Design wind loads on hyperbolic cooling towers during construction

The fundamental theory of structural reliability was used to predict the design wind load on hyperbolic cooling towers during construction to give the same reliability during construction as for the design reference period. The relationships between the reliability for the design reference period for various time intervals and the reliability during construction for various time intervals are given based on the time interval method for analyzing the structural reliability using the stationary binomial stochastic process model for wind loads. The structural resistance during construction is found to be proportional to that of the design reference period. The characteristic wind loads also preserve the proportionality relation with the wind load factor during construction defined in this paper using partial safety factor design expressions for these two periods. A general wind load factor solution procedure was given and the predicted wind load factors were computed for typical probabilistic distributions of the random variables. The wind load factor increases with the extension of the construction cycle or with a lower resistance partial safety factor. The relationship between the wind load factor and the construction time is well fit by a logarithmic function. The design wind load for hyperbolic cooling towers during construction can be determined with the correlations or simplified tables of the wind load factor. © 2015, Press of Tsinghua University. All right reserved.