civil works for pilkington industrial complex

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UDC 624

Paper to be read beforehe Inst itut ion of Structural Engineers at Upper Belgrave Street, ondon SW l X 8BH, on Thursday8 November 1973

Civil engineering wo rks for the new float glass

plant for Pilkington Brothers l im it ed St. Helens

J.

D.

Harr is

BSc(Eng), CEng, FIStructE, FICE, FIMunE, MConsE, FIE(Aust)

Partner. Harris Sutherland

A

E.

Johnson, BSc(Eng), CEng, FICE

Chief Civil Engineer, Pilkington Brothers Limited

I./

,t

--

After service in the Royal Navy, Mr. J D. Harris joined the Surrey

County Council to work in their Highways and Bridges

Department. In 1951 he was appointed chief engineer of the

Prestressed Concrete Company n Australia and spent six years on

Asia. In 1957 he returned to London and set up

in private practice

design and construction work both inAustralia

and south east

wi th his brother and Mr. R. J. M. Sutherland. Since then he has

been responsible or the design of structures of all kinds, bridges

and industrial works. Both in the U and abroad he has

collaborated closely wi th contractors and manufacturers for the

design and erection of specialist precast concreteproducts. He is

a Miller prizewinner and Culrnann Travelling Fellow of the

Inst itut ion of Civil Engineers, and a Bronze medallist of the

Institution of Municipa l Engineers.

On release from the services, Mr. A.

E

Johnson spent three years

at Portsmouth Municipal College where he obtained an external

degree to London University. He then spent one year as a pup il

engineer wi th the Nigerian Railways, but on return to the

U

he

spent 12 years wi th the Central Electrici ty Generating Board. He

Palmer Tritton before joining Pilkington Brothers Limited where

then worked for the Portsmouth Corporation and for Rendel,

he has been chief ci vil engineer for the last five years.

Synopsis

A new loa t glass plan t has beenconstructed nside he

boundaries of the Cowley Hill Works of Pilkington Brothers

Limited, St. Helens. The site of the plant was extremely varied

due both to the natural topography and geology and to the

man-madeobstructionsofa very large ndustrial ipand

massive foundat ions for an o ldrocess.

A float glass plant t o produce massive quantit ies of clear

plate or windo w glass consists of fo ur major components: a

tank furnace operating at above500 C; a bath r flo at section;

the annealing section (Lehr); and the cutting and handling of

the finished product (automatic warehouse).

The Structural Engineer/October 1973/No. 1O/Volume 51

In constructing such a plant t o produce glass efficiently,

there are tw o major problems for the civil engineer, namely,

the dispersion of heat through the furnace column foundations

carrying loads of between 15 and

350

tonne (150 and350

ton) and the fact that each major component of he plant

must remain horizontal during ts working ife as well as at

precisely the same relative level to the aqo ini ng sections, in

spite of he arge expansions of steel and refractories. The

refractory ined tank must also retain the fluid molten glass

without leakage through the block joints.

Brief outline of the flo at lass process

There are fourmajor stages in he loat glass process,as

follows

:

Melting. The raw materials are fed into a tank furnace and re

meltedatabove 1500°C. From he ank hemolten glass

passes to the bath.

The bath, or float section. The ribbon of glass is ormed by

floating on a molten metal n an nert atmosphere t o give a

truly flat surface finish. The ribbon then passes t o the Lehr.

The Lehr, or annealing section.The ribbon

o

glass is annealed

and cooled at a controlledate so that it may be cut and worked.

Automatic warehouse. The finished product s cut nto trade

sizes and withautomatichandlingequipment ormed nto

packs for storage in the stockrooms or for direct distribut ion

outside the works.

This process replaces the old grinding and polishingrocess

in which cast glass was ground and polished to give ruly

flatand parallel surfaces. Theby-productof hisobsolete

process was a material known t o the glass trade as burgy ,

comprising fine waste sand, glass dust and cast iron. At the

endof he process theburgy became aslurry which was

pumped into agoons, thus progressively raisingthei r banks. In

thecentury or so duringwhi ch these operationswere in

progress, three tianks containing some 3 million m3

4

million

yd3) of burgy were formed, one within the works boundaries

on the site of the proposed float glass plant, and two in th e

immediate vicinity.

