Michael Klippel

Experimental Analysis of the Fire Behavior of Finger-Jointed Timber Members

AbstractFire design models for timber structures usually consider both the loss in cross section attributable to charring and the temperature-dependent reduction of strength and stiffness of the uncharred residual cross section. For bonded timber elements such as glued laminated timber beams, it is assumed that the adhesive in use does not significantly influence the resistance of structural timber beams. To investigate the influence of adhesives in bonded timber elements, a comprehensive research project is currently in progress. The aim of this project is the development of a simplified design model for the fire resistance of bonded structural timber elements, taking into account the behavior of the adhesive at elevated temperature. The paper presents the results of an extensive test series on finger-jointed timber members loaded in tension and exposed to a transient ISO 843 standard fire. The fire tests were performed with different adhesives that fulfill current approval criteria for the use in load-b...

Influence of the Adhesive on the Load-Carrying Capacity of Glued Laminated Timber Members in Fire

Design models for timber structures in fire usually take into account the loss in cross-section due to charring and the temperature-dependent reduction in strength of timber. For bonded timber elements like glued laminated timber beams it is assumed that the adhesive used does not influence the resistance of structural timber beams significantly. To investigate the fire resistance of bonded timber elements a comprehensive research project is currently in progress at the Institute of Structural Engineering of ETH Zurich, Switzerland. The aim of this research project is the development of a simplified design model for the fire resistance of bonded structural timber elements taking into account the behavior at elevated temperature of the adhesive used. This paper presents experimental analyses and results of first calculations performed on the influence of the adhesive on the load-carrying capacity of glued laminated timber members in fire. It is shown that the temperature-dependent material properties of the adhesive used in the bondline of glued laminated timber beams have small influence on the shear resistance. For the investigated timber beams failure occurs mainly due to exceeding the bending moment resistance. Because of the steep temperature gradient in timber beams during fire exposure the temperature in the inner region of the cross-section is rather low; hence the shear capacity in the bondline between the different lamellas is still sufficient. However, in case of finger jointed lamellas of glued laminated timber beams, the influence of adhesive used in the finger joints is more significant and has to be considered. Tensile tests at elevated temperatures on finger jointed specimens confirmed the significant influence of the adhesive used.

Design of Cross-Laminated Timber in Fire

Abstract Cross-laminated timber (CLT) is a popular engineered wood product for loadbearing wall, floor and roof elements to realise innovative and high-quality modern timber structures. The behaviour of CLT panels exposed to fire requires careful evaluation to allow the expansion of CLT elements’ usage in buildings. This paper first presents a new charring model for timber in general and CLT specifically, based on the results of numerous fire tests with CLT and the current fire design according to EN 1995-1-2. In addition, the char depth obtained from numerous fire tests with CLT is compared with results based on a charring model from Europe.

Fire Safety of Glued-Laminated Timber Beams in Bending

AbstractDesign models for timber structures with fire-resistance requirements usually take into account the loss in cross section due to charring and the temperature-dependent reduction in strength...

Extension of data sets for a more reliable prediction of the fire resistance of finger joint connections

Large-scale fire tests are time intensive and expensive. Thus, usually only a limited number of test results are produced. In order to produce a more reliable description of the parameters of interest, the data set can be extended. This paper shows, as an example, how fire resistance tests investigating different parameters can be connected and further how censored test results can be considered in the evaluation of the results. The goal of the whole investigation is to extend the information of a limited number of fire tests in order to produce a more reliable description of the test results.

Improving the planning and design phases of construction projects by using a Case-Based Digital Building System

Abstract The construction industry is known for having well-defined and systematic processes for the different phases of a project. Improvements, however, are possible with respect to how information is used in these phases and how the experience gained from previous projects is exploited. In this paper, an example of how new technologies can be used to improve the planning and design of buildings is shown. In the example, a Case-Based Digital Building System (CB-DBS) in which every building as an integrated structural system consisting of highly parameterized standard elements is used in the planning phases of projects. In the planning phases, case-based reasoning is used to identify similar completed projects that would enable faster starts of new projects. In the design phases, case-based design is used to identify similar portions of completed projects that would enable faster designs of the more detailed parts of the buildings. A proof of concept using housing projects from a design–build–operate company based in Switzerland is used to test the viability of the proposed system. It is shown that the CB-DBS enabled faster planning and design phases of new projects and improved exploitation of the knowledge gained in previous projects.

