Shape finding of incomplete cable-strut assemblies containing slack and prestressed elements

This paper concerns the problem of shape finding of cable-strut assemblies which could be incomplete with missing or slack cables, and consist of cables with lengths greater than their eventual assembled lengths. The work was motivated by the analysis for erection simulation of a ring cable strut tensile structure, typical of the class of structures called cable domes. The principal difficulty is that structural assembly is geometrically unstable due to lack of self-stress and insufficiency of elements during construction. A new shape finding method for the solution of this special problem, based on the principle of the force density method, is developed. Two illustrative examples are provided to show the accuracy and validity of this method, and a whole simulation of the erection process for a real cable-strut structure is carried out successfully. Some discussions are also provided to benefit the understanding to this type of shape finding problems.