Descript ion of the site

The site chosen was alongside the existing float plants ith in

the boundaries of the Cowley HillWorks, St. Helens. The area

availablecontained he old discgrindingshedwithplant

foundations some 7.6 m

25

ft)

deep, aburgybank some

9

m 10.6 m (30 ft 5 ft) above ground level, and a .river

valley in which he water evelwas15.2m 50 t)below

ground level.

347



Main civ i l works

The main civil works were s foll ows :

demolition of existing buildings and their foundations

culverting of Rainford Brook for 333 m (1 100 ft)

levelling and filling site

construction of tank furnace basement and main buildings

whichcompri sed: he ank urnace house, bath house,

Lehr building, automaticwarehouse, S2 stockroom, finished

size stockroom, Lehr end size stockroom

construction of reinforced concrete chimney of0 m (300 ft)

in height, ervice ucts, ncillary uildings,oads nd

railways.

Geology

The Cowley Hill Workswere established originally on the high

ground to the west of the flood plain of Rainford Brook, and

the waste products of the glass-making process consisting of

ash, cullet (scrap glass) and burgy had been used for ill ing

the old alley. The result was hat Rainford Brook was confined

into

a

narrow ravine on he eastern side of the plain and

a

burgy bank had been formed some 24.3 m (80 ft) above the

normal brook level.

The St. Helens area is a highly faulted complex of the coal

measures overlain with drift consisting mainly

f

boulder clays

and sands. For this reason, a detailed sub-soilsurvey involving

some 300 boreholes was completed before the work began.

Simplified soil profiles are shown in Figs 4 and 5. The profiles

were further supported by the evidence from the batch plant

foundations constructed in 1968 and fromarlier investigations.

Generally, the stratum dipped rom south west to north east

across the site with sandstone at, or about,basement wall

foundation level in hesouth western ornerof the ank

house. This was further confirmed when the excavation was

completed at chimney base level. Along the line f the Rainford

Brook and beneath the base level of the proposed culverthere

was 3 m

4 . 5

m (1

0

t 15 ft) of soft alluvium. These con-

dit ions wou ld have produced arge differential settlements of

the completed structure and would have equired expensive

temporary works for construction. Boreholes sited to the east

of the existing water course showed that the alluvium ran out

andwasplacedbyboulder clay. It wasbysiting henew

culvert along his ine hat he whole operation was carried

out in open cut with the exceptionf the south end.

A coal seam was ocated beneath he ank basement but

this did notcause concern because it was not within a signifi-

cant distance. As a precaution combustion tests were carried

out on the upper shales, bu t the results showed less than one

per cent of combustible materials in

all

samples.

Coal measures and mineshafts

There have been extensive workings of the coal measures in

the St. Helensarea over the last two centuries. Some ndication

of past activities is shown by the fact that some 29 old mine-

shafts exist within the boundaries of Cowley Hill Works.

The measures beneath the sitehad not beenworked or

some 100 years

so

there were no subsidence problems from

this source. It willbe noted that here were several shafts near

the new line. These were owned by the National Coal Board

and could not be built over unt il consolidated t o their satis-

faction. The procedure equired by the NCB was s follows :

1. locate byprobing he shaft whichcould becovered

by feet of fill (in one case a t Cowley Hill to

a

depth of

17.1 m (57 ft) )

;

2. drill to the bottom f the shaft;

3. backgrout he shaft wit h PFA cement gro ut;

4 cap off theshaft

a t

rock head or where this was at depth,

pressure grout

a

series of boreholes from rockhead to

ground level to form

a

solid plug.

This was

a

costly and aborious operation, and at Cowley

Hill-although the NCB had checked the location-only one

shaft out of seven which we tried to ocate n order to con-

solidate has been found. In one case, some 15 0 probes were

sunk before agreement was reached thathe shaft had merged

with the sub-strata and hat we could acquire the shaft and

proceed wit h the works.

