Conventional Indian construction industry has been forced to look for technology to address its demand & supply gap, diminishing skilled labour and stringent time frame. Precast concrete construction methodology fits perfectly as an alternative for traditional construction with shorter construction duration and reduction in labor, while exceeding quality standards of conventional construction practices in India. The success of this technology fully depends on the Architects, the Structural engineers and the Execution team who are willing to adapt this change from convention method of construction to the precast construction. Change gives us a lot of opportunity to adapt, innovate and implement new efficient technology which will be beneficial to the society at large margin. This technology is becoming trend due to its huge advantages. But in recent past hazards attended to such construction due to collapse. So from the Structural Engineering point of view we have to design keeping in mind the structural safety against this type of collapse.

1. Under the Guidance of: Dr. Aswath M.U.
Presented by- Rahul Das Biswas
USN: 1BI14CSE14,
M.Tech (Structural Engineering)

2. Contents
 Introduction
 Advantages
 IS Recommendations
Materials
Prefabrication Systems
 Types according to IS
Design Requirement as per IS
Progressive Collapse
Design of Ties
 Design of Vertical Pillars (Walls, Diaphragms, Cores)
Frame installation
Conclusion
References

3. Introduction
 WHAT ?
WHY ??
HOW ???

4. “What”
Precast:
 Produced in Factories
 Transported to Site
Assembled at Site

5. “Why”
Advantages of Precast:
Partial or total saving of materials
Multiple using of shuttering
Better accuracy of workmanship
Less Man Power Required
Interruption in concreting can be omitted

6. “Why”
Advantages of Precast:
 Fewer expansion joints
 High capacity
 Shorter construction time
 Independent of adverse weather conditions
during construction
 Continuing erection in winter time until -20 °C

7. “Why”
Advantages of Precast:
 Opportunities for good architecture
 Reduced energy consumption
 Safety in construction
 Low shrinkage with high strength
 High modulus of elasticity
 Very little micro cracks

8. “Why”
Advantages of Precast:
 Resistance to chemical attack
 Toughness and impact resistance
 Volume stability
 Durability against chloride attack
 Reduced maintenance cost
 Higher Strength at earlier ages and low heat of hydration

9. “How”
From Structural Engineering Point of view:
 Material
 Aspect
 Type of Construction
 Design (With all Safety Concern)
Detailing

10. IS CODES TO BE FOLLOWED
 IS 15916: Precast Construction
 IS 875: Design Loads
 IS 456: Concrete
 IS 1893 and IS 13920: Seismic Design

11. Characteristics of Material
Recommended by IS: 15916: 2011
• Easy Availability
• Light- Weight
• Thermal Insulation Property
• Easy Workability
• Durability

12. Characteristics of Material
Recommended by IS: 15916: 2011
• Non-combustibility
• Sound insulation
• Easy assembly and compatibility to form a complete
unit
• Economical
• Any other special requirement required for particular
application

13. Aspects to be considered as per the
Recommendation of IS: 15916: 2011
 Effective utilization of spaces
 Straight and simple walling scheme
 Limited sizes and numbers of components
 Limited opening in bearing walls

14. Aspects to be considered as per the
Recommendation of IS: 15916: 2011
 Regulated locations of partitions
 Standardized service and stair units
 Limited sizes of doors and windows with
regulated positions
 Structural clarity and efficiency

15. Aspects to be considered as per the
Recommendation of IS: 15916: 2011
 Suitability for adoption in low rise and high rise
building
 Ease of manufacturing, storing and transporting
 Speed and ease of erection and
 Simple jointing system

16. Types of Precast System according to
IS: 15916: 2011
Prefabrication
System
Open
Prefabrication
System
Partial
Prefabrication
System
Full
Prefabrication
System
Large Panel
Prefabrication
System
Staircase
Systems
Precast Floors Precast Walls
Box Type
Construction

17. Design Requirement as per IS: 15916: 2011
Progressive Collapse
(A Major Threat to Safety of Structure)
Collapse or Failure of the major part
Due to the damage of small areas or
Failure of single element

18. Precaution: Against Progressive Collapse
1) All buildings should be capable of safely
resisting the minimum horizontal load of 1.5% of
characteristic dead load applied at each floor or
roof level simultaneously.

19. 2) All Buildings Shall Be Provided With Effective
Horizontal Ties
1) Around The Periphery
2) Internally (In Both Directions) &
3) To Columns & Walls.
3) All Buildings of Five or More Storeys Shall Be
Provided With Vertical Ties.
Precaution: Against Progressive Collapse

20. Design of Ties
(Peripheral Ties)
At each floor and roof level an effectively continuous tie should be
provided within 1.2 m of the edge of the building or within the
perimeter wall.
The tie should be capable to resisting a tensile force of Ft equal to 60 kN
or (20 + 4N) kN whichever is less, where N is the number of storeys
(including basement).

21. Design of Ties
(Internal Ties)
These are to be provided at each floor and roof level in two directions
approximately at right angles. Ties should be effectively continuous
throughout their length and be anchored to the peripheral tie at both
ends, unless continuing as horizontal ties to columns or walls.

22. Design of Ties
(Internal Ties)
• The tensile strength, in kN per meter width shall be
the greater of-
• gk + qk = Avg. characteristic D.L. + L.L in kN/m2
• lr = Greater of-
• The distance between the centre of columns
• Frames or walls supporting any two adjacent floor spans in the
direction of the tie under consideration.

