NRC’s upgraded column furnace a unique research facility

Volume 17, Number 4, December 2012

Designers and manufacturers of columns and protection systems are benefitting from recent upgrades to NRC's column furnace. Researchers can now employ the unique research facility to test and advance cost-effective technologies for enhancing the safety of buildings and infrastructure.

The NRC facility is one of the largest column furnaces in the world and the only one in North America capable of testing a full-scale loaded column. The furnace can apply axial loads up to 9790 kN (2200 kips), lateral loads up to 110 kN (25 kips) in the north-south direction, and lateral loads up to 310 kN (70 kips) in the east-west direction, with or without fire loads. This means a column can be fire tested while loaded in the three main directions. While other facilities determine fire resistance using temperature failure criteria, the NRC furnace employs load failure criteria, which usually provide more realistic results.

The furnace upgrade consists of the installation of a new digital control system by which fire performance of a whole system can be simulated using a hybrid fire testing (HFT) method (see Construction Innovation, December 2011). This means that a column can be tested in the fire compartment while other structural aspects of the building can be simulated using a computer numerical analysis. Tests showed that the HFT could provide more cost-effective and realistic results than the traditional single element test approach, since the effects of the whole structure are considered by the HFT.

The HFT is an objective/performance-based method that is becoming recognized by building codes worldwide, including the National Building Code of Canada.

New projects

NRC researchers are now planning projects that will exploit the unique capabilities of the furnace. One potential use is to help owners, designers and code authorities to determine what happens when mid-to-highrise buildings in seismic zones are damaged by fire. There is a lack of knowledge on how to inspect these structures to assess the remaining level of seismic resistance.

Repair and retrofitting solutions also need to be developed to recover the deteriorated seismic resistance. The NRC furnace is capable of simulating such a fire scenario. It can then be used to assess the residual seismic resistance of the fire-damaged column. The same test process could be performed to evaluate the effect of seismic retrofitting materials on the damaged columns.

One of the new capabilities of the column furnace currently being explored is that of performing hydrocarbon fire testing. This would be required to evaluate the fire resistance of structural elements in refinery, offshore and transportation infrastructures.

The furnace has already been used to determine the fire resistance of more than 200 columns made of a wide variety of materials under various test conditions. In recent years a series of studies were carried out to investigate the fire resistance of strengthened structural concrete systems such as fibre reinforced polymer-strengthened concrete systems (Construction Technology Update No. 74). The future holds even greater promise, as new technologies are developed and new requirements for testing are identified.

For more information

Contact Hossein Mostafaei at hossein.mostafaei@nrc-cnrc.gc.ca or 613-993-9729.