Role of a Fireboards in Enhancing the Fire Performance of Glued-Laminated Timber Columns

High-rise timber buildings have emerged as a sustainable solution to reduce carbon emissions in the construction sector, offering advantages over multistory steel and concrete structures. However, concerns regarding the structural performance of these buildings during fire remain. Thus, to enhance fire resistance, timber elements are encapsulated in noncombustible materials. This study examines (i) the charring behavior of glued-laminated timber (GLT) columns made from three commonly used wood species in Korea (red pine, cedar, and larch) and (ii) the effect of fireboard types (gypsum, MgO, and CRC boards) on fire performance. Fire tests were conducted on unloaded GLT columns under ISO 834 standard fire conditions. The results include the temperature profiles and charring rates for both protected and unprotected columns, revealing that higher-density GLT columns exhibit reduced charring rates and greater fire resistance. Overall, encapsulation significantly delayed the onset of charring, highlighting its effectiveness in enhancing fire performance.