Study Of The Effect Of Opening On The Behaviour Of Composite Steel-Concrete Diaphragms In Low-rise Steel Structures

Document Type : Research Article



The most important function of structural diaphragms is to support and transmit gravity loads to vertical structural elements such as columns. In addition, diaphragms play an important role in collecting lateral loads at specific elevations and distributing them to the lateral resistance system. Thus, in-plane behaviour of diaphragms can be considered for structural analysis and design of structural elements and securing the optimum seismic performance of the structure. In order to investigate structural behaviour of composite steel-concrete diaphragms in low-rise steel structures, one to six storey steel structures with planar aspect ratios of one, three and five with different areas of openings have been analysed by  the ETABS code. Results from response spectrum dynamic analysis indicate that the assumption of rigid diaphragms in the studied structures, in particular in the lower floors, is inappropriate. Diaphragms with openings of 20 to 50 percent of area have a flexible behaviour. An opening area of more than 20 percent increases the natural frequency of the structure; hence, necessity for an expansion joint.     


[1]اوشک سرایی، رضا (مترجم)، ”کتاب مرجع طراحی سازهها . در برابر زلزله“، جلد دوم، انتشارات دانشگاه گیلان، ۱۳۷۴
[2]Muto, K. A., “Seismic Design Analysis of Buildings”, Maruzen Ltd., Tokyo, pp. 241-260, 1974.
[3]Saffarini, H. S., and Qudaimat, M. M., “In-Plane Floor Deformations in RC Structures”, Journal of Structural Engineering, ASCE, Vol. 118, No. 1, pp. 3098-3102,November 1992.
[4]Colina, J. D. L., “In-Plane Floor Flexibility Effects on Torsionally Unbalanced Systems”, Earthquake Engineering and Structure Dynamics, Vol. 28, pp. 1705-1715, June 1999.
[5]Joel, M. B., Mary, B. D., “Diaphragm Effects in Rectangular Reinforced Concrete Buildings”; ACI Structural Journal, Vol. 101, No.5, pp. 615-624,September-October 2004.
[6]Lee, D. G., Kim, D. K. and Ahn, S. K., “Efficient Seismic Analysis of Building Structure Including Floor Slabs”, Engineering Structures, Vol.27, pp. 675-684,2005.
[7]Lam, D., and Fu, F., “Experimental Study on Semi- Rigid Composite Joints with Steel Beams and Precast Hollowcore Slabs”, Journal of Constructional Steel Research, Vol. 62, pp. 771-782, 2006 .
[8]Ji, T., and El-Dardiry, E., “Modeling of the Dynamic Behaviour of Profiled Composite Floors”, Engineering Structures , Vol. 28, pp. 567-579, 2006.
[9]Tokoro, K. T., Anderson, J. C. and Bertero, V. V., “Uncertainties in Determining Diaphragm Flexibility”, Proceeding of the 13th World Conference on Earthquake Engineering, Vol. 1, pp. 565-580, Canada, August 2004.
[10]Rodriguez, M. E., Restrepo, J. I., and Carr, A. J., “Earthquake-Induced Floor Horizontal Accelerations in Buildings”, Earthquake Engineering and Structural Dynamics, Vol. 31, pp. 643-718, 2002.
[11] کمیته دائمی بازنگری آیین نامه طراحی ساختمانها در برابر زلزله، ”آیین نامه طراحی ساختمانها در برابر زلزله -. استاندارد ۲۸۰۰ “، ویرایش سوم، تابستان ۱۳۸۶
[12]Salmon C. G., Johnson J. E., “Steel Structures: Design and Behavior”, 5th ed., Prentice-Hall, New York, 2009.
[13]دفتر تهیه و ترویج مقررات ملی ساختمان، ”مبحث دهم: طرح. و اجرای ساختمان های فولادی“، نشر توسعه ایران، ۱۳۸۷
[14] حجازی، مهرداد؛ معمارزاده، پرهام؛ سبحانی، محمدعلی، ”بررسی رفتار دیافراگم مرکب فولادی – بتنی در سازههای فولادی کوتاه مرتبه“، مجموعه مقالات کنفرانس بینالمللی . سبک سازی و زلزله، دانشگاه شهید باهنر کرمان، ۱۳۸۹