Inverted T-bar
An inverted T- bar consists of a plate on which bars or webs are placed in a shear-proof manner. Thus, in contrast to the T-beam , in which the webs are arranged under the plate, these are above. The inverted T-beams are used for high wall constructions where earth and / or water pressure has to be absorbed.
Load-bearing behavior
The inverted T-beam should transfer the load on the supports with larger spans . The bending in the cross section caused by the load generates tensile and compressive forces. Since the permissible tensile and compressive stresses are very different in fiber-reinforced concrete , the area that the tensile or compressive cross-section is used is assigned to the bending moment , consisting of compressive and tensile force, that occurs during bending. Therefore, the pressure cross-section is much smaller (web area) than the tension cross-section (plate). The thickness of the plate depends on the thickness of the tensile area, which is normally half the cross-sectional height of the total cross-section.
Rating
The dimensioning takes place with an uncracked cross-section (state 1). Therefore, with pure bending, the web width to the effective plate width is in the same ratio as the permissible compressive stress to the permissible bending tensile stress. These two values depend on the strength of the concrete and the type of fiber and dosage . Once the fiber-reinforced concrete strength has been determined, the relevant slab width can easily be determined and the dimensioning carried out in state 1.
literature
- Bernhard Wietek : Steel fiber concrete: Basics and practical application. 2nd edition, Vieweg + Teubner, Wiesbaden 2010, ISBN 978-3-8348-0872-1 .