Experiments on deformation measurements of "Helsinki Design Week 2005" Info Pavilion

The ”Helsinki Design Week” info pavilion is an example of a challenging mass customisation based industrial construction planned with CAD techniques. The final pavilion was modelled using both close-range photogrammetric methods and terrestrial laser scanning. The as-built model was compared to the design model revealing the maximum difference of 0.035 m. Two load tests (20 and 100 kg) were arranged to simulate low and moderate snow loads on a roof structure and to arrange two different loads versus deformation cases for measurements. Both modelling methods yielded similar result indicating that the 20 kg load did not cause significant deformations to the pavilion. In the case of 100 kg load, the rim arcs kept their shapes well, but some deformations was found from the shell structures. The results from photogrammetry and laser scanning were compared and both methods had some advantages and disadvantages. The strength of photogrammetry was more accurate alignment when corners were measured and the strength of the laser scanning was the more complete surface model. In our case, the photogrammetric models were measured from free-network image blocks. One model appeared to have some distortion along the z-axes. The disadvantages with laser data included difficulties to measure accurate corner points and the strong deformation of reference spheres in moist conditions.