Spectra provided a ground penetrating radar investigation at Lake Mills Road Bridge in Greene County in order to evaluate the presence of reinforcement, the depth of concrete and asphalt, and any voids or deteriorated areas of the structure.
To evaluate the bridge deck, Spectra used a high frequency ground-coupled radar antenna with a frequency of 1.6 GHz. It has an estimated penetration depth of 18”. The GPR technology was used to access the internal condition of the concrete deck since it was covered by a reconstructed asphalt overly and constructed with a stay-in-place metal form.
Spectra collected multiple GPR transects parallel and perpendicular to the direction of traffic. The GPR data identified several potential internal voids and areas of deterioration. Layer thickness and steel reinforcement patterns were also determined.