An Experimental Investigation and Numerical Analysis on The Behavior Of Reinforced Concrete Thick Slabs under Static Loading Adel A. Al-Azzawi 1 Ahmad S. Ali 2 Yousif Kh. Yousif 3 (Received 19/8/2016 ; accepted 16/10/2016) ABSTRACT This paper presents the testing results and numerical results of nine reinforced concrete thick slabs with and without openings. All slab specimens have the same planar dimensions 4 (1000mm×1000mm) with three different thicknesses of (120mm,100mm,and 80mm).The slabs resting on 4 corner steel columns and tested under concentrated static loading up to failure. These slabs were also analyzed using nonlinear finite element method assuming nonlinear material properties. From the experiments, it was found that, The presence of openings in slabs supported on their four corners decreases the strength and rigidity of slabs to about (12-23) % depending on the slab thicknesses and the shape of these openings. The slabs with (circular opening) recorded a reduction in ultimate strength to about(20) % from those with square openings having an equivalent opening areas. The yielding of main steel reinforcement occurred at load about 85% of the slab ultimate load. The ultimate loads predicted by ANSYS model have showed a good agreement with the experimental results. Keywords: Thick slab, Reinforced concrete, Slab with opening, Finite element, Nonlinear analysis. ق الميل ام تميك امل الي ي امكونك قو ام لو مديل امعلع ام يب م ام ام ف لف يو ف .يو  علط .د.اح. ا اي امع ام عد.د.ع. ا ل ال  امذج من نع مليليئ ام امن  ب الئ امف ها ام ى يقة بة ح عة ية الميك امل الي ي امكونك قو. ذج ميةيةع امةج ج ( دع ا هف0111 x 0111 ( كب ل مل) 021 ، 011،01 ( ذية حوي امةواحاة بيط دانقف اد نوذج امن مل. ت ا) 021 x 021  مةل) ام ت اء امفت ا ، ع يه ارا ك من زدييلب ع اء تلل ت ا. لل ث امف من لي ام ل الميل - دع ايل - اذج به امج مي ةن ال قو ام بود امف  ابيب ال و امفل ي من . نلموادطي ي دة مع احتاضص ال امعن يق ط- يط دان ا-  ارك  د ي(ن  قو ام مض مق انف ا02 - 22  تلة يةااب اة ذاب امف قو امج بن ت اب. لك امف قف سك امتدا ع اع%) ( ن  و امق ا ض انف21 ) ام اة ل. ، لة يااب ا نلف بل الكحعب ال ذاب امف قول ام عن% طة ا مية ةقو ( نم ا بديل امعل نوذج ام ال. مق امف عنق حANSYS ن امو ع ر ق)  بلا مةعية واحقة ئة ب امن اهيةية ، و امق .ي ي ام ا 1. Introduction Reinforced concrete slabs are among the most well known types of structural members. In design of slab without beams, punching shear is one of the most critical problems, the use of slabs with large thicknesses was one of the successful solutions. This led to an experimental and 1 Assist. Prof.at the Department of Civil Eng., Al- Nahrain University 2 Assist. Prof. at the Department of Civil Eng., Baghdad University 3 Lecturer, at the Department of Civil Eng., University of Anbar.