Progressive collapse resistance analysis of RC frames

• Main Author: Wee, Yun Han
• Other Authors: Tan Kang Hai
• Format: Final Year Project
• Language: English
• Published: 2015
• Subjects: DRNTU::Engineering::Civil engineering::Structures and design
• Online Access: http://hdl.handle.net/10356/64136
• Institution: Nanyang Technological University

To mitigate progressive collapse, indirect and direct designs are the two main types of approaches currently adopted in building codes. Of the various methods such as the tie force method and enhanced local resistance method under indirect design and specified local resistance method and alternate load paths (ALP) method under direct design, the ALP is the more rigorous approach since it explicitly identifies threat-specific scenarios and provide sufficient ductility and continuity for the successful transfer of loads. Hence, the ALP method is often used in conjunction with column removal to assess whether progressive collapse will occur. Previous research work in this area explored the effects of varying parameters on the development of ALPs, such as varying the boundary conditions and changing the detailing of the specimens (normal/seismic). However, experimental data with regard to torsional effect is limited although this type of eccentric loading might be more relevant in a blast scenario as compared to normal gravity loading. Hence, to investigate the development of ALPs in structures subjected to torsional loading, 3 specimens with the same detailing were tested under 3 different loading scenarios: normal loading (Specimen A), torsional loading with a lever arm of one beam depth (Specimen B) and torsional loading with a lever arm of half beam depth (Specimen C). The results were analysed at 3 levels: structural, cross-sectional and fiber levels and corroborated to improve the accuracy of the analysis. Failure analysis was also conducted using the space truss model for Specimens B and C to check how the extent of torsional loading affected the failure mode and hindered the development of ALPs.