Tuned Mass Damper Control of Cross-Wind Excitation of a Solar Tower

The Ivanpah Solar Electric Generating Facility will be the largest concentrated solar electric generating facility in the world when it is completed. This power plant consists of three identical 340 foot tall lattice steel towers, each supporting a 2,062 ton 120 foot tall steam generator capable of producing approximately 125 megawatts of electricity. Each tower receives solar flux reflected from more than 55,000 mirrors. Although these towers are classified as seismic design category C, due to their dynamic characteristics the controlling lateral loads are due to wind. Early in the design process, it was postulated that a cross-wind excitation of the structure, as a result of vortex shedding from the steam generator, could be a critical portion of the wind load. This dynamic response of the structure was confirmed by a wind tunnel study. A tuned mass damper (TMD) was ultimately selected as an established, economical solution to mitigate the cross-wind loading. Use of the TMD resulted in a substantial savings in structural steel and foundation costs when compared to a tower designed to resist the un-damped cross-wind loading. This paper discusses the structural design of the tower, and the chosen solution to mitigate the cross-wind excitation. Results of the wind tunnel study are reviewed. The effect of spatial constraints on the design of the TMD is highlighted. Structural design considerations, including the combination of cross-wind with along-wind loads, are addressed.