Tensile Crack Exposure Tests. Report 4. Statistical Analysis of the Long-Term Durability of Series 'B' Beams

摘要

In November 1954, a long-term durability program was begun to determine the effects of severe natural weathering on reinforced concrete beams loaded to different stress levels and containing reinforcing steel with different types of bar deformation in either top-as-cast or bottom-as-cast positions. The beams were fabricated, cured, and loaded at the U.S. Army Engineer Waterways Experiment Station (WES) in 1954, then shipped to Eastport, Marine, and placed on the beach at the natural weathering exposure station on the south side of Treat Island in Cobscook Bay. The beams were subjected to twice daily tidal cycles exposing them to wetting under considerable head and drying to surface dry conditions. In addition, during the winter months, the beams were subjected to cycles of freezing and thawing with each tide when the air temperature was at or below 28 deg F (-2.2 deg C). The beams were inspected annually during the exposure period and evaluated by a team of inspectors rating the degree of deterioration. Nondestructive tests were also performed. Each year data on condition, percent velocity squared (v2), and maximum crack width were collected.