Kev cai I-beam

Lus piav qhia luv luv:

I-beam, tseem hu ua universal beam, yog ib txoj hlua ntev ntawm cov hlau nrog I-shaped seem.I-beam muab faib ua kub dov I-beam thiab lub teeb I-beam.Nws yog ib seem hlau nrog I-section zoo.