Accession Number:

ADA336038

Title:

Design and Performance Testing of Prestressed Precast Reinforced Concrete Hybrid Joists

Descriptive Note:

Final rept.

Corporate Author:

CONSTRUCTION ENGINEERING RESEARCH LAB (ARMY) CHAMPAIGN IL

Report Date:

1997-12-01

Pagination or Media Count:

121.0

Abstract:

This report describes an innovative design for prestressed precast reinforced concrete joists. The joist is a hybrid design that uses large web openings for passage of environmental pipes and ducts, replicating an advantage of steel truss construction. The design also exploits the stiffness and strength of precast concrete double-tee beams. Alternative designs were investigated by varying parameters such as concrete strength, prestressing strand layout, and reinforcement. Test results from eight hybrid joists are presented to substantiate finite element analysis results, and a simple method for designing the beams is presented. It is concluded that hybrid joist demonstrates remarkable performance and the capability to behave like a conventional double-tee beam. The behavior of the hybrid joist meets the requirements of ACI 318-95. Experimental failure loads were very high compared with design service and ultimate loads. The analytical and experimental results indicate that the hybrid joist has a predictable ductile response, and the experimental results verify that the analytical model provides a reliable and simple method for determining the load-deflection response. Vibration analysis showed that the hybrid joist has acceptable response to established criteria and compares well with the response of both concrete and steel bar joists.

Subject Categories:

  • Construction Equipment, Materials and Supplies

Distribution Statement:

APPROVED FOR PUBLIC RELEASE