رفتار سازه‌ای پانل‌های ساندویچی بتنی پیش‌ساخته با اتصالات برشی خرپایی شکل تحت بارهای جانبی

در این مقاله رفتار سازه ای پانل های ساندویچی بتنی پیش ساخته جهت امکان استفاده آنها به عنوان اجزاء دال در ساخت و سازهای صنعتی بصورت تجربی و عددی مطالعه شده است. این پانل ها  متشکل از سه لایه می باشند، لایه ها عبارتند از: یک لایه بتن مسلح به عنوان لایه فوقانی، یک لایه ضخیم از بتن سبک به عنوان لایه میانی یا هسته و یک لایه بتن معمولی یا بتن سبک مسلح مقاوم در مقابل کشش به عنوان لایه تحتانی. این لایه ها توسط شبکه میلگرد با اتصالات برشی خرپایی شکل به یکدیگر متصل شده اند. اهداف این تحقیق بررسی عملکرد مرکب و پارامترهای تاثیرگذار در باربری پانل های ساندویچی بتنی برای کاربرد در سازه ها در راستای سبک سازی و صنعتی کردن ساخت و ساز می باشد. برای این منظور، ابتدا نمونه های آزمایشگاهی تحت آزمایش خمش قرار گرفت. سپس مطالعه تحلیلی مدل المان محدود پانل های ساندویچی با مشخصات و خصوصیات مکانیکی مشابه آزمایش تجربی با نرم افزار abaqus انجام شده است. نتایج نشان داد؛ پانل های ساندویچی با دو لایه بتن نسبت به پانل های ساندویچی با سه لایه بتن، دارای ظرفیت باربری و سختی کمتر می باشند، همچنین وقتی که پانل  های ساندویچی پیش  ساخته به عنوان دال یک طرفه رفتار می کنند، قراردادن اتصالات برشی موازی محورx (بعد بزرگتر) برای همبستگی دو لایه بتنی به منظور عمل کردن آنها به عنوان یک واحد کافی است. نتایج مطالعات آزمایشگاهی و مدل المان محدود مقایسه شد و درجه قابل توجهی از دقت بدست آمد. بنابراین دال ساندویچی بتنی پیش ساخته می تواند بعنوان جایگزین مناسب برای سیستم دال بتنی معمولی در ساختمان باشد.

structural behavior of the precast concrete sandwich panels with truss-shaped shear connector under lateral loads

construction of buildings using non-industrial traditional systems have lots of shortcoming in both quality and quantity. during recent years considerable needs to increase the efficiency in building sector has indicated the fact that using old building construction systems is not responsive to community needs and using superior technology in this field is quite inevitable. constructing building systems with potential, for industrial and prefabricated production, can meet the quantitative and qualitative needs of the construction industry.  in this paper, the structural behavior of precast concrete sandwich panels (pcsps) to feasibility of their usage as slab elements in the construction industry is experimental (exp) and numerical analyses studied. these panels consist of three layers: 1) a regular reinforced concrete layer as the upper face, 2) a thick lightweight concrete (lc) layer as the core, and 3) a normal concrete and tension-resistant reinforced lightweight concrete layer as the bottom face. these layers are joined via a rebar network with truss-shaped shear connectors. the structural behavior of precast concrete sandwich panels under flexure is studied. for this purpose, first, laboratory samples were made and tested for bending. subsequently, a finite element analysis (fea) was performed on a sandwich panel model with the specifications and mechanical properties similar to the exp model in the abaqus software. comparing the results of the experimental and numerical studies revealed a good level of accuracy.  the effect and orientation of the shear connectors in one or two directions were also investigated. the results of experimental and numerical investigation, show a logical behaviour of load-deflection curves according to the results, the pcsps with two concrete layers had a smaller stiffness and load capacity than those with three concrete layers, when the prefabricated sandwich panels behave as one-way slabs, placing shear connectors parallel to the x-axis (larger dimension) is sufficient to bond two concrete layers for them to act as a single unit, , and the ultimate strength and the composite action of desired were found to depend to a large extent upon the stiffness of the shear connector used. this sandwich panel system can constitute an effective step toward lightening regarding its high bearing capacity and ductility, industrial manufacturing capability, prefabricated nature, multi-layer nature, high quality, lightweight, high construction speed, and reduced costs. hence, the precast concrete sandwich panels slabs with high-strength faces and lc cores can be a suitable replacement for regular slab systems in buildings based on the economic and weight comparisons under the code dead and live loads, the proposed prefabricated sandwich composite slab system is approximately 20 percent lighter than the regular slab. due to possibility of industrial production of precast sandwich panels under standard conditions and simplicity of construction, the introduced novel panels system can be a viable alternative for common floor systems. besides, the novel system can save amount of material, labor, time, and cost in building construction. this research aims to investigate the composite performance and influential parameters in bearing capacity and improve and develop hybrid concrete sandwich panels for structural purposes to lighten and industrialize construction, a topic of interest in structural engineering.