JFTS offers specialist concrete bridge assessments for BA35/90 post-tensioned bridges and BA53/90 culverts, as well as confined space inspections.
Typical investigation works involve concrete cover surveys, half-cell surveys, depth of carbonation, sampling and testing for chloride, ion and cement content; resistivity, delamination and breakouts.
We can provide project management from start to finish, including traffic management arrangements and comprehensive reporting.
Post-tensioned bridge inspections
The post-tensioning of steel tendons in concrete beams has been widely used in both road and rail bridges, where the tendons are usually carried in ducts which are injected with grout to protect them from corrosion.
Where the injection process has been unsuccessful the tendons are left unprotected and prone to deterioration. This process can be accelerated if the concrete has been contaminated, for example with chlorides from de-icing salt.
In addition to standard bridge tests, a typical inspection of post-tensioned bridges may involve several of following test methods:
- Impulse radar - using a high frequency antenna to locate re-bars and tendon ducts
- Intrusive surveys and duct inspection by drilling and using a flexible video-imagescope
- Pressure testing to establish the size of any ductvoids
- Chemical testing to check for contamination
- In-situ stress determination to check existing stresses in both concrete and steel