Rainford Brook culvert

RainfordBrooks ontrolledbyheMerseyand Weaver

River Boardwho, as a matterofpolicy, do not permit ong

culverts although they did agree to the proposal on the basis

that heculvertcould pass a 1 in 5 year flood of 1100

seconds3. On this basis a cross-section for flow was 17.2 mz

(1 85 t’), wit h

a

dry weather channel of 8.1 mz (27 ft’).

Whatever construction was used the culvert would have to :

-have an indefini te ife with minimal maintenance.

ustain heavy irregular loading during construction

-sustain up to 16.2 m 54 t) of fill ndefinitely

-resistandomattack from corrosivemedia from the

Steelculvertsectionswereconsideredanddiscarded ona

short life basis, whilst their use as permanent formwork would

have beenuneconomic.Concretebox sections, in s tu or

precast, were examined, but discarded on economic grounds

and because of theancient argument thata structure i n tension

would not withstand ong-term oading n bad conditions, or

wi th inevitable maltreatment during construction, as would

a

structure designed to act in compression.

A more economic and satisfactory solution was ound to

be an insitu concrete two-pinned parabolic arch 0.46 m (1 in)

thick with 50 mm (2 in)over to the twoayers of high tensile

reinforcement. The links and spacers were of mi ld steel.

Thedesignof the culvert had to take in to accountvarious

loadings

-fill-embankmentondition (very wideub-trench

ill- wide sub-trench condition

uperload due to buildings and contents over

A loading on access road a t new ground level

onstruction plant passing before fill is placed

orizontal earth pressures a t construction period.

The bearing pressures under the footings were within the

limits of the ground as revealed in the borings. However, extra

excavation had to be carried out n some sections where, on

inspection,ariations ad ccurred. heoncrete ad a

minimum design strength of 26 N/mmz (3750 bf/inz), using

sulphate esistingcement. Extra protect ion against chemical

attack from he ground and ground water was provided by

three coats of Tretolastex over the arch. The base was cast

against three layers of Visqueen wit h lapped and rolled joints.

The total length of the culvert was 333 m (1 100 ft)nd it was

cast in lengths of 9 m (30 ft) . Expansion join ts were made at

36.6 m (1

20

ft) intervals, but contractors and settlement oints

were at 9 m (30 ft) intervals. The minimum concrete strength

of 13.8N/mm2 2000 bf/inz)was requiredbefore striking

shutters.

Fill around he culvert was designed to be carried out n

compacted 600 mm 2 ft) thick layers simultaneously on both

sides, but weather conditions prevented this and a condition

arose where

a

considerable surcharge was made on one side

of the culvert which moved

it

1.283 m (4 ft 2 in) ou t f line.

Due to the choice of construction, no damage was ncurred

and the culver t was left in itseflected state. The opened joints

were f illed with

a

9 mm ( in) aggregate concrete.

The culvert was constructed in open cut up to the junction

with the existing brick culvert, at the point where the existing

culvert changed rom

a

tw in to single circular brick section.

This point was some 7.6 m (25 ft) away and 15 .8 m (52 ft)

to invert from the main railway access to the works and thus

required careful consideration.

industrial waste in thearea.

348

The Structural Engineer/October

1973/No 1

O/Volume 51



Fig 1 Locat ion p lan

Three sides of the rectangular chamber were formed using

theentoniteiaphragmwallechnique. As excavation

proceeded the three walls were exposed and braced apartith

a steel frame. When the new culvert section had been cast up

to he U-section of diaphragm walling, he ourth wall was

cast, thus closing the gap.

arth moving

Burgy is

a

man-made material being the residue from the past

glass-grinding processes. Merseygritcombined wi th emery

wasoriginally used as anabrasive under rotating cast iron

runners to grind glass whil e it was held n position on a wet

bed of gypsum. The composition of burgy s approximately

90 per cent of

a

rounded silt sized siliceous material with the

remaining percentage cons isting of particles of cast iron,glass,

gypsum and ewellers' ouge. As a waste material this was

dumped on he burgy bank ip by means of suspension in

water. The burgy bank was started in 1875 and believed o

be last used fordumping n he1930s. n he meantime,

woodland had been planted and thearea had become

a

nature

reserve for the animal kingdom. The bank would have to be

moved but was found o be in a hard state because of he

cementitious action of the gypsum, the method of deposition

and age. It was doubtful if, after moving, the hard state could

be reinstated in the time available.

