TY - CONF A1 - Fürst, Richard A1 - Häßler, Dustin A1 - Peter, A. A1 - Rohleder, R. A1 - Hothan, Sascha T1 - European test standard intumescent coatings applied to steel tension bars with solid section N2 - Intumescent coatings are used in civil engineering to improve the fire resistance of steel constructions. Due to the thin coating thickness and the profile-following application, the architectural appearance of the steel structure can be preserved. EN 13381-8 provides regulations to determine the contribution to the fire resistance of intumescent coatings applied to steel beams and columns. The scope of this standard excludes tension members and steel members with solid sections. For products that have already been successfully tested and assessed on beams and columns, EN 13381-10 offers the possibility based on unloaded fire tests to extend the scope of application of intumescent coatings to tension bars with solid sections. This approach contradicts the national safety level in Germany, where mechanically loaded testing is mandatory. Therefore, a new part of the test standard series EN 13381 is currently developed to enable the application of intumescent coatings on steel tension bars with solid section based on mechanically loaded fire tests. BAM has already carried out numerous fire tests on loaded steel tension members with intumescent coatings. Currently, in the BAM research project FIRESTEMIC, the influence of the steel bar orientation and the profile type on the thermal performance of intumescent coatings are investigated. Both questions concerning the thermal protection ability of intumescent coatings were analysed based on three different test sets, which were carried out in the tension furnace (Fig. 1a). The fire exposure corresponds to the standard temperature-time curve according to EN 1363-1. This paper summarises the main findings from the fire tests conducted in the FIRESTEMIC project. The results serve as an experimental background for the proposal of the new standard. Regarding the bar orientation, a new test setup was developed and proposed for the new standard. The two tested commercial water-based intumescent coatings with applied dry film thickness from 1.5 mm to 2.5 mm showed only a slight dependence on the bar orientation. In terms of the steel profile type, circular and rectangular solid sections with identical section factor and applied dry film thickness were tested. It was observed that the circular solid bars with diameter 30 mm heat up faster compared to the solid rectangular bars with dimension 30×30 mm (Fig. 1b). Also at larger steel bars, i.e. diameter 40 mm and dimension 40×40 mm, the same trend occurred. Thus, it is recommended for the new test standard to allow a transfer of the test results from circular to rectangular solid sections. In addition, the paper will describe and explain the test and assessment procedure proposed for the newly developed standard. T2 - 8th Symposium Structural Fire Engineering CY - Brunswick, Germany DA - 13.09.2022 KW - Fire test KW - Steel KW - Tension member KW - Intumescent coating KW - Test standard PY - 2022 SP - 1 EP - 14 PB - TU Braunschweig CY - Braunschweig AN - OPUS4-55703 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Häßler, Dustin A1 - Becker, Andreas A1 - Fürst, Richard A1 - Hothan, Sascha ED - Simões da Silva, Luís ED - Vila Real, Paulo ED - Santiago, Aldina ED - Craveiro, Hélder ED - Laim, Luís T1 - Fire resistance testing of steel tension members with hollow section protected by intumescent coating N2 - This book presents the proceedings of the Thirteenth International Conference Structures in Fire. The conference took place at the Department of Civil Engineering, University of Coimbra, Portugal, from 19 to 21 June 2024, under the auspices of the SIF movement. Structural fire safety is a crucial aspect of the design of buildings and infrastructures. Significant advances in research have increased the knowledge on this topic. However, until the 1990s, there were few forums for structural fire engineers to exchange ideas and share research findings. SIF (Structures in Fire) specialised workshop series was conceived in the late 1990s and the “First International SIF Workshop” was held in Copenhagen, Denmark in 2000, followed by workshops in Christchurch, New Zealand (2002), Ottawa, Canada (2004) and Aveiro, Portugal (2006). The series of workshops evolved into conferences and the 2008 event in Singapore was the fifth International Conference on Structures in Fire. This was followed by events in East Lansing, USA (2010), Zurich, Switzerland (2012), Shanghai, China (2014), New Jersey, USA (2016), Belfast, UK (2018), Brisbane, Australia (2020) and Hong Kong, China (2022). Information about previous conferences, including complete proceedings, can be found at www.structuresinfire.com. The main mission of SIF conferences is to provide an opportunity for researchers and engineers from the global structural fire engineering community to participate, share and discuss the recent findings, innovations and developments with their peers in an open and international forum. Following the great success of the previous International Conferences, the University of Coimbra was selected to host the 13th International Conference on Structures in Fire. As with most of the recent conferences, the number of papers submitted far exceeds the number of papers that can be accommodated in the three-day programme, even with two parallel sessions. SIF 2024 received 249 abstracts before the deadline and accepted 172 abstracts after the review process by at least three reviewers from the scientific committee. These