Ứng dụng kỹ thuật dao động ngẫu nhiên trong quan trắc sức khỏe kết cấu công trình=Application of random vibration technique in structural health monitoring

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Tác giả: Trọng Lâm Hoàng

Ngôn ngữ: vie

Ký hiệu phân loại:

Thông tin xuất bản: Tạp chí Xây dựng, 2024

Mô tả vật lý: tr.50

Bộ sưu tập: Metadata

ID: 478632

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Bridge health monitoring system are installed almost on long-span bridge during construction state and sevices state. Structural health monitoring (SHM) rapid assesment of a bridge’s health and is recognized as one of the best ways to increase the safety and optimize bridge operation and maintenance. Modal identification methodologies are performed to determine the dynamic characteristics of structures. In SHM, these dynamic parameters (including natural frequencies, mode shapes and damping properties) play an important role in the understanding of the dynamic behavior of structures. In term of bridge health monitoring, the excitation sources of structures have used several methods such as impact excitation, harmonic force excitation and difference mode of truck excitation, which are subsequent to free decay responses. These methods must be prevented or control vehicle flow. The other excitation is ambient such as wind, traffic which is more advantage and does not need to interrupt traffic flow. This study focuses on the using of Natural Excitation Technique combined with the Eigen Realization Algorithm (Next-ERA) for modal identification. This is an output-only system identification with first step to compute a covariant or cross spectra of output and then which is an input of ERA. The study includes providing a mathematic algorithm on Next-ERA method and then application to analyze dynamic responses of the bridge under ambient excitation. Key words: Ambient vibration
Structural health monitoring, modal parameters.Hiện nay các công trình cầu nhịp lớn như cầu dây văng, cầu dây võng, cầu vòm.. đều được lắp đặt hệ thống quan trắc sức khỏe phục vụ cho quá trình thi công cũng như trong quá trình khai thác cầu. Quan trắc sức khỏe kết cấu nhằm thu thập các thông tin về ứng xử của công trình, làm cơ sở cho việc đưa ra các đánh giá khả năng khai thác phục vụ của công trình. Các thông số dao động kết cấu (tần số dao động riêng, mode dao động và hệ số cản) rất quan trọng trong việc phân tích ứng xử động của kết cấu. Các thông số này được xác định dựa trên dữ liệu dao động kết cấu thu thập từ hệ thống các sensor và các thuật toán phân tích. Trong lĩnh vực quan trắc sức khỏe kết cấu công trình cầu thường sử dụng một số các phương pháp kích thích dao động như kích thích bằng lực xung kích, lực tác động tuần hoàn hoặc dưới tác dụng của xe tải di động. Mục đích thu được các thông số dao động của kết cấu. Yêu cầu đối với những phương pháp này là phải dừng lưu thông trong quá trình đo đạc. Một phương pháp khác được áp dụng khá phổ biến trong thời gian gần đây dựa trên dao động ngẫu nhiên của kết cấu dưới tác dụng của gió tự nhiên hoặc phương tiện giao thông ngẫu nhiên trên cầu với ưu điểm là đảm bảo giao thông liên tục. Bài báo tập trung ứng dụng thuật toán phân tích dao động theo giá trị riêng kết hợp với kỹ thuật kích thích dao động tự nhiên. Đậy là thuật toán chỉ dựa vào kết quả phản ứng ngẫu nhiên của kết cấu để xác định các đặt trưng dao động. Từ khóa: Dao động ngẫu nhiên
quan trắc sức khỏe công trình
thông số dao động.

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