详情

原文传递 Shallow precast concrete floor without beam ledges or column corbels

题名：	Shallow precast concrete floor without beam ledges or column corbels
正文语种：	英文
作者：	George Morcous; Eliya Henin; Maher K. Tadros
关键词：	Beam ledge; column corbel; hollow-core; shallow floor system
摘要：	The use of shallow floor systems in office buildings is desirable because it reduces the overall building height and saves on the cost of architectural, mechanical, and electrical building systems. Precast, prestressed concrete floors consisting of hollow-core slabs on inverted-tee beams are known for their superior quality and speed of construction. However, when the depth of the hollow-core slab, inverted-tee beam ledge, and column corbel are added, the total floor depth becomes significantly larger than that of cast-in-place, post-tensioned slabs. This paper presents a system by which the hollow-core slabs are framed next to the beam rather than on top of a ledge, and the beams are framed into the column without the aid of a permanent concrete corbel. For the development of the system, a 30 by 30 ft (9.1 by 9.1 m) bay size is considered typical for office floors. Hollow-core slabs that are 8 in. (203 mm) deep are supported on 10 in. (254 mm) deep beams using a new beam–hollow-core connection that is designed using shear-friction theory. Methods of temporary support until the composite topping is cured are presented. Full-scale testing confirmed satisfactory performance. A beam–column connection is also developed using column recesses at the beam location and reinforcing bars through a void in the column to allow the beam to be continuous and its reaction to be resisted by the column without the conventional corbel. A temporary steel angle support is used until the connection grout is hardened. Full-scale testing of the beam–column connection showed excellent behavior. The main advantages of this shallow floor system are its high span-to-depth ratio (up to 30) and its efficient and economical production and erection techniques. Some of the features of the developed system were implemented in a four-story office building in Lincoln, Neb. Experience with this application is also discussed.
出版年：	2019
期刊名称：	PCI-Prestressed Concrete Institute Journal
期：	4
页码：	41-54