Analysis and testing of a new prototype power transmission structure and an alternative design approach for longitudinal loads

摘要

As the power transmission infrastructure is expanded, structures that can be rapidly constructed and are cost efficient, reliable, and sustainable will be needed. A prototype power transmission structure designed to address the issue of cascading collapse, be efficiently constructed, and be easily repaired in the event of a catastrophic load such as a transmission line break was investigated. This structure utilizes post-tensioning and a joint to allow for large deflections. The specially designed joint isolates inelastic deformation to structural fuses that are inexpensive and easy to replace. The structure\u27s high deflection capacity could isolate damage from extreme loads to a few structures near the origin of the load and prevent a cascading collapse. A scale model was constructed and tested in the laboratory. The test procedure and structural behavior are discussed and compared to predictions from alternative methods of analysis. The prototype satisfied primary design objectives for behavior and could offer significant advantages relative to current design practice for power transmission structures. Currently, many resources exist to help designers accurately define and apply transverse loads to power transmission structures. However, there is less guidance available for longitudinal loads such as those applied by broken conductors. Current practice focuses on mitigating the effects of cascade events rather than stopping them altogether. An alternative approach for considering longitudinal loading is discussed that could prevent cascades through the use of the prototype structure that can sustain high loads while undergoing large longitudinal deflections. Such an approach could increase system reliability and security while reducing both initial and life-cycle costs of the power transmission infrastructure.