Some structural design issues on a timber bridge for pedestrians

The use of wood in timber bridges is increased over the past 20 years, mainly since wood is a renewable and sustainable resource. Nevertheless wood is a natural engineering material that is prone to deterioration caused by fungi decay, insect attack and temperature. For wood and wooden bridges there is in fact a strong correlation between durability of the material and bearing capacity. Deformations in a timber structure are often a good indicator of the structural condition. Within this context, in this study some structural issues dealing with the design of a timber bridge for pedestrians are investigated. In a first step, the bridge shape is designed taking into account various aspects: timber as a bridge material; properties of structural wood products; rain systems for preservation and protection; wearing surfaces for timber decks in order to ensure durability; static and dynamic loads; static scheme. In a second step, the bridge shape is optimized by a procedure based on the calibration of natural modes of vibration.