Cable Stayed Portals

Cable stayed structure in general is a structure in which high strength cables are used to provide intermediate support to the structure. Portal frames are the two dimensional rigid frames that have the basic characteristics of a rigid joint between column and beam. The main objective of this form of design is to reduce bending moment in beam which allows the frame to act as one structural unit. An attempt to use the principle of cable staying in building construction is the essence of the present work. The beam in the portal frame are supported at intermediate points by cables, which resulted in strengthening the beam. The load carrying capacity of the beam is increased for the same cross-section or the depth of the beam can be reduce for carrying the same load which resulted in overall economy of the structure. In present study the bent up bars of tensile reinforcement are taken out from beam and anchored in column which serves the purpose of cable stay on both side of beam. The analysis for single storey two bay portal, with and without cable stay, are carried out and deflection, bending moment formulae for cable stayed portal are presented. It is observed that there is a considerable reduction in deflection bending moment in cable stayed portal as compared to simple portal. Thus, the load carrying capacity of cable stayed portal increases considerably as compared to simple portal and hence for the same span and loading the cable stayed portal is ecomical than the simple portal.