Research

Field Investigation of Corrosion of Steel Piles (Sponsor: NC Department of Transportation)

Corrosion of steel piles has been observed in highway bridges across North Carolina. Typically, these piles have been galvanized prior to construction, which is intended to provide maintenance-free performance throughout the bridge lifetime. Our group is developing and deploying field monitoring kits at select bridge throughout the state to determine the environmental factors which may lead to premature corrosion. This work may also inform revised specifications for steel pile corrosion protection.

Finite Element Study to Support Revised AISC 341 Slenderness Limits (Sponsor: AISC)

Local buckling is a critical failure mode in steel components which resist earthquake ground motions. Slender steel elements (as measured by their width-to-thickness ratio) are more susceptible to local buckling. As a result, the width-to-thickness ratios of elements which are expected to undergo significant inelastic deformation are limited by values in Table D1.1 in AISC 341.

However, the origins of many values in Table D1.1 are unclear, and it has not been rigorously demonstrated that elements satisfying the limits in this table will display consistent, reliable performance. Our group is performing an analytical study of HSS braces under cyclic loading to determine rational slenderness limits, consistent with expected system performance.

Modeling Fatigue Crack Propagation in Marine Hydrokinetic Turbines (Sponsor: NC Renewable Ocean Energy Program)

Marine hydrokinetic (MHK) turbines are renewable energy devices which are critical in our national effort to increase the share of energy which comes from renewable resources. MHK turbine blades resist loads which vary over time, which can lead to the formation and propagation of fatigue cracks. These cracks, if sufficiently long, can lead to reduced performance and structural failure.

Inspection of MHK turbine blades for fatigue cracking is challenging, due to the harsh marine conditions in which these devices operation. Thus, it is critical that computational tools are developed which can reliably simulate the initiation and propagation of fatigue cracks. We are currently working on developing and testing computational methods which can achieve this goal.