Multi-phase Approach to Bridge Deck Scanning Provides Agencies with Maximum Value

Nondestructive scanning methods such as ground penetrating radar and infrared thermography are being used by an increasing number of transportation agencies to more efficiently obtain comprehensive deck condition information. The ability to evaluate the condition of a large number of decks in a single inspection season is a valuable tool for bridge owners to make data-driven planning and design decisions. Infrasense has utilized a multi-phase approach for a number of agencies to provide the maximum amount of information for a given budget. Phases include the following:

Phase 1 – Quantities for Planning-Level Decisions

A large group of decks are scanned with high-speed NDE methods and condition quantities are provided (e.g. delamination, deterioration, patching, spalling). This level of information is used by agencies to program and prioritize decks for specific preservation, rehabilitation, or replacement efforts. 

 

Phase 2 – Maps for Rehab Design

Decks are selected for Phase 2 based on the Phase 1 results and specific agency needs. Phase 2 includes detailed mapping of the detected concrete deterioration, rebar-level delamination, spalling, and patching. AC overlay thickness and rebar cover maps can also be provided. Conditions are mapped in plan-view and provided in a CADD compatible format. Agencies use the condition maps to plan and spec rehabilitation efforts (e.g. construction bid quantities).

Phase 3 – Confirmation Testing

Some agencies have implemented a third phase to confirm the Phase 2 findings for select decks. Phase 3 is typically reserved for cases where there are significant cost implications; such as when an agency is deciding between rehab and replacement of a relatively large deck carrying a high-volume roadway. Phase 3 consists of localized confirmation testing at locations selected using the Phase 2 maps. Confirmation testing has included coring, chloride content sampling, half-cell, impact-echo, and sounding.