precast 1 concepts pdf

Dr. Kim S Elliott

University of Nottingham, UK

The Design and Construction of Precast Concrete Structures

www.nottingham.ac.uk

Lecture course and frame design workshop

KL : 24-25 July 2006

KK : 27-28 July 2006

Programme:1. Conceptual issues and architectural features

2. Precast concrete in mixed construction

3. Precast flooring and composite slabs

4. Precast frame analysis and components

5. Diaphragm action and frame stability

6. Connections

7. Progressive collapse

8. 10 storey frame design exercise

+ Special presentation from Belgium (May 2006)

Conceptual Issues and Architectural Features

The Design and Construction of Precast Concrete Structures

Precast concrete – friend or foe

?

Precast concrete – friend ……

Vaux

hall

Cro

ss, L

ondo

n, 1

995

Precast concrete – … foe

Prec

ast w

all f

ram

e, c

196

0, M

anch

este

r, U

K

Padd

ingt

on S

tatio

n, L

ondo

n.

7 September 2003

“British Precast” – concerted efforts

Aalborg’s prize winning staircase

Prec

ast s

tairs

for T

ubor

g, D

enm

ark

and many special projects ….

UK Concrete Society Winner …

Cam

brid

ge S

cien

ce P

ark,

UK

, 198

8

and Loser !

Nat

iona

l Bui

ldin

g Fr

ame,

Por

tsm

outh

Uni

vers

ity, U

K, 1

966

..and all in safe working conditions ?

DO YOU KNOW THESE MEN ?

Contents

Background to the problem

Conceptual Issues and Architectural Features

Contents

Current climate for precast concrete

Contents


Buildability of skeletal frames

34

Contents



Integrated architectural structures

4

Contents




Discussion and future developments


Understanding the basic principles of precast concrete design and construction



Infill wall diagram

DIAGONAL TENSION


Diagram of floor slab with no tie steel and screed Bournemouth




FRICTION

END REACTIONNO TIE STEEL


Spalling photo Bournemouth Spalling


500 kN connector made and tested

Wel

ding

bra

cket

s fo

r Llo

yds

of L

ondo

n


100 % repetition increases productivity by up to 50 %

3.6

m w

ide

hollo

w c

ore

floor

s, M

GM

Hot

el, L

as V

egas

11 m x 3.6 = 40 sq.m per unit


Modular construction - repeated 360 times

Sim

mon

s H

all o

f Res

iden

ce, M

IT, U

SA


‘Egan Report’ 1998Rethinking Construction :

… sustained improvement targets:

10 % savings in capital costs

10 % reduction in construction time

20 % less defects

20 % improvement in predictability


Egan Report called for maximum use of standard components and processes ….


Egan Report called for maximum use of standard components and processes

Prec

ast c

oncr

ete

tow

n ne

ar to

Hel

sink

i


Stack cast wall panels in Far East

Stac

k ca

st p

anel

s at

Joh

orB

aru,

Mal

aysi

a


Economic indicators of

precast concrete

C factor =Cost of 1 day skilled labour

Cost of 1 cu. m. insitu concrete


UK where ratio of factory/site labour costs 1.5 – 2.0 : 1

Let C = 1.0

LABOUR £40-50

RC £50

Not

tingh

am U

nive

rsity

, UK

, 200

3


Scandinavia C = 1.4

LABOUR €120

RC €80-90

Arla

nda

Airp

ort,

Stoc

khol

m, 2

000


Southern Europe (Italy, Portugal)

C = 0.7

LABOUR €50

RC €70

italy

Current climate for precast concreteLABOUR US$40

RC US$75Brazil

C = 0.55


Australia

C = 0.5

LABOUR AUS $65

RC AUS $130

Economic indicators for precast concrete

Hong Kong

C = 0.2

LABOUR HK$100

RC HK$480


Far East (e.g. Malaysia)

C = ?

Scho

ol B

uild

ing

at K

uant

an, M

alay

sia,

199

4

italy


Far East (e.g. Malaysia)

C = 0.2 - 0.3

LABOUR R 50-70

RC R 180

Scho

ol B

uild

ing

at K

uant

an, M

alay

sia,

199

4

italy



precast concrete

Crane factor =Daily hire of typical crane

Daily labour rate

50 t mobile over 3 months


Crane factor UK

Scandinavia

Europe

Far East

Brazil

Australia


Crane factor UK 8 - 12

Scandinavia 6 - 10

Europe 10 - 15

Far East ?

