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Sandström, Joakim, Teknisk licentiatORCID iD iconorcid.org/0000-0002-0071-6637
Publications (10 of 12) Show all publications
Sandström, J. (2020). Life safety in single-story steel frame buildings, Part II - probabilistic design. Journal of Structural Fire Engineering, 11(3), 379-394
Open this publication in new window or tab >>Life safety in single-story steel frame buildings, Part II - probabilistic design
2020 (English)In: Journal of Structural Fire Engineering, ISSN 2040-2317, E-ISSN 2040-2325, Vol. 11, no 3, p. 379-394Article in journal (Refereed) Published
Abstract [en]

Purpose

This paper aims to investigate the probability of unacceptable consequences from structural fire damage in a typical Scandinavian single-story steel frame building and discusses it in relation to life safety. This paper is a complement to the paper “Life safety in single-story steel frame buildings, Part I – deterministic design” by Sandström (2019) which considers the same design philosophy but with a probabilistic design approach.

Design/methodology/approach

The reliability of a single-story steel frame building is investigated by using crude Monte Carlo simulation by including consideration to the fire conditions.

Findings

The investigated building does not meet the safety levels as stipulated by EN 1990 for structural fire damage. However, by including consideration to the fire conditions in the compartment, it is shown that the life safety objective is not compromised by the structural fire damage, i.e. the structure remains intact as long as any individuals/firefighters can survive within the fire area compartment.

Originality/value

This paper presents practical application of a conceptual paper presenting a general approach to structural fire safety design and the life safety objective.

Place, publisher, year, edition, pages
Emerald Group Publishing Limited, 2020
Keywords
Structural fire safety design, Performance based design, Fire engineering, Life safety, Monte Carlo
National Category
Other Civil Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-73614 (URN)10.1108/JSFE-04-2019-0021 (DOI)000532718200001 ()2-s2.0-85084564873 (Scopus ID)
Funder
Svenska Byggbranschens Utvecklingsfond (SBUF), 13330
Note

Validerad;2020;Nivå 2;2020-08-28 (cisjan)

Available from: 2019-04-12 Created: 2019-04-12 Last updated: 2020-10-01Bibliographically approved
Sandström, J. (2019). Alternativ metod för värdering av personrisk i hallbyggnader vid brand.
Open this publication in new window or tab >>Alternativ metod för värdering av personrisk i hallbyggnader vid brand
2019 (Swedish)Other (Other (popular science, discussion, etc.))
National Category
Building Technologies
Identifiers
urn:nbn:se:ltu:diva-74949 (URN)
Funder
Svenska Byggbranschens Utvecklingsfond (SBUF), 13330
Available from: 2019-06-25 Created: 2019-06-25 Last updated: 2019-11-11Bibliographically approved
Sandström, J. (2019). Life safety in single-story steel frame buildings, Part I - deterministic design. Journal of Structural Fire Engineering, 10(4), 435-445
Open this publication in new window or tab >>Life safety in single-story steel frame buildings, Part I - deterministic design
2019 (English)In: Journal of Structural Fire Engineering, ISSN 2040-2317, E-ISSN 2040-2325, Vol. 10, no 4, p. 435-445Article in journal (Refereed) Published
Abstract [en]

This paper discusses fire safety design of single story-, single compartment buildings and evaluates whether time to structural damage is a relevant criterion when lethal fire conditions develop long before any structural fire damage can occur. Current performance-based design practice aims at achieving the life safety objective by preventing structural failure for the entire duration of a natural fire or for a fixed time of standard fire exposure. Prevention of structural fire damage is always relevant for multistory buildings, or buildings with complex geometries as structural fire damage may then threaten occupants and/or firefighters outside the area directly affected by the fire. However, for single-story-, single-compartment buildings, prevention of structural fire damage is less relevant in relation to the life safety objective.

The advantage of the new design philosophy presented in this paper is the possibility to define how the level of structural fire resistance in single-story-, single-compartment buildings can be determined in a consistent way. This level of fire resistance requirement in these buildings differ amongst countries but could be harmonized by accepting of the design philosophy suggested in this paper.

The proposed approach is demonstrated in a design case study of a steel truss in a typical Swedish single-story steel frame building. While not complying with deemed to satisfy fire resistance ratings, it is argued that the proposed design still can fulfill the life safety objective.

