Jack Arch Roof

Instead they are flat in profile and are used under the same circumstances as lintels.

Jack arch roof.

In addition to the strength of the arches the jack arch floor or roof derives strength from the lime concrete layer by 3. Unlike regular arches jack arches are not semicircular in form. The joists are spaced 1 0 to 1 5 m centre to centre and are supported at their ends either on walls or on longitudinal girders. The rise of the arch is kept 1 12th of the span.

The minimum depth at the crown is kept at 150 mm. Jack arch roof construction can be done in brick or concrete. The more traditional ones are called jack arches where the arches are formed in the roof itself supported by the centering while the recent researched type is arch panel roof where the arches are made on ground to be lifted up and placed. The rolled steel joists are supported at their ends on the walls or on the longitudinal girders.

A jack arch is a structural element in masonry construction that provides support at openings in the masonry. Alternate names are flat arch and straight arch. The dimension of the arch at the skewback which is perpendicular to the arch axis except that the depth of a jack arch is taken to be the vertical dimension of the arch at the springing. The arch is supported on the lower flange of mild steel joists rsjs.

The arch of the jack arch roof is either made of brick or of concrete. Above them concrete fill is laid providing a level surface upon which the flooring finish can be if there is another level in the structure. Jack arch roof is composed of arches of either brick or lime concrete supported on lower flange of r s j s.