also: かわげた
noun
stringer; slanted staircase beam
Technical term in architecture for the inclined beam supporting the steps of a staircase.
階段の側桁が老朽化しているので、補強工事が必要だ。
The staircase stringer is deteriorating, so reinforcement work is needed.
Compound of 側 (gawa, 'side') and 桁 (keta, 'beam'). The reading がわげた is a standard rendaku form.