During compaction rials before he start o construction,

burgy was aken rom various parts of the ip and found o

have a moisture content of about 35 per cent. This was after

a

long dry summer hence it was fair tossume that the minimum

moisturecontentofburgyunder hebuildingswas never

likely to all much below 30er cent. This is againstn optimum

moisture content of 27 per cent. Earth moving was begun

using ubberwheel scrapers and

D9

bulldozersbutwithin

three weeks it was apparent that this method was noteasible.

Continued unningon henewlydepositedburgyplus ain

did not permit the compaction of the materialnd

it

also made

it impassable. To continue operationso meet the glass-making

target date, theburgywasexcavatedby71 R.B. Cranes

equipped as face shovels, transported in Euclid trucks and end-

tipped. I n moving some 0.38 million m3 (0.5 million yd3) of

burgy, some 38 000 m3 50 00 yd3) of quarry waste etc. was

used toprovide unning roads, but heoperation eftun-

compacted burgy, which gave settlement problems.

Settlement problems

It is essential that n a continuous ine process, such as float

glass, each element-tank, bath, Lehr, and cuttting line-must

remain horizontal and at the correct relative evel to the next

element throughout he ine. n these buildings and hose

adjoining it was necessary that hedifferentialsettlements

should be kept small for the following reasons:

-t o ensure that hebuildingswould remainwatertight

for he ife of the structure:

-t o allow the safe and continuous operation of fast over-

head travelling cranes;

- s o

that the pallets when fully aden with glass could be

stored ourhigh providing heslopedidnot exceed

25 mm n 3 m

1

in n

10

ft))

;

o

that in the

area

of the glass storage racks, differential

settlementwouldnot exceed 25mm n

3 9

m

1

in

in 13 ft)


1973/No. 1

O/Volume

5

349



Fig

2

Simpl i f i ed s i te p lan

F ig

3

Aer ia l v iew of s i te before const ruct ion

- s o that the front nd side loaders who would be handling

glass packsof he order of 10 tonne

10

ton)could

safely traverse all operational areas of the warehouses.

The above limitations imposed restraints on the design of the

structure and there were the following complications of the

site

:

-the sub-stratum at the underside levelof the tank furnace

basement slab lay partly on compacted sand and com-

pressible boulder clay. The tank urnace column loads

varied from 150 -3 30 tonne 150- 330 on) and he

heat affected the clay;

-the site of the bath building nd foundation consisted of

loose fill verlyinghe rift material which was in

places some 2.4 m

7

ft

10

in) below the finished level;

-th e Lehr building also Lehr endstockroom)and he

plant oundation covered the area on which the burgy

bankwassi tuated,andthusgavegood

bearingconditions;

-t he remainder of he main buildings and plant were toe

sited over the area of newly tipped oose burgy fill and

an old waste tip.

To liminatehe roblems of ifferential ettlement,he

following action was taken :

-tank suppor ting steelwork large diameter bored piles

-bathuildingnd slab vibroconsolidation

ehr, Lehr buildinganddirect oundingon he

and bath foundation

Lehr end size stockroomundisturbedconsolidated

stockroomolduildingoundations,iled

utowarehousendloor slabs, vibroconsoli-

-finished size stockroomdirect oundingon he

burgy

l

dated

undisturbed consolidated

burgy

-automatic uttingine art large iameter ored

piles

Design and con struction

o f

low level tan k b asement

Genera l

The area inwhich hewallshad obeconstructedwas

encumbered by old works, some known and some unknown,

which founded t about half the required heightf the proposed

tank walls. These oldworkscomprisedmainlyengineering

brick combined with mass concrete slabs and steel and cast

iron sections. The total depth of these from ground level was

7 6 m 25 t). Three solutions were onsidered in the foll owing

order:

-steel sheet piling with ties;

a 1.5 m 5ft) thick reinforced concrete wall tied back;

-a diaphragm wall with counterforts.

