Evaluasi dan Retrofit Struktur Gedung Beton Bertulang Akibat Kebakaran

ABSTRACT Several studies have been carried out related to the impact of fire on the strength of reinforced concrete material. It shows that there is a decrease in strength and a decrease in structural stiffness. The degree of damage is dependent on the temperature and duration of the fire. To ensure accessibility, the building needs to be evaluated whether the building can be re-functioned immediately. The results of site investigation are evaluated to determine the structure retrofit and reinforcement methods and cost-effectiveness compared to the cost of a new building. The office building structure under review is analytically evaluated based on SNI 1726:2019 and SNI 1727:2018. The results showed that 31% of columns and 32% of beams need to be strengthened. In addition, steel bracing and CFRP wrapping on the structural elements were applied. The cost of retrofitting required Rp2.998.488.781,07, which is lower than the cost of the new building structure, which costs Rp4.950.087.016,34. ABSTRAKBeberapa penelitian yang telah dilakukan terkait dampak kebakaran terhadap kekuatan material beton bertulang, memperlihatkan bahwa terdapat penurunan kekuatan dan kapasitas struktur. Tingkat penurunan tergantung antara lain pada suhu dan durasi kebakaran. Untuk meyakinkan tingkat fisibilitas, gedung tersebut perlu dievaluasi kemungkinan dapat atau tidaknya gedung itu difungsikan kembali. Hasil evaluasi tersebut dijadikan pertimbangan dalam menentukan metode perbaikan dan perkuatan yang efektif untuk kemudian dibandingkan dengan biaya pembangunan gedung baru. Struktur gedung kantor PLN Unit Cabang Distribusi Jakarta Raya ini akan dievaluasi dengan cara analitis berdasarkan SNI 1726:2019 dan SNI 1727:2018. Terdapat total 31% kolom dan 32% balok yang perlu diperkuat. Metode perkuatan yang digunakan adalah penambahan bracing baja dan CFRP. Material CFRP tersebut dililitkan pada elemen struktur. Biaya perkuatan yang diperlukan adalah Rp2.998.488.781,07, lebih rendah dibandingkan nilai struktur gedung, yaitu Rp4.950.087.016,34.

Experimental Determination of the Residual Compressive Strength of Fire-Damaged Concrete Columns Retrofitted using CFRP Wrapping

The study presented in this paper aimed to experimentally investigate the residual compressive strength of fire-damaged concrete columns retrofitted using carbon fibre-reinforced polymer (CFRP) wrapping sheets. The experimental program involved testing of ten column specimens (200 mm × 200 mm × 1500 mm) that were previously exposed to standard fire before being retrofitted using CFRP wrapping sheets. The study imitated a real-life scenario where concrete columns previously exposed to one- and two-hour standard fire while being subjected to service loads (20% and 40% of the column’s ultimate design capacity) were retrofitted using one and two layers of CFRP wrapping sheets. Test results show that the effect of increasing the applied load ratio in reducing the post-fire residual compressive strength was more pronounced in the columns wrapped with two layers of CFRP sheets and exposed to the longer fire duration (2 hours).

The The Resistance of Fiber-reinforced Concrete with Steel Fibers and CFRP to Drop-weight Impact

In this paper, the effects of macro-synthetic steel fibers and bidirectional carbon fiber-reinforced polymers (CFRPs) on the impact resistance of concrete specimens were studied. 54 concrete cylindrical specimens with different compressive strengths (20, 30, and 40 MPa) and with different fiber content ratios (0 %, 1 %, 1.5 %, and 2 %) were tested under impact loading. Half of these specimens were tested with the CFRP wrapping. The specimens were subjected to weight (46.7 and 66.8 kg) dropping at a height of 1.62 m. The process of weight dropping was continued until 30 % weight loss in the specimens was observed and the number of weight droppings related to this loss was recorded. Results indicated that the impact resistance of the concrete specimens (corresponding to the number of weight droppings) increased by using steel fibers or CFRP wrapping, separately. However, the results demonstrated that the specimens wrapped with the CFRP sheets had much further impact resistance than the FRCs without wrapping. Finally, the results showed that the greater the compressive strengths of the concrete, the better the impact resistance.

Behaviour of Steel Reinforced Concrete Section with CFRP Wrapping Under Axial Compression

The composite structural element under study is a carbon fiber wrapped, steel I section reinforced concrete column. The wrapped CFRP is under tension and reinforced concrete under radial compression. The aim of the research is to determine the behavior of the composite structural element under axial loads. The Stress-strain characteristics and load bearing capacity of control and CFRP wrapped tubular columns were determined experimentally. Further, Finite element analysis of steel, reinforced concrete and CFRP wrapped concrete columns sections, was conducted using ANSYS Workbench 15.0 software. The experimental and analytical results were compared.