TY - JOUR A1 - Covi, Patrick A1 - Tondini, Nicola A1 - Korzen, Manfred A1 - Lamperti Tornaghi, Marco T1 - Hybrid fire following earthquake testing of a steel braced frame N2 - The paper presents the results of an experimental-numerical analysis aimed at investigating the performance of passive fire protections applied to steel columns under fires following earthquake (FFE) scenarios. In particular, five FFE tests on columns belonging to a steel braced frame were performed at the Bundesanstalt für Materialforschung und -prüfung (BAM, Federal Institute for Materials Research and Testing) by means of hybrid fire testing technique. In particular, an internal steel column of the ground floor belonging to a three-bay, four-storey concentrically braced steel building was tested, whilst the effect of the remainder of the structure was numerically simulated by means of an equivalent axial stiffness. Since the structure has a low degree of redundancy, the loss of a column can trigger global structural collapse. Two FFE tests were performed without any fire protection system and the other FFE tests were performed with three different fire protection solutions, i.e. conventional and seismic-resistant calcium silicate boards as well as vermiculite spray-based protection. Each column was firstly subjected to horizontal and vertical displacements resulting from seismic nonlinear time-history analysis performed on the numerical model of the case study. Then, the furnace was switched on and the ISO 834 standard fire curve was applied to the specimen. Numerical models were developed and calibrated on experimental data using different types of finite elements. The calibrated models with the presence of axial and rotational springs accurately captured the transition from pre- to post-buckling behavior. These findings highlight the importance of accurate modelling of the boundary conditions. Despite the fact, that seismic intensity was at life safety limit state, it was also found that the seismic damage of the fire protections was not high enough to hinder the fire performance of the fire protections. KW - Fire following earthquake KW - Concentrically braced steel frames KW - Fire protections KW - Numerical simulations KW - Experimental tests KW - Post-earthquake fire PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645186 DO - https://doi.org/10.1016/j.conbuildmat.2025.143731 SN - 0950-0618 VL - 496 SP - 1 EP - 22 PB - Elsevier CY - Oxford AN - OPUS4-64518 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tornaghi, M. L. A1 - Tsionis, G. A1 - Pegon, P. A1 - Molina, J. A1 - Peroni, M. A1 - Korzen, Manfred A1 - Tondini, N. A1 - Covi, P. A1 - Abbiati, G. A1 - Antonelli, M. A1 - Gilardi, B. T1 - Experimental study of braced steel frames subjected to fire after earthquake N2 - The EQUFIRE project aims to study the post-earthquake fire Performance of steel frame structures and is part of the Transnational Access activities of the SERA project (www.sera-eu.org) at the ELSA Reaction Wall of the European Commission - Joint Research Centre. As it has happened in many historical occasions, after an earthquake, earthquakeinduced rupture of gas piping, failure of electrical systems, etc. may trigger fire. The structural fire performance can deteriorate because the fire acts on a previously damaged structure. In addition, the earthquake may have damaged fire protection elements and the fire can spread more rapidly if compartmentation walls have failed. This is particularly relevant for steel structures as the high thermal conductivity of elements with small thickness entails quick temperature rise with consequent fast loss of strength and stiffness. EQUFIRE studied a four-storey three-bay steel frame with concentric bracings in the central bay. The structure was designed for reference peak ground acceleration equal to 0.186g, soil type B and type 1 elastic response spectrum according to Eurocode 8. Tests were performed at the ELSA Reaction Wall and at the furnace of the Federal Institute for Materials Research and Testing (BAM). The experimental activities at the ELSA Reaction Wall comprise pseudo-dynamic tests on a full-scale specimen of the first storey of the building, while the upper three storeys are numerically simulated. The aim is to study the response of the structure and fire protection elements, including their interaction, under the design earthquake and for different configurations: bare frame without fire protection, specimen with three fire protection solutions (conventional and seismic-resistant boards, and vermiculite sprayed coating) applied on the bracing and one column, and with conventional and seismic-resistant fire barrier walls built in the two external bays of the specimen. The testing programme at BAM included fire tests of five columns (two specimens without fire protection elements and three specimens with the types of fire protection mentioned above). Before the fire test, each column was subjected to a horizontal and vertical displacement history resulting from the seismic action. During the fire tests, the effect of the surrounding structure was simulated by limiting the axial thermal expansion. The experimental results will serve to study the response of structural and non-structural components to fire following earthquake scenarios, with a view to improving existing design guidelines and future standards. T2 - The 17th World Conference on Earthquake Engineering - 17WCEE CY - Meeting was canceled DA - 13.09.2020 KW - Fire following earthquake KW - Concentrically braced steel frames KW - Large-scale tests KW - Pseudo-dynamic testing KW - Substructuring PY - 2020 SP - 2i-0104-1 EP - 2i-0104-12 AN - OPUS4-51426 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -