Bamboo bow of the Spring and Autumn Period: the arch was made of a single piece of bamboo, so it was called monomer bow.

文物：春秋竹弓，弓臂用单根竹材弯曲而成，称为单体弓。

youdao

The new arch spring of composite truss arch bridge is used to support the middle truss arch of the bridge and the structural formation and force conditions of the joint of the spring are complicated.

桁式组合拱桥的新拱脚支撑着中部桁架拱，新拱脚结点构造和受力复杂。

youdao