Parametric study of radial hanger patterns for network arch timber bridges with a light deck on transverse crossbeams

This paper studies network arch timber bridges. The network patterns considered in the paper are suitable for bridges with a light deck on evenly spaced transverse crossbeams. Therefore, the equidistant distribution of hangers fastening points along the deck is assumed. In bridges made of steel and concrete, hangers are usually equally distributed along the arch. In presented cases, hangers distribution along the arch results from values of parameters like: a number of hangers, an arch rise, a bridge span and hangers inclination. This paper introduces a new network pattern as a modification of a radial pattern. The presented analyzes were performed as a parametric study of variable geometric parameters, on a vast set of 2D FEM models of the network arch with modified radial pattern. The focus was on bending moment distribution on the arch, as it is highly sensitive to even small changes in hanger arrangement. In addition, as a light deck may increase hanger relaxation, the number of relaxed hangers was also analyzed. Values of bending moments were obtained from static analyzes of different load cases, with symmetrical and unsymmetrical load applied on the deck. The results indicate, that introduced radial network pattern modification can improve the performance of the network arch.