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Wind-induced response of lattice structures subjected to atmospheric boundary layer and downburst winds

Lattice towers are widely used as primary structural systems for transmission lines and telecommunications infrastructure in the United States and worldwide. Their widespread deployment increases their exposure and vulnerability to extreme wind events such as hurricanes, tornadoes, and downbursts. A Climate Central report noted that, in 2025, thunderstorms caused 67 fatalities and approximately $50.70 billion in economic losses in the United States. Accordingly, this study investigates the wind-induced response of lattice towers under downburst winds and compares it with that under atmospheric boundary layer (ABL) winds.

Downbursts can generate intense near-surface winds that impose substantial demands on the built environment. Their severity is especially critical for lattice towers, which are slender and flexible and therefore particularly vulnerable to such events. Understanding downburst effects on lattice towers is essential for identifying response characteristics distinct from those under ABL winds and for informing future design improvements. This can be pursued through field measurements, wind tunnel experiments, and numerical simulations. However, progress remains hampered by (i) the scarcity of field data capturing downburst-induced structural response, (ii) the transient nature of downbursts, which requires specialized simulation techniques and scaling approaches for wind tunnel testing, and (iii) the difficulty of conducting realistic vulnerability assessments.

To address these gaps, this study (1) investigates the wind-induced response of lattice towers under ABL and downburst winds through a field data collection campaign, (2) provides insights into experimentally simulated downburst-like outflows at the Wall of Wind Experimental Facility at Florida International University using 3D Particle Image Velocimetry (3D PIV), (3) proposes a generalized time-frequency scaling approach adaptable to existing wind tunnels, and (4) introduces, to the best of the authors’ knowledge, the first experimental approach for simulating a damaged lattice tower and examining its wind-induced response under downburst winds using a large-scale aeroelastic model.

Concisely, based on full-scale data, the results indicate the presence of vortex shedding that leads to excessive across-wind vibrations, compromising structural safety, although this phenomenon has not been discussed in the literature and receives limited attention in ASCE 74. Under downburst winds, the across-wind RMS acceleration is approximately 1.35 times that in the along-wind direction.