High-resolution 3D condition survey of a masonry arch bridge using Ground Penetrating Radar

Condition surveying is essential before rehabilitation and modification of a structure. It implies information collection and analysis for structural performance evaluation. Common condition surveying often requires obstructive and invasive techniques that can affect the structure’s integrity. Also, the extent of internal disorders and their distribution in the structure is not obtained. The use of non-destructive techniques combined with external analysis, can provide useful information for structural condition surveying. This paper presents the application of Ground Penetrating Radar for the condition survey of a massive natural stone masonry bridge with twin large span arches. Emphasis is placed on the determination of the condition of the arches. The paper describes the processing steps leading to a high-resolution 3D reconstitution of spatial and structural information for disorder mapping. Benefits and limits of this novel representation method for massive bridge structures will be reviewed

Prediction of the creep rupture strength of GFRP bars

•Creep rupture behavior is affected by both fatigue and viscous phenomena.•A statistically-based empirical approach is viable for creep-rupture modelling.•Mean creep rupture strength of investigated GFRP bars is equal to 65%–69% UTS.•The creep rupture knock-down factor of investigated GFRP bars is equal to 0.46. The experimental portion of this study presents the results of an investigation into the unconditioned creep rupture strength of two different types of 12.7 mm GFRP bar both made with vinylester resin and ECR glass fibers but with different surface enhancements. An overview of the behavior and performance of FRP composites and bars under sustained load is discussed to determine whether a statistically-based empirical approach represents a viable method for the definition of a safe value of creep rupture strength. A refined approach to data handling and the extrapolation of a safe value of creep rupture strength is discussed, including statistical considerations. Results show that the creep rupture knock-down factor prescribed by current design guidelines is conservative when designing using the GFRP bars considered in this study. The surface preparation of the two types of GFRP bar has an effect on their tensile strength, but no additional influence on their creep rupture performance