Abstract
Fatigue Strength of Concrete due to Sustained Loading.
The crushing strength under sustained loading in ratio to the statical crushing strength is difficult to be determined, because the actual strength of the sustaindly loaded specimen itself is previously unknown. According to the literatures available, the ratio of fatigue strength to statical strength is believed to be roughly 80-95%. The auther takes the compressive strain at the begining of loading as a measure of limit avoiding to crush down and comes experimentally to the conclusion that the initial limiting strain is 1‰.
Almost independently of the ultimate strength of concrete the stress/strength ratio is about same for a given strain value which is sufficiently large. Corresponding to Strain of 1, 3‰, for instance, the stress/strength ratio becomes 88%. From this fact the auther assumes that, corresponding to 1‰ strain, the crushing strength under sustained loading is about 76% of the statical strength.
