一、导言随着技术及交通运输的发展,公路上出现了重型车辆或高速车辆,由于经济上的原因,即使在大交通量情况下,也得尽可能地保留旧的构造物,或者在原有构造物上容许一次或多次通行大型货物运输,因此构造物在 I. INTRODUCTION With the development of technology and transportation, heavy vehicles or high-speed vehicles have appeared on the road. Due to economic reasons, it is necessary to retain the old structures as much as possible even in the case of large traffic volume, The construction allows one or more large-scale cargo transportation, so the structure in