جستجوی مقالات مرتبط با کلیدواژه « cylindrical concrete tanks » در نشریات گروه « عمران »

Fluid storage tanks are one of the most important components of vital arteries that play a key role in various water and industry networks, including oil, petrochemical, and water transmission systems. A study of seismic damage reports of tanks in previous earthquakes shows that one of the major damages in reinforcement concrete tanks that are commonly used to store water is cracking and liquid leakage. Therefore, in the present paper, the analysis and evaluation of ground concrete tanks are investigated to develop the fragility curve for these tanks. For this purpose, nonlinear numerical analyzes have been performed for three types of concrete cylindrical tanks with variable height to diameter ratio, taking into account the cracking of concrete. Then, the fragility curves of the tanks for the critical crack width are extracted according to the recommendation of Journal 123. These curves are compared with the results of previous research conducted in a linear manner without considering the cracks in the reservoir body, and the effects of applying crack widths in the analyses are discussed. The results indicate the need to apply tank cracking conditions in increasing dynamic analysis and extraction of fragility curves.

In this paper the response modification factor due to ductility and saved strength of cylindrical concrete elevated and ground tanks is obtained using finite element method and nonlinear push over analysis considering the lateral effective modes of tanks. To modeling the behavior of the tank materials، the five parameters William-Warnke and prefect elastoplastic models are used for concrete and reinforcement rebars respectively. In the calculations the reinforced bars are modeled both exactly and as percentage of concrete surface area. In addition it is assumed that the foundation of the structure is absolutely rigid and contained water has linear behavior. The response modification factor is obtained for different performance levels by changing different parameters such as height، thickness، radius، and percentage of the reinforcementbars of the shaft and shell، thickness and dimensions of stiffener and water level. The obtained results show that the factor for the elevated tanks changes between 4and 5 and the factor for the ground tanks varies between 1 and 2. 5 these changes depend on the performance levels for the tanks.