免费一级国产生活片,国产满18av精品免费观看视频,国内精品一级毛片免费看,一级毛片免费观看不卡的,一区二区三区视频免费观看,国产女人18毛片水真多18精品,麻豆精品一区二区综合av

This cross H steel column made of carbon steel. Most of the columns of large and medium-sized industrial plants, large-span public buildings, high-rise buildings, light mobile houses, working platforms, trestle bridges and brackets are made of steel columns. There are many types of solid web steel columns, the most common ones are factory steel columns and high-rise steel columns. Among them, the steel columns of high-rise projects are commonly called "steel skeleton columns", and their function is to support the core of the entire building. The common high-rise building used steel columns include box columns, cross columns, and round pipe columns.

Cross column

Round pipe column