Work

Computational analysis of wildland fire resistance for transmission line tower

Year: 2024

Type: article

Abstract: Finite element (FE) analysis of the transmission towers under a fire event and the accompanying wind is presented. Several key aspects (including temperature-dependent non-linear material properties, geometric non-linearity, member eccentricity due to the single-leg bolted connection, and the temperature-dependent connection behaviour in both the axial and the rotational directions) are considered. A quasi-static analysis is also employed in the FE model using the explicit solver available in Abaqus. The member temperature variation during a realistic fire event is derived analytically based on the fire intensity and the resultant vertical gas temperature distribution so that the effect of the realistic wildland fire can be input as a member temperature profile. First, fire design guidance in terms of the most critical heating and wind pattern, as well as the effect of fire-affected heights are provided based on the case study results. Then, further fire analysis is carried out to investigate the most critical fire scenario and to evaluate the vulnerability of the tower during a realistic fire event. Lastly, an evaluation of a commonly used spray-on thermal insulation and its effectiveness in reducing the member temperature and preserving ultimate strength during a catastrophic wildland fire event are presented. The FE simulations revealed that a 45-degree wind associated with partial side heating leads to a more critical degradation of the overall strength, whereas the effect of fire height is less obvious. In terms of the fire scenario, a longer fire duration associated with a slower wind is more critical for the fire resistance/rating. • Establish a nonlinear FE model for wildfire analysis of transmission tower. • Incorporate axial & rotational connection semi-rigidity to capture realistic behaviour. • Study effect of fire-affected sides, heights, different scenarios on tower behaviour. • Predicting overall strength reduction patterns/factors due to elevated temperature. • Evaluate effect of spray-on insulation to improve tower resistance against wildfire.

Source: Journal of Constructional Steel Research

DOI: 10.1016/j.jcsr.2024.109097

Authors: Chang Chen, Hamid R. Valipour, Mark A. Bradford, Xinpei Liu, Donghong Zhang

Institutions: UNSW Sydney, China Energy Engineering Group Guangdong Electric Power Design Institute Co., Ltd. (China)

Language: English

Topic: Fire effects on concrete materials

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $4,180

Funder: Australian Research Council