The sheet pili ng scheme was rejected because nobody could

be sure there would be no further underground obstructions.

Phis proved obe

a

wisedecision despite theeconomic

savings thatcommended it Theother tw o schemes both

allowed orconstructionup to half he inishedheight n

excavation ndhe rest free nd backf illed behind. The

diaphragm wall scheme, as wel l as costing 1 per cent more

350

The Structural Engineer/October 1973/No.

1

O/Volume 51



Y S

S H A L f

6 MU D S1

OHE

B B

T Y P I C A LE O L O G I C A LO N G I T U D I N A LE C T I O N

T H R OU GH

T A N K

B A T H

Fig 4 Geolog ical sect ions in furnace and bath area

than he concrete wall scheme,also had he disadvantages

of that technique, i.e. the disposal of bentonite and spoil, the

requirement of a working area, and would have had

a

finished

concrete appearance. The scheme adoptedwas he1 e5 m

(5

ft)

thick reinforced concrete wall ith ties to anchor blocks

the dimension of 1 e5 m being the practical minimum for men

to work in. The base slab was reinforced and varied in thick-

ness from 753 mm (2 ft 6 in) to 543 mm (l f t 6 in) depending

on the superimposed oads. Blind ing varied from 75 mm (3 in)

to 153 mm (6 n) thick, the greater thickness being over the

clay areas. This scheme had the advantage of taking less time

to construct, and the contractor was able to carry it through

efficiently and economically.

Tank foundation

Lo

W level area

The foundation was primarily 24 1 a053 m (3 ft 6 i n) diameter


l 5

boredpileswhichhad anaverage length of 5.2 m 17 t).

They wereeach toed 305 mm (1

t)

into firm rock. he concrete

was 26 N/mm2 (3750 Ibf/in2) using sulphate resistingement.

1.6 mm (1 6 gauge) x 3 m (10

ft)

long x 1 e053 (3 t 6 n)

diameter steel liners were placed evel wi th the cut-off evel

of the piles. These liners gaveextra protectionagainst he

variable sulphate ontent in the round nd houldhe

furnace heat penetrate the ground, the liners would also hold

the top of the pile together.

High level area

The foundation was again mainly 24 1a053 (3 ft 6 in) diameter

boredpilesbut in his case theyhad anaverage length of

10.9 m (36 ft). A s the heat problem was not so acute as in

the low level basement, steel linerswerenotemployed. In

both the high and low level areas the piles were capped with

0.9 m (3 t) thickness

of

highaluminacementconcrete to

act as

a

heat barrier to the pile.

351



-_

T Y

P l C A L O N G l T U D lNA L GEOL.OGICA-L->ECTION THROUGJ VA_LLE _V_

T Y P I C A LO N G I T U D I N A L G EO -L OG IC AL S E C T I O NH R O U G HE f l

Fig 5 Geolog ica l sect ions In L ehr and warehouse area

Genera l

The main civil engineering problem encountered in thedesign

of oundati ons or ank furnaceswas aused by lackof

knowledge of underslab temperatures and

on

the heat osses

through the bases of the regenerators. The emperatures en-

visaged would cause

a normal concrete base slab to disinte-

grate and the ground beneath to become very hot. It had been

considered that ventilation underneath the regenerator, either

by naturalor orceddraught,couldkeep he emperature

within reasonableoperating limits or he concrete. If he

amount of ventilation required were underestimated, however,

there would have been the problem of keeping he air space

clear of debris whi lst too much entilation wou ld increase the

costs. Furthermore, any heat removed wou ld be a loss of heat

from he regeneratorand

it

would need tobe replaced by

more fuel. It was decided, therefore, that

it

woul d be better to

avoid heproblem han ry to overcome it. Thishadbeen

donepreviously n

1966

byconstructing he base lab in

refractoryconcretecomposed

ot

highalumina cement wit h

a firebrick aggregate.

