Maraveas, C.

Swailes, T.

Wang, Y.C.

English

Masonry jack arches are commonly encountered in fire proof flooring systems constructed during the 19th century in Britain and central Europe. Masonry arches provide insulation to the steel girders and the load bearing elements. Because brick and mortar types/classes varied considerably in such historical construction, determining the thermal and mechanical properties of masonry at elevated temperatures is a difficult task. This paper presents the results of a research to resolve the difficulties to researchers when analysing such structures under fire conditions. Firstly, this paper will present collated experimental data reported in the literature for the variations of the thermal (thermal conductivity and specific heat) and mechanical (compressive strength and thermal expansion) properties of burnt clay masonry units and mortars at elevated temperatures. Lower and upper bound temperature dependent curves will be proposed to account for the variability of the material properties based on the collected data. This makes use of the boundary curves of the constituent materials according to expressions found in current design codes (for determination of the compressive strength), the rules of mechanics (applicable for calculating the thermal expansion) or the laws of physics (i.e. the additivity theorem for determining the specific heat of solid multi-component systems). Finally, the boundary curves are used in a series of sensitivity studies to examine the influences of these variations on the fire resistance time of the flooring systems. Results from this sensitivity study will show that even though the thermal and mechanical properties of masonry at elevated temperatures change considerably, with the exception of one case, the variability has little effect on the calculated fire resistance time. As a general rule, the elevated temperature properties of modern brick, given in literature for a similar density, can be used to approximately (but with sufficient accuracy) model masonry in elevated temperature analysis of 19th century jack-arch flooring systems

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The University of Manchester ResearchSensitivity of fire resistance of 19th century fireproofflooring systems to thermal and mechanical properties ofmasonryLink to publication record in Manchester Research ExplorerCitation for published version (APA):Maraveas, C., Swailes, T., & Wang, Y. C. (2014). Sensitivity of fire resistance of 19th century fireproof flooringsystems to thermal and mechanical properties of masonry. In host publication (pp. 475-481)Published in:host publicationCiting this paperPlease note that where the full-text provided on Manchester Research Explorer is the Author Accepted Manuscriptor Proof version this may differ from the final Published version. If citing, it is advised that you check and use thepublisher's definitive version.General rightsCopyright and moral rights for the publications made accessible in the Research Explorer are retained by theauthors and/or other copyright owners and it is a condition of accessing publications that users recognise andabide by the legal requirements associated with these rights.Takedown policyIf you believe that this document breaches copyright please refer to the University of Manchester’s TakedownProcedures [http://man.ac.uk/04Y6Bo] or contact uml.scholarlycommunications@manchester.ac.uk providingrelevant details, so we can investigate your claim.Download date:21. Oct. 2022475Proceedings of the 2nd International Conference on Protection of Historical ConstructionsBoğaziçi University Publishing, Istanbul, 2014, ISBN 978-975-518-361-9F. M. Mazzolani, G. Altay (Eds)476477478479480481

Sensitivity of fire resistance of 19th century fireproof flooring systems to thermal and mechanical properties of masonry

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Sensitivity of fire resistance of 19th century fireproof flooring systems to thermal and mechanical properties of masonry

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