Measuring method of stresses borne by twice-successively-poured concrete at construction joint

The invention discloses a measuring method of stresses borne by twice-successively-poured concrete at a construction joint. An oil-sac-type strainometer is installed on the construction joint to measure stress on the construction joint. The measuring method comprises the following steps: 1) after concrete is poured on one side of the construction joint for the first time, the oil-sac-type strainometer and an automatic wireless thermodetector are installed at the construction joint; 2) after the concrete is poured on the other side of construction joint for the second time, indicators measured by the oil-sac-type strainometer are noted every other arranged timing, and are expressed by epsilon 1; 3) temperature change values within arranged time are about afterward poured concrete, automatically measured by the automatic wireless theromodetector, noted and are expressed by delta T; 4) coefficient of thermal expansion of oil of the oil-sac-type strainometer is alpha, temperature strain of the concrete poured for the second time is generated because of changes of hydration heat temperature and is expressed by epsilon 0, and a calculation formula is epsilon 0 = alpha * delta T; 5) actual stress on the construction joint is calculated and is expressed by epsilon, and a calculation formula is epsilon = epsilon 1 - epsilon0.