Construction Technology 3

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25 Νοε 2013 (πριν από 3 χρόνια και 10 μήνες)

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Construction Technology 3

D39 TA


Dr Mohamed Abdel
-
Wahab

Edwin Chadwick Building, Room 1.16

m.abdel
-
wahab@hw.ac.uk

www.mohamedabdel
-
wahab.co.uk




Lecture 5: Factory production

(Pre
-
cast concrete)

Week

Topic

1

Introduction to the
module

Part I: Offsite production

2

University is
closed on

Monday 19 September

(NO lecture this week but there is a lecture on Thursday)

An overview of MMC

3

Types of offsite

production

4

Case studies and p
ractical issues

5

Factory production

Part II: Modern methods for substructure and
superstructure
construction

6

Foundations

7

Basements

8

External Walls and
insulation

Guest Lecture (3

November
)

9

Project week

10

Structural frames and Tall buildings

Part III: Innovative methods for construction

11

Construction
automation and free form construction

12

Revision

Go to
m.socrative.com

Quiz

1)
What are the general issues associated with
offsite production?

2)
How to know that the workers on
-
site are
qualified?

3)
What is
CSkills

and what do they do?

Lecture Outline

Modern pre
-
cast concrete frames offers
design flexibility
.

Closed v open environment

PRECAST FACTORY PRODUCTION

Production of reinforcement
cages and main connections

Assembly of reinforcement

Buildability

Quality and accuracy

Structural efficiency

(pre
-
stressed concrete)


Issues to consider

Pre
-
stressed concrete

Source:
Pre
-
stressed concrete


Designer’s Handbook

The cross
-
section of the member can be smaller, since the whole of the concrete is
put to structural use; and the resistance of beams to shearing and flexural cracks is
considerably increased. It is therefore possible to design longer spans or cantilevers
using comparatively shallow and slender sections.

Examples of pre
-
stressed concrete sections produced in a factory

• The elimination of beams and columns

• Reduced on site labour costs

• Utilising floor area for high density parking

• Elimination of formwork and scaffolding

• Early access to following trades; and

• Speed of construction.

What are the implications for using long span planks?

Maximum flexibility is obtained in floor layouts by eliminating load
-
bearing components.

Spans up to 17m give clear, uncluttered space

Precast columns and beams used to
complement the long span Hollow Core
planks.

More issues to consider

Production programming

When

the

dates

for

phased

deliveries

to

site

are

agreed
,

the

components

will

be

produced

in

a

predetermined

sequence

to

ensure

that

matured

concrete

components

are

ready

for

instant

erection
.

Supply of steel reinforcement

PRODUCTION METHOD

Placing carefully specified concrete into mould

Compaction of concrete using poker vibrator

Fixings for services

Pre
-
stressed v reinforced concrete

Concrete with Zero slump!

Finishes from the mould

Curing

HANDLING AND STORAGE

Prestressed

double
-
tee unit being moved to the storage area

Quality control

Verification of supply

Aggregate testing

Testing for workability

The certification process can take over a year and cost up to
£100,000, meaning that not all companies apply!

Testing the performance of building products is imperative.

QUALITY ASSURANCE

BRITISH STANDARDS INSTITUTION. BS 5750
Quality
systems. Part 1 : 1987. Specification for the
design, development, production, installation and servicing. Milton Keynes, BSI, 1987. 12 pp.

Quality is not only about the production process
itself, but also it relates to conformance to the
project requirements as set
-
out by the client.

Pre
-
stressed / Precast Plant Tour

Construction stages of precast wall

Summary









1)
Introduction

2)
Issues to consider

3)
Production method




Suggested references

Superior Walls by Weaver Precast

www.hollowcore.com.au