bascule leaf west bank 上开桥扇

single leaf bascule bridge 单扇上开桥

leaf of bascule bridge 竖旋桥桥翼

double-leaf bascule bridge 双叶竖旋桥

single-leaf bascule bridge 单叶竖旋桥

leaf bascule bridge 单叶竖旋桥 ; 双叶竖旋桥

double-leaf bascule 双翼竖旋桥

twin-leaf bascule bridge 双翼衡重式仰开桥

double leaf bascule bridge 双翼式开合桥