A column mounted shoring bracket has a support sub-assembly attached to a column or other supporting surface, a jack sub-assembly attached to the support and a head sub-assembly attached to a part of the jack that varies in height relative to the support. The head has a head base that supports one or more rollers for moving a form. The head also has a supporting plate for supporting the form. The supporting plate is connected to the head base so that it may be slid upwards and fixed in a position where the top of the supporting plate is above the top of the rollers, for example to carry the weight of a slab being built, or slid downwards so that the top of the supporting plate is below the top of the rollers which do not have to carry the weight of the slab being built. The angular position of the rollers may be aligned with an external reference such as the side of a column, a wall, or a jig. The bracket is adapted for use with parts of forms that may be made or assembled in or adjusted between a set of widths within a range that differ from each other by a selected increment. The forms include structures for spanning between shoring brackets or other supports that can be pre-cambered so as to have acceptable deflection when loaded.