Influence of frequency of cyclic load on creep of concrete

Abstract

Synopsis Short-term creep of sealed and drying concrete under a sinusoidal compressive load has been determined at various frequencies ranging from 1 cycle per day to 1 Hz, Under cyclic loading, creep has to be dejined carefully because of the changing shape of the stress-strain curve. When compared with static creep under a stress equal to the mean cyclic stress, creep under a cyclic stress is greater by an amount which decreases with time under load. Between frequencies of 1 cycle per day and 30 cycles per hour, the increase in creep under a cyclic load is approximately equal but, at higher frequencies, there is a further increase in creep. Compared with drying static creep under a stress equal to the mean cyclic stress, drying creep measured at the mean cyclic stress is similar and unaflected by frequency of loading. Expressions are given which give estimates of the full strain cycle when the static creep is known.