Timber arch bridges with V-shaped hangers

Thearch is a very efficient load bearing structure, especially when itsshape is affine to the funicular of forces. However, if live loads are predominant as compared to permanent uniformly distributed gravity loads,the arch will be subjected to substantial bending moments, thus losing a great part of its structural efficiency. In traditional arch bridges with hangers arranged in a vertical manner, asymmetrical loads would cause a substantialdeviation of the pressure line from the axial line of the arch.In this paper,an innovative concept for timber arch bridges is introduced where V-shaped hangers, rather than vertical hangers, are used. The adoption of V-shapedhangers significantly contributesto the reduction of the eccentricity between the pressure line and the axial line of the arch, thus decreasing the magnitude of bending moments in the arch.The paper discussesthe advantages of using V-shaped hangers as an alternativetovertical hangers, both in terms ofstatics, in-plane stabilityand dynamic efficiency. Moreover, the design and the recent construction of a parabolic three-hinged archmade of timber, with a steel V-shaped hangeris thoroughly discussedin the pape

Topology optimisation of lattice telecommunication tower and performance-based design considering wind and ice loads

With increasing demand of infrastructure to support power transmission and telecommunication systems, the need of erecting more towers has also been rising significantly. For many years, these towers were designed by using a conservative approach and the opportunities lying in the design optimisation of the towers were not leveraged. This paper presents the application of structural topology optimisation to lattice self-supported telecommunication towers in developing an improved solution in terms of weight-to-stiffness ratio. 2D and 3D topology optimisation studies were performed with highly optimised bracing systems reducing the amount of steel material used, thus its carbon footprint. The new exoskeleton structure is representing a lattice tower composed of ‘high-waisted’ bracing type and elliptical hollow sections (EHS). Comparative modal analyses demonstrated the structural performance of the optimised tower models. In addition, a research-led design was carried out for optimising the geometric cross-sectional properties of the optimised lattice tower subjected to quasi-static analysis followed by regression analysis. The cross-sectional parameters were progressively changed; explicitly the diameter and thickness of the members. The performance-based analysis and design of a topologically optimised lattice tower present alternatives to onerous approaches such as wind tunnel testing or finite element modelling. The results were further analysed to understand their viability in different loading design cases and the effect of cross-sections. Conclusions highlighted the benefits gained by introducing the structural topology optimisation process in the design of slender support structures