Civil Engineering Reference
In-Depth Information
by stave churches, and creates enormous airy timber structures from specially-grown tim-
ber, held together by wooden plugs.
The rendered wattle wall really started to develop when masonry walls were
enforced by law. After a series of town fires during the seventeenth century, rendered
wattle walls were almost the only alternative to brick and stone. At the end of the eigh-
teenth century massive vertical load-bearing timbers were introduced as an alternative
to log construction in Scandinavia. This technique was developed because builders
wanted to be able to set up external panelling directly after the structure was ready,
rather than having to wait for the building to settle, as is necessary in log construction.
This structural technique disappeared around 1930. Log construction also started to
disappear around this time, and by 1950 it had almost totally disappeared. It has
enjoyed a sort of renaissance in the holiday cabin industry. In Scandinavia over the last
200 years the stave technique has been used mainly in outhouses. Immigrants in the
USA, however, had access to timber of large dimensions, and further developed the
stave technique for use in large storage buildings, barns etc., during the eighteenth
and nineteenth centuries.
To a certain extent modern post-lintel construction can be seen as a further develop-
ment of the stave technique. In Europe today, the main form of structural technique is the
timber frame building, and this has gone through many improvements and different
forms. There are also new methods in the structural timber industry: space frames and
laminated timber beams have opened many new possibilities. Through looking at the his-
tory of building in other cultures shell construction has also been developed in Western
culture.
Structural elements in timber
Materials in solid timber occur in different sizes, either as round logs or rectan-
gular sections. There is an obvious limitation depending upon the size of the tree
that is used, and this varies between different types of tree. Generally, the small-
er the size of the element, the more effective the use of the timber available. The
use of small timber sections from certain deciduous trees is important, as they are
not particularly large trees. To resolve the problem of the limitations of some
components, timber jointing can be used.
It is necessary to differentiate between timber jointing for increasing the length
or increasing the breadth or cross-section. Jointing for increasing the length can
be achieved with timber plugs, bolts, nails or glue. It is normal to use spliced
joints for sills, logs, columns or similar components where compressive strength
is more important than the tensile strength. Certain spliced joints, such as the
glued finger joint, have a good tensile strength.
Increasing the breadth can be achieved by using solid connections or I-beams.
Solid connections consist quite simply of the addition of smaller sized timbers
to each other. The fixing elements are bolts, nails or glue. Bolted joints are often
complemented by steel or timber dowels to stop any lateral movement between
the pieces of timber, as in Figures 13.29 and 13.30. Dowels and toothing were
