Nonlinear Finite Element Analysis on Shear Behaviour of Two-way Thick Concrete Slabs under Varied Influencing Factors

Zufarihsan, Rafif (2023) Nonlinear Finite Element Analysis on Shear Behaviour of Two-way Thick Concrete Slabs under Varied Influencing Factors. Masters thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

The shear strength of the two-way concrete slab depends on several factors such as thickness and concrete compressive strength. These two parameters are always present in various prediction from the design codes, while other parameters such as longitudinal steel ratio, column size, shear span-to-depth ratio, and aggregate size, are only taken into limited codes. A number of research has been undertaken to study the influence of size effect in two way slab. However, limitations is still present particularly on large scale specimen due to limited testing facility. To address these limitations, in this study numerical analyses using non-linear finite element method was performed in the ATENA Science software in conjunction with the smeared fixed crack and fracture-plastic material model approaches. The experimental slab testing data from Guandalini et. al. in 2009 was taken as a validation of analysis model. The nonlinear analyses using ATENA Science was capable to provide accurate nonlinear response and maximum load results with mean prediction-to-experiment results of 0.97 and a COV of 4.8%. Furthermore, a parametric study of 14 re-designed slabs with various parameters such as the combination of thickness and shear span-to-depth ratio, concrete compressive strength, slab size, and longitudinal steel reinforcement was carried out. This analysis found that the normalized shear strength of over-reinforced slabs decreases on the deeper slabs even with the smaller shear span to depth ratio, but is constant in the under-reinforced slabs. The normalized shear strength degradation due to the size effect occurs in the double-sized slabs both on the over-reinforced and under-reinforced slabs. The size effect factor in ACI-318 can produce conservative shear strength prediction for thick slabs. The analytical calculation of Simplified Modified Compression Field Theory can provide the most accurate and conservative results with a ratio of calculations to parametric predictions of 0.94 and 0.97.
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Kekuatan geser pada pelat beton dua arah dipengaruhi oleh beberapa faktor seperti ketebalan dan mutu beton. Kedua parameter inilah yang selalu ada di berbagai perhitungan dari peraturan sedangkan parameter seperti rasio besi tulangan longitudinal, ukuran kolom, rasio bentang geser terhadap tebal efektif, dan ukuran agregat hanya ada pada paraturan tertentu saja. Para peneliti telah melakukan peneltian mengenai size effect berkenaan dengan ketebalan pelat terhadap kapsitas geser, akan tetapi spesimen dengan ukuran besar memiliki keterbatasan dalam pengujiannya. Untuk mengatasi keterbatasan tersebut, pada penelitian ini analisis numerik dengan menggunakan metode elemen hingga non-linear dilakukan dengan perangkat lunak ATENA Science dengan pendekatan smeared crack dan model material fraktur-plastik. Data pengujian slab dari Guandalini dkk. pada tahun 2009 digunakan sebagai validasi model analisis. Dari hasil perbandingan antara prediksi ATENA dengan eksperimen, diperoleh respon non-linear dan beban maksimum yang akurat dengan rata-rata hasil prediksi dibanding eksperimen sebesar 0.97 dan COV 4.8%. Pengujian parametrik dengan memodelkan 14 slab baru dengan berbagai parameter seperti kombinasi ketebalan dan rasio bentang geser terhadap tebal efektif, mutu beton, ukuran slab, dan rasio besi tulangan longitudinal dilakukan. Dari analisa tersebut diperoleh kekuatan geser ternormalisasi pada pelat dengan rasio penulangan besar mengalami penurunan seiring bertambah tebal pelat meskipun dengan rasio bentang geser dan tebal efektif yang mengecil namun konstan pada pelat dengan rasio penulangan kecil. Penurunan kekuatan geser ternormalisasi akibat size effect terjadi pada pelat berukuran dua kali lipat dengan rasio penulangan besar maupun kecil. Faktor size effect pada ACI-318 dapat memberikan prediksi kekuatan geser pelat tebal yang konservatif. Prediksi perhitungan kekuatan geser dengan Simplified Modified Compression Field Theory memberikan hasil yang paling akurat dan konservatif dengan rasio perhitungan terhadap prediksi parametrik sebesar 0.94 dan 0.97.

Item Type:	Thesis (Masters)
Uncontrolled Keywords:	pelat tebal dua arah, kekuatan geser, size effect, rasio penulangan, non-linier ATENA. two-way thick slab, shear strength, size effect, reinforcement ratio, ATENA nonlinear.
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) T Technology > TA Engineering (General). Civil engineering (General) > TA347 Finite Element Method T Technology > TA Engineering (General). Civil engineering (General) > TA440 Concrete--Cracking. T Technology > TA Engineering (General). Civil engineering (General) > TA444 Reinforced concrete
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Civil Engineering > 22101-(S2) Master Thesis
Depositing User:	Rafif Zufarihsan
Date Deposited:	03 Feb 2023 02:32
Last Modified:	19 Nov 2024 04:06
URI:	http://repository.its.ac.id/id/eprint/95939

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