AccResSpec

代码说明：

  给定离散地震动加速度数据a、反应谱控制周期点tp、离散时间间隔dt、阻尼比z，计算地震动加速度反应谱rspa以及最大反应值出现的时刻tMax。(Given the discrete ground-motion acceleration data a, the response spectral controlling period tp, the discrete time distance dt, and the damping ratio z, calculate the ground-motion acceleration response spectrum rspa and the time loction of the occurrence of maximum response.)