آنالیز خرابی پیش رونده ساختمان های دال تخت با درنظرگرفتن اثر پس پانچ

نوع مقاله : یادداشت فنی

نویسندگان

1 استادیار گروه مهندسی عمران ، دانشگاه ملایر

2 Malayer university

3 گروه مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه گیلان، رشت، ایران

چکیده

دراین مقاله، اثر مقاومت پس پانچ در خرابی پیش رونده ساختمان دال تخت 3 طبقه بررسی شده است. اکثر مطالعات پیشین به شکست برش پانچ دال های تخت محدود شده است و رفتار پس پانچ اتصالات نادیده گرفته شده است. سه سناریو بارگذاری، شامل حذف ناگهانی ستون گوشه، ستون کناری و ستون میانی در طبقات اول و سوم ساختمان بررسی شده است. نتایج نشان می دهد که ظرفیت پس پانچ در اتصالات، مانع از خرابی کلی ساختمان می شود. برای سازه های مدل شده، ضریب بزرگنمایی دینامیکی نیز محاسبه شده است. اثر عواملی همچون آسیب های قبلی در اجزای سازه به علت بارگذاری لرزه ای و شرایط مرزی بر رفتار سازه دال تخت بررسی شدند. نتایج حاصل از تحلیل ها نشان می دهد که درنظرنگرفتن اثر پس پانچ می تواند منجر به ایجاد خطا در ارزیابی پتانسیل خرابی پیش رونده ساختمان های دل تخت شود.

کلیدواژه‌ها


عنوان مقاله [English]

Progressive collapse analysis of flat slab buildings with post-punching effect

نویسندگان [English]

  • Vahed Ghiasi 1
  • ESMAEIL Mousapoor 2
  • RAHMAT Madandoust 3
1 Department of Civil Engineering, Faculty of Civil Engineering, Malayer University, Malayer, Iran
2 Malayer university
3 Department of Civil engineering, Faculty of Engineering, Gilan University, Rasht, Iran
چکیده [English]

The reinforced concrete flat slab is one of the types of floor systems used to construct residential, office and parking buildings. Because of the direct transfer of floor loads to columns, flat slabs are susceptible to punching failure in slab-column connections. The punching failure in one column can initiate failure in adjacent columns and cause progressive punching shear failures resulting in the progressive collapse of the complete structure. Using the post-punching capacity of the connections can prevent or minimize the likelihood of such failures. The post-punching resistance of slab-column connections in the absence of shear reinforcements is provided by the dowel action and vertical component in flexural and integrity bars when they deflect after punching. Most studies of flat plate performance were attended to punching shear failure and the post-punching behaviour of flat slabs is ignored. This can reduce accuracy in progressive collapse analysis.

This paper validates analytical methods previously proposed by the authors to simulate post-punching behaviour a multi-panel flat plate system. Then, the progressive collapse potential of a three-story flat slab building was evaluated using the proposed analytical model. The effect of factors such as column removal position, structural member damage due to previous seismic loads on subsequent failures, floor load intensity, and boundary conditions (slab expansion around the building) on flat slab structural behaviour were investigated. The analysis results showed that the building internal column removal would cause the punching failure in the adjacent slab-column connections, but due to the post-punching resistance of the connections, overall failure did not occur. Therefore, ignoring the effect of post-punching resistance on slab-column connections can lead to an error in the evaluation of the progressive failure potential of flat slab structures. The analysis results revealed that the internal column removal of the building is the most critical. In the structure, with the slab expansion around the building, the removal of the edge column is the most critical scenario. The Dynamic Amplification Factor (DAF) was calculated by comparing static and dynamic vertical displacements for model structures. The analysis results showed that DAF could be greater than 2 in the flat plate slabs.

کلیدواژه‌ها [English]

  • Flat slab building
  • slab-column connection
  • Post-punching resistance
  • Progressive collapse