Temperatures

Temperatures normally experienced below the 75 mm (3 n)

firebrick lining covering the reinforced concrete raft ere

:

a t

thebottomof he regenerator 55OOC

inhenterconnectinglues 450°C

mainhimney pulllue 400°C

352

L

.1

n

I 5

The maximum temperature for the use of reinforced concrete

in PortlandCements 15OOC. Theemperature at whi ch

PortlandCementconcretes made wi th siliceous aggregates

breaks down whe n subsequently cooled is 250

-

300OC. The

breakdown is of tw o types

-

mechanical and chemical

:

the expansiveeffectsof iliceousype aggregatesover

lime s released from he concrete in he orm ofquick

limewhich subsequently s slaked as the concrete s

cooled down.

Specia l concre te mixes

The following concreteswere used in he areas where he

heat would affectrdinaryortland Cement reinforced

concrete

:

Pi le cap covers A concrete composed of Ciment Fondu and

Firebrick aggregate produces

a

concrete of 17

-

20 N/mm2

(2500

-

3000 Ibf /in2) ompressive strength under temperatures

up to 12OOOC. The mix used wa s:

Cimentondu

1

part

Fine aggregate

2

parts byolume

Coarse aggregate 2 parts

Aggregate-35 per cent alumina crushed firebrick

Fine aggregate 3 mm

X

in)-dust

Coarse aggregate 1 9 mm (% in)-3 mm

(%

in)

3OOOC ;


1973/No. 1

O/Volume 51



Fig 6 Furnace basement

/

Type

2 c f r o c t o r y o n c r t t c

j y p a r e f r a c to r y

c o n c r e t e

t-<

4, S o n d r t o n c

H I G H

L E V E LO W

T Y P I C A L P I L E S

Fig 7 Furnace pi les

with as low water content as possible. Strengths

a t

24 hours

were 6000 - 7 bf/inz. Strengths after fi ring a t 450 - 50OOC

were approximately 25.5 N/mm2 3700 Ibf/in2).

Grou nd s lab under regenerators The mix used was :

Cimentondu 1 part

Fine aggregate

Coarse aggregate

l

2 parts

by volume

2 parts

irebrick

Thewatercement ratiowas as lo w as possibleconsistent

wi th complete compaction water cement of

0.35- 0.4.

The

concrete strength after firing at 55OOC was about

25.5

N/mmz

3700 Ibf/in2). The maximum bay size in one pour was306 m

320 t2).

Stanch ion base plates

The dry packing under the base plates

of a 3 :l mortar with a low water content ratio made from fine

3 mm (?h n)-d us t) firebrick, 35 per cent alumina aggregate

andCimentFondu.

Peripheralareas

of

the tank basement

As the heat effects wou ld

be less, a refractory concrete of the fol lowing mix was used :

Cimentondu 1 part

Medium solite 1 part

by volume

Fine soli te 3arts

The water content ratio was

0.5.

This concrete produced

a

minimum cube crushingstrength of 6.9 N/mmz 1 bf/in2)

after firing a t 55OOC. The maximum bay size permitted in one

pour was 306 m Z

(320

h ).

Cold end foundations

The area covered by this complex of buildings-which includes

the S2, stockroom, the automatic warehouse and the finished

size stockroom-was largely the old ravine of Rainford Brook.

Thevalley ormedwas illed, as alreadydescribed, by end

tipping with depths of fill up to 15.8m 52 t) in depth. This

produced settlements over the f ill area because of :

compaction of the looseill under its own weight nd ground

water movements ;

varyingamountsdue to consolidationof heunderlying

compressible ub-stratum caused by constantly arying

depths of fil l across the area;

the different hicknesses of compressible sub-strata affected

by the fill.

Apart from he building column loads the plant loadswere

generally not significantcompared wit h thesuperimposed

loads of the fill, namely 20 to 30 tonne/m2 2 to 3 ton/ft2).

Based on he opography of the site and wit h the above

information in mind, a plan was prepared which showed the

predictedettlements across the site. This howedhat

settlements up to458 mm 1 8 in) could occur across the site,

while within 15 m

(50

ft) spacings there could be differential

settlements of the order of 75 mm to 127 mm 3 n to 5 in).

Such results were clearly unacceptable in view of the criteria

for the storage racks and the bui lding structures.

