Effects of Strengthening the Masonry Infills by Reinforced Shotcrete on Seismic Behavior of Steel Frames with Khourjeeni Connections and their Elements

Authors
S. Garivani
S. Garivani
A. Aghakouchak
M. Soltani Mohammadi
M. Soltani Mohammadi
Tarbiat Modares University
Abstract
Abstract: Steel frames with Khorjeeni connections have been widely used in the traditional construction of buildings in Iran during the past decades. In the traditional form of Khorjeeni connections, double section beams are not cut at the intersection with columns, rather they are connected to the column by means of two angles placed over the top and under bottom of the beam flanges. This type of connection offers advantages for frames, which carry gravity loads, but it has deficiencies when the frames are subjected to lateral loads. Like other structural frames, there are masonry infills in many frames with Khorjeeni connections. The behavior of composite frames subject to lateral loads differs from that of bare steel frames. In this paper, positive and negative effects of masonry infills, when strengthed by reinforced shotcrete, are studied on the behavior of steel frames with Khorjeeni connections. Finite element method was used to carry out nonlinear static analysis of subassemblages of this type of frames. Initially, the results of some experiments were utilized to verify the details of the model. Then numerical models of two span or four span frames with different configuration of bracings and masonry infills and characteristics of shotcrete were studied. The results showed that infills increase the stiffness and strength of frames in the absence of bracing considerably. Even when bracings are present, the increase in stiffness and strength is significant. When the infills are strengthened, their effects on stiffness and strength of composite frames increase. However if the steel frames are not strong enough, their strength limit the effects of infills. The masonry infills, however, have some negative effects on the behavior of Khorjeeni frames. Parts of the column in the vicinity of connections are prone to plastic damage, particularly when the infills are relatively strong. The Khorjeeni connections are subjected to vertical forces and tortional moments. Due to limited vertical strength of these connections, top stories of this type of frames may suffer when compressive action of strut is mobilized. For other bays, this action introduces additional moments, which may damage the connections. Therefore, considering these negative effects of infills is very important when seismic behavior of the existing frames is assessed. When the infills are strenghted by shotcrete, these negative effects become even more important and the inter story drift rations need to be limited in order to avoid failure in conections.

