InTrans / Aug 14, 2018

Durability and detail design – The result of 15 years of systematic improvements

Most weather exposed wooden structures do not fail
due to structural errors but due to decay of essential
parts of the carrying system. To avoid further
substitution by concrete and steel, wooden
structures must be built for a service life of 25-50
years. Chemical wood preservation being
increasingly criticized, it was necessary to rethink
environmentally less harmful possibilities. By
following old and proven design principles, a
number of essential constructive details were
developed and tested. Service life of exposed
wooden structures can be comparable to other
building materials. With a minimum of maintenance,
there is no quick failure mechanism to
destroy a covered bridge. As wood reacts quickly to
adverse influences, shorter maintenance intervals are
recommended for exposed wood structures to keep
repairs, if needed, easy and cheap – a feature
substitute materials cannot offer. The quintessence
of fifteen years of supervision of pilot structures is
being presented to enhance the awareness of
designers as well as craftsmen for the importance of
proper detail design for the durability.