美国钢结构设计手册 FABRICATION AND ERECTION.pdf

SECTION 2 FABRICATION AND ERECTION Thomas Schflaly* Director, Fabricating Standards American Institute of Steel Construction, Inc., Chicago, Illinois Designers of steel-framed structures should be familiar not only with strength and service- ability requirements for the structures but also with fabrication and erection methods. These may determine whether a design is practical and cost-efficient. Furthermore, load capacity and stability of a structure may depend on design assumptions made as to type and magnitude of stresses and strains induced during fabrication and erection. 2.1 SHOP DETAIL DRAWINGS Bidding a structural fabrication project demands review of project requirements and assembly of costs. A take-off is made listing each piece of material and an estimate of the connection material that will be attached to it. An estimate of the labor to fabricate each piece is made. The list is sorted, evaluated, and an estimate of the material cost is calculated. The project estimate is the sum of material, fabrication labor, drafting, inbound and outbound freight, purchased parts, and erection. There are many issues to consider in estimating and purchasing material. Every section available is not produced by every mill. Individual sections can be purchased from service centers but at a premium price. Steel producers (mills) sell sections in bundle quantities that vary by size. A bundle may include five lighter weight W18 shapes or one heavy W14. Material is available in cut lengths but some suppliers ship in