Ảnh hưởng của các tham số thiết kế đến khả năng chịu lửa của sàn bê tông cốt thép bị cháy

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Tác giả: VĂN VUI CAO, VĂN ĐẸT ĐOÀN, PHI GIANG NGÔ

Ngôn ngữ: vie

Ký hiệu phân loại:

Thông tin xuất bản: Tạp chí Xây dựng, 2023

Mô tả vật lý: tr.122

Bộ sưu tập: Metadata

ID: 340775

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Bài báo này trình bày kết quả nghiên cứu về ảnh hưởng của các tham số thiết kế đến khả năng chịu lửa của sàn bê tông cốt thép (BTCT) bị cháy. Kết quả nghiên cứu này dựa trên việc phân tích cơ nhiệt đồng thời cho sàn BTCT bị cháy theo tiêu chuẩn ISO 834. Phần mềm SAFIR đã được sử dụng để phân tích ứng xử độ võng theo thời gia cháy. Kết quả phân tích nhiệt sẽ tiếp tục được sử dụng để phân tích cơ học để xác định độ võng của sàn BTCT. Kết quả nghiên cứu cho thấy rằng quan hệ độ võng-thời gian cháy của sàn có thể được chia làm ba giai đoạn: giai đoạn một gần như tuyến tính, giai đoạn hai là giai đoạn chuyển tiếp, và giai đoạn ba là giai đoạn sụp đổ. Đồng thời, kết quả mô phỏng cho thấy khả năng chịu lửa của sàn tăng đến 35,7% khi tăng chiều dày lớp bê tông bảo vệ từ 12,5 mm lên 20 mm. Khả năng chịu lửa của sàn tăng đến 31,8% khi tăng bề dày sàn từ 7 cm lên 9 cm. Đặc biệt, khả năng chịu lửa của sàn tăng đến 93,3% khi tăng diện tích cốt thép chịu lực từ 141 mm2 lên 452 mm2. Các kết quả này cho thấy, trong các tham số khảo sát, diện tích cốt thép có vai trò quan trọng nhất đối với khả năng chịu lửa của sàn BTCT. Từ khóa: Sàn bê tông cốt thép
ứng xử
độ võng
lửa
khả năng chịu lửa.This paper presents research results on the effects of design parameters on the fire resistance of reinforced concrete (RC) slabs exposed to fire. The results of this study were based on simultaneous thermal-mechanical analyses of RC slabs exposed to ISO 834 fire. SAFIR software was used to analyse the deflection with respect to fire time. The results of thermal analysis were used for mechanical analysis to determine the deflection of RC slabs. The research results showed that the deflection-fire time relationship of RC slabs can be divided into three phases: phase one was almost linear, phase two was a transitional phase, and phase three was the collapse phase. Furthermore, the results indicated that the fire resistance of RC slabs increased by 35.7% when the thickness of the concrete cover increased from 12.5 mm to 20 mm. The fire resistance of RC slabs increased by 31.8% when the thickness of the slabs increased from 7 cm to 9 cm. Especially, the fire resistance of RC slabs increased by 93.3% when the steel area increased from 141 mm2 to 452 mm2. These results indicated that, among the considered parameters, the steel area plays the most important role in the fire resistance of RC slabs. Keywords: Reinforced concrete slabs
behaviour
deflection
fire
fire resistance.

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