This paper presents a mechanical model which is used to analyse the sliding resistance at the cold joint of nearly quadratic basement walls. The analysis is done on a building with a height of 40m and a basement wall size of 4m x 4m. In the parameter study the axial force and the reinforcement ratios, at the boundary and in the web, are varied. Analysed are the resistances of aggregate interlock, dowel action and the shear resistance of the reinforcement which is under compression. The study shows that for a quadratic wall in most cases, failure due to sliding occurs before the maximum flexural deformation is reached. Thus the flexural ductility, e.g. in pushover analysis, is overestimated when the anchorage lengths of the structural wall is short. Therefore it is recommended for squat walls to take a previous sliding failure into account in a performance-based earthquake analysis.