The Steps in Constructing a Simple Platform Frame Building - Notes | CM 2121, Study notes of Introduction to Business Management

Download The Steps in Constructing a Simple Platform Frame Building - Notes | CM 2121 and more Study notes Introduction to Business Management in PDF only on Docsity! The Steps in the Construction of a Simple Platform Frame Building: 1) Positioning- Corners are staked and then batter boards are placed safely beyond the limits of the excavation area. A saw kerf or nail is placed on the batter boards in the plane of each wall so that strings may be stretched to define each plane after excavation is complete. A plump bob is used initially to align the marks on the batter boards with the stakes, later a plump bob is suspended again from the intersecting strings to locate the corners of the walls. 2) Excavation and Foundations-Anchor bolts are cast into the top of the foundation wall every 6’ to 8’. Two #6 steel bars are placed at the top and bottom of the foundation wall to prevent cracking of the concrete. A waterproof or damproof coating is applied to the outside of the concrete to prevent water penetration from the soil outside. A perimeter drain of perforated pipe in coarse crushed stone prevents groundwater from rising above the slab level. Soil is backfilled against the foundation only after the first floor framing is in place to help resist the lateral pressure of the soil. A slab on grade may be delayed until after structure is closed in. Interior steel pipe columns are placed before the floor slab is poured. After excavation, concrete footings are poured to spread the load of the building across the surface of the soil and to make a level surface in which the wall forms can be placed. A platform is built on top of the foundation. 3) Ground-Floor platform-Sill plates are anchored with anchor or expansion bolts to the foundation. Girders are placed. Floor joists are laid and toenailed to the sill. Subflooring is applied, sheathing is made of plywood or OSB and installed perpendicular to the floor joists. 4) Ground-Floor walls-Sections of wall are assembled lying down on the floor platform, and then are tilted into place, nailed to the floor and to one another, and supported by temporary braces. Wall sheathing may be applied before the walls are stood up, or later after the frame is fully erected. Bottom plates are nailed to the floor platform. The double top plate along the frame provides joist support for the second story joists and the upper plate overlaps the bottom plate to tie together adjacent sections of wall that were assembled and tilted up separately. Studs are continuous between top and bottom plates except at door and window openings. Adjustable, bowed “springboards” allow more precise alignment of walls. a. Window framing-Window header is supported by two supporting “jack studs” at either ends. The rough sill and head are also doubled. OSB sheathing is placed higher on the wall, and preservative-treated plywood below for greater protection from moisture damage due to the differences in finish and grade conditions on the exterior side. b. Shear wall framing-shear walls are put in to aid a building in protection from lateral forces. Steel strap seismic hold-downs cast into the concrete foundation will be nailed to the shear wall after the sheathing is applied. 5) Second-Floor platform-When the first floor walls are complete and sheathed, much of the temporary bracing can be removed. The second floor platform is framed the same as the first, with its joists resting on the double top plates of the first floor walls. At joist ends and intermediate bearing points, continuous rim joists or intermittent solid blocking close off joist spaces and brace the joists against tipping. Because of their relatively thin webs, I-joists may