Umbau Dock B am Flughafen Zürich

Grossmassstabliche Versuche an Blechverbunddecken (Holorib 51) wurden vom Institut fur Baustatik und Konstruktion (IBK) der ETH Zurich im Zuge der Umbaumassnahmen am Dock B am Flughafen Zurich durchgefuhrt. Das Flughafendock B wurde 1974 mit einem Tragwerk aus Stahlrahmen und Blechverbunddecken erstellt. Nach 35 Jahren Nutzung wurde es im Sommer 2009 im Zuge des Beitritts der Schweiz zum Schengen Raum um- und teilweise ruckgebaut. Das Tragwerk besteht aus einer Stahlrahmenkonstruktion, das uber Sekundartrager in Querrichtung das Auflager fur eine Blechverbunddecke bildet. Die experimentellen Untersuchungen sollten insbesondere das Verbundverhalten der Verbunddecke zwischen Profilblech und Beton uberprufen. Es wurden insgesamt zehn grossmassstabliche Biegeversuche an Einfeldtragern mit unterschiedlichem Abstand der Belastung vom Auflager durchgefuhrt. Hierdurch konnte die Langsschubtragfahigkeit sowie der Einfluss der 35 Jahre Nutzung untersucht werden. Zudem wurden Versuche an Durchlauftragern, an Kragarmen sowie an Offnungen durchgefuhrt. Weitere Versuche zur Untersuchung des Durchstanzverhaltens erganzten das umfangreiche Versuchsprogramm. Zur Durchfuhrung der Versuche wurden die Versuchskorper mit einer Diamantsage aus der Verbunddecke freigeschnitten. Anschliessend wurden mit einer speziell entwickelten Versuchseinrichtung die Versuche auf der Baustelle durchgefuhrt. Um den Ruckbauprozess nicht zu behindern, mussten die Versuche innerhalb der zwei Wochen Bauferien durchgefuhrt werden. Die generierten Versuchsdaten ermoglichten es eine Entscheidung hinsichtlich Ruckbau oder Umnutzung des Flughafendocks mit wirtschaftlichen und okologischen Folgen zu treffen. Die Versuche wurden mit den gangigen Bemessungsansatzen m-k-Methode und Teilverbundverfahren ausgewertet und die Tragfahigkeit der Verbunddecke ermittelt. Die Versuche zeigen, dass noch ein ausreichender Verbund zwischen Profilblech und Beton vorhanden ist und die Bemessungsmodelle den Tragwiderstand auch nach langerer Nutzung noch gut vorhersagen. Im ersten Abschnitt dieses Versuchsberichts werden die Versuche detailiert beschrieben. Im darauffolgenden Abschnitt werden die Versuchsergebnisse dargestellt und ausgewertet. In conjunction with the conversion of Dock B at Zurich Airport an experimental study on composite slabs with profiled steel sheeting (Holorib 51) was performed by the Institute of structural Engineering (IBK) of ETH Zurich. The examined structure was built in 1974. After 35 years in service it will be converted to implement the Schengen agreement with the European Union. The structure consists of composite floor slabs, a steel frame with stub-girder beams and hot rolled steel columns as supporting structure. The experimental investigation focused on the bond behavior of the composite slabs and the influence of the 35 years service life. In total ten large-scale tests were carried out on simple beams with different shear span length to evaluate the shear capacity between the steel sheeting and the concrete. In addition, tests on continues beams, on cantilever beams as well as tests on openings and punching tests completed the extensive test program. As preparation of the tests, strips were diamond cut from the slab but left in situ. Further, a special testing device was developed that’s frame had to be light but stiff and easy to adapt to perform the different type of tests on site in a very short time. The entire testing program had to be carried out within two weeks to avoid any interference with the ongoing reconstruction process. The data generated by these tests enabled the assessment of the composite slabs regarding demolition or adaption of the structure with the associated economic and ecologic effects. The evaluation of the results was done with common design methods, such as the m-k-method and the partial shear connection theory. The tests showed that a sufficient bond still exists between the steel sheets and the concrete and that current design rules properly assess the loadbearing capacity of structures after long-term use. In the first part of this report the performed tests are described in detail. In the following section, the results of the tests are presented and evaluated.

Umbau Dock B am Flughafen Zürich - Belastungsversuche an Holorib-Blechverbunddecken: Belastungsversuche an Holorib-Blechverbunddecken

Grossmassstabliche Versuche an Blechverbunddecken (Holorib 51) wurden vom Institut fur Baustatik und Konstruktion (IBK) der ETH Zurich im Zuge der Umbaumassnahmen am Dock B am Flughafen Zurich durchgefuhrt. Das Flughafendock B wurde 1974 mit einem Tragwerk aus Stahlrahmen und Blechverbunddecken erstellt. Nach 35 Jahren Nutzung wurde es im Sommer 2009 im Zuge des Beitritts der Schweiz zum Schengen Raum um- und teilweise ruckgebaut. Das Tragwerk besteht aus einer Stahlrahmenkonstruktion, das uber Sekundartrager in Querrichtung das Auflager fur eine Blechverbunddecke bildet. Die experimentellen Untersuchungen sollten insbesondere das Verbundverhalten der Verbunddecke zwischen Profilblech und Beton uberprufen. Es wurden insgesamt zehn grossmassstabliche Biegeversuche an Einfeldtragern mit unterschiedlichem Abstand der Belastung vom Auflager durchgefuhrt. Hierdurch konnte die Langsschubtragfahigkeit sowie der Einfluss der 35 Jahre Nutzung untersucht werden. Zudem wurden Versuche an Durchlauftragern, an Kragarmen sowie an Offnungen durchgefuhrt. Weitere Versuche zur Untersuchung des Durchstanzverhaltens erganzten das umfangreiche Versuchsprogramm. Zur Durchfuhrung der Versuche wurden die Versuchskorper mit einer Diamantsage aus der Verbunddecke freigeschnitten. Anschliessend wurden mit einer speziell entwickelten Versuchseinrichtung die Versuche auf der Baustelle durchgefuhrt. Um den Ruckbauprozess nicht zu behindern, mussten die Versuche innerhalb der zwei Wochen Bauferien durchgefuhrt werden. Die generierten Versuchsdaten ermoglichten es eine Entscheidung hinsichtlich Ruckbau oder Umnutzung des Flughafendocks mit wirtschaftlichen und okologischen Folgen zu treffen. Die Versuche wurden mit den gangigen Bemessungsansatzen m-k-Methode und Teilverbundverfahren ausgewertet und die Tragfahigkeit der Verbunddecke ermittelt. Die Versuche zeigen, dass noch ein ausreichender Verbund zwischen Profilblech und Beton vorhanden ist und die Bemessungsmodelle den Tragwiderstand auch nach langerer Nutzung noch gut vorhersagen. Im ersten Abschnitt dieses Versuchsberichts werden die Versuche detailiert beschrieben. Im darauffolgenden Abschnitt werden die Versuchsergebnisse dargestellt und ausgewertet. In conjunction with the conversion of Dock B at Zurich Airport an experimental study on composite slabs with profiled steel sheeting (Holorib 51) was performed by the Institute of structural Engineering (IBK) of ETH Zurich. The examined structure was built in 1974. After 35 years in service it will be converted to implement the Schengen agreement with the European Union. The structure consists of composite floor slabs, a steel frame with stub-girder beams and hot rolled steel columns as supporting structure. The experimental investigation focused on the bond behavior of the composite slabs and the influence of the 35 years service life. In total ten large-scale tests were carried out on simple beams with different shear span length to evaluate the shear capacity between the steel sheeting and the concrete. In addition, tests on continues beams, on cantilever beams as well as tests on openings and punching tests completed the extensive test program. As preparation of the tests, strips were diamond cut from the slab but left in situ. Further, a special testing device was developed that’s frame had to be light but stiff and easy to adapt to perform the different type of tests on site in a very short time. The entire testing program had to be carried out within two weeks to avoid any interference with the ongoing reconstruction process. The data generated by these tests enabled the assessment of the composite slabs regarding demolition or adaption of the structure with the associated economic and ecologic effects. The evaluation of the results was done with common design methods, such as the m-k-method and the partial shear connection theory. The tests showed that a sufficient bond still exists between the steel sheets and the concrete and that current design rules properly assess the loadbearing capacity of structures after long-term use. In the first part of this report the performed tests are described in detail. In the following section, the results of the tests are presented and evaluated.