Place, publisher, year, edition, pages
Emerald Group Publishing Limited, 2019
Keywords
Structural fire safety design, Performance-based design, Fire engineering, Life safety
National Category
Building Technologies Other Civil Engineering
Research subject
Structural Engineering
Identifiers
urn:nbn:se:ltu:diva-73434 (URN)10.1108/JSFE-01-2019-0013 (DOI)000491539800004 ()2-s2.0-85071144372 (Scopus ID)
Funder
Svenska Byggbranschens Utvecklingsfond (SBUF), 13330
Note

Validerad;2019;Nivå 2;2019-12-03 (johcin)

Available from: 2019-04-04 Created: 2019-04-04 Last updated: 2020-10-01Bibliographically approved
Sandström, J. (2019). The life safety objective in structural fire safety design. (Doctoral dissertation). Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>The life safety objective in structural fire safety design
2019 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Personsäkerhet vidbrandteknisk dimensionering av bärande konstruktioner
Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2019. p. 219
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
National Category
Building Technologies Infrastructure Engineering
Research subject
Steel Structures
Identifiers
urn:nbn:se:ltu:diva-73663 (URN)978-91-7790-360-4 (ISBN)978-91-7790-361-1 (ISBN)
Public defence
2019-06-13, F1031, Luleå, 13:00 (English)
Opponent
Supervisors
Funder
SBUF - Sveriges Byggindustriers Utvecklingsfond, 13330ÅForsk (Ångpanneföreningen's Foundation for Research and Development), 14-401Brandforsk, 312-131
Available from: 2019-04-16 Created: 2019-04-15 Last updated: 2023-09-06Bibliographically approved
Sandström, J., Sjöström, J. & Wickström, U. (2019). Thermal exposure from localized fires to horizontal surfaces below the hot gas layer. Luleå: Luleå University of Technology
Open this publication in new window or tab >>Thermal exposure from localized fires to horizontal surfaces below the hot gas layer
2019 (English)Report (Other academic)
Abstract [en]

The temperature in the lower chord of steel trusses subjected to localized fires is difficult to estimate as most thermal exposure correlation formulas presented in the literature focus on heating along the ceiling where the temperature is very different from that of the lower chord [1], [2]. At the same time as the upper chord is engulfed in a ceiling jet from a localized fire, the lower chord may be surrounded by air at ambient temperature.

Two existing methods by Zhang and Usmani [3] and Guowei et al. [4], [5] along with one new approach for calculating the thermal exposure of the lower chord are presented in this paper and compared to the results from experiments conducted in Trondheim 2015 [6].

A new approach presented in this paper is evaluated based on two separate assumptions of the thermal exposure. Outside the plume, the radiative contribution is assumed originating from the plume in the form of a cylinder and inside the plume, the temperature is assumed decreasing according to a Gaussian shape from the central axis temperature to the temperature down to the temperature from the first part of the model at the transition between inside and outside the plume.

All models provide good correlation to the experimental data outside the plume perimeter. Inside the plume perimeter, the thermal impact depends to a high degree to the relation between the flame height and the height of the horizontal surface of interest.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2019. p. 18
Series
Research report / Luleå University of Technology, ISSN 1402-1528
Keywords
Performance-based design, heat transfer, localized fires
National Category
Building Technologies Infrastructure Engineering
Research subject
Steel Structures
Identifiers
urn:nbn:se:ltu:diva-73430 (URN)978-91-7790-663-6 (ISBN)
Funder
Brandforsk, 312-131
Available from: 2019-04-04 Created: 2019-04-04 Last updated: 2020-09-30Bibliographically approved
Sandström, J. & Thelandersson, S. (2018). Comparing performance-based fire safety design using stochastic modelling to Eurocode partial coefficent method. In: Anne Dederichs; Ove Njå; Luisa Giuliani; Aleksandra Zawadowska (Ed.), Book of Proceedings Nordic Fire & Safety Days 2018: . Paper presented at Nordic Fire & Safety Days (NFSD 2018), Trondheim, Norway, June 7-8, 2018 (pp. 19-25). Research Institute of Sweden (RISE)
Open this publication in new window or tab >>Comparing performance-based fire safety design using stochastic modelling to Eurocode partial coefficent method
2018 (English)In: Book of Proceedings Nordic Fire & Safety Days 2018 / [ed] Anne Dederichs; Ove Njå; Luisa Giuliani; Aleksandra Zawadowska, Research Institute of Sweden (RISE) , 2018, p. 19-25Conference paper, Published paper (Refereed)
Abstract [en]

In performance based structural fire safety design using the parametric fire curve, Eurocode has adopted a partial coefficient applied only on the fuel load density for calibrating the code to the desired safety level. Probabilistic analyses are presented in this paper to investigate the impact on the reliability due to variation of opening factor, and thermal inertia as well as the ratio between variable and permanent static load. It is shown that the partial coefficient method in Eurocode, with fire exposure expressed via parametric fire curves gives adequate reliability levels with certain margins on the safe side compared to stochastic evaluation based on the same assumptions. This margin is particularly high for load combinations with dominating variable load.

