Plate girder

…Beams are also subjected to bending due to loads from above, but an I-section can effectively resist this with the least amount of material. Girders assembled from steel plates are specifically called plate girders. Box girders, which are made by connecting the upper and lower horizontal plates (flanges) of parallel I-section girders to form a closed cross section, are resistant to torsion and have the advantage that the upper flange can also be used as the bridge deck. …

*Some of the terminology that mentions "plate girder" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…桁も上からの荷重によって曲げを受けるが，I形断面はもっとも少ない材料でこれに有効に抵抗しうる。鋼板で組み立てた桁はとくにプレートガーダーplate girderと呼ばれる。並列したI形断面の桁の上下の水平な板(フランジ)をつなぎ閉断面とした箱桁はねじりに強く，上フランジを橋床に兼用できるという利点がある。…

※「plate girder」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報