headroom; vertical clearance; maximum height
Technical term used in civil engineering, architecture, and transportation to describe the vertical space available under a bridge, beam, or overhead structure. Often measured from the road or water surface to the lowest point of the structure above.
この橋の桁下は4.5メートルです。
The vertical clearance of this bridge is 4.5 meters.
大型トラックが通れるように、桁
The headroom was designed high so that large trucks can pass.
Standard kanji spelling for this technical term.
Mixed kanji-kana spelling; less common but still used.
Compound of 桁 (けた, 'beam' or 'girder') and 下 (した, 'under' or 'below'), literally meaning 'under the beam'.