proceedings represent 132 full papers, collectively representing the state of the art in fundamental knowledge and practical application of structures in fire. Forty-two countries from around the globe have contributed to them. The papers are grouped into the following research topics: Applications of Structural Fire Engineering, Composite Structures in Fire, Concrete Structures in Fire, Timber Structures in Fire, Masonry Structures in Fire, Steel Structures in Fire, Experimental Research of Structures in Fire, Numerical Modelling of Structures in Fire, Other Topics Related to Structures in Fire. Finally, the Organizing Committee would like to thank the continuous support from the SIF Steering Committee chaired by Prof Jean-Marc Franssen. We also would like to thank to the Scientific Committee chaired by Prof Paulo Vila Real, the authors and all the supporting staff (and volunteer team) from the Institute for Sustainability and Innovation in Structural Engineering (ISISE) in Coimbra, for making SIF 2024 a successful conference. DA - 19.06.2024 KW - Fire resistance KW - Fire test KW - Intumescent coating KW - Steel KW - Tension member PY - 2024 DO - https://doi.org/10.30779/cmm_SIF24 SP - 1173 EP - 1183 PB - CMM – Portuguese Steelwork Association AN - OPUS4-60815 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fürst, Richard A1 - Häßler, Dustin A1 - Hothan, Sascha T1 - Influence of the profile type and bar orientation on the performance of intumescent coatings applied to steel tension bars N2 - Intumescent coatings are commonly used in civil engineering to improve the fire resistance of steel constructions. Especially in the case of tension bars, where mostly circular or rectangular solid sections are used, intumescent coatings offer an efficient measure to improve the fire resistance taking advantage of profile-following application and low coating thickness requirements. Thus, the architectural appearance of slender profiles can be preserved. The paper describes real-scale mechanically loaded and unloaded fire tests of circular and rectangular solid steel tension bars with intumescent coating. The aim of these tests is to investigate the influence of the different profile types as well as different bar orientations on the performance of intumescent coatings. The results are used to specify a normative test and assessment procedure to be implemented in a new European standard for determining the contribution of intumescent coatings to the fire resistance of circular or rectangular bars used as tension members. KW - Fire test KW - Intumescent coating KW - Steel tension member KW - Fire resistance PY - 2022 DO - https://doi.org/10.1016/j.firesaf.2022.103678 SN - 0379-7112 VL - 134 SP - 1 EP - 14 PB - Elsevier CY - Amsterdam AN - OPUS4-56172 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klimek, André A1 - Stelzner, Ludwig A1 - Hothan, Sascha A1 - Zehfuß, Jochen T1 - Influence of thermal strain on concrete spalling N2 - Understanding the susceptibility to spalling of concrete members in case of fire is important to evaluate the residual load-bearing capacity. The investigations of the spalling phenomenon of a concrete mixture using real scale members are necessary but expensive to carry out. Reducing the specimen size leads to an increase of boundary effects that can result in a reduced spalling or absence of spalling. In this study, fire tests were carried out on unrestrained, single-sided exposed, cuboid shaped specimens (0.6 m x 0.6 m x 0.29 m) as well as unrestrained and steel ring restrained cylindrical specimens (Ø = 0.47 m, h = 0.29 m), which induce different boundary conditions. These fire tests were carried out on two ordinary concrete mixtures. The two mixtures differ only in the type of aggregates (quartz gravel and basalt grit) and were used to investigate the influence of the thermal expansion of the aggregate on the spalling behaviour of the concrete. The results show a significant increase of the spalling depth due to the restrained thermal expansion achieved by the applied steel rings. Additionally, the type of aggregate has a direct influence on the spalling behaviour of a concrete mixture. The reduction of the boundary effects by the steel rings recreate the test conditions in the centre of a large concrete member. Thus, this type of specimen is suitable to determine the susceptibility to spalling of a material (screening-tests) as preliminary investigations to full scale fire tests. KW - Spalling KW - Concrete KW - Fire test KW - Restraint KW - Screening test PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593350 DO - https://doi.org/10.1617/s11527-023-02274-x VL - 57 SP - 1 EP - 14 PB - Springer AN - OPUS4-59335 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klimek, André A1 - Stelzner, Ludwig A1 - Hothan, Sascha A1 - Rogge, Andreas T1 - Fire induced concrete spalling in combination with size effects N2 - The size effect has its origin in fracture mechanics and describes the formation as well as propagation of cracks in brittle and solid materials in dependence of the specimen size. However, the size effect in concrete spalling describes the damage behaviour on a macroscopic scale for different sized specimens in case of fire. Concrete spalling is a very complex and yet not fully understood phenomenon. To reduce the effort of fire tests to analyse the spalling behaviour of concrete mixtures, this study investigates the susceptibility to spalling for six different concrete mixtures and three specimen sizes. The sizes were divided in full scale slabs (1.8 m x 1.2 m x 0.3 m), intermediate scale cuboids (0.6 m x 0.6 m x 0.3 