1. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME
267
RETROFITTING OF DAMAGED INDUSTRIAL BUILDINGS
Dr. Suchita Hirde*
, Ms. Minakshi Jagtap**
* Professor, Dept. of App. Mechanics Govt. College of Engineering Karad 415124 India
** PG student, (Civil- Structure), Govt. College of Engineering, Karad 415124, India
ABSTRACT
The cost of civil infrastructure constitutes a major portion of the national wealth. The rapid
damage of structure is thus created an urgent need for the development of novel, retrofit & new
construction. Retrofitting of existing structures is a difficult task as compared to the construction of a
new building as each building poses an unique set of constraints & problems requiring due care in
design & detailing. The development of any retrofit scheme involves a thorough study of the
performance of the structure subjected to design forces.
In this paper an attempt has been made to present case studies of rehabilitation & retrofitting
of industrial buildings. Retrofitting of two industrial buildings has been described in this paper. The
case studies include retrofitting of industrial steel structures damaged due to faulty design and a
structure requiring modification for operational purpose. The best possible retrofitting strategy
which is both economical & effective have been worked out and presented in this paper.
KEYWORDS: Damaged industrial building, rehabilitation, retrofitting, analysis
INTRODUCTION
In this paper, analysis of the damaged industrial building for ascertaining the current
performance is carried out by using static linear analysis. Retrofitting strategies required for the same
building is suggested based upon the current performance of structure, expected performance of
structure & type of damage. Strength is ascertained by carrying out the analysis of retrofitted
building. Finally best possible retrofitting strategies that will be both economical & effective are
determined. During the damage stage of any building, a survey is required to investigate the
conditions of such distressed building. Because of the vast variety of the building structures, the
development of a general rule for retrofitting measure is rather difficult and to a large extent each
structure must be approached as a strengthening problem on its own merits. It is necessary to take a
decision whether to demolish a distressed structure or to restore the same for effective load carrying
system. Many a times, the level of distress is such that with minimum restoration measure the
building structure can be brought back to its normalcy and in such situation, rehabilitation or
INTERNATIONAL JOURNAL OF CIVIL ENGINEERING AND
TECHNOLOGY (IJCIET)
ISSN 0976 – 6308 (Print)
ISSN 0976 – 6316(Online)
Volume 4, Issue 4, July-August (2013), pp. 267-277
© IAEME: www.iaeme.com/ijciet.asp
Journal Impact Factor (2013): 5.3277 (Calculated by GISI)
www.jifactor.com
IJCIET
© IAEME

2. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME
268
retrofitting is preferred. The process of keeping things in working order is called maintenance.
Proper maintenance of structure is required to prevent damages & decay due to natural agencies &
wear and tear & to keep them in good appearances and working condition as well as to repair the
defects occurred in the structure & strengthen them, if necessary. Maintenance includes servicing,
repairing, rectification, replacement, rehabilitation, retrofit, renovation & restore of structure. In the
process of rehabilitation the existing strength of the structure is retained while in case of retrofitting
it is the structural enhancement for improved performance during hazards. In this paper rehabilitation
and retrofitting of two industrial buildings has been described The case studies include retrofitting of
industrial steel structure damaged due to faulty design and a structure requiring modification for
operational purpose.
RETROFIT OF DAMAGED INDUSTRIAL BUILDINGS
Survey of damaged industrial buildings in Pune region have been carried out and based upon
the review of industrial site visits, two damaged industrial structures are selected for retrofitting
strategy so as to include different type of damages such as steel structures damaged due to faulty
design & structure required modification for operational purpose. The name of the industry is
purposefully omitted from the paper.
Case study 1-Structure damaged due to faulty design
An industrial steel building which is structurally failed due to faulty design is presented this
section. In this steel building most of the members of steel roof trusses are deflected along one side
as well as purlins are also failed due to faulty design. Therefore this structure is required to be
redesigned & strengthen.
Building description: The details of this industrial structure are given as follows
Height of Shed = 5.00 m;
Span of truss = 9.00 m;
Length of Shed = 25.9 m
Figure 1 shows photograph of existing structure. The plan & elevation of existing industrial building
is shown in figure 2 & 3 respectively.
Modeling of existing & retrofitted building
The existing & retrofitted building is modeled using STAAD-Pro software. The retrofitting
is carried out for an existing industrial building by two ways. In first option additional members are
welded to the various existing structural members while second option consists of introduction of
Figure 1- Photograph of existing structure

3. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME
269
additional truss at the bottom side of the existing truss. Thus the following models have been studied
and presented in the paper.
Model I: Modeling of existing industrial building in order to ascertain the current performance of the
structure.
The existing sizes of various structural members of damaged industrial building are as given
in the following table 1 and model is shown in figure 4.
Table 1: Sizes of structural members of damaged industrial building
Member Size of Section
Bottom chord ISA 50x50x6
Top chord ISA 50x50x6
Inclined member ISA 50x50x6
Vertical member ISA 50x50x6
Column ISMC 100 box 200mm apart
Purlin Angle 50x50x6
Model II : Modeling of retrofitted industrial building in which retrofitting is carried out by
welding unequal angle sections to the existing top & bottom chord members and welding of equal
angle sections to existing inclined members. Existing purlins having size of section
Figure 2- Plan of original structure

4. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME
270
Figure 3- Elevation of original structure
ISA 50x50x6 are replaced by ISMC 75. The existing purlins ISA 50x50x6 are used for welding to all
inclined & vertical members of truss. (Refer figure 5 and figure 6)
Retrofitted sizes of various structural members for option I are as given in the table 2
Table 2: Sizes of structural members in retrofitted building (option I)
Member Size of Section
Bottom chord ISA 50x50x6 welded with ISA 65x65x6
Top chord ISA 50x50x6 welded with ISA 65x65x6
Inclined member ISA 50x50x6 welded with ISA 50x50x6
Vertical member ISA 50x50x6 welded with ISA 50x50x6
Column ISMC 100 box 200mm apart
Purlin ISMC 75
Model III : Modeling of retrofitted industrial building in which retrofitting is carried out by
introduction of additional truss at the bottom side of the existing truss. (Refer figure 7)
Retrofitted sizes of various structural members for option II are as given in the table 3
Table 3: Sizes of structural members in retrofitted building (option II)
Member Size of Section
Bottom chord Existing ISA 50x50x6
Top chord Existing ISA 50x50x6
Inclined member Existing ISA 50x50x6
Vertical member Existing ISA 50x50x6
Column ISMC 100 box 200mm apart
Purlin ISMC 75
Additional bottom member (0.7m below
bottom chord)
16mm bar
Additional tie members between bottom
chord & additional bottom member
16mm

5. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME
271
Analysis of building
Equivalent static analysis is performed on the above 3D models. As the existing building is
industrial building wind load is predominant load along with the dead load & live load because area of
opening is more as compared to other structural buildings. This building is structurally failed
immediately after the construction of building due to faulty design.
Figure 4- Model I : Original structure
Figure 5- Model II: Retrofitted structure (option I)

6. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME
272
Figure 6- Welding of different angle sections
Figure 7- Model III: Retrofitted structure (option II)
Thus for the gravity model analysis only dead load & live load are considered; while wind
load is considered for the analysis of retrofitted model. The building model is then analyzed by the
software STAAD-Pro in order to ascertain the performance of retrofitted structure. Number of trials
has been carried out to get safe sizes for various members. The final sizes which are safe for the
calculated loads have been given in table 2 and 3.

7. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME
273
Comparison of retrofitting Strategy
Based on the analysis & design results for damaged industrial building due to faulty design,
retrofitting was suggested for failed structural members by the application of two strategies. In first
retrofitting strategy additional members are welded to the various existing structural members while
second strategy consists of introduction of additional truss at the bottom side of the existing truss.
The static analysis of retrofitted structures is also carried out by using STAAD-Pro software.
Analyzing strategies i.e. strategy-1, welding of different angle sections to the existing top & bottom
chord members and welding of equal angle sections to existing inclined members & strategy-2,
introduction of additional truss at the bottom side of the existing truss, it is observed that strategy two
is effective and economical. But in strategy-2 clear ceiling height is reduced by 0.7 m, also as per
aesthetic point of view strategy-2 is not good as compared to strategy-1. Hence in order to have more
headroom, strategy-1 is suggested.
Case Study 2- Structure required modification for operational purpose
In an industrial building, it is required to remove one column so as to form the large opening
for the industry work facilities. Due to creation of large opening the two columns near the opening
are subjected to heavy loads & for this load these two columns are required to be redesigned as well
as strengthened. Also the footings of same column may require to be redesigning as well as
strengthening.
Building description
The details of this industrial structure are given as follows
Height of Shed = 11.00m; Span of truss = 11.00 m; Length of Shed = 30.9m
The plan of existing industrial building is shown in figure 8. In plan column marked with circle is
required to be removed for the industry work facilities.
Modeling of building
The retrofitting of existing industrial building is carried out by introduction of additional
beam having span 10m between two columns which are adjacent to the opening. to support the truss
which is supported by removed column. The building is modeled using STAAD-Pro software. Thus
the following models have been studied and presented in the paper.
Model I : Modeling of the existing truss which rest on removed column in order to calculate the
reaction of truss.
Model II : Modeling of introduced beam to support the truss (Refer figure 9 and 10)
The sizes of various structural members of this beam are as given below in table 4
Table 4: Details of beam
Member Size of Section
Bottom chord ISMC 250
Top chord ISMC 250
Inclined member ISA 50x50x6
Vertical member ISA 50x50x6
Model III : Modeling of existing columns which are adjacent to the opening to check for additional
load of introduced beam (as shown in figure 11)

8. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME
274
Analysis of building
Equivalent static analysis is performed for all 3D models. As the existing building is
industrial building wind load is predominant load along with the dead load & live load because area
of opening is more as compared to other structural buildings. The building model is analyzed by the
software STAAD-Pro in order to ascertain the performance of retrofitted structure.
Retrofitting Strategy
In this structure, modification of structure is done for operational purpose by removing one
column, so as to form large opening. Due to this two columns near the opening are subjected to
additional load.
Figure 8 – Plan

9. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME
275
Figure 9- Model of trusses and beam
Figure 10- Load on beam

10. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME
276
Figure 11- Model of columns
Thus retrofitting of existing structure is carried out by introduction of additional beam
having span 10m between two columns which are adjacent to the opening. The static analysis of the
beam for given reaction of truss is carried out using STADD-Pro software. From the result of
analysis, it is noticed that all members of introduced beams are safe for the applied load. The
analysis of column is carried out to support the beam with additional loads due to trusses. Based on
the result of analysis, it is noticed that the existing sizes of column i. e. 2 ISMC 300 – 900 mm apart
are sufficient to carry the additional load. This strategy of introducing the beam to support the truss is
found to be effective in this case because it is easily feasible on site also it requires less time without
any disturbance to the various structural members & daily activities of industry work.
CONCLUSION
As the number of civil infrastructure systems increases worldwide, the number of damaged
buildings & structures also increases. In those cases complete replacement is likely to be an
increasing financial burden & might certainly be a waste of natural resources. To overcome this
difficulty a viable alternative in the form of upgrading or strengthening is required. The suggested
retrofitting strategies or measures have been found to be effective & economical in order to ensure
the safety of the life & property of the occupants.
REFERENCES
1. Michel Bruneu (2005), “Seismic Retrofit of Steel Structure”, 1st Canadian Conference on
Effective Design of Structure McMaster University Hamilton, Ontario, Canada July 10- 13.
2. Yu, Q.S., Uang, C.M. and Gross, J.L., (2000), “Seismic Rehabilitation Design of Steel Moment
Connection with Welded Haunch”, Journal of Structural Engineering, ASCE, Vol. 126, No. 1,
pp. 57-68.

11. International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 4, July-August (2013), © IAEME
277
3. IS : 875 (Part 1) – 1987: Indian Standard Code of Practice for Design Loads (Other Than
Earthquake)For Buildings And Structures, Bureau of Indian Standards, New Delhi 110002.
4. IS : 875 ( Part 2 ) – 1987: Indian Standard Code Of Practice For Design Loads (Other Than
Earthquake) For Buildings And Structures, Bureau of Indian Standards, New Delhi 110002.
5. IS : 875 ( Part 3) – 1987: Indian Standard Code Of Practice For Design Loads (Other Than
Earthquake) For Buildings And Structures, Bureau of Indian Standards, New Delhi 110002.
6. Design of steel structure by N. Subramanian, Oxford University press New Delhi.
7. Design of steel structure by V. L. Shah & Gore, Structural Publication Pune.
8. A.S Jeyabharathy, Dr.S.Robert Ravi and Dr.G.Prince Arulraj, “Finite Element Modeling of
Reinforced Concrete Beam Column Joints Retrofitted with GFRP Wrapping”, International
Journal of Civil Engineering & Technology (IJCIET), Volume 2, Issue 1, 2011, pp. 35 - 39,
ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316.
9. Nilendu Krishna Paul and R.P.Nanda, “Shape Memory Alloy as Retrofitting Application in
Historical Buildings and Monuments – A Review in Indian Perspective”, International Journal
of Civil Engineering & Technology (IJCIET), Volume 4, Issue 1, 2013, pp. 117 - 125,
ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316.