Search Results for O on center A measurement of the distance between the centers of two repeating members in a structure. on grade A concrete floor slab resting directly on the ground. one-pipe system A heating circuit in which all the flow and return connections to the radiators come from the same pipe. The radiator at the far end is therefore much cooler than the radiator which is nearest the heat source. one-way slab A slab panel bound on its two long sides by beams and on its two short sides by girders. The dead and live loads acting on the slab area may be considered to be entirely supported in the short or transverse direction by the beams, hence, the term one-way. open excavation Excavation in which no shores, piles, or sheeting are used to hold back the soil at the edge of the excavation. open plan A building plan that has relatively few interior walls or partitions to subdivide areas for different uses. open roof (open-timbered roof) A style of roof with exposed rafters, sheathing, and supporting timbers visible from beneath and no ceilings. open web A form of construction on a truss or girder in which multiple members, arranged in zigzag or crisscross patterns, are used in place of solid plates to connect the chords or flanges. operable window A window that may be opened and shut to accommodate ventilation needs, as opposed to a fixed light or fixed sash. optimum moisture content The percentage or degree of moisture in soil at which the soil can be compacted to its greatest density. organic soil A highly compressible soil with heavy organic content, considered generally undesirable for construction because of its inability to bear sizable loads. out-of-plumb Deviating from a true vertical line of descent, as determined by a plumb line. out-of-true Description of a structural member that is twisted or otherwise out of alignment. outside studding plate The soleplate or double top plate in the construction of a wood-frame wall or partition, usually built with stock of a size equal to the studding. outside-air intake (fresh air intake, outdoor-air intake) An opening or inlet to the outside of a building, through which fresh air is introduced to the boiler room or to an air-conditioning system. overdesign A term used to describe adherence to structural design requirements beyond service demands, as a means of compensating for statistical variation, anticipated deficiencies, or both. overlay A layer of concrete or mortar, seldom thinner than 1" (25 millimeters), placed on and usually bonded to the worn or cracked surface of a concrete slab either to restore or to improve the function of the original surface. overlay flooring Finish flooring of maple, mahogany, oak, or other hardwood cut into narrow tongue-and-groove strips. ownerís representative The designated official representative of the owner (may be an architect, engineer, or contractor) to oversee a project. Search Again