Analisis Non-Linear Finite Element Pada Balok Beton Prategang Sebagian

Yunanto, Mochammad Ilham (2024) Analisis Non-Linear Finite Element Pada Balok Beton Prategang Sebagian. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Dalam berbagai literatur, kombinasi antara tulangan lunak dan tulangan prategang sebagai penguatan beton dalam menahan lentur dikenal sebagai elemen prategang sebagian. Penelitian mengenai perilaku beton pratekan sebagian di bawah beban lentur saat ini tidak hanya dilakukan melalui uji eksperimental tetapi juga dengan model elemen hingga. Pemodelan elemen hingga telah terbukti memberikan hasil yang mendekati simulasi eksperimental. ACI 318-19 kini memperbolehkan penggunaan tulangan lunak mutu tinggi hingga 690 MPa. Namun, penelitian eksperimental dan numerik pada balok prategang sebagian umumnya terbatas pada penggunaan tulangan lunak mutu 420 MPa. Penelitian ini melakukan analisis non-linear berbasis elemen hingga menggunakan software ATENA-GiD untuk memodelkan dan memvalidasi hasil pemodelan analitis terhadap hasil pengujian eksperimental serta mengevaluasi pengaruh penggunaan tulangan mutu tinggi ASTM A615 Grade 690. Lima spesimen balok dengan bentang 2800 mm dan nilai PPR (Partial Prestressing Ratio) masing-masing sebesar 0%, 40%, 60%, 80%, dan 100% digunakan dalam studi ini. Studi parametrik juga dilakukan dengan menggunakan tulangan lunak ASTM A615 Grade 690 pada balok dengan PPR 0%, 40%, 60%, dan 80%. Dalam analisis, balok setengah simetri dimodelkan dalam bentuk 3D pada ATENA-GiD dengan kondisi batas pada sumbu simetri dan perletakan untuk mendapatkan respons yang serupa dengan hasil eksperimental. Dalam pemodelan, perilaku non-linear beton direpresentasikan dengan model konstitutif fraktur-plastik, pendekatan bi-linear untuk tulangan prategang, dan multi-linear untuk tulangan lunak. Model elemen hingga berhasil memprediksi dengan baik perilaku beban-perpindahan balok prategang sebagian serta perilaku retaknya. Keakuratan analisis pada beban retak mencapai 104%, beban puncak 96%, defleksi retak 103%, dan defleksi maksimum 78,5%. Perilaku daktilitas balok numerikal memberikan hasil yang lebih tinggi dibandingkan dengan eksperimental. Selain itu, penggunaan tulangan mutu tinggi pada balok prategang sebagian dapat mengurangi kebutuhan tulangan sebesar 25% hingga 30%. Namun, tulangan mutu 690 MPa mempengaruhi respons kurva beban-perpindahan pasca retak menjadi kurang kaku. Daktilitas balok prategang sebagian dengan tulangan mutu tinggi ASTM A615/615M Grade 690 mengalami penurunan sebesar 12% hingga 50%. Tulangan mutu tinggi menaikkan tegangan tulangan sebesar 18% hingga 55%. Sedangkan regangan hanya menunjukkan pengaruh yang jelas ketika balok mengalami leleh saja.

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In various literature, the combination of mild steel reinforcement and prestressed reinforcement for concrete flexural strength is referred to as partially prestressed elements. Current research on the behavior of partially prestressed concrete under flexural loads is conducted not only through experimental tests but also using finite element models. Finite element modeling has been shown to provide good approximations to experimental simulations. ACI 318-19 now allows the use of high-strength mild steel reinforcement up to 690 MPa. However, experimental and numerical studies on partially prestressed beams are generally limited to the use of 420 MPa mild steel reinforcement. This study conducts a non-linear analysis based on finite elements using ATENA-GiD software to model and validate the analytical modeling results against experimental test results and to evaluate the impact of using high-strength ASTM A615 Grade 690 reinforcement. Five beam specimens with a span of 2800 mm and Partial Prestressing Ratio (PPR) values of 0%, 40%, 60%, 80%, and 100% were used in this study. A parametric study was also conducted using ASTM A615 Grade 690 mild steel reinforcement on beams with PPR values of 0%, 40%, 60%, and 80%. In modeling, a half-symmetric beam was modeled in 3D using ATENA-GiD with boundary conditions at the symmetry axis and supports to achieve responses similar to experimental results. In the modeling, the non-linear behavior of concrete was represented by a fracture-plastic constitutive model, a bi-linear approach for prestressed reinforcement, and a multi-linear approach for mild steel reinforcement. The finite element model successfully predicted the load-displacement behavior of partially prestressed beams as well as the cracking behavior. The accuracy of the analysis for cracking load was 104%, peak load 96%, cracking deflection 103%, and maximum deflection 78.5%. The ductility behavior of numerical beams provided higher results compared to experimental beams. The use of high-strength reinforcement in partially prestressed beams can reduce the reinforcement requirement by 25% to 30%. However, the 690 MPa reinforcement affects the post-cracking load-displacement curve response to become less stiff. The ductility of partially prestressed beams with high-strength ASTM A615/615M Grade 690 reinforcement decreases by 12% to 50%. High-strength reinforcement increases the reinforcement stress by 18% to 55%. However, strain only shows a significant impact when the beam yielding.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Concrete beams, Finite Element, High Strength Steel, Non-Linear Analysis, Partially Prestressed Concrete, Analisis Non-Linear, Balok Beton, Beton Pratekan Sebagian, Elemen Hingga, Tulangan Mutu Tinggi
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA347 Finite Element Method T Technology > TA Engineering (General). Civil engineering (General) > TA444 Reinforced concrete
Divisions:	Faculty of Civil Engineering and Planning > Civil Engineering > 22201-(S1) Undergraduate Thesis
Depositing User:	Mochammad lham Yunanto
Date Deposited:	06 Aug 2024 08:09
Last Modified:	06 Aug 2024 08:09
URI:	http://repository.its.ac.id/id/eprint/110587

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