| 释义 |
extrados Arch.|ɛkˈstreɪdəs|
[a. F. extrados, f. L. extrā outside + F. dos the back.]
The upper or exterior curve of an arch; esp. the upper curve of the voussoirs or stones which immediately form the arch. Cf. intrados.
1772Hutton Bridges p. iii, The relations between their intrados and extrados. 1823P. Nicholson Pract. Build. 338 Extrados of a Bridge—The curve of the road-way. 1828Hutton Course Math. II. 172 So that the extrados is a parabola equal to the intrados, and everywhere vertically equidistant from it. 1879Sir G. Scott Lect. Archit. II. 141 We have..supposed our arches to be of moderate depth from extrados, or outer line, to intrados or inner line. |