Fire resistance of RC columns with regard to spalling of concrete

Bajc, Urška (author), Kolšek Češarek, Jerneja (author), Planinc, Igor (author), Bratina, Sebastjan (author)

At date a common agreement seems to be established among researchers that for a proper prediction of fire-induced concrete spalling on structural fire resistance a fully-coupled thermo-hygro-mechanical model should be used in general. Such sophisticated models may engage complex systems of equations. For everyday practical applications, however, the accompanying computational procedures may be found to time-consuming. Proper input material data such as permeability tensor and diffusion coefficients may be found difficult to define as well, especially for modern special-type concretes. Thus, simplified procedures for rough assessments of spalling are still desirable. For reinforced concrete (RC) columns, one of such is proposed here. The model combines two essential analyses, i.e. a hydro-thermal and a mechanical analysis, and runs them separately but simultaneously. For rough estimation of spalling different semi-empirical criteria are used. They consider concrete pore pressure, velocity of spalled-off pieces and buckling length of delaminated concrete. The proposed model is validated against experimental data and shows promising results. In the final part of the paper, the model is implemented in an investigation of the effects of different spalling scenarios on a fire-engulfed column. This shows that spalling may reduce its ultimate fire resistance as much as by 70%.

• Language: English
• Keywords: RC column, fire, spalling, simplified procedure, buckling
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FGG - Faculty of Civil and Geodetic Engineering
• Publication status: Published
• Publication version: Version of Record
• Publication date: 01.06.2022
• Year: 2022
• Number of pages: 15 str.
• Numbering: Letn. 130
• PID: 20.500.12556/RUL-138588
• UDC: 624.012.45:624.075.2
• ISSN on article: 0379-7112
• DOI: 10.1016/j.firesaf.2022.103568
• COBISS.SI-ID: 113518851
• Publication date in RUL: 29.07.2022

Record is a part of a journal

• Title: Fire safety journal
• Shortened title: Fire saf. j.
• Publisher: Elsevier
• ISSN: 0379-7112
• COBISS.SI-ID: 25463040

Secondary language

• Language: Slovenian
• Keywords: AB steber, požar, luščenje, poenostavljena metoda, uklon

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0158
• Name: Gradbene konstrukcije in gradbena fizika

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0260
• Name: Mehanika konstrukcij