m) and small scale cylinders (Ø0.15 m x 0.3 m). For this purpose, a novel test set-up was built to test six intermediate scale or twelve small scale specimens simultaneously to ensure a similar heating regime for every specimen. All specimens were fire exposed on one side and remained unrestrained. A size effect occurred for four of the six concrete mixtures. Compared to the full scale specimens the spalling was reduced significantly for all smaller specimen sizes. Additionally, spalling did not occur for the small scale specimens. The results show that the specimen size is an essential parameter to investigate the susceptibility to spalling of a concrete mixture. For future investigations the testing conditions must be adjusted for the intermediate scale specimens to recreate the conditions of the slabs. KW - Concrete KW - Spalling KW - Size effect KW - Fire test PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559231 DO - https://doi.org/10.1617/s11527-022-02051-2 VL - 55 IS - 8 SP - 1 EP - 14 PB - Springer AN - OPUS4-55923 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klimek, André A1 - Stelzner, Ludwig A1 - Hothan, Sascha A1 - Zehfuß, J. T1 - Screening-tests on the susceptibility to spalling of two ordinary concretes N2 - Investigating the spalling behaviour of a concrete mixture using large scale members is complex and expensive. Thus, the susceptibility of concrete to spalling is investigated by means of fire tests on small scale specimens. However, the reduction of the fire exposed surface increases the influence of boundary effects. Macrocracking and the water loss via the lateral surfaces reduce the impact of the thermomechanical and thermohydraulic damage mechanisms and therefore, lower the risk of spalling. Thus, the influence of different restraints on the spalling behaviour of intermediate scaled specimens (Ø=0.47 m; h=0.29 m) was investigated for two ordinary concrete mixtures. Both mixtures had the same composition except the type of aggregate. One mixture contained only quartzitic aggregates, whereas the other mixture was made with basalt grit as coarse aggregates. Applied steel rings restrained the thermal expansion of the specimen and prevented the loss of water, whereas applied steel sheet primarily reduced the loss of water during the fire test. Additionally, the fire exposed surface of one specimen of each mixture was pre-dried under controlled climate conditions and fire tested with applied steel rings. The results show a higher spalling volume for the ring restrained specimens compared to the other covering types. Further, the pre-dried boundary zone leads to delayed and decreased occurrence of spalling compared to the non-dried specimens for the concrete with quartzitic aggregates and to a prevention of spalling for the mixture with basalt aggregates. Additionally, the results show that the influence of the thermomechanical behaviour of the coarse aggregates increases with increasing restraint. The restrained conditions of the specimens with applied steel ring are comparable to the conditions in the centre of a large scale member. This test series is a further step for possible concept of steel ring restraint concrete specimens as “screening-tests” in upcoming projects. T2 - IWCS 2022 CY - Berlin, Germany DA - 12.10.2022 KW - Spalling KW - Fire test KW - Concrete KW - Restraint PY - 2022 SP - 15 EP - 24 PB - Bundesanstalt für Materialforschung und -prüfung (BAM) CY - Berlin AN - OPUS4-56020 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Häßler, Mai A1 - Häßler, Dustin A1 - Hothan, Sascha A1 - Krüger, Simone T1 - Fire tests of steel tension rod systems with intumescent coating N2 - Purpose – The purpose of this paper is to investigate the performance of intumescent coating on tension rod systems and their components. Steel tension rod systems consist of tension rods, fork end connectors and associated intersection or gusset plates. In case of fire, beside the tension rods themselves, the connection parts require appropriate fire protection. Intumescent fire protection coatings prevent a rapid heating of the steel and help secure the structural load-carrying capacity. Because the connection components of tension rod systems feature surface curvature and a complex geometry, high demand is placed on the intumescence and thermal protection performance of the coatings. Design/methodology/approach – In this paper, experimental studies were carried out for steel tension rod systems with intumescent coating. The examined aspects include the foaming and cracking behaviour, the influence of different dry film thicknesses, the heating rate of the steel connecting parts in comparison to the tension rods, and the mounting orientation of the tension rods together with their fork end connectors. Findings – The results show that a decrease in surface curvature and/or an increase inmass concentration of the steel components leads to a lower heating rate of the steel. Moreover, the performance of the intumescent coating on tension rod systems is influenced by themounting orientation of the steel components. Originality/value – The findings based on fire tests contribute to a better understanding of the intumescent coating performance on connection components of tension rod systems. This subject has not been extensively studied yet. KW - Steel KW - Fire test KW - Intumescent coating KW - Reactive fire protection system KW - Tension rod system PY - 2019 DO - https://doi.org/10.1108/JSFE-01-2019-0005 SN - 2040-2317 VL - 11 IS - 1 SP - 22 EP - 32 PB - Emerald Publishing Limited AN - OPUS4-48714 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -