Novel Methodology for Quantifying the Performance of Constructed Bridges in Cold Regions.

摘要

This report presents a two-part research program examining the performance of constructed bridges in a cold region, represented by those in the State of North Dakota, and the behavior of concrete members strengthened with carbon fiber reinforced polymer (CFRP) composite sheets in such a service condition. For the first phase, a total of 1,328 decks are sampled from a 15-year inspection period. These data are statistically characterized and probabilistically analyzed. The importance of timely technical action is discussed to enhance the condition rating of the bridge decks. The stochastic response of the existing decks is effectively represented by Gaussian probability distributions, regardless of inspection years. The performance of the decks tends to converge to a certain state with time. The state-transition of the in-situ decks is identified through the global health index proposed. The second part of the research concerns predictive investigations into the axial behavior of concrete exposed to aggressive service environments. Two types of concrete cylinders are studied: unconfined and confined with CFRP sheets. The aggressive environment and service traffic load are represented by freeze-wet-dry cycles with various levels of instantaneous compression load varying from 0% to 60% of the capacities of the unconfined and confined control concrete. Research approaches include three-dimensional deterministic finite element and probabilistic models, associated with a previously conducted experimental program.