Experimental and theoretical evaluation of progressive collapse capacity of reinforced concrete framed structures

Alogla, KD

Abstract

Progressive collapse is a situation when local failure is followed by collapse of adjoining members, which in turn causes global collapse, threatening life. Local failure of a vertical load carrying member, can be caused by abnormal loading such as explosion, bombing, sudden vehicle impact and design errors.
The design of structures against progressive collapse has not been an integral part of structural design. It is difficult to predict the structural behaviour of building members during progressive collapse because of the dynamic nature of the event and the limited experimental tests conducted to understand the nature of progressive collapse. An experimental program comprising eight reinforced concrete (RC) beam-column sub-assemblages is presented to investigate the structural behaviour and progressive collapse resistance of RC frame members subjected to column removal scenario (CRS). The specimens were tested under quasi-static loading.
Mitigation of progressive collapse has become a primary concern of engineers in recent years. A new mitigation scheme is proposed in this study to increase the resistance of RC beams against progressive collapse using modified detailing of reinforcement. The effect of the proposed scheme on the structural behaviour of sub-assemblages is investigated through testing some of the specimens with modified detailing. The test results showed that the proposed scheme was able and efficient to increase progressive collapse capacity.
A finite element (FE) model was developed using the software package ANSYS in order to numerically simulate the structural behaviour of RC beam-column sub-assemblages under CRS. A macro-model based approach was used in the analysis using beam elements and a series of non-linear springs to capture the real behaviour of structural members associated with the redistribution of loads under CRS. Numerical results were compared with those obtained from the experimental program, and showed a good agreement.
An analytical model was developed to predict the structural behaviour of RC structures under CRS. The development of the model equations was based on the concepts of equilibrium, compatibility, and material properties. Steel bar fracture and the reduction in the effective beam depth due to concrete crushing were included in the model. The model was validated by comparing the results with the experimental results. The comparison shows that the model was able to capture the structural behaviour of RC beams under CRS. A parametric study was conducted to investigate the effect of different factors on the progressive collapse capacity.

Citation

Alogla, K. Experimental and theoretical evaluation of progressive collapse capacity of reinforced concrete framed structures. (Thesis). University of Salford

• Thesis Type: Thesis
• Deposit Date: Jan 19, 2018
• Publicly Available Date: Jan 19, 2018