مرکز منطقه ای اطلاع رساني علوم و فناوري -

چكيده لاتين :

The strut-and-tie method can be used for the design of Disturbed regions (D-regions) of structures where the basic assumption of flexure theory, namely plane sections remaining plane before and after bending, does not hold true. Such regions occur near statical discontinuities arising from concentrated forces or reactions and near geometric discontinuities, such as abrupt changes in cross section etc. The strut-and-tie method of design is based on the assumption that the D-regions in concrete structures can be analysed and designed using hypothetical pin-jointed trusses consisting of struts and ties interconnected at nodes. Continuous deep beams occur as transfer girders in multi-storey frames, as pile caps and as foundation wall structures etc. The usual design practice for continuous deep beams has been to employ empirical equations, which are invariably based on simple span deep beam tests. Given the unique behavioural pattern of continuous deep beams, this practice is unrealiable. Since continuous deep beams contain significant extents of Dregions and they exhibit a marked truss or tied arch action, the strut-and-tie method offers a rational basis for the analysis and design of such beams. The mechanics and behavior of continuous deep beams are briefly discussed from which a strut-and-tie model for such a beam is developed. A complete example on the analysis and design of a continuous deep beam using the strut-and-tie method is presented. The design has been carried out using the recommendations of the ACI Code 318-02.