High performance tunnel lining systems as a cost effective ... · High performance tunnel lining...

High performance tunnel lining systems as a cost effective part of a fire

protection system

Dr.-Ing. Roland Bornemann

Contents

• material introduction

• structural safety in tunnels according to ZTV-regulations and xicompensation measures

• user safety – retrofit of smoke extraction

• quick installation methods

• Colouring of lining systems and effect of colour

Group of companies

Xella International GmbH

Building materials / bricks & elementsDry lining

systems / boardsRaw

materials

Calcium silicateblocks

Aerated concrete

Aerated concrete

Gypsum fibreboards

Fireprotection

boards

Lime &limestone

Mineralinsulation

boards

What we are taking about: cementitious fire protective boards

consisting mainly out of:

• Hydraulic binder• Perlite

• AR-resistent fibres

• Water

Highly resistant against

• Humidity• frost/thaw

• Deicing agents

Fire protection via:

• Low lambda values

• Water evaporation

Protection of tunnel structures -Type I: cast on version

Protection of tunnel structures -Type I: cast on version

Installation of boards and fixation

of backing strips

Placing of steelreinforcement

Placing of concrete

Protection of tunnel structures -Type I:cast on version

Fire protection boards on framework

Bolted version –Type II: for new structures and retrofit

Bolted to concrete of circular tunnels with backing strip es.

Lilla Bommen, GothenburgHerrentunnelLübeck, D

Backing stripes in order to safeguard

protection in joint area

View into a completed structure

Bolted version –Type II: for new structures and retrofit

Why tunnel lining systems?

Montblanc tunnel 24/03/1999

• Truck with 9 tons of margarine and 12 tons of flour caug ht fire

• Other vehicles caught fire

• fire burnt for over 53 hours

• Peak temperatures higher than 1000°C were reached

• 39 people died

• tunnel was closed for over 3 years

Objectives of a protection system

• Structural safety

• Protection of users (self rescue, 15 minutes)

• Third party rescue (fire fighters)

Theses targets are similar worldwide

Measures taken differ according to national regulations

Structural safety

• Keep temperatures at reinforcement steel < e.g. 300°C (ZTV-Ing criteria)

resi

dual

str

engt

h

resi

dual

str

engt

h

Structural safety

• Avoid spalling of concret

Tensile strength of HPC

Tensile strength of OPC

Vap

our

pres

sure

[N/m

m²]

Temperature [°C]

Vapourpressure

Destruction of concrete due to:

• Limit concrete deterioration

Structural safety

Bornemann, Roland et al.: fire restistance of UHPC. IN: beton, p.418-422 (9/2002)

Measures for structural safety – ZTV-ING

• peak temperature at reinforcement shall not exceed 300°C

• concrete cover of 60mm plus N94 mesh keeps concrete cove r in place when spalling starts

• further measures are not taken – is that sufficient?

With N94 mesh

Check*) of ZTV-criteria

*) Dehn, F.; Nause,P.; Juknat,M.; Orgass, M.; König, A.: Brand- und Abplatzverhalten von Faserbeton in Straßentunneln. IN: Berichte der Bundesanstalt für Straßenwesen Heft 73B

Tubbingconstruction

Open construction

Fly ash

HWRA

water

Aggregates

Fibres

CEM I 32,5R

Fly ash

w/c(eq.)

w/c

Open construction

ZTV-Ing fire curve and effect on open construct.: steel d12/15mm test with N94 mesh

Thermocouples at 60mm

Thermocouples at 3 – 60mm

ZTV-Ing fire curve and effect on open construct.: steel d12/15mm test with 2kg/m³ PP-fibre

Thermocouples at 60mm

Conclusion:

• No spalling possible because of a porous structure >60vol-%

• better insulation properties

• easy to replace

•Concrete is not kept from spalling by using a N94 mesh

• This is an unreliable approach

• PP-fibres enhance performance

• PP is not perfect because the ZTV-Ing- criteria of <300°C at 60mm is notxfulfilled in all parts

• Concrete cover nevertheless is destroyed > repair with sprayed concrete

Improvement

Solution = porous tunnel lining system

• concrete cover can be reduced > savings• Lining boards can be used as formwork > savings

Positive side effects

Complete heat consumption

At 1.200°C = cp + phase change =

For a 30mm board = 11.700Wh

This equals 19Liter/m² of water

Fundamental idea: consumption of energy from fire

Porous structure: No spalling possible > room for vapour expansion

Stark et al.:Durability of conrete

Calcium Silicate phases dehydrate

� 3CaO*SiO2 + 3*H2O

� 24wt.% are chemically bound water

Ca(OH)2 about 25% of cement weight

Example: tunnel ceiling with 20mm board as lost formwork

Boards 20mm

ceiling

Concrete cast on fireprotective board withoutfixations

Test setup:

• temperature and duration according to ZTV-Ing

• Thermocouples at interface and at 50mm

In order to simulate this setup test according to ZTV-Ing on a furnace

150

20

50

1200

Thermocouples 7 and 8: 50mm fromconcrete surface

Results

∆ 220°C

Conclusion 1:

