SPA Application: Bridge Decks
Periodic replacement or repair of bridge decks is needed in many areas, especially when they are subjected to harsh environmental conditions. In many urban areas, the closure of the bridge decks has to be minimized because of the sheer volume of traffic.
The decision on whether or when to replace or repair a bridge deck is usually dictated by rebar corrosion and delamination. The extent of delamination of the decks has previously been determined by chain dragging. Even though chain dragging is rapid and reliable for grossly delaminated areas, as documented by several highway agencies, it may not identify the areas that are marginally delaminated. If the marginal areas are not repaired simultaneously with the grossly delaminated areas, the bridge will have to be re-closed for periodic maintenance. Several studies, especially in the State of New Jersey, have shown that the combination of impact echo and surface wave method can provide more reliable results than chain-dragging alone. Thus the deck can be repaired properly once. The evaluation time with the PSPA is longer than chain dragging, but the quantitative results from the SPA technology allow the "get in, get out and stay out" philosophy to be well implemented.
Case Studes for Bridge Decks
Comprehensive Instpection of Bridge
Decks with Ultrasonic Methods
Center for Geotechnical and Highways Materials Research
University of Texas at El Paso
El Paso, TX 79968-0516
Geomedia Research and Development
6040 Strahan Rd.
El Paso, TX 79932
A new nondestructive testing device, the Portable Seismic Pavement Analyzer, has been developed to rapidly perform seismic tests on bridge decks. The main tests used are Impact Echo for determining delamination in slabs, the Ultrasonic Body Wave and the Ultrasonic Surface Wave for determining the modulus. The theoretical background and recent advancements in real-time implementation of each method are discussed here. A case study is included to demonstarate the usefulness of the methods.
Geomedia SPA Application: Bridge Decks