Like the flying arch, the inverted arch is not usually used to support a load (with teh exceptions of the foundations of the piers and retaining walls, see below), as for a bridge, but rather to resist sideways, inwards loads.In most cases, this sideways force is a nuisance and must be resisted by either strong foundations or a further 'bowstring' girder, in the form of a tied-arch bridge.Inverted arches are used where sideways forces must be restrained, and where space is most easily available beneath a construction (for example, the strainer arches are built as an afterthought, had to fit into the space available, and thus sometimes include the inverted components[1][2]).Such arches were used beneath the Hownes Gill Viaduct, on the advice of Robert Stephenson.Inverted arches have also been added to existing bridges, to reinforce them after their banks start to slide inwards.
"Scissors" strainer arch arrangement in
Wells Cathedral
includes an inverted arch
The Iron Bridge
in 1974, during the construction of the concrete inverted arch
