Lub tshuab no tsuas yog siv rau hauv kev lag luam steel qauv xws li kev tsim kho, txuas hniav, kev tswj hwm hauv nroog, thiab lwm yam.
Lub luag haujlwm tseem ceeb yog rau beveling grooves, kawg lub ntsej muag thiab lub vev xaib arc grooves ntawm H-shaped steel thiab flanges.
Kev pabcuam thiab lav