Progressive collapse of structures

Background: Rana Plaza building collapse is the worst industrial disaster of Bangladesh so far. The 9-storied structure collapsed suddenly on April 24, 2013, with more than 4000 people inside. Bangladesh Armed Forces played a key role in the massive rescue operations. Methods: We conducted a cross-sectional study with 423 victims who were treated at a Combined Military Hospital to review the pattern of injuries and management provided. Results: Middle-aged (35 ± 12.75 years) females (68.32%) were the majority of the victims. Among the injured, 42.35% had soft tissue injury, 22.55% had abrasions, 18.79% had fractures, 3.75% had facial injuries, and 2.5% each had head and abdominal injuries. We treated the injured with various surgical approaches, such as soft tissue debridement (38.84%), fasciotomy (18.79%), amputation (3.75%), and other procedures. We had to refer 8.27% of the patients to different advanced centers. The mortality rate was 5.91%, including 1 volunteer rescuer. Conclusion: Pattern of injuries and modalities of management needed in an industrial disaster is a valuable experience which can be utilized in preparing to face disasters in the future and beyond. Death of a voluntary rescuer once again warrants the necessity of using a helmet and safety gear during any rescue operation. (Disaster Med Public Health Preparedness. 2016;page 1 of 4)

Robustness, structural integrity and prevention risk of progressive collapse (PC) are among main design objectives for structures. After the (PC) of many remarkable structures, the need for better designing techniques has motivated engineers to prevent similar incidents.
The main objective of this study is to investigate different structural systems to detect more practical and cost effective systems to enhance the (PC) resisting capacity. The study is extended to numerically investigate the effectiveness of these systems by analyzing a ten storey steel office building using alternative pass method discussed by UFC09 code. The study shows that one of the preferred practices to reduce the potentiality for (PC) is the use of belt trusses at the top of the building. The use of belt truss system holds the initial failure of the damaged elements and redistributes the loads supported by the failed elements with the least increase in the structure’s weight.

This work investigates the response of two reinforced concrete (RC) plane frames after the loss of a column and their potential resistance for progressive collapse. Nonlinear dynamic analysis is performed using a multilayered Euler/Bernoulli beam element, including elasto-viscoplastic effects. The material nonlinearity is represented using one-dimensional constitutive laws in the material layers, while geometrical nonlinearities
are incorporated within a corotational beam formulation. The frames were designed in accordance with the minimum requirements proposed by
the reinforced concrete design/building codes of Europe (fib [1-2], Eurocode 2 [3]) and Brazil (NBR 6118 [4]). The load combinations considered for PC analysis follow the prescriptions of DoD [5]. The work verifies if the minimum requirements of the considered codes are sufficient for enforcing structural safety and robustness, and also points out the major differences in terms of progressive collapse potential of the corresponding designed structures.
Keywords: progressive collapse, reinforced concrete, nonlinear analysis, corotational formulation, layer discretization