Research on damage quantitative evaluation of laminated bamboo lumber under realistic fire exposure

As a green and low-carbon building material, bamboo meets the sustainable development needs of the construction industry. However, there is still limited research on the fire resistance of bamboo, especially under realistic fire exposure. In this paper, the fire behavior of laminated bamboo lumber (LBL) under two types of realistic fires, the EN 1991–1–2 parametric fires and travelling fires, exposures was investigated, and the relationship between the energy equivalence of imported the LBL specimens and their fire damage equivalence under two types of realistic and standard fires was examined. The results show that if the energy transmitted into the LBL specimens is equivalent, the damage degree of the specimens is also equivalent, thus confirming the validity of the energy equivalence method (EEM) for the LBL, and realizing the transformation of the fire damage evaluation of realistic fires to the one of standard fires. On this basis, the fire performance of the LBL under standard fire was analyzed, and the values of charring rate and charring line temperature of the LBL were determined. Further, the temperature distribution model of pyrolysis region was established, and the calculation model of zero-strength layer (ZSL) thickness considering the fire exposure time, charring rate, fire condition and force condition was proposed. In this way, the quantitative assessment of the LBL damage using the effective cross-section method (ECSM) was realized, and the ECSM was effectively applied in the fire-resistant design of bamboo structures. This study can provide a theoretical basis for the fire-resistant design of bamboo structures, which can help to improve the fire safety of bamboo structures.