Computational and Modeling Design Techniques Used in the Progressive Collapse Analysis of Structures

Abstract

Progressive collapse has been recently a major concern in the design of structures since the events of September 2001 in New York City. A weak link in the structure rather than causing a localized failure could cause an overall collapse of the whole structure leading to human fatality, destruction and damage to the infrastructure. Design for Progressive collapse has been an oversight during the design phase by most of the structural engineers in the industry. This paper focuses on describing the modeling philosophy used in the analysis of the progressive collapse of structures without emphasis on actual analyses and computations. It defines the two methods of analyses: Specific Local Resistance (SLR) focuses on the loading and analysis/failure of the individual components of a structure resulting in mitigating each individual member to prevent collapse of overall structure. The Alternate Path Method (APM) is independent of the loading and failure is initiated through member removal. This approach is represented as a “load initiator” and serves as a means to introduce analysis, redundancy and resiliency into the structure. The analyses are based on different procedures including the Linear Elastic Static Procedures, Non-Linear In-Elastic Static Procedures and Non-Linear In-Elastic Dynamic Procedures. The paper describes the different design criteria and procedures that are used in analyzing structures against progressive collapse. For each procedure in the (SLR) and (APM), the most appropriate computational and modeling tool is described to best and accurately perform the analyses on the structural components and overall structure. Advanced analysis can and should play an important role in understanding and addressing the issues concerning the protection against progressive collapse