three-pinned arch

three-hinged arch

An arch with hinges at the two supports and at the crown.
References in periodicals archive ?
Several people have suggested a relationship to Grimshaw and Hunt's Waterloo Channel Tunnel Terminus (AR May 1993), and they are right in some respects, for the basic structures of the two are very similar: eccentric three-pinned arches formed of two bow-string trusses.