Development in stress-Laminated Timber Arch Bridges

For over 3 years the authors have been involved in optimization of the performance of stress-laminated timber (SLT) structures by utilising the strength properties of timber in an arching action for use as vehicle and pedestrian bridges. During this time over 20 permanent bridges have been built and 8 have been load tested. The tested bridges were a half-scale of a 12m span bridge (i.e6m span) and a full-scale bridge of 15m span. Laboratory tests have also been carries out on a series of third-scale half – scale models with 3 different arch profiles and with 2 flat decks to study the interactions of friction and arching profiles with different pre-stressing tensions. The research has shown that the design rules for flat SLT decks do not necessarily apply to arches. Furthermore, a study of the structural behaviour of a full-scale 20m long span SLT arch structure has been carried out at Napier University, and the static and dynamic responses to vandal loading has been examined and evaluated. The extensive testing programme, augmented by analysis work aims to develop reliable design procedures.

Keywords:

Timber structures , bridges , design methods' load testing