Arch thrust - Arch thrust

…The members that support both ends of an arch are called imposts, and serve as decorations for the tops of the columns and walls that support the arch, and as supports for both ends of the formwork. Arches have the advantage that the members that form the arch experience almost no bending force, but in exchange, they experience lateral pressure (also called thrust or arch thrust) that is diagonally downward toward the outside at both ends of the arch. In order to absorb this lateral pressure and safely transmit it to the ground, the arch must be sandwiched between strong walls of sufficient weight on both sides, and these wall parts on both sides are called abutments. …

*Some of the terminology explanations that mention "arch thrust" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…アーチの両端を支える部材を迫元(インポスト)といい，アーチを支える柱や壁の上端の装飾ともなり，また型枠の両端を支持する支承物の役割を果たす。アーチは，アーチを形づくる部材にほとんど曲げの力が生じないという長所がある代りに，アーチの両端部に，外方へ向かって斜め下方への横圧力(スラスト，アーチ推力ともいう)を生ずる。この横圧力を吸収して安全に地盤に伝えるため，アーチは両側から十分な重量のある堅固な壁ではさんでやる必要があり，このような両側の壁体部分を迫台(アバットメント)という。…

※「アーチ推力」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