Download - Introduction of Prefabricated structures
PREFABRICATED STRUCTURES
BY- S Yogesh 15MST1003VIT University, Chennai Campus
Prefabrication is the practice of assembling components of a structures in a factory or other manufacturing site and transporting complete assemblies or sub assemblies to the construction site where the structure is to be located.
Definition
Aim To effect economy in cost
To improve quality
To speed up construction since no curing is necessary
To use locally available materials
Advantages Work time is reduced
Less workers needed
Work done with better technology
Interruption in connection can be omitted
Limitations size of the units.
location of window openings has a limited variety.
site access and storage capacity.
require high quality control.
enable interaction between design phase and production planning.
difficult to handling & transporting.
Materials of Construction Materials like concrete, steel, hard wood,
aluminium etc…
Special characteristics while choosing materials
- Easy available
- Economy
- Easy workability
- Light weight
- Durability
MODULAR COORDINATIONModular coordination is a concept of coordination of dimension and space in which building components are positioned in terms of MODULE(M).
1M= 100mm
DIMENSIONS OF PRE FAB COMPONENTS
• Flooring and Roofing– Length- multiple of 3M– Width – multiple of 1 M– Thickness – multiple of M/4
• Beams– Length – multiple of 3M– Width – multiple of M/4– Depth – multiple of M/4
As per IS 15916(2011)
• Column– Height – multiple of 1M for height up to 2.8m and height above
28m is multiple of 2M– Lateral dimension- multiple of M/4
• Wall - Thickness – multiple of M/4
• Staircase– Width – multiple of 1M
• Lintels
– Length – multiple of 1M– Width – multiple of M/4– Depth – multiple of M/4
• Sunshade– Length – multiple of 1M– Projection- multiple of 1M
The following aspects of pre fabrication system:
a)Effective utilization of spaces
b) Straight and simple walling scheme
c) Limited sizes and numbers of components
d) Limited opening in bearing walls
e) Regulated locations of partitions;
f) Standardized service and stair units;
g) Limited sizes of doors and windows withregulated positions
ComparisonSite-cast
no transportation
the size limitation is depending on the elevation capacity only
lower quality because directly affected by weather
proper, large free space required
Precast at plant
transportation and elevation capacity limits the size-
higher, industrialized quality – less affected by weather
no space requirement on the site for fabrication
unlimited opportunities of architectural appearance
Hindustan Prefab limited.A Government of India Enterprise
ISO 9001: 2008 certified company was incorporated in 1953
HPL has built a wide spectrum of civil engineering structures using both conventional in-situ as well as prefab techniques and
supplied components for the building industry & the national railways
It also became the first company to produce precast pre stressed concrete railway bridge girders for making railway bridges in the country
HPL has a modern factory for manufacturing precast concrete products, which includes the following.
1) Precast pre stressed concrete products like Railway Sleepers and Electric Poles.
2) Autoclaved aerated cellular concrete. These are light weight yet have sufficient strength for walling and other applications.
3) Reinforced concrete products like pavements slabs, frames, water tanks, bridge girders, interlocking solid blocks for pavement & for retaining walls, kerb stone etc.
4) Timber joinery components and wood substitute items manufactured with wood/medium density fibreboard in the company’s timber workshop
HPL had designed and built many prestigious Institutional buildings. These comprise Schools, Colleges, Training Centres, Hospitals, Office Complexes and Airport Terminal Buildings.
The National Academy for Training and Research in Social Security (NATRSS) is a training centre with class rooms, auditorium, offices, lecture theatres, hostel block, health club, swimming pool and underground parking with a total covered area of 7200 sq. meters
The project cost was INR 62.4 Million.
Conclusiono Reduce adverse environmental impact on sites.
o Enhance quality control of concreting work.
o Reduce the amount of site labour.
o Increase worker safety .
o The use of precast concrete construction can significantly reduce the amount of construction waste generated on construction sites.