Assessment of FRP Rehabilitation at a Systems Level Through Progressive Damage and NDE

摘要

Fiber Reinforced Polymer (FRP) composite materials are finding increased acceptance in the civil infrastructure as an effective means of rehabilitation of concrete bridge decks. However a true assessment of the effectiveness of rehabilitation over time has not been undertaken to date. Moreover usually only the bridge decks are rehabilitated without taking into account the possibility of the un-strengthened longitudinal girders reaching their critical limit states as a result of the higher load transfer. Thus it becomes necessary to carry out health monitoring through the application of cost and data effective non-destructive evaluation (NDE) techniques to evaluate the performance of the rehabilitated structure over its useful life and to monitor any progression of damage or change in load paths between the structural components. Research is currently underway to evaluate rehabilitation of bridge decks at the "systems level", in which a three-girder bridge deck system is being constructed and tested. The objective of the study is to evaluate the damage progression in the deck slabs and the longitudinal girders under wheel load applications and to detect changes in the overall response of structure caused by the strengthening of only individual components that pushes the other components towards critical levels. The deck slab-girder system is tested to simulate behavior under field loading in which the deck slabs are found to be susceptible to punching shear type failures and the longitudinal girders are usually found to be deficient in terms of shear demand. NDE techniques are evaluated as means to identify the shifts in damage localization, overall response and damage progression caused by subsequent modifications to the structure. The test data on the failure modes, capacity loads and specimen behaviors are correlated to the available analytical models and design guidelines.