Reinforcement of Lattice Structures with Applications to Communication Towers Retrofiting

Abstract

The extensive use of wire-less communication demand structures to support the antennas. The most common types are self-supported towers or guyed towers, depending on various factors as the height, terrain availability, etc. Also, due to economical reasons, lattice towers are used in both typologies. The design of these structures is, in general, carried out following the standard codes and simplified models. Moreover, as a result of changes in design code requirements and the increasing demand of the communication industry, the retrofitting of existing steel lattice has become a common practice. Sometimes due to environmental reasons, new structures are not accepted and the new communication requirements must be satisfied by installing the antennas on existing towers (named co-localizations) that should be strengthened so as to meet increased loads. A reinforcing method used in practice in our country is through leg strengthening. A previous study addressed the behavior of reinforcing members in a one-panel reinforced single leg and a portion of the tower (legs and diagonals) under compressive load with small eccentricity. In the present work, the study is extended to lateral static and dynamic loads. The analysis is carried out with a standard finite element software and different configurations of the reinforcement connections are considered. The connections are made with bolts and fasteners and the effectiveness of the reinforcement is analyzed mainly through the force distributions between the existing leg and the reinforcing member. Also, the behavior of the joint is studied in detail through for two configurations. Finally, these results will be useful to design a physical experiment to be carried out in the future.