RCC jacketing is a method for re-strengthening a structure

1. KUNAL CHAKRABORTY
CIVIL ENGINEER
Email- kunal.chakraborty977@gmail.com

2. Concrete jacketing or
retrofitting is a procedure
by which we can increase
the strength of a building
structure. It is the
modification of existing
structure to make them
more resistance to seismic
activity, ground motion and
soil failure due to earth
quakes

3. The main purposes of jacketing are-
 To increase concrete confinement by transverse fibre
reinforcement, especially for circular cross-sectional
columns
 To increase shear strength by transverse fibre
reinforcement,
 To increase flexural strength by longitudinal fibre
reinforcement provided. They were anchored at critical
sections. Transverse fibre should be wrapped all around
the entire circumference of the members possessing close
loops sufficiently overlapped or welded in order to
increase concrete confinement and shear strength

4. TYPE OF JACKETING
LOCAL
JACKETING OF
BEAM
JACKETING OF
COLUMN
JACKETING OF
FOUNDATION
JACKETING OF
SLAB
GLOBALA
Adding shear wall
Adding bracing
Seismic damper
Chemical rebaring

6. Performance related to the mechanical characteristics of structures

13.  The load carrying capacity of the original
section=90492.8N
The load carrying capacity of the jacket section = 271776N
Percentage of improvement = (271776/90492.8)X 100 =
300.328%
The load carrying capacity has been
increase 3times
 Ultimate moment carrying capacity of the original
section = 11.3116X106N-mm
Ultimate moment carrying capacity of the jacket section =
33972949.9N-mm
Percentage of improvement= (33972949.9/
11.3116X106N)X100= 300.33%
The Ultimate moment carrying capacity
has been increase 3times

14.  Average cube compression test result for original
section (M20) = 21.3 N/mm^2
Average cube compression test result for jacket section
(M20) = 21.6N/mm^2
 Average load carrying capacity of the original section=
Average load carrying capacity of the jacket section =
Percentage of improvement =
The load carrying capacity has been
increase
 Deference between theoretical and practical results
=

15.  Moment carrying capacity of the original section(M)=( PL/4)
=
Moment carrying capacity of the jacket section (M)= (PL/4)
=
REMARKS
There is some differences between theoretical and practical results because it is
really hard to maintain all the technical parameter in a exact way. And there
is no specific Indian standard guide line for RCC jacketing. This
experiment is under research.
Percentage of improvement=
The Ultimate moment carrying capacity has been
increase
Deference between theoretical and practical results
=

16. 1. If we want to repair any structure without demolishing
the existing structure then retrofitting or jacketing of
structures is the best way out.
2. For any structural repairing work retrofitting is a
economic and useful process.
3. Retrofitting or jacketing are very useful for repairing and
maintain purposes of historical monuments.

17.  Retrofitting reduces the vulnerability of damage of an existing
structure during a future earthquake. It aims to strengthen a
structure to satisfy the requirements of the current codes for
seismic design.
 In this respect, seismic retrofit is beyond conventional repair or
even rehabilitation. The principles of seismic retrofit refer to
the goals, objectives and steps.
 The steps encompass condition assessment of the structure,
evaluation for seismic forces, selection of retrofit strategies and
construction.
 The applications include different types of buildings, industrial
structures.