• ZTV-Ing (car) criteria of 300°C over 90 minutes can be m atched with a reduced concrete cover (e.g. cmin 40mm exposition class XD > EC2-1-1/ZTV-5)

• Spalling is avoided by highly porous material

• Fire protective board can easily be replaced (anchored version)

Conclusion 2:

• In order to take advantage of a reduced concrete cover, the material mustsufficiently resistant against frost and thaw

• If not it will deteriorate and no longer offer a sufficient fire protection

Water spray, splash water and leaks > sources of water

Passive fire protection boards should withstand frost

According to ZTV-Ing Part 3 tunnel members should comply with the exposition classes:

� Ceilings exposed to spray = XF2/XD2 (modestly water saturated + deicing agent/Clorides)

� Ramps and portals (spray and splash water) = XF2/XD2

Cementious boards underneath a leakybutt joint Water sprag at portals

Test method: EN 12467 „fibre reinforced boards“

�100 Cycles (class X for all usages, exposed to weather) �Frost (-20°C) / deicing in water bath (20°C) � Comparision of bending strength of frosted/unfrosted samples

(ratio of bending strength >0,75)

Problem: X-class can´t be matched with XF2

Deicing in water Frosting

Surface resistance to thaw and deicing agents

Test method: Slab test (Ö-Norm B3003), 56 cycles

• Guideline „Protective coatings for enhanced fire protection in undergroundtransport systems of the austrian association of concrete and engineering

Number of CyclesScaling

Exposition class Scaling [cm³/m²]

XF4 = for road tunnels without protective coating for portals

XF2 = for road tunnels without protective coating in frosted areas

XF2 = XF 3 = for road tunnels with protective coatings

Surface resistance to thaw and deicing agents

Uncoated specimen > Test method: Slab test > extrapolation of 25 years of use

Before cycling

After 56 cycles

Exposition classes XF1 / 2 / 3

• Guideline „Protective coatings for enhanced fire protection in undergroundtransport systems of the austrian association of concrete and engineering

Surface resistance to thaw and deicing agents

After 56 frost and deicing cycles

• Epoxy coated surfaces

Exposition classes XF1 / 2 / 3 / 4

Other fire curves are more challenging in terms of temperature and duration –what can we do?

Higher requirements than ZTV-Ing:

Femern-belt-Tunnel

RWS 180 minutes

Comparison of ZTV-Ing.-curve versus RWS-curve with regard to temperatureof steel behind 60mm concrete cover*)

*)Dehn, F.; Hauswaldt, S.; Juknat, M.: Grundsätzliche Überlegungen zur Brandprüfung von Tunnelbauteilen. IN: Beton- und Stahlbetonbau 104 (2009), Heft 12

ZTV-ING curve 140 minutes

Exposure to RWS-curve over120Minutes and defined coolingafterwards

Concrete with 2 kg/m³ PP-fibre addition (mix 1)

Concrete with 2 kg/m³ PP-fibre addition (mix 2)∆ 300°C

Elevation:

RWS 120 with 40mm and anchored boards

Temperatures on concrete surface

Elapsed time [min.]

tem

pera

ture

[°C]

Thermal analysis of fire protective board lined walls• finite element analysis

• unidirectional

• parameters: λ(temp), α and enthalpy > dE/dtemp

Layer temperatures 20mm boards with equilibrium moisture and firecurves according to ZTV-Ing and EBA

�Good match between measurement and calculation

� substitute for real fire test

Inner surface

Outersurface

Objectives of a protection system

• Structural safety �

• Protection of users (self rescue, 15 minutes)

• Third party rescue (fire fighters)

EC guideline 2004/54/EG to improve safety in tunnels

Emergency exits accord. to RABT every 300m > retrofit sometimes difficult

Alternatively smoke extraction system > installation at night shifts

Idea: retrofit of existing tunnels with prefabricated smoke extraction ceilings

Example: Elbtunnel Hamburg, tube 4 (Kaefer Construction)

• 3100m long – transverse smoke removal

• smoke extraction every 60m by four extraction flaps

• 1700 prefabricated elements with Aestuver 2x50mm boards

• Installation speed 10 – 12m per night (8h shift, closin g of tunnel)

� Quick and effective installation overnight� Design according to ZTV-Ing 5

> Stainless steel substructure class II (ZTV-4 betriebstech. Ausstatt.)> matches 300°C criteria for steel substructure> average surface temperatures < ∆140K> leakage <10Vol.-%

� Complies with RABT-requirements> tunnel longer >1200m > smoke extraction via electric driven flaps> adjustable flaps at a distance of 60m> Air extraction approx. 240m³/s

Idea: retrofit of existing tunnels with prefabricated smoke extraction ceilings

Film

Other ways to make installation easier

Wesertunnel

Experience of safety –

or what people prefer

What should be changed?

Which are the prefered colours?

Andreas Mühlberger, university of würzburg:behaviour of humans in tunnel. IN: Solid² conference 2012 in Berlin

Epoxy coated surfaces

Light blue Patterns Orange

Gloss