Brazil 15 - 20

Australia 17 - 20


Crane factor UK 8 - 12

Scandinavia 6 - 10

Europe 10 - 15

Far East 25 - 30

Brazil 15 - 20

Australia 17 - 20



precast concrete

Factory and site labour efficiency

Man x day / sq.m.


Case study is 10 storey frame of area 16,000 m comprising :

RC Columns

PSC Beams

RC Walls

RC Staircases

200 deep PSC hollow core slabs

60 mm insitu concrete topping

2


Man x day rate

RC Columns 2.5 / cu.m

PSC Beams

RC Walls

RC Staircases

PSC slabs

Insitu topping

UK rates 1996-2000


Man x day rate


PSC Beams 2.0 / cu.m

RC Walls 2.2 / cu.m

RC Staircases 3.2 / cu.m

PSC slabs

Insitu topping

UK rates 1996-2000


Man x day rate


PSC Beams 2.0 / cu.m

RC Walls 2.2 / cu.m

RC Staircases 3.2 / cu.m

PSC slabs 0.13 / sq.m

Insitu topping 0.05 / sq.m

Average = 0.35 – 0.40 man days /sq.m.

Contents


34

Buildability of precast skeletal structures

Dimensional stability to within 6 mm


Precast Concrete Technology

Cube strength : 50 – 100 MPaVariation : 3 - 5 MPaWater / cement ratio : 0.3 – 0.4PFA : < 30% x cement contentSelf compacting concrete in all precast factoriesRecycled concrete coarse aggregate : < 20%18 hour strength : 20 – 30 MPa Shrinkage strain : 150-300 x 10-6


Stockyard after 24 hours

Prec

ast b

eam

s fo

r Llo

yds

of L

ondo

n


6 st

orey

col

umns

at G

rand

isla

nd, M

anch

este

r

Column pitching on-site Day 1


Fixing shear walls by Day 5

Shea

r wal

ls a

t Gra

nd is

land

, Man

ches

ter


Fixing beams by Day 8

Bea

m-c

olum

n bo

lted

conn

ectio

n


Fixing prestressed slabs by Day 12

16 m

spa

n x

400

mm

dee

p ho

llow

cor

e flo

or u

nits


Skeletal structure after 4 weeks

Dud

ley

Hill

sho

ppin

g ce

ntre

, Birm

ingh

am, U

K


Parking structure after 4 weeks

Cro

ss s

pan

car p

ark,

UK


Parking structure after 5 months

The

Big

App

le, H

elsi

nki


500,000 sq. m Europark, Italy


218 m

192

m


218 m

6 expansion zones, mainly 75-100 m x 75 m


Shopping centre after 6 months

Kep

ong

Mal

l, M

alay

sia


..in spite of interruptions!!

Kep

ong

Mal

l, M

alay

sia


Frame and wall construction in Sydney


Speed of precast constructionm per week

Floor bay area

100 m

75 m

50 m

Floor bay = beam span x slab span

2

2

2

2



Floor bay area < 4 storey

100 m 1000 - 1500

75 m 900 - 1200

50 m 700 - 1000

2

2

2

2


Speed of precast construction?? m per week2

2

2

2


Speed of precast construction1200 m per week2

2

2

2



Floor bay area < 12 storey

100 m 600 - 900

75 m 400 - 700

50 m 300 - 500

2

2

2

2

Contents


4

Alternative finishes

Natural stone

Polished granite

Acid etched

Grit blasted

Polished

Recon Portland stone

Recon sandstone

Brick slips/halves

Pigments

Paint

Spun columns.

Opera House, Erfurt, Germany (2006)c. BFT Journal 26 March 2006


RM6000

per sq. m !!

Contents

Discussion and future developments

Future Developments

Self compacting concrete, now upto C90

Future Developments

Self compacting concrete with 1% volume steel or polypropylene fibres

Future Developments

Self compacting concrete: surface crazing, corner bleeding and mould oil patches

Future Developments

Mixed construction and SCC (New Wembley terraces)

Future Developments

Accurate SCC surface finish: 2 mm depression / 3 m length

Future Developments

Prestressed tee beams

Double – tee slabs

Future Developments

75 kg/m Termacol floor units2

Future Developments

Robotic formwork

Future Developments

Concrete delivery

Future Developments

Future Developments

Split skin system

Phase 1

Future Developments

Split skin systemPhase 2

Future Developments

Split skin system

Phase 3

Future Developments – mixed construction

precast 1 concepts pdf

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