adobe walls made of adobe units and mud mortar was investigated under different constant axial loads. The experimental specimens were comprised of four adobe wall panels measuring 1000 mm in length, 900 mm in height, and 200 mm in thickness. The main experimental parameter was the magnitude of axial compression applied on the wall. The experimental results were compared in terms of load-displacement hysteretic curves, cracking pattern, failure mode, stiffness degradation, cumulative energy dissipation, and hysteretic damping. With increasing axial stress from 0.1 to 0.7 MPa, the failure mode was changed from shear to shear-compression. Also, with increasing axial stress, lateral resistance increased, but the corresponding displacement decreased.

کلیدواژه‌ها [English]

  • Adobe wall
  • Failure mode
  • Cyclic loading
  • Lateral strength
  • Hysteretic damping
[1]-Ahmadi Nejad Qarache.M, Foroghi.M, Rahimi.H.A, “Investigating Methods to Retrofit Mud and Adobe Constraction against Eearthquake,” Master’s Thesis of Structural Engineering, Yazd Univesity, 2016.
[2]-Feng Wu, Hai-Tao Wang, Gang Li, Jin-Qing Jia, Hong-Nan Li, “Seismic performance of traditional adobe masonry walls subjected to in-plane cyclic loading,” Materials and Structures, pp. 50-69, 2017.
[3]-Fadakar.S, Eftekhar.M.R, “The Effect of Engineered Cement Composite [ECC] on the Reinforcement of the In-Plane walls,” Master’s Thesis of Civil Engineering of Esfahan University, 2017.
[4]-Rogiros Illampas, Ioannis Ioannou, Dimos C. Charmpis, “Adobe bricks under compression: Experimental investigation and derivation of stress–strain equation,” Construction and Building Materials, vol. 53, no. 1, pp. 8390, 2014.
[5]-Dora Silveira, Humberto Varum, Aníbal Costa, Tiago Martins, Henrique Pereira, João Almeida, “Mechanical properties of adobe bricks in ancient constructions,” Construction and Building Materials, vol. 40, pp. 36-44, 2012.
[6]-Elisa Adorni, Eva Coïsson, Daniele Ferretti, “In situ characterization of archaeological adobe bricks,” Construction and Building Materials, vol. 40, pp. 1-9, 2013. [7]-Dora Silveira, Humberto Varum, Aníbal Costa, “Influence of the testing procedures in the mechanical characterization of adobe bricks,” Construction and Building, vol. 40, p. 719–728, 2013.
[8]-Humberto Varum, Aníbal Costa, Jorge Fonseca, André Furtado, “Behaviour characterization and rehabilitation of adobe construction,” ScienceDirect, vol. 114, pp. 714721, 2015.
[9]-Mohamed A. ElGawady، Pierino Lestuzzi، Marc Badoux, “Static Cyclic Response of Masonry Walls Retrofitted with Fiber-Reinforced Polymers,” Journal of Materials in Civil Engineering, vol. 50, 2007.
[10]-A. Figueiredo • H, Varum • A. Costa, D. Silveira, C. Oliveira, “Seismic retrofitting solution of an adobe masonry wall,” Materials and Structures, vol. 46, pp. 203219, 2013.
[11]-Stanislav Hracˇov , Stanislav Pospı´sˇil, Angelo Garofano, Shota Urushadze, “In-plane cyclic behaviour of unfired clay and earth brick walls in both unstrengthened and strengthened conditions,” Materials and Structures, vol. 49, p. 3293–3308, 2016.
[12]-Dora Silveira, Humberto Varum, Aníbal Costa, Henrique Pereira, Laura Sarchi & Ricardo Monteiro, “Seismic behavior of two Portuguese adobe buildings: Part I - in-plane cyclic testing of a fullscale adobe wall,” International Journal of Architectural Heritage, 2018.
[13]-R. Capozucca, “Experimental response of historic brick masonry under biaxial loading,” Construction and Building Materials, vol. 154, p. 539–556, 2017.
[14]-Vatani Oskouei, M. Afzali, M.R. Madadipour, A.Bakhshi, “Experimental Investigation on Mud Brick Walsl with Mortar Containing Straw Fibers,” Sharif J. of Civil Engineering, 1395, pp. 65-73.
[15]-”Determenation of compressive strenght of chemical- resistant mortars, grouts, monolithic surfacings, and polymer concretes,” Iranian National Standardization Organization, vol. INSO 21082, 2016.
[16]-ASTM, “Standard Practice for Capping Cylindrical Concrete Specimens,” ASTM, 2003.
[17]-ASTM, “Standard Test Methods for Physical Testing of Gypsum, Gypsum Plasters and Gypsum Concrete,” ASTM, 2004.
[18]-ASTM, “Standard Test Method for Compressive Strength of Masonry Prisms1,” 2016.
[19]-L Miccoli, U Müller, S Pospíšil, “Rammed earth walls strengthened with polyester fabric strips: Experimental analysis under in-plane cyclic loading,” Construction and Building Materials, vol. 149, pp. 29-36, 2017.
[20]-Davood Mostofinejad، Alireza Akhlaghi, “Experimental Investigation of the Efficacy of EBROG Method in Seismic Rehabilitation of Deficient Reinforced Concrete Beam–Column Joints Using CFRP Sheets,” ASCE, 2016.
[21]-Davood Mostofinejad، Alireza Akhlaghi, “Flexural Strengthening of Reinforced Concrete Beam-Column Joints Using Innovative Anchorage System,” ACI Structural Journal, vol. 114, no. Davood Mostofinejad، Alireza Akhlaghi, 2017.
[22]-Magenes G, Calvi GM, “In-plane seismic response of brick masonry walls,” Earthquake Engineering and Structural Dynamics, vol. 26, pp. 1097-1111, 1997.
[23]-Shedid MT, EI-Dakhakhni WW, “Behavior of fully grouted reinforced concrete masonry shear walls failing in flexure: analysis. Eng Struct,” Drysdale RG, vol. 31, p. 2032–2044, 2009.