Abstract: Elastic and elastic-plastic equivalent single-degree-of-freedom (SDOF) differential equations are established for blast load. The relation of load equivalent duration and load real duration can be reached using the same values of overpressure peak and positive overpressure impulse. The displacement solutions are solved for linear and exponential attenuation blast loads. Elastic-plastic process is divided into later and earlier entering elastic-plastic stages for entering plastic time. The function expressions of ductility ratio and dynamical coefficient are deduced for linear and exponential attenuation blast loads with elastic-plastic stages. Three dynamical coefficients for linear and exponential attenuation blast loads with shape adjustment parameters a of 1.27,1.44 and 1.61 were calculated according to a of exponential attenuation blast load and current anti-blast design specifications. The results show that the linear exponential blast load model adopted by anti-blast design code is more suitable for structure design with ductility ratio β＜3.0. The exponential attenuation blast load model can be used for structure design with ductility ratio β≤5.0, especially β≥3.0. Key

Key words: blastload, equivalentstaticload, dynamiccoefficient, elastic-plasticstage, anti-blastdesign