Experimental and theoretical investigation of the shear resistance of steel fibre reinforced prestressed concrete X-beams—Part II: Theoretical analysis and comparison with experiments

This is the second part of two papers on the experimental (Part I) and theoretical (Part II) resistance of steel fibre reinforced precast concrete beams.High strength steel wire, and thin amorphous metal fibres have been introduced into prestressed concrete X beams in order to study their behaviour under shear loads. Experimental tests have determined shear strengths at the ultimate and cracking loads, and shown increased ductility with up to 2% fibre content. From these tests two different methods are proposed for predicting the ultimate shear capacity—these are the fibre supplement additive method, and the modified FRC principal tensile stress method. The principal tensile strength of the fibre reinforced concrete is given as a function of compressive strength and fibre volume. The means value of the ratio of the calculated to the test strength is 0.89 without partial safety factors, and, being conservative, is proposed for use in design. A calculation model is presented.RésuméCette partie est la deuxième de deux articles sur les expériences (part I) et la théorie (partie II) sur la résistance des poutres en béton préfabriqué renforcé de fibres d'acier.Des aciers à haute adhérence et de minces fibres métalliques amorphes ont été introduits dans des poutres X en béton précontraint pour étudier leur comportement sous l'action des efforts tranchants. Des essais expérimentaux ont déterminé la résistance ultime au cisaillement et les charges de fissuration, et ont montré une hausse de la ductilité avec un volume allant jusqu'à 2% de fibres. Sur la base de ces essais, deux méthodes différentes sont proposées pour la prédiction de la résistance ultime au cisaillement—la méthode des fibres supplémentaires additionnelles et la méthode de la contrainte de tension principale du béton de fibres d'acier. La résistance principale en tension du béton renforcé de fibres est donnée comme fonction de la résistance à la compression et du volume de fibres. La valeur moyenne du rapport entre la résistance calculée et celle donnée par les essais est de 0,89 sans facteur de majoration, et, étant conservatrice, elle est proposée comme méthode de calcul. Le modèle de calcul est présenté.

[1]  Perumalsamy N. Balaguru,et al.  Behavior of Partially Prestressed Beams Made with High Strength Fiber Reinforced Concrete , 1987 .

[2]  H. Stang,et al.  Evaluation of crack width in FRC with conventional reinforcement , 1992 .

[3]  S. L. Lee,et al.  Analytical Model for Tensile Behavior of Steel-Fiber Concrete , 1987 .

[4]  João Bento de Hanai,et al.  Shear behaviour of fiber reinforced concrete beams , 1997 .

[5]  P. Paramasivam,et al.  Shear Strength of Fibrous Concrete Beams Without Stirrups , 1986 .

[6]  D E Nemegeer,et al.  MEASURING TOUGHNESS CHARACTERISTICS OF SFRC--A CRITICAL VIEW OF ASTM C1018 , 1995 .

[7]  A W Beeby,et al.  CONCISE EUROCODE FOR THE DESIGN OF CONCRETE BUILDINGS. BASED ON BSI PUBLICATION DD ENV 1992-1-1: 1992. EUROCODE 2: DESIGN OF CONCRETE STRUCTURES. PART 1: GENERAL RULES AND RULES FOR BUILDINGS , 1993 .

[8]  R. Swamy,et al.  INFLUENCE OF FIBER REINFORCEMENT ON THE DOWEL RESISTANCE TO SHEAR , 1979 .

[9]  Lucie Vandewalle,et al.  Dramix guideline. Design of Concrete Structures - Steel wire fibre reinforced concrete structures with or without ordinary reinforcement , 1995 .

[10]  Sydney Furlan Jtinior.  Prestressed fiber reinforced concrete beams with reduced ratios of shear reinforcement , 1999 .

[11]  Sung-Woo Shin,et al.  Shear Behavior of Laboratory-Sized High-Strength Concrete Beams Reinforced With Bars and Steel Fibers , 1994, SP-142: Fiber Reinforced Concrete Developments and Innovations.

[12]  V. Li,et al.  Micromechanics of crack bridging in fibre-reinforced concrete , 1993 .

[13]  R. Narayanan,et al.  Shear in prestressed concrete beams containing steel fibres , 1987 .

[14]  K. Tan,et al.  Steel fibers as shear reinforcement in partially prestressed beams , 1995 .

[15]  N. Fattuhi.  Reinforced corbels made with plain and fibrous concretes , 1994 .

[16]  P. Rossi,et al.  CAN STEEL FIBERS REPLACE TRANSVERSE REINFORCEMENTS IN REINFORCED CONCRETE BEAMS , 1997 .

[17]  Samir A. Ashour,et al.  Shear Behavior of High-Strength Fiber Reinforced Concrete Beams , 1992 .

[18]  Hashim M. S. Abdul-Wahab,et al.  EFFECT OF SFRC ON SHEAR STRENGTH OF PRESTRESSED CONCRETE BEAMS , 2000 .

[19]  R. Narayanan,et al.  USE OF STEEL FIBERS AS SHEAR REINFORCEMENT , 1987 .

[20]  K. Paine.  Steel fibre reinforced concrete for prestressed hollow core slabs , 1998 .

[21]  James L Noland,et al.  Computer-Aided Structural Engineering (CASE) Project: Decision Logic Table Formulation of ACI (American Concrete Institute) 318-77 Building Code Requirements for Reinforced Concrete for Automated Constraint Processing. Volume 1. , 1986 .