Investigation of the spatial coherence function of wind loads on lattice frame structures

Abstract

This study investigates the spatial coherence function of wind loads on the lattice frame structure through a simultaneous double high frequency force balance (HFFB) wind tunnel test. The wind forces on two segment models of the lattice frame structure are simultaneously measured by the wind tunnel test for several configurations of the models with different lateral and vertical distances. Coherence functions from the test are then calculated and compared with the existing coherence functions for tall buildings or tapered stacks. Results show that none of the existing coherence functions can provide an accurate enough estimate of the coherence function of wind loads on the lattice frame structure. Additionally, the coherence function of wind loads is affected by the frequency of wind loads, force direction, lateral and vertical distances. An expression of the coherence function specific for the lattice frame structure is then developed based on the wind tunnel test results. An example is presented to show the application and significance of the developed expression. The findings of this research can provide a more accurate estimate of the coherence function of wind loads on similar lattice frame structures, and hence the resultant generalized wind forces and wind performance of similar structures.