Phương pháp lai MPA-CSM trong phân tích phi tuyến khung thép phẳng chịu địa chấn có xét tương tác giữa đất nền – kết cấu

The unpredictable and destructive nature of earthquakes necessitates robust and efficient methods for assessing the seismic performance of structures. While Nonlinear Response History Analysis (NL-RHA) offers high accuracy, its computational intensity often limits practical application in engineering design. Consequently, Nonlinear Static Procedures (NSPs) have gained prominence as simplified yet reliable alternatives. This study introduces and evaluates the accuracy of a hybrid MPA-CSM procedure (Modal Pushover Analysis – Capacity Spectrum Method) for analyzing the seismic response of steel frames. A critical aspect of this research is the comprehensive consideration of soil-structure interaction effects, aiming to provide a more practical and cost-effective approach for seismic assessment.

Kỹ sư kết cấu, nhà nghiên cứu trong lĩnh vực kỹ thuật động đất và thiết kế kháng chấn, sinh viên và giảng viên ngành xây dựng.

This study presents a comprehensive evaluation of the hybrid MPA-CSM procedure (Modal Pushover Analysis – Capacity Spectrum Method) for seismic assessment of steel moment-resisting frames, aiming to bridge the gap between computational accuracy and practical design applicability. The methodology involves applying the proposed nonlinear static procedure to 3, 9, and 18-story steel frames under two distinct sets of seismic ground motions, representing 2% and 10% probabilities of exceedance in 50 years. A significant contribution of this research is the explicit incorporation of soil-structure interaction (SSI) effects, modeled using a nonlinear Winkler foundation (BNWF) in Opensees, which is often neglected in simplified analyses. The study meticulously compares the MPA-CSM procedure's predictions for target displacement and story drift against results from conventional methods such as Standard Pushover Analysis (SPA), Modal Pushover Analysis (MPA), and the more rigorous Nonlinear Response History Analysis (NL-RHA). Key findings indicate that while the MPA-CSM procedure offers a simpler and more time-efficient calculation process than traditional MPA and NL-RHA, its accuracy for target displacement and story drift can vary. Specifically, the method's bias tends to increase with building height and ground motion intensity, and it is significantly influenced by soil-structure interaction effects, particularly for taller structures and stronger seismic events. The research concludes that the MPA-CSM procedure provides a viable, practical alternative for preliminary seismic analysis, offering a balance between computational effort and sufficient reliability, especially for low to mid-rise structures under moderate ground motions, thereby contributing to more efficient seismic design practices.