Report No.: CCEER-05-8

Title: Performance of Steel Props at the UNR Fire Science Academy subjected to Repeated Fire

Authors: Lyle P. Carden, Ahmad M. Itani and Patrick Laplace

Date: July 2005

Sponsoring Agency: UNR Fire Science Academy

Performing Organization:
Department of Civil Engineering/258
University of Nevada, Reno
Reno, NV 89557


The University of Nevada, Reno Fire Science Academy located in Carlin, Nevada provides props for training of firefighters in a range of industrial fire scenarios. A structural evaluation of these props is described. Temperatures are monitored on two of the props, Tri-level and Pump Row using RTD sensors connected to a data acquisition system. Temperatures of up to 700 °F are measured in the steel of the structures, which is below the 900 °F temperature considered the maximum allowable temperature, but sufficient to induce large stresses in the structures. Differential temperatures, where one side of the member is heated by a greater amount than the opposite side of the member, result in the greatest stresses. These explain the large permanent curvatures observed in the columns in Pump Row. These columns should be straightened or replaced if the lateral offset exceeds 2.4 in. Measures to reduce the temperatures on these columns should also be implemented. The damaged truss members in the Truck Loading Rack prop should also be replaced. Welded connections are categorized into three categories; critical, necessary and redundant. Critical welds should be check regularly and repaired if cracking is observed. Where fatigue and cracking is regularly observed, the removal of redundant welds is recommended to reduce restraint forces in the connections. Based on this short term monitoring, no aspects of the structures are considered to present an immediate hazard to the safety of the users, however, several other recommendations are proposed to maintain the proper performance of the structures.