Abstract: A new method was proposed to reckon the nodal positions of an existing grid shell structure using surface interpolation, based on the structural characteristics of the high in-plane stiffness and overall capacity of load bearing. In the proposed method, the degree of structural deformation is estimated firstly by statistical analysis of nodal deviations. Then horizontal nodal coordinates are calculated by regression equations from statistic regression analysis theory. Lastly, vertical nodal coordinates can be determined by the structural shape and interpolation from the measured nodal positions according to surface interpolation theory. By applying the proposed method to the practical grid shell structures, it was concluded that the method can give realistic results and is effective for the assessment of existing structures.

Key words: existing grid shell structure, structural assessment, nodal position, reckoning, surface interpolation