after the specified curing period without disturbing the forms under the soffits of beams and girders. You should never permit the removal of soffit forms and supports and reshoring in advance of the time specified. Furthermore, make certain that all forms are accurately and adequately constructed, are adjusted to exact grade, are lined with absorptive lining if specified, and are oiled or otherwise treated as indicated. Take special care to secure clean, true surfaces with straight edges and uniform chamfer strips if the underside of the structural floor will be exposed in the finished work. You must check the work to make sure that all inserts, hangers, anchors, sleeves, and other fittings are provided as required and are accurately located.
You must be sure that curing is performed as shown in the project specifications and that forms and form supports are left in place for the minimum length of time specified for slabs, beam and girder sides, and beam and girder soffits. In addition, you must note particularly concrete that may have been frozen and report the circumstances and conditions to the proper authority.
Concrete framing of buildings generally consists of columns, girders, beams, and slabs. Slab construction consists of columns, capitals, plinths, and slabs with girders and beams used only to frame around openings and to support spandrel walls (area of wall between the header of one window and the sill of the window above). On building construction, you must be sure that all wall ties, anchors, inserts, and other appliances for fastening are installed in the forms in the exact locations needed and that all the openings for pipes, ducts, vents, and other purposes are formed in the correct locations. A thorough check must be made before permission is given to start concreting. This action ensures that no item has been overlooked.
On building work, pay special attention to the accuracy of alignment, the trueness of exposed surfaces, and the finish. You must ensure that full compensation is made for the change of floor levels caused by the shrinkage of columns. You must give close attention to the location of construction joints and expansion joints, if required. You must make sure that slab forms are kept in position for the full period specified, that forms under beam and girder soffits are kept in place for the additional period required, and that all concrete is cured in the proper manner for the full period prescribed.
Concrete masonry units (CMUs) are made with stone, gravel, shale, slag, or cinders as the coarse aggregate. Units usually are made with nominal widths of 3, 4, 6, 8, 10, or 12 inches. Walls and webs usually are 2 inches in nominal thickness, but actual thicknesses may run one-fourth to three-eighths inch less. Units are made with 2, 3, 4, and 6 cores. They are also manufactured in half units and in special units, such as jamb blocks, end blocks, headers, and double-corner units.
In construction involving the use of concrete block, check all material for damage, imperfections, stains, color, size, and marking and make certain that only material conforming fully with the requirements is used in the work. You should also verify the course heights, bond, color pattern, and similar basic requirements.
You must make sure that all masonry units are handled carefully at all stages of the work to prevent damage and see to it that scaffolds and floors are not overloaded by stacking them too heavily.
You must determine that joints conform to the specifications in materials, type, pointing, and finish. To assure sound watertight construction, you must ensure that joints are:
Completely filled for their entire length and depth and are free of voids.
Correctly struck without excessive troweling and that the horizontal joints are truly level and that the vertical joints are broken, staggered, or patterned as specified or shown.
When inspecting, you must determine that all joints are tooled to the specified form, if indicated. Where pointing is specified, you must ensure that the mortar joints are raked out to the specified depth, saturated with clean water, refilled solidly with mortar, and tooled. You should also require that all surplus mortar and stains be removed as the work progresses. You should ensure that horizontal or bed joints are finished first and then the vertical joints.
In addition, make sure that the exposed surfaces of masonry units are washed with water and brushed with a stiff brush until all mortar stains have been removed. A weak solution of muriatic acid may be used for stubborn stains, but care should be exercised to require thorough flushing with clean water. Finished terra cotta facing should be cleaned with a stiff brush, using soap powder boiled in water. The brushing should beContinue Reading