Load Transfer and Weight Analysis of Angular and Tubular Profile Towers in Transmission Lines for Large-Span Crossings

This research addresses the need to optimize the structural design of suspension towers by comparing conventional angle-profile towers (widely used in Colombia) with tubular-profile towers, which offer potential structural advantages but remain underutilized due to limited local experience and infrastructure. An advanced modeling methodology and guidelines were developed using industry-standard tools such as PLS-CADD and PLS-TOWER software; both of which are extensively validated in the transmission lines sector. The analysis complies with both national and international standards, including ASCE 10-15, ASCE 74, TIA-222,

-10 and RETIE.

The comparison was conducted under identical design conditions for both tower types: same geometry, span configuration, climatological parameters (wind and temperature), and load hypothesis (normal, construction and abnormal contingency scenarios). Foundation design and structural connection details were not included; however, correction factors were applied to account for non-modeled elements such as bolts, splice plates, and galvanization.

Results indicate that tubular-profile towers offer significant advantages over angular towers.

A substantial reduction of 38.69% in overall structural weight is achieved, leading to shorter construction times and reduced costs. Additionally, an improved load distribution is demonstrated at foundation (19.1% reduction in compression loads) and maintained adequate structural performance in relation to horizontal deflection under extreme loading conditions. An empirical equation is proposed to estimate tower weight as a function of structure height, validated against international data from similar projects, enabling early-stage feasibility assessments for transmission line projects.

Nonetheless, several challenges were identified for the local implementation of tubular towers in Colombia, including limited industrial manufacturing capacity, lack of standardized welding and connection methods, and limited domestic experience in the fabrication and erection of transmission tubular structures.

In conclusion, this study provides a valuable technical foundation and guidelines for evaluating structural alternatives during the conceptual and basic engineering stages of highvoltage transmission line design. Tubular towers are proposed as a viable option for largespan applications, offering structural efficiency and reduced weight and foundation loads.