Imre Kovács

Facsapos kapcsolatok kísérleti vizsgálata

A ttitude change is needed in design of timber struc tures. T russ girder made of timber elements wi th small cross sections can be used on large spans. Constructing struc tures with the use of these prefabricated trusses reduces the need of in-site work, and makes the use of ti mber struc tures econo mic. Rods of truss c an be connected with the use of hardwood stud. On this way all steel components can be eliminated from the truss, so it can be used in aggressive environment as well. Do wel type connec tion, with hard wood stud is the subject of the present research. Hardwood studs were investigated individually and also as the part of separated connections of the truss girder.

Structural performance of steel fibre reinforced concrete — Part III. Behaviour in tension

The present paper of a series deals with the experimental characterisation of tensile splitting strength and compressive behaviour of different structural concrete containing different volume of steel fibre reinforcement (0 V%, 0.5 V%, 1.0 V%, 75 kg/m3, 150 kg/m3) and different configuration of steel fibres (crimped, hooked-end). Tensile splitting tests were carried out on standard cylinder (∅ = 150 mm, l = 300 mm) specimens (so-called Brazilian test) considering random fibre orientation. Since the fibre orientation may significantly affect the tensile behaviour test series were also performed on cross-section (100 mm × 100 mm) of steel fibre reinforced concrete beams (100 mm × 100 mm × 240 mm) sawn out of steel fibre reinforced slab elements. Taken as a whole behaviour of steel fibre reinforced concrete was examined in tension taking into consideration different experimental parameters such as fibre content, type of fibres, fibre configuration, fibre orientation, size of specimens (size effect) and concr...

Structural performance of steel fibre reinforced concrete — Part IV. Toughness properties

The present paper of a series deals with the experimental characterisation of flexural toughness properties of structural concrete containing different volume of hooked-end steel fibre reinforcement (75 kg/m3, 150 kg/m3). Third-point flexural tests were carried out on steel fibre reinforced concrete beams having a cross-section of 80 mm × 85 mm with the span of 765 mm, hence the shear span to depth ratio was 3. Beams were sawn out of steel fibre reinforced slab elements (see Part I) in order to take into consideration the introduced privilege fibre orientation (I and II) and the position of the beam (Ba-a, Ba-b, Ba-c) before sawing (see Part I). Flexural toughness properties were determined considering different standard specifications, namely the method of the ASTM (American Standards for Testing Materials), the process of the JSCE (Japan Society of Civil Engineering), and the final proposal of Banthia and Trottier for the post cracking strength. Consequently, behaviour of steel fibre reinforced concrete...

Structural performance of steel fibre reinforced concrete — Part II. Compressive behaviour and stress-strain relationship

Abstract The present paper of a series deals with the experimental characterisation of compressive strength and compressive behaviour (stress-strain relationship) of different structural concrete containing different volume of steel fibre reinforcement (0 V%, 0.5V%, 1.0V%, 75 kg/m3, 150 kg/m3) and different configuration of steel fibres (crimped, hooked-end). Compressive tests were carried out on standard cube (150 mm × 150 mm × 150 mm) and cylinder (O = 150 mm, l = 300 mm) specimens considering random fibre orientation. Since the fibre orientation may significantly affect the compressive behaviour, test series were also performed on cylinders (O = 70 mm, l = 100 mm) drilled out of fibre reinforced concrete beams and prisms (100 mm × 100 mm × 240 mm) sawn out of steel fibre reinforced deep beams. Throughout the tests stress-strain relationships were registered on the standard cube and cylinder specimens as well. In conclusion, behaviour of steel fibre reinforced concrete was examined in compression taking...

STRUCTURAL PERFORMANCE OF STEEL FIBRE REINFORCED CONCRETE - PART I. OVERVIEW OF THE EXPERIMENTAL PROGRAM

Abstract The papers of the series deal with experimental characterisation of mechanical as well as structural properties of different steel fibre reinforced concretes that can be used for several structural applications. An extensive experimental programme (six years) has been developed to investigate the effect of steel fibre reinforcement on the mechanical performance and structural behaviour of concrete specimens. Specimens and test methods were selected to be able to detect realistic behaviour of the material, representing clear effect on the structural performance. Material compositions, test methods, type of test specimens will be detailed in the presented paper (Part I). Furthermore, compressive strength (Part II), stress-strain relationship (Part II), splitting strength (Part III) and toughness (Part IV) will also be discussed. In the light of the motivation to determine the structural performances of 1D concrete structural element affected by steel fibre reinforcement, bending and shear behaviour...