CAD-supported preliminary column force calculations in multi-storey buildings

[摘要] The predominately manual, time-consuming and error-prone procedure currentlyused in engineering offices for the calculation of preliminary column forcesin multi-storey buildings constitutes the motive for the research described in thisstudy. Identifying the current procedure as in need of improvement, techniquesand prototype software posing a semi-automated alternative, are developed.Influence areas used for load-assignment are established with the use of aVoronoi diagram calculated for a specific floor geometry. The forces transferredto the columns are based solely on the size of the influence areas thus calculated.The definition of the floor geometry, as well as the definition of loads andother necessary input parameters, are performed in a CAD-system, into whichthe Voronoi functionality is integrated.The accuracy of the forces obtained with the implemented procedure and,consequently, the accuracy of the forces as they are calculated in current practice,is determined through comparison with the results of finite element analyses.The comparative analysis of a sample of typical floor geometries allows anevaluation of the results and the identification of tendencies observed regardingthe errors obtained.It is concluded that calculating column forces based on influence areas, i.e.solving a geometrical problem without taking any stiffness properties into account,is unsafe. The implication hereof is twofold. Firstly, it serves as a warningconcerning the technique currently used in practice and secondly, it steers the investigationin the direction of a finite element analysis: using the influence areasas a basis for automatic meshing, a semi-automated analysis can be performedrelatively inexpensively, using plate elements.

[发布机构] Stellenbosch University