In 1968 the vibroconsolidation technique was successfully

used to eliminatesettlements on heoriginal S1 stockroom

which was constructed on loosely tipped fill of ashes, glass,

bricks, etc. The structure was monitored for a year after com-

pletion but no ettlement wasobserved. The vibroconsolidation

process was then investigated for the end of the line, and a

similar plan was prepared which showed predicted settlements

after treatment. The results showed that by setting the floor

slabs high a t the outset, the final positionfter settlement would

be within theacceptable limits. Thisprocess was thus adopted

for the floor slabs.

B y

superimposing the column grid on the

layoutplan

it

was evident that there would be differential

settlementsbetweencertainpairsof frames of the order of

75 mm 3 n) to100 mm

4

in) which was learly unacceptable

if

a

watertight building was to be achieved. The problem was

caused by

a

large amount

of

fill on differing depths of clay

which were not affected by vibroconsolidation. The problem

could only be resolved by pili ng under the building columns,

but since these and the adjacent columns supported the crane

tracks thepilinghad obe extended to hewholeof he

buildings. As a further complication the stratum which would

not be affected by settlement, .e. the sandstone, was some

24 m to 42 m 80 ft to 140 ft) below foundation level, thus

large diameter bored piles were used. This decision was taken

wi th reluctance because due to the ground conditions some

40 to 50 per centof he otalpile design oad wou ld be

negative skin friction owing to the fill and sub-stratum with

an additional 10 to 20 per cent or heself-weight of the

ground beams spanning between the piles to carry the dado

brickwork.

Because thedifferential settlement limits weregenerally

tighter or S2 stockroom, the probesweresunk

a t 1

a 8 m

6 ft ) centres on an equilaterial rangle over the area to an

average depth of 10.6m (35 ft). Elsewhere 2.1 m and 2.4 m

7 ft and 8 ft ) spacings of an average depth of 6.7 m 22

ft)

were used.

Tank furnace house steelwork

The tank furnace house steelwork followed the ou tline of t he

basement walls (seeFig I O ) with bay centres arranged as

shown in Fig 13. The design parameters for the frames were

as

follows :

loading to CP3 : Chap. V ; Pt I ;

wind loading to CP3, Chap. V : Pt II using the wind speed

for the area with a 1 in

5

year probability actor;

The Structural Engineer/October 1973/No.

1

O/Volume 51 353



INSPECTION

C H A H B E R .

Proposed new road

-

trrincdiatc ins

GENERAL RRANGEMENT

OF

RAINFORD BROOK

CULVERT

76mm.(J )blinding

7 926 m(2603

REINFORCEMENT

To

CULVERT

SECT IO N

TYPICAL CULVERT

SECTION



T A N KU R N A C E

S U P P O R T I N G S T E E L W O R K

S E C T I O N

A A

Fig 9 Furnace support ing steelwork

D E T A I L

Fig 10 Furnace hous e steelwork


D E T A I L

OF

K N E E

_-

E T A I LTP E X

3 5 5



Fig

l l

Furnace basement -o ld foundat ions

Fig 13 Furnace suppor t s tee lwork -h igh leve l

Fig 12 Furn ace basement-walls

loading due to 3.34 m (1 l f t) throat monitor ventilators;

provision for loadings fromservices, etc. of 1 tonne 1 ton)

an estimated rise in ambient temperature in the bui lding o f

From these parameters ahree-pinnedportaldesignwas

selected sincehis would givehemaximumlexibility,

particularly with the temperatures anticipated in the building.

The frames were abricated rommild steel andhigh-yield

steel autofab beams, withmade-up haunches. Sincehe

services provisions were not fixed t was necessary to analyse

the frames as follows:

loads at 3.7 m (1 t) centres across the frames;

5OOC.

- ead load plus superload

-dead oad plus superload with ull services;

-dead load plus superload with services on one side only;

-dead load plus wind.

Frame numbers 2 and 3 were specially designed to carry the

tank urnace eedingequipment inaddit ion o he service

loads. It was fortunate that provision was made for theervice

loads because the feeding equipment during the development

of the design ncreased in weigh t by a factor f three between

the ordering of the steel and the erection of the equipment.