Place, publisher, year, edition, pages
Research Institute of Sweden (RISE), 2018
Series
RISE Rapport ; 2019:54
Keywords
Performance based design, Fire resistance, Reliability anlysis, Monte Carlo simulation
National Category
Building Technologies
Research subject
Steel Structures
Identifiers
urn:nbn:se:ltu:diva-73611 (URN)
Conference
Nordic Fire & Safety Days (NFSD 2018), Trondheim, Norway, June 7-8, 2018
Funder
ÅForsk (Ångpanneföreningen's Foundation for Research and Development), 401-14
Note

ISBN för värdpublikation: 978-91-88907-57-8

Available from: 2019-04-12 Created: 2019-04-12 Last updated: 2021-10-24Bibliographically approved
Sandström, J. & Wickström, U. (2015). Calculation of Steel Temperature in Open Cross Sections Based on Fire Exposure from CFD (ed.). In: (Ed.), Markku Heinisuo; Jari Mäkinen (Ed.), The 13th Nordic Steel Construction Conference: NSCC-2015. Paper presented at Nordic Steel Construction Conference, 23/09/2015 - 25/09/2015, Tampere, Finland (pp. 195-196). Tempere: Tampere University of Technology, Department of Civil Engineering
Open this publication in new window or tab >>Calculation of Steel Temperature in Open Cross Sections Based on Fire Exposure from CFD
2015 (English)In: The 13th Nordic Steel Construction Conference: NSCC-2015 / [ed] Markku Heinisuo; Jari Mäkinen, Tempere: Tampere University of Technology, Department of Civil Engineering , 2015, p. 195-196Conference paper, Published paper (Refereed)
Abstract [en]

Evaluation of steel temperature for small and complex structural elements directly in FDS introduces local effects which can lead to over prediction of the solid temperatures. The sol-id temperature calculation in FDS is based on a one dimensional assumption and cannot handle all the aspects of heat loss due to conduction. FDS is therefore likely to over predict the temperature in, for example, the web in open cross sections. In this paper, this issue is demonstrated and handled with by the use of shadow effects in FE analysis. Two different methods handling the local effects are presented. The different methods show different lev-els of accuracy presenting a more complete method for thermal response calculations based on numerical calculations of experimental data.

Place, publisher, year, edition, pages
Tempere: Tampere University of Technology, Department of Civil Engineering, 2015
National Category
Building Technologies
Research subject
Steel Structures
Identifiers
urn:nbn:se:ltu:diva-32491 (URN)70153570-9bf6-42c9-a762-ce58dc5b964d (Local ID)978-952-15-3578-9 (ISBN)978-952-15-3579-6 (ISBN)70153570-9bf6-42c9-a762-ce58dc5b964d (Archive number)70153570-9bf6-42c9-a762-ce58dc5b964d (OAI)
Conference
Nordic Steel Construction Conference, 23/09/2015 - 25/09/2015, Tampere, Finland
Note

Godkänd; 2015; 20151001 (joasan)

Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2019-04-30Bibliographically approved
Sandström, J., Wickström, U., Veljkovic, M., Iqbal, N., Sjöström, J. & Sundelin, J. (2015). Steel truss exposed to localized fires: Experimental report from a large scale experiment with a steel truss exposed to localized fires (ed.). Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Steel truss exposed to localized fires: Experimental report from a large scale experiment with a steel truss exposed to localized fires
Show others...
2015 (English)Report (Other academic)
Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2015. p. 53
National Category
Building Technologies
Research subject
Steel Structures
Identifiers
urn:nbn:se:ltu:diva-22393 (URN)2b5d5d0b-2729-4ef2-93dc-f61f2cec67a1 (Local ID)2b5d5d0b-2729-4ef2-93dc-f61f2cec67a1 (Archive number)2b5d5d0b-2729-4ef2-93dc-f61f2cec67a1 (OAI)
Note
Godkänd; 2015; 20151001 (joasan)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2023-09-05Bibliographically approved
Sandström, J. & Wickström, U. (2013). Steel temperature calculations in performance based design: Advanced techiques for thermal response calculations with FE-Analysis. In: Wald F.; Burgess I.; HorováK.; JánaT.; Jirk J. (Ed.), Proceedings of International Conference in Prague 19-20 April 2003: Applications of Structural Fire Engineering. Paper presented at International Conference Application of Structural Fire Engineering in Prague,19 - 20 April 2013 (pp. 153-159).
Open this publication in new window or tab >>Steel temperature calculations in performance based design: Advanced techiques for thermal response calculations with FE-Analysis
2013 (English)In: Proceedings of International Conference in Prague 19-20 April 2003: Applications of Structural Fire Engineering / [ed] Wald F.; Burgess I.; HorováK.; JánaT.; Jirk J., 2013, p. 153-159Conference paper, Published paper (Refereed)
Abstract [en]

