Progressive collapse is the result of a localized failure of one or two structural elements that lead to a steady progression of load transfer that exceeds the capacity of other surrounding elements, thus initiating the progression that leads to a total or partial collapse of the structure. The present study is to evaluate the behavior of G+8 reinforced concrete building subjected to potential collapse. The reinforced concrete structure is analyzed by Pushover Analysis using ETABS Software. It shows the maximum storey displacement and a maximum storey drift values of the components are studied. And the potential of the progressive collapse is determined.

1. R.JEYANTHI

2. PROGRESSIVE COLLAPSE

3. CAUSES
 Design mistake
 Faulty construction
 Abnormal load events
Pressure Loads Impact Loads
- Internal gas explosions - Aircraft impact
- Blast - Vehicular collision
- Wind over pressure - Earthquake
- Extreme values of - Overload due to
environmental loads occupant overuse

4. PROGRESSIVE COLLAPSE DESIGN STRATEGIES
TYPE OF
APPROACHES
DIRECT
SPECIFIC
LOCAL
RESISTANCE
ALTERNATE
PATH
METHOD
INDIRECT
PRESCRIPTIVE
DESIGN RULES

5. OBJECTIVE
 To design G+8 RC structure
 To analyze the structure by Non linear static analysis method
 To perform pushover analysis for the structure with removal of critical
columns fully and partially
 To determine the potential for progressive collapse
 To give the preventive measures
SCOPE
 Reduction of potential for progressive collapse in new and renovated
Federal buildings
 Potential of progressive collapse is assed using Non linear static analysis
method since it gives economical design

7. STUDYING THE VULNERABILITY OF STEEL MOMENT RESISTANT FRAMES
SUBJECTED TO PROGRESSIVE COLLAPSE
Mojtaba Hosseini, Nader Fanaie and Amir Mohammad Yousefi
Steel
Building
10 storey building, 5x5 panels each 5x5m
Analysis Nonlinear Dynamic Procedure
Removal Corner columns from 1st storey, 5th storey, 8th storey and 9th storey
S/W Open Sees program
Results After the removal of corner column A1
compressive axial forces of adjoining column and in other columns
CASE I increased 8.8 times the primary forces and 5.21 times.
CASE II increased 8.6 times the primary forces and 5.16 times
CASE III
CASE IV
increased 8.67 times the primary forces and 5.19 times
increased 8.66 times the primary forces and 5.23 times
Conclusion The axial force values of adjoining columns are 30% and 40% greater than
their ultimate strengths
Safety is achieved by increasing column dimensions or using new materials
and methods.

8. PROGRESSIVE COLLAPSE ANALYSIS OF A REINFORCED CONCRETE
FRAME BUILDING
Shefna L Sunamy, Binu P, Dr. Girija K
Building
description
 12 storey R.C. building.
 Six bays of 5 m in the longitudinal direction ,
four bays of 5 m in the transverse direction
Modeling &
analysis
 The structure is modeled using SAP 2000
 Non Linear static progressive collapse analysis
Seismic loading is considered (Zone II, III, IV ,V)
Column
removal
scenario
 Long side column removed
 Short side column removed
 Corner column removed
DCR Demand capacity ratio should satisfy acceptance criteria
GSA
guidelines
 DCR < 2.0 for typical structural configurations
 DCR < 1.5 for atypical structural configurations
Conclusion Seismically Designed building resist progressive collapse.
Nonlinear static analysis reveals hinge formation starts from
the location having maximum demand capacity ratio.
To mitigate progressive collapse an alternate load path has to be
provided (Providing bracings, increasing column dimension)

9. Progressive Collapse Analysis of Reinforced Concrete Framed Structure
Raghavendra C, Mr. Pradeep A R
Building
description
-For the analysis, a typical frame of height 37.5 m is considered
-All the supports are modeled as fixed supports
Analysis - Linear Static analysis is used to analyze the structure
Software -ETABS v9.7 for the IS 1893 load combinations
Column
removal
- For PC analysis the columns at eight different location is removed
for each case
Progressive
Collapse
Analysis
-RC frame in the earthquake zones 2, 3, 4 and 5 is designed using
ETABS program for dead, live, wind and seismic loads.
- The specified GSA load combination was applied
- The Demand Capacity Ratio (DCR), the ratio of the member force and the
member strength is calculated.
Conclusion - While removing the column the intersecting beams of the shorter
span beams tend to take the extra burden load and DCR values of
that beams were more compared to longer span beams.
- To avoid the progressive failure of beams and columns, adequate
reinforcement is required to limit the DCR within the acceptance
criteria.

10. PROGRESSIVE COLLAPSE ANALYSIS OF REINFORCED CONCRETE FRAMED
STRUCTURE
Rakshith K , Radhakrishna
Building
description &
Modeling
 Typical frame structure of height 37.5m is considered.
 It is modeled using ETABS v9.7 software.
 Linear static analysis is conducted on each of these models.
Analysis  Analysis is carried out by ETABS Software for IS 1893 load combinations.
Column
removal
 Critical Column are removed for progressive collapse analysis in different cases.
 Separate linear static analysis is performed for each case.
Demand
Capacity ratio
 DCR for flexure at all storeys is calculated for three cases of column failure.
 Demand capacity ratio < 2.0 (acceptance criteria as per GSA 2003
Results C1
removed
B1 and B5 exceed acceptance criteria value suggested by GSA for
progressive collapse guidelines
C16
removed
B23 and B24 exceed acceptance criteria value suggested by GSA for
progressive collapse guidelines as
C18
removed
B25 and B26 exceed acceptance criteria value suggested by GSA for
progressive collapse guidelines
Conclusion  Progressive failure of beams and columns is avoided by adequate
reinforcement is required to limit the DCR within the acceptance criteria.
 It can develop alternative load paths

11. Progressive Collapse of Steel Frames
Kamel Sayed Kandil, Ehab Abd El Fattah Ellobody
Steps carried out:
Modeling
Cases considered
Results
 2D models for different cases and 3D model is analysed and
compared
 3, 6, 9, 12 storey building is considered for damping ratio 5%,
6%, 8%, 10%
 Finally all the cases were compared
Conclusion:  Increase in damping ratio decrease the lateral deflection
 Increase in no of stories decreases the potential for
progressive collapse

12. Evaluation of progressive collapse potential of multi-story moment resisting
steel frame buildings under lateral loading
H.R. Tavakoli , