Szafran Jacek, Juszczyk-Andraszyk Klaudia, Kaszubska Paulina
Department of Structural Mechanics, Faculty of Civil Engineering, Architecture and Environmental Engineering, Lodz University of Technology, Al. Politechniki 6, 90-924 Łódź, Poland.
Compact-Project.pl Company, Al. Politechniki 22/24, 90-924 Łódź, Poland.
Materials (Basel). 2025 Mar 11;18(6):1242. doi: 10.3390/ma18061242.
This paper presents an analysis of the effectiveness of the existing reinforcement of steel lattice tower legs made of L-sections by expanding to closely spaced built-up members. Due to the significant differences between the standard assumptions and the existing reinforcement, numerical analyses based on the component-based finite element method (CBFEM) were used to estimate the capacity of the existing structure's tower legs. Geometrically and materially nonlinear stress analysis and linear buckling analysis were performed. The obtained results (stress distribution maps, buckling forms, and corresponding critical forces) were used to modify the geometric parameters of the section of the analyzed tower legs in order to adapt the standard formulas in the calculation procedure. In the analyzed case, distance of the connections between the branches exceeded that indicated in EN 1993-1-1:2005 for the condition concerning the possibility of ignoring the deformation susceptibility in the calculation process. However, it did not result in the separate operation of each branch of the section. Thus, in the case of the analyzed reinforcement, it is possible to neglect the form susceptibility when calculating the buckling resistance of the element. The buckling capacity of the reinforced legs of the tower and the compression capacity of the section of the analyzed structure were calculated according to the method that took into account the results of the numerical analyses. These values are about 35-48% and 30-39% higher, respectively, than the capacity of the unreinforced angle calculated according to EN 1993-1-1:2005 and EN 1993-1-8:2006 standards. Thus, it may be possible to avoid costly and labor-intensive retrofitting of the existing reinforcement to meet the standard requirements. A key issue, and one that is particularly important in light of the lack of standard guidelines aimed at designing reinforcements for telecommunications structures, seems to be the performance of full-scale experimental tests.
本文分析了通过扩展为间距紧密的组合构件来加强由L形截面制成的钢格构式塔腿的现有加固措施的有效性。由于标准假设与现有加固措施之间存在显著差异，基于构件有限元法（CBFEM）的数值分析被用于估算现有结构塔腿的承载能力。进行了几何和材料非线性应力分析以及线性屈曲分析。所得结果（应力分布图、屈曲形式和相应的临界力）被用于修改所分析塔腿截面的几何参数，以便在计算过程中适配标准公式。在所分析的案例中，各分支之间的连接距离超过了EN 1993-1-1:2005中关于在计算过程中可忽略变形敏感性条件所规定的距离。然而，这并未导致截面各分支的单独作用。因此，在所分析的加固情况下，在计算构件的抗屈曲能力时可以忽略形式敏感性。根据考虑数值分析结果的方法计算了塔的加固腿的屈曲能力和所分析结构截面的抗压能力。这些值分别比根据EN 1993-1-1:2005和EN 1993-1-8:2006标准计算的未加固角钢的能力高出约35-48%和30-39%。因此，有可能避免为满足标准要求而对现有加固措施进行昂贵且费力的改造。一个关键问题，鉴于缺乏针对电信结构加固设计的标准指南，这一问题尤为重要，似乎是进行全尺寸试验测试。
