Experimental investigation of creep recovery of T-shaped RC beams and validation of creep and creep recovery models

Many structures are designed for a lifetime of over a 100 years; however, laboratory data for multidecade creep and creep recovery are very scarce. The development of da realistic model regarding creep recovery is of importance in predicting the long-term behaviour of concrete specimens submitted to stress variations with time and requires careful analysis of extensive data from long-term tests. Since 2013 at the Magnel laboratory for concrete research, four T-shaped concrete beams were subjected to various load histories to determine the influence of the load history on the time-dependent behaviour of concrete beams including the effect of creep recovery. Three of these beams are simply supported (span 5m) and loaded in a four point bending configuration. One beam is statically indeterminate supported by three supports (two spans of 4 m) and loaded by two point loads at each mid-span. The beams were placed in a large climate controlled room (20°C, 60% RH) during the entire testing period. The deflections and crack-patterns were measured during a period of four years. During the second phase of this research, the behaviour of these beams upon the removal of the current sustained loads after 4 years are investigated. Several measurement techniques, both electronic and manual, were applied. The results of the measurement data during and after the unloading process of the T-shaped beams and the accompanying concrete prisms (sealed and unsealed prisms) are reported. This data can be used to reinvestigate the results based on actual creep and shrinkage models (including those for creep recovey, although rarely available) and is of great interest to assess the structural response due to load histories.Many structures are designed for a lifetime of over a 100 years; however, laboratory data for multidecade creep and creep recovery are very scarce. The development of da realistic model regarding creep recovery is of importance in predicting the long-term behaviour of concrete specimens submitted to stress variations with time and requires careful analysis of extensive data from long-term tests. Since 2013 at the Magnel laboratory for concrete research, four T-shaped concrete beams were subjected to various load histories to determine the influence of the load history on the time-dependent behaviour of concrete beams including the effect of creep recovery. Three of these beams are simply supported (span 5m) and loaded in a four point bending configuration. One beam is statically indeterminate supported by three supports (two spans of 4 m) and loaded by two point loads at each mid-span. The beams were placed in a large climate controlled room (20°C, 60% RH) during the entire testing period. The deflections and crack-patterns were measured during a period of four years. During the second phase of this research, the behaviour of these beams upon the removal of the current sustained loads after 4 years are investigated. Several measurement techniques, both electronic and manual, were applied. The results of the measurement data during and after the unloading process of the T-shaped beams and the accompanying concrete prisms (sealed and unsealed prisms) are reported. This data can be used to reinvestigate the results based on actual creep and shrinkage models (including those for creep recovey, although rarely available) and is of great interest to assess the structural response due to load histories.C