Construction Systems

 

Date of this Version

5-2012

Comments

A DISSERTATION Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Doctor of Philosophy, Major: Engineering, Under the Supervision of Professors George Morcous and Maher K. Tadros. Lincoln, Nebraska: May, 2012

Copyright (c) 2012 Eliya E. A. Henin

Abstract

Precast floor systems provide a rapidly constructed solution to multi-story buildings that is economical, high quality, fire-resistant, and with excellent deflection and vibration characteristics. Conventional precast concrete floor system cannot compete with cast-in-place post tensioning flat slab floor systems when high span-to-depth ratio and flat soffit are required. This is due to the significant depth of standard precast beams, and use of column corbels and beam ledges. This research presents the development of a new precast concrete floor system that eliminates the limitations of conventional precast floor system and provides a competitive precast alternative to cast-in-place flat slab floor systems. The main features of the proposed system are: span-to-depth ratio of 30, and flat soffit (no ledges or corbels), and adequate resistance to lateral loads, in addition to economy, consistency with prevailing erection techniques, and speed of construction. The new system is a total precast concrete floor system that consists of continuous columns, prestressed rectangular beams, prestressed hollow-core planks, and cast-in-place composite topping. Fully insulated precast sandwich panels that are alternative to hollow-core planks are also proposed for thermally efficient floor applications. These panels can be easily produced, as they do not require specialized equipment for fabrication, in addition to having comparative weight and capacity to hollow cores.

The dissertation presents the main concepts adopted in the system development as well as the design procedures and construction sequence. Also, full-scale specimens have been erected and tested at the structural laboratory to ensure the structural performance of the proposed system and validated the results of the analytical models.

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