Nghiên cứu ứng xử chịu xoắn thuần túy của dầm bê tông cốt thép bằng mô hình màng hóa mềm cho xoắn=Studying the pure torsional behavior of reinforced concrete beams using a softened membrane model for torsion

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Tác giả: Đăng Dũng Lê, Anh Dũng Nguyễn, Ngọc Thắng Nguyễn, Vĩnh Sáng Nguyễn

Ngôn ngữ: vie

Ký hiệu phân loại:

Thông tin xuất bản: Tạp chí Khoa học công nghệ xây dựng (Đại học Xây dựng Hà Nội), 2024

Mô tả vật lý: tr.84-96

Bộ sưu tập: Metadata

ID: 231282

Thêm vào giỏ

Mô hình giàn hóa mềm (STM) đã được sử dụng để phân tích ứng xử xoắn của các cấu kiện bê tông từ những năm 1980. Tuy nhiên, phương pháp STM này bỏ qua ảnh hưởng của ứng suất kéo bê tông và chỉ có thể dự đoán ứng xử sau nứt. Trong khi đó, mô hình màng hóa mềm (SMM), được phát triển để dự đoán ứng xử cho các phần tử màng bê tông cốt thép chịu cắt, được mở rộng cho các cấu kiện bê tông cốt thép chịu xoắn, được gọi là mô hình màng hóa mềm cho xoắn (SMMT). Mô hình SMMT đã xem xét ảnh hưởng của ứng suất kéo bê tông và có thể dự đoán toàn bộ đường cong mô men – góc xoắn trước và sau nứt. Mô hình SMMT sử dụng có sửa đổi mô hình vật liệu cốt thép là mô hình hai đoạn thẳng, chảy dẻo lý tưởng. Ảnh hưởng của hệ số khếch đại Hsu/Zhu tại điểm phân giới cũng được xem xét. Mô hình SMMT sửa đổi này cho kết quả rất tốt về ứng xử chịu xoắn và mô men xoắn cực hạn so với các nghiên cứu thực nghiệm trước đây. Cuối cùng, điểm phân giới 0,002 được đề xuất sử dụng để tránh sự thay đổi đột ngột mô men xoắn.Since the 1980s, the softened truss model (STM) has been employed to examine the torsional characteristics of concrete elements. Nevertheless, techniques relying on the (STM) fail to account for the impact of specific tensile stress and are limited to forecasting post-cracking responses. The Softened Membrane Model (SMM), originally designed to predict the behavior of reinforced concrete (RC) membrane elements under shear, has been expanded to include RC members experiencing torsion. This extension is called the softened membrane model for torsion (SMMT). The SMMT model effectively accounts for the impact of tensile stress on concrete and can accurately forecast the complete torque-twist relationship, encompassing both in pre-cracking and postcracking. The SMMT model was used to modify the reinforcement material model. This model is a simple bilinear model with full plastic. The influence of the Hsu/Zhu amplification ratio at the demarcation point was also considered. This modified SMMT model results in very good torsional behavior and ultimate torque compared to previous experimental studies. Finally, a demarcation point of 0.002 was suggested to avoid sudden changes in torque.

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