DOI

10.5703/1288284313315

Report Number

FHWA/IN/JTRP-2003/05

Abstract

Design methods for the shear resistance of reinforced and prestressed concrete beams are based on empirical evidence. Due to different approaches in their development different equations are used to calculate the shear strength of reinforced and prestressed concrete. Recent research conducted by Tureyen has proposed a simplified shear model for reinforced concrete which is primarily based upon mechanics and corresponds well with a wide range of test results. The objective of this research was to determine the applicability of the shear model to prestressed concrete. The applicability of the shear model was evaluated by a comparison of its results with the results of a database of 84 specimens which failed in shear. This analysis indicated that the shear model is applicable to prestressed sections. The shear model was simplified to develop an equation which is suitable for design office use. This equation is consistent with that proposed by Tureyen for reinforced concrete and unifies the design of these sections. As most prestressed sections designed are either T or I in shape, the research also investigates the use of the simplified design equation for these sections. Based on a comparison with test results, it is shown that the simplified design equation works well and provides a consistent factor of safety. A design example is presented to illustrate the differences between the proposed design equation and the current ACI 318 and AASHTO 16th Edition provisions. Differences resulting from the different design methods are highlighted and discussed. As the proposed design equation requires calculation of the neutral axis depth, a simple hand-calculation procedure is also developed to approximate this value for prestressed sections. Finally, recommendations are provided for the proper implementation of the proposed method in design practice.

Keywords

prestressed concrete, reinforced concrete, shear, shear strength structural concrete, SPR-2798

SPR Number

2798

Project Number

C-36-58EE

File Number

5-13-5

Performing Organization

Joint Transportation Research Program

Publisher Place

West Lafayette, IN

Date of this Version

2003