FLEXIBLE POLYMER CONNECTIONS FOR CLT STRUCTURES

This paper explores the possibility of using flexible polymer adhesives to dissipate energy in CLT buildings
during earthquakes. In the first series of tests, pull-off tests of various polyurethane (PUR) adhesives were performed.
The connection was tested in pull-pull configuration using monotonic, tension-only loading. The tests have shown that the
adhesive can resist large deformations already in tension loading and with small thicknesses of the bond-line. Based on
the pull-off test results, one adhesive has been selected for further testing. Monotonic lap-shear tests were performed with
the selected adhesive and thick bond-line (3 mm and 6 mm). The results show, that the standard method for lap-shear
testing (EN 205) needs to be adapted for thick glue-line. It was found that the strength of 3 mm glue-line is higher than 6
mm one, which is in agreement with adhesion theory. The flexible PUR adhesives could potentially be used in CLT
structures for anchoring the CLT wall with “flexible” glued-in rods or as a “flexible” vertical shear connection between the
CLT walls. Such systems have a potential to dissipate energy in seismic areas.