23. Design of Ties
(Internal Ties)
The bars providing these ties may be distributed evenly in the
slabs or may be grouped at or in the beams, walls or other
appropriate positions but at spacings generally not greater
than 1.5 lr.

24. Design of Ties
(Horizontal ties to column and wall)
• All external load-bearing members such as columns and
walls should be anchored or tied horizontally into the
structure at each floor and roof level. The design force
for the tie is to be greater of-
 a) 2 Ft kN or ls × Ft × 2.5 kN, whichever is less for a column
or for each metre length if there is a wall. ls is the floor to
ceiling height, in meter.
 b) 3 percent of the total ultimate vertical load in the column
or wall at that level.
• For corner columns, this tie force should be provided in
each of two directions approximately at right angles.

25. Design of Ties
(Vertical ties)
 Should be provided for buildings of five or more
storeys
Each column and each wall carrying vertical load
should be tied continuously from the foundation to the
roof level. The reinforcement provided is required only
to resist a tensile force equal to the maximum design
ultimate load (dead and imposed) received from any
one storey.
In situation where provision of vertical ties cannot be
done, the element should be considered to be removed
and the surrounding members designed to bridge the
gap.

26. Design of Vertical Pillars
(Walls, Diaphragms, Cores)
 Indian Standards for Designing Precast is
unavailable
 Adopt any code of practice which is-
 Safe
 Durable
 Economical
 Reliable from Past Experience
 Methods of mounting precast structures used in Russia will
be discussed

27. Primary Load-bearing Members of the Building

28. Optimal Configuration
 The frame members to securely perform their
functions without “extra” efforts. This means that
the columns operate only for compression, floor
structures operate only for bending, with no
forces in the plane of the slab (the membrane
group of efforts), pylons take horizontal forces
ensuring the necessary rigidity of the building.

29. Optimal Configuration
• The principle of concentration of material is
observed. To reduce the material consumption the
load should be transmitted through the minimum
number of elements.
• The main feature of the framework is the ability
to ensure the integrated operation of all its
elements: columns, pylons, floor slabs, foundation
slab, piled and/or soil foundation. Proper use of
these features can improve the design
characteristics of the building frame while
reducing the consumption of its materials.

30. Rules of the Pylons Distribution
(Rule No. 1)
• All of the pylons should not be
intersected by straight lines on
which they are rested at one
point
• All of the pylons should not be
parallel
Building plan (slab & pylons)

31. Rules of the Pylons Distribution
(Rule No. 2)
 The pylon should be sufficiently hard with a height of the
cross section equal to 1/10 – 1/5 of the building height.
With a smaller size the pylon will be more flexible and
will transmit a significant portion of the horizontal load
onto the columns or originate the need for more pylons.
 If several flat diaphragms are connected to one core, the
height of their cross section can be reduced by virtue of a
more rigid joint operation with respect to the total
cumulative individual work.
 It is necessary to strive for the minimum number of
pylons in the building.

32. Rules of the Pylons Distribution
(Rule No. 3)
Determining efforts in the plane of the slab
aab 5.26 

33. Rules of the Pylons Distribution
(Rule No. 4)
 If one looks at the aggregate of all the diaphragms of the
building combined with floor structures, it is possible to
find the shear center of the building. If the shear center
does not coincide with the center of gravity, the building
will have additional bending stresses. If the resultant
wind load does not pass through the shear center, the
building will be subject to additional twisting forces. The
configuration in which all three centers coincide will be
optimal. The easiest way to achieve is to prepare a
symmetrical in the two axes building plan with a
symmetrical arrangement of the pylons.

34. Frame installation
(Column)
Schemes Of Installation of Multi-story Columns Using A Set of Individual Installation
and Mounting Devices and Tooling
a — the location of columns and accessories, b — securing columns by knees, c — clamp for
securing knees in the column; 1 — foundation socket, 2 — readymade mount, 3 — column, 4 —
clamp 5 — knee, 6 — drawbar of the knee, 7 — wedges, 8 — anchoring device, 9 — crimping
rope

35. Frame installation
(Cross beams)
Cross beam installation: a — applying an axial mark
on the column pillar; b — installing cross beam; c —
column pillar alignment

36. Frame installation
(Pylons)
Installation of interior walls — diaphragm plates — in a framed building: a —
installation, b — temporary fastening; 1 — knee-piece, 2 — diaphragm with a
cantilever replacing a collar beam, 3 — a universal sling, 4 — movable L-
clamp with a rack.

37. Frame installation
(Slab panels)
Laying bracing (spacing) (а) and lintel (b) floor slab panels

38. Conclusion
 Considering its huge advantage, Technology
should be adopted in India
 Safety should be the 1st concern
 Past Hazards should be analyzed and
precautions to avoid it should be taken
 Indian Standard Code required for Design

39. References
• http://en.wikipedia.org/wiki/Precast_concrete
• IS: 15916: 2011
• IS: 13920: 1993
• “DESIGN RULES FOR PRECAST CONCRETE:
VERTICAL PILLARS (WALLS, DIAPHRAGMS,
CORES)” By- Mark P. Son & Denis V. Konin, Redecon
2014, Bangalore
• “Design and Construction of Multi-Storey Residential
Buildings with Precast Concrete” By- Dr. H S Lai ,
Redecon 2014, Bangalore