Load-bearing capacity of slender unreinforced masonry compression members under biaxial bending / Tragfähigkeit schlanker unbewehrter Mauerwerksdruckglieder unter schiefer Biegebeanspruchung

Dedicated to Prof. Dr.-Ing. Carl-Alexander Graubner on the occasion of his 60th birthday
Masonry members have to resist vertical loads and bending moments about the weak axis due to rotation of adjacent slabs. If the compression member is part of the bracing system, there are also bending moments about the strong axis. This paper deals with the load-bearing capacity of biaxially eccentrically compressed unreinforced compression members with rectangular cross-sections. For linear-elastic material, the principles of an analytical model is presented, which considers geometrical and physical (cracking) non-linearity. The deflections of the wall can be determined by using moment-curvature relations, making possible the analytical analysis of compression members considering the effects of 2nd order theory. For a non-linear stress-strain relation, the calculation of the load carrying capacity of rectangular compression members under biaxial bending is complex and has to be determined numerically. The good accordance of the results of the analytical model with the numeric calculations is also shown for various eccentricities. In addition, a simplified proposal for the calculation of the load-bearing capacity of biaxially eccentrically compressed unreinforced compression members is shown. The proposal is based on the load-bearing capacity of uniaxially eccentrically compressed unreinforced compression members. Therefore it is possible to use the proposal considering existing models, for example according to Eurocode 2 or 6.