After exhausting all principles of construction applied to day it becomes evident that the realisation of wide span structures is far more limited by the necessity to avoid undue deformations than by insufficient material strength. In research for potentialities to overcome these limits unconventional methods of dealing with forced deformations are analysed in the field of improved subsidence and earthquake resistance. In further developing those methods designs are presented to control deformations independent of the actual stress situation by the application of self adjusting hydraulic gears. Reflections on the margin of safety conclude the paper. Resume En exploitant tous les possibilites des procedes de construction actueIle- ment connus, la realisation de constructions a grande portee n'est pas teIle- ment limitee par la resistance des materiaux mains plut8t par la necessite de garder les deformations dans des limites restreintes. Dans le but de la recherche de moyens techniques permettants d'exclure ou de rendre inoffen- sif les deformations non souhairees, de procedes speciaux de protection des constructions contre les mouvements dynamiques du sol dus aux phenomenes miniers ou aux tremblements de terre sont presentes et analyses.