The unique
telecommunication tower, over 110 m high, was built in 1933 as a spatial truss completely from
larch
wood. All connections were made with brass bolts. During 65 years of
continuous service the tower was examined and protected several times but there
were also long periods without proper maintenance. In 1998 the structure was
carefully inspected, measured and checked by calculations. Imperfections in
geometry of truss joints as well as damages in wooden members have been recorded.
On the basis of tests of material specimens and computer analyses the range of
necessary
strengthening has been assumed. The tower was old enough to be
treated as a monument of technology, so, the methods of repair, strengthening
and protection were limited. The specific method of strengthening by means of
carbon fibre polymer strips was introduced in the most endangered members of
the structure. General protection works have been used for the entire tower.