By using advanced FEA techniques, the predicted temperature in steel elements can be reduced significantly (see paper by Ulf Wickström). By in addition assuming a performance based fire exposure obtained with numerical fire models such as Fire Dynamics Simulator, FDS, the steel temperatures can be even further reduced.

 

Most calculation methods assume the fire exposure of the steel sections to be uniform. By using section factors A/V, i.e. the circumference over the area, and the most onerous of the fire exposing temperatures from computer fluid dynamics, CFD, calculations, the temperatures is over-estimated which leads to very conservative and costly solutions.

 

By considering the cooling effect of concrete structures and shadow effects, the temperatures can be reduced in the steel. By combining differentiated fire exposing temperatures from CFD calculations with consideration to shadow effects and the cooling of concrete, the temperature in the steel beam can be reduced even further.

National Category
Building Technologies
Research subject
Steel Structures
Identifiers
urn:nbn:se:ltu:diva-71836 (URN)978-80-01-05204-4 (ISBN)
Conference
International Conference Application of Structural Fire Engineering in Prague,19 - 20 April 2013
Available from: 2018-11-30 Created: 2018-11-30 Last updated: 2023-09-06Bibliographically approved
Sandström, J. (2013). Thermal boundary conditions based on field modeling of fires: Heat transfer calculations in CFD and FE models with special regards to fire exposure represented with adiabatic surface temperatures (ed.). (Licentiate dissertation). Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Thermal boundary conditions based on field modeling of fires: Heat transfer calculations in CFD and FE models with special regards to fire exposure represented with adiabatic surface temperatures
2013 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Combining computer fluid dynamic, CFD, models with finite element, FE, models to calculate temperature in fire exposed structures can reduce design temperatures in structures while still obtaining the level of structural fire safety stipulated by society. A better understanding of heat transfer and the concept of adiabatic surface temperatures, AST, the transition of data between models can be simplified and more accurate temperature predictions can be made.The thesis focuses on heat transfer calculations by employing AST in particular, and how this can be used as a means of coupling any CFD and FE-analysis code. The thesis presents a method for performing FE-analysis of the thermal response with input data calculated with the computer code FDS, Fire Dynamics Simulator. Parallel to this, the heat balance equation in FDS is tested and an alternate numerical algorithm is developed and tested.Firstly, a verification model is developed to test the radiative and convective part of the existing heat balance equation in FDS. An alternate numerical algorithm for calculation of the heat transfer at surfaces is developed as a more homogenous alternative for CFD codes.Secondly is a study on how to extract AST from an arbitrary point with direction in a CFD calculation using an infinitesimal surface. Instead of modeling numerous small surfaces for extracting AST, a post processor is developed to calculate AST independent of any modeled surface. For CFD codes, such as FDS that depend on a rectilinear grid, this enables calculation of AST in any direction, not only directions normal to the Cartesian planes.Finally, a comparison is made between different methods for calculating temperatures in steel with AST from numerical fire dynamics/modeling calculations. In this thesis there is a comparison between simplified Eurocode techniques, simple finite element analysis and advanced finite element analysis. This study shows the benefit of understanding heat transfer in numerical codes and to implement the concept of AST in a proper way.This way, the concept of combining numerical fire dynamics calculation with numerical (or simplified) thermal calculations can be better understood and implemented.

Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2013. p. 81
Series
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757
National Category
Building Technologies
Research subject
Steel Structures
Identifiers
urn:nbn:se:ltu:diva-17367 (URN)31527e3b-713e-46dc-a6ba-82795d81e7b9 (Local ID)978-91-7439-772-7 (ISBN)978-91-7439-773-4 (ISBN)31527e3b-713e-46dc-a6ba-82795d81e7b9 (Archive number)31527e3b-713e-46dc-a6ba-82795d81e7b9 (OAI)
Presentation
2013-12-05, F1031, Luleå tekniska universitet, Luleå, 13:00
Opponent
Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2023-11-29Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-0071-6637

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