Limb-Inspired Bridge Column Design Offers Protection Against Earthquakes

Photo credit: Steven Pavlov, CC BY-SA 4.0

Research into a new bridge design offers potential relief for the expensive and dangerous threats posed to bridges by seismic events.

Contemporary bridge designs follow a monolithic model: forms are constructed then concrete is poured over the forms, yielding a final structure. These traditional monolithic bridges are strong enough to support their own weight plus additional loads such as traffic but are often damaged by unexpected seismic events like earthquakes.

Restoration to a bridge damaged by seismic activity is a lengthy and expensive process, and the damage itself can result in injuries and loss of life. In recent months, researchers at the University of Colorado Boulder and Texas A&M University set out to evaluate a theoretical bridge design, called the hybrid sliding-rocking (HSR) bridge, that aims to mitigate the issues plaguing traditional bridges as a result of seismic events.

Where a monolithic bridge emphasizes unyielding concrete, an HSR bridge offers columns containing limb-inspired joints that slide and rock to diffuse seismic energy as it travels through the ground. Not only is an HSR bridge more capable of energy dispersal—the uniquely complex sliding-rocking interaction also allows HSR bridges to self-center amidst seismic activity, almost like the adjustments to joint movement made by a person who has achieved “sea legs.”

Researchers at CU Boulder and Texas A&M conducted earthquake simulations on experimental HSR columns and found that the HSR columns sustained less damage when compared to practical evaluations of conventionally designed columns. Damages sustained by the HSR columns also proved relatively quick to fix with common restoration materials.

Although HSR bridge design remains theoretical, with no practical implementation into real world bridges at this time, findings from this latest research study generate optimism for the future of bridge safety and durability amidst seismic activity. You can learn more about the research study conducted by CU Boulder and Texas A&M here.