Other main features of the design were as foll ows :

-w in d reactions on he gable were carried through he

purlins in compression and tension and thence distributed

through the central bracing ystems do wn to he column

anchorages

-the roof purlins were stayed, thus a brace which also

restrained this langewasprovided rom hebottom

-th e portal knee was abricated in high-yield steel wit h

profiling and welding detailed to ensure transmission of

bending moment around the haunch;

-the rafters at the apex pin were shaped to transmit the

loadings hrough he centroid of the pin, and similarly

at the column bases;

-th e parapet to hebuildingwas ormedbya attice

girder which lso supported thesag rodsfrom the sheeting

rails.

l an k furnace supporting steelwork

The steelwork contractor proposed a novel solution to cater

for the expansion of the tank supportingrillage. The calculated

overall expansion was of the order of 1.71 m (4 ft 2 in) based

on measurements of thesteelworkofexisting anks which

showed a emperature of 150OC. The structure was anchored

near the central point by vertical bracing in wo planes whilst

horizontal bracings were provided over the length of the tank.

In each column was ocated a cast cup and socket bearing

at he opandbottom,

so thatshould there beanysmall

flangefheafter; Fig 14 Generaliew of si te Apr i l 97

356 Thetructuralngineer/October 1973/No.

10/Volume

5



m

1 I ,

Fig 75 Furnace house roof steelwork

movement no momentwou ld be transferred to the column and

the load would be virtually axial.

Organization

The whole project was arried out under the overall control of

Mr. C. J. Schofield, BSc(Eng), FIMechE, FIEE, chief engineer

of

Pilkington Brothers imited. The direct control wasxercised

by Mr. D. N. Cledwyn-Davies, BSc, FIMechE, and the project

manager was Mr.

J.

G.Freeman, BSc(Eng), MIEE. Harris

Sutherland were responsible for the design of the tank base-

ment and building, the main plant foundations, and Rainford

Brook culvert andearthworks. The remaining civil engineering

workswere designed in he offices of PilkingtonBrothers

Limited, with Gerald

R.

Smith Partners of Belfast as consul-

tant architects.

Contractors

Mainivilontractorolland Hannen Cubitts

(North West) Limited.

Sub contractors

Piling

Cementation Piling Foun-

Vibroconsolidation

Cementation Ground Engin-

Road surfacing Val de Travers Limited.

dations Limited.

eering Limited

Structuralteelwork

RobertWatson Co.

(Constructional Engineers)

Ltd.

Fig 76 Furnace house Apr i l 7971

Sub

contractors

Cladding

Glazing

Folding doors

Ventilators : roof

side wall

Reinforced concrete chimney

Painting

Aerial survey

Site investigations

R. M. Douglas Limited

Crittall-Hope Limited

Mather

t

Platt Limited

H.H. Robertson (UK)

Limited

Crittall-Hope Limited

Tileman Company Limited

Hawkins Holmes Limited

Hunting Surveys

GKN Foundations Limited

Acknowledgements

The authors wish o thank the directors and the chief engineer

of Pilkington Brothers Limited for their permission to publish

this paper.

References

1.

2.

3.

4.

5.

6.

7.

AmSocCE Paper no. 2868, October 1957.

Rowe,

R.

R. Rigid culverts under high overfills , Transactions

Jones, G .

A.,

The construction o shallow tunnelsanddeep

Brown, C. B. Forces on igid culverts underhigh fills , AmSocCE.

culverts , f r o c .

South Wales lnst of Engineers

Vol. LXXV, June

1960, p.66.

Spangler, M G. The structural design of flexible

pipe

culverts ,

Iowa

Eng. Exp. Stn 1941.

Clarke, N W. B., The oads mposedon conduits laid under

embankments or valley fills , f r o c . ICE, Vol. 36, January 1967,

p.63;Wide renchcondition , f roc . lCE Vol.26,September

1963, p.105.

Keller, J. D. The flow of heat through hearths , American Soc.

of Mech. Engineers 1928.

Robinson, T. D., High alumina cements and concretes Contrac-

tors Record, 1969.


357

civil works for pilkington industrial complex

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