Magnel Laboratory for Concrete Research – Department of Structural Engineering

Fundamental design approaches for improvement of the fire safety in car parks

UGent: structural aspects

Prof. dr. ir. Luc TaerweIr. arch. Emmanuel Annerel

Magnel Laboratory for Concrete Research 2

Objectives of the project withrespect to structural aspects

• to develop advanced mechanical models for the structural behaviour of car park structures taking into account non-linear behaviour due to indirect actions in the accidental situations of fire and explosion

• to develop a particular analysis of the punching shear problem in case of fire and explosions

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WP1: Determination of design parameters, scenarios and objectives

Determination of design parameters for- large scale structural tests- numerical simulations of structural behaviour under fire and explosions

This implies decisions on:- geometrical conditions, such as size, ceiling configurations, etc.;- performance conditions, such as fire scenarios and explosion scenarios.

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Column-slab connections

Mushroom slabs (paddestoelvloeren)Flat slabs (vlakke plaatvloeren)Precast thin slabs with lattice girders

(breedplaatvloeren of predallen)

Slab types

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Parking structures in the city of Ghent

KouterSint-PieterspleinVrijdagsmarktZuidSint-Michiels

Magnel Laboratory for Concrete Research

General classification of loads according to variation in time

Permanent loads (G)

P[G] = 1 δG ≅ 0

Live loads (Q)

0 < P[Q] < 1 δQ↑

Accidental loads (A) e.g. fire and explosions

P[A] ≅ 0 A ↑

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WP4: Structural models

The objectives of this work package are to develop- an appropriate methodology for the analysis and design of underground car park structures in case of fire in combination with explosions. - the analysis of structural members of car park structures for fire in combination with explosions, with emphasis on slab / column behaviour and on punching resistance;- protection measures from a structural point of view.

Note: The choice is made not to include the extrapolation of the results obtained for elements, towards robustness analysis of a whole building structure. Moreover, the initially foreseen WP on masonry walls is also not considered in the present two year project.

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Temperatuur:- Thermische geleidbaarheid- Volumetrische specifieke warmtecapaciteit- Coefficiënt voor convectie en straling

Mechanische acties:-Sterktedegradering staal/beton

Vervormingen, bezwijkvorm-Effect van explosie?

Implementeren als kortstondig optredende kracht

Task 4.1: Parametric analysis of structural members

Het brandeffect: thermo-mechanisch model DIANA

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Task 4.2: Connections

Focus on- study of moment resisting connections between structural elements - analysis of the punching resistance in case of fire

and fire in combination with explosions.

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Punching

A : referentienazichtsdoorsnedeB : referentienazichtsgebied Acont

C : referentienazichtsomtrek u1

D : belast gebiedrcont : straal van een andere

nazichtsomtrekuout,ef : omtrek vanaf waar geen

ponswapening meer nodig is

Magnel Laboratory for Concrete Research

Controle aan de omtrek van de kolom

cd0

EdEd f5,0

duVv ν≤

β=

)dv/(vu c,RdEdef,out β=

u0 volgens type kolom

Bepaling uout,ef

afstand uiteinde ponswapening tot uout

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Gretzenbach 2004 (CH)

Example

Fire of one parked car: 6 amCollapse of roof slab: 7.30 am

(7 fire workers killed)

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Collapse is combination of mistakes during design and excution- thicknes of soil layer larger in reality than assumed in design- top reinforcement at lower level than planned- top of columns partly in slab

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Kolom-plaatverbindingenProblemen bij brand

Thermische uitzetting Afschuifbreuken kolommen !!

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Kolom-plaatverbindingenProblemen bij brand

Uitwendige vervormingsverhindering

verschuiving van momentenlijn→ toename steunpuntsmomenten

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Test program

1. Three full scale column – slab connections (Magnel Lab and Warringtonfire)

2. Blast tests on selected connection configurations (KMS)

Objectives: - Influence of reinforcement configurations on failure modes- Elaboration of mechanical model for punching resistance

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WP5: Reliable design calculation methods

WP8: Dissemination