PSI - Issue 22

7

H. Daou, W. Raphael, A. Chateauneuf, F. Geara / Structural Integrity Procedia 00 (2019) 000 – 000

H. Daou et al. / Procedia Structural Integrity 22 (2019) 17–24

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Fig. 6. Sensitivity analysis of the variables

ratio obtained based on the deterministic analysis. The long term deflection obtained by the deterministic analysis does not exceed the admissible value (12 cm) while it reaches 14.8 cm based on the probabilistic analysis. Thus, conducting a probabilistic analysis is important to ensure the reliability and the safety of the structure. The probability of failure obtained is equal to 1.64x10 -2 which is largely greater that the target probability of failure. So, the structure is not safe and presents deficiencies in long term deflection. According to the sensitivity analysis, Figure 6 shows the influence of the input variables on the moment value of the shell. The density of concrete has the main effect on the value of flexural moment but the modulus of concrete, the wind velocity and the temperature have also an effect on the moment value of the shell. Therefore, the poor quality of concrete and its weakness in addition to the rapid change in temperature affected the flexural moment value and thus led to the failure. 3. Conclusions In this study, probabilistic analysis of the terminal in terms of flexural moment and long term deflection was investigated using a combination of Response Surface Method (RSM) and Monte Carlo Simulations (MCS). For this purpose, nine arches including the collapsed ones were modelled using Ansys taking into consideration structure complexity, material nonlinearity, holes in the shell, asymmetry of the structure and loads applied. The random variables considered were the density, the compressive strength and the modulus of elasticity of concrete, the temperature and the wind velocity. Structural safety of the terminal was assessed by studying the flexural moment and comparing the required reinforcement calculated with the existing reinforcement ratio in the shell. Based on the probabilistic and reliability analyses, the required reinforcement ratio is greater than the existing ratio in the shell and the long term deflection exceeds the admissible value. Therefore, the structure is not safe and present deficiencies in terms of moment and long term deflection. Moreover, probabilistic analysis gives more reliable and realistic results than deterministic analysis concerning the structural safety because it takes into consideration the uncertainty of material properties and loads. The self-weight had the main effect on the value of moment of the shell in addition to the modulus of concrete, the wind velocity and the temperature. The poor quality and weakness of concrete and the rapid change in temperature affected the flexural moment value and thus led to the failure.

References

Abdelouafi, E., Benaissa, K., Abdellatif, K., 2015, Reliability analysis of reinforced concrete buildings: Comparison between FORM and ISM, Procedia Engineering (114), 650-657. Biondidni, F., Bontempi, F., Malerba, P.G., 2004, Fuzzy reliability analysis of concrete structures, Computers and Structures (82), 1033-1052. Daou, H., Abou Salha, W., Raphael, W., Chateauneuf, A., 2019. Explanation of the collapse of Terminal 2E at Roissy-CDG Airport by nonlinear deterministic and reliability analyses. Case Studies in Construction Materials (10). El Kamari, Y., Raphael, W., Chateauneuf, A., 2015. Reliability study and simulation of the progressive collapse of Roissy Charles de Gaulle Airport. Case Studies in Engineering Failure Analysis (3), 88-95.