Initial stress state at installation of a single-layer lattice dome due to errors of its assembly

Abstract

The paper presents the results of the numerical modeling of the assembly process of single-layer lattice domes with respect to random deviations in lengths of individual bars which was performed with a special purpose software SBORKA developed by the author. Modeling of the installation process of the dome frame was performed by sequential calculation of the coordinates of its nodes through simulation of the connection of individual bars in these nodes. The inaccuracies of the bar lengths used were random variables with a normal distribution law. Due to errors in the length of the bars, the actual geometric scheme of the dome frame is distorted in relation to the design scheme. To obtain objective data on such distortions, numerical computer modeling was performed repeatedly with statistical processing of the results obtained. The sequence of assembly of the dome frame was chosen such that the largest number of different types of rods were used. Distortions in the geometric scheme of a single-layer lattice dome do not allow its frame to be installed simultaneously on all support nodes. First, the dome frame is installed only on three support nodes, and then due to deformation under its own weight, the remaining support nodes are included in the work. This deformation of the dome frame leads to the appearance of initial stress state in the bars. In this research, computer static analysis of a single-layer lattice dome was performed for the action of the self-weight load of its frame. The analysis was made taking into account the sufficiency of the load to exhaust the existing gaps in the support nodes. Based on the results of these calculations, the initial stress state in the bars of the dome frame are obtained, which should be taken into account in the analysis and design of the structure.