Abstract
L-type flanges used for wind turbine towers need high bearing resistance when they install in storm
and earthquake active areas. Petersen, Seidel, and RISO/DNV introduced methods for evaluation of
L-type flange ultimate strength based on elastoplastic theory, however they didn’t consider the elastic
deformation of flange and caused underestimation of the load acting on bolts. VDI2330, Petersen, and
Seidel also showed the location of equivalent flange reaction force by using flange thickness direction
bending moment equilibrium, but these methods are complicated. An action point correction factor of
L-type flange is proposed to consider the effect of flange deformation and to expand the applicable range
of flange dimension. The results show good agreement with those by the formula of Seidel at the ultimate
condition by using load transmitting factor for L-type flange proposed in this paper.