Keywords

[1] دستورالعمل بهسازی لرزه­ای ساختمان های موجود (نشریه 360)، 1385، انتشارات سازمان مدیریت برنامه‌ریزی کشور.
[2]  Polyakov, S. V.,1960, “On the Interaction Between Masonry Filler Walls and Enclosing Frame When Loaded in the Plane of the Wall”, Translations in Earthquake Engineering, Earthquake engineering Research Institute, Oakland, California, pp.36-42.
[3]  Stafford Smith, B., 1966, “Behavior of Square Infilled Frames”, Journal of the Structural Engineering Division, American Society of Civil Engineers, New York, pp.381-403.
[1]  Stafford Smith, B., 1968, “Model Test Results of Vertical and Horizontal Loading of Infilled Frames”, ACI Structural Journal, American Concrete Institute, Detroit, Michigan, pp.618-624.
[2]  Mainstone, R. J., 1971, “On the Stiffness and Strength of Infilled Frames”, Current Paper CP 2/27, Building Research Station, Garston, United Kingdom, reprinted from Proceedings of  Institution of Civil Engineers, 1971 Supplement (iv), Paper 7360 S, pp. 57-90.
[3]  Mainstone, R. J., 1974, “Supplementary Note on the Stiffness and Strength of Infilled Frames”, Current Paper CP 13/74, Building Research Station, Garston, United Kingdom.
[4]  M. Baran and T. Sevil,"Analytical and Experimental Studied on Infilled RC Frames", International Journal of the Physical Sciences, Vol.5(13), 2010.
[5]  P. G. Asteris, D. J. Kakalestsis, C. Z. Chrysostomou and E. E. Smyrou, "Failure Modes of In-Filled Frames", Electronic Journal of Structural Engineering Vol.11(1), 2011.
[6]  P. M. Pradhan, P. L. Pradhan, R. K. Maskey, "A Review on Partial Infilled Framess Under LAteral Loads", Kathmandu University Journal of Science, Engineering and Thechnology,Vol. 8 (1), 2012.
[7]      Kahn L.F,1984, Shotcrete strengthening of brick masonry walls, Con-crete Inst., Vol.6, No. 7,pp 34-40.
[8]      Abrams D. P., Lynch J. M., Franklin S., 2001, Performance of Rehab-ilitated URM Shear Walls: Flexural Behavior of Piers, Technical Report (NO.03-03) for MAEC, Civil Eng. Dept. University of Illinois, USA.
[9]      Moghadam H. A., Mohammadi M. Gh and Ghaemian M. (2006), ''Ex-perimental and analytical investigation into crack strength determination of infilled steel frames'' J. of Construct. Steel Research, vol. 118(7), pp.1-12.
[10] ص گریوانی، ع ا آقاکوچک و م سلطانی محمدی، " اثر میانقاب­های مصالح بنایی بر رفتار لرزه­ای قاب­های فولادی دارای اتصالات خورجینی و اجزای آن". مجله علمی پژوهشی عمران مدرس، دوره دوازدهم، شماره 1، بهار 1391.
[1]      Mosalam., M., White., N., Gergely., P., 1997, “Static Response of Infilled Frames Using Quasi-Static Experimentation”, Journal of the Structural Engineering, pp.1462-1469.
[2]   ی. نصیرا، "مقاوم سازی قاب های فولادی با دیوار برشی 3D و بررسی شکل پذیری آن"، پایان نامه کارشناسی ارشد به راهنمایی دکتر رهایی و دکتر کبیر، دانشگاه صنعتی امیر کبیر، 1383.
[3]   أ. یعقوبی­فر، "بررسی رفتار دیوارهای آجری تقویت شده با شبکه فولادی و پوشش بتن به روش آزمایشگاهی و تحلیلی"، پایان نامه کارشناسی ارشد به راهنمایی دکتر تسنیمی، دانشگاه تربیت مدرس، 1387.
[4]   م. فتحی، "بررسی رفتار دینامیکی غیر خطی قاب های با اتصال خورجینی تحت نیروهای زلزله"، پایان نامه کارشناسی ارشدبه راهنمایی دکتر آقاکوچک، دانشگاه تربیت مدرس، 1376.
[5]   م. سعادت نیا، "بررسی اثر مولفه قائم زلزله بر رفتار ساختمان های فولادی با اتصالات خورجینی"، پایان نامه کارشناسی ارشد به راهنمایی دکتر شکیب، دانشگاه تربیت مدرس، 1384.
[6]     ضوابط طراحی ساختمان­های با اتصال خورجینی (نشریه 324)، 1385، انتشارات سازمان مدیریت برنامه ریزی کشور.
[7]      Mehrabi A. B. and Shing P. B., Schuller M. P., and Noland J. L. (1996), "Experimental evaluation of masonry-infilled RC frames." J. of Struct. Eng., 122(3), 228-237.
[8]     مقدم ح؛ طرح لرزه­ای ساختمان های آجری؛ انتشارات دانشگاه صنعتی شریف، 1373.
[9]      Federal Emergency Management Agency (1998), Evaluation Of Earthquake Damaged Concrete And Masonry Wall Buildings,FEMA 306.
[1]      Federal Emergency Management Agency (2000), Prestandard And Commentary For The Seismic Rehabilitation Of Buildings, FEMA 356.
[2]      American Society of Civil Engineers (2006), Seismic Rehabilitation of Existing Buldings. ASCE/SEI 41-06.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Mehmet Baran and Tugce Sevil ”Analytical and experimental studies on infilled RC frames”, International Journal of the Physical Sciences Vol. 5(13), pp. 1981-1998, 18 October, 2010
Modares Civil Engineering journal
Volume 13, Issue 4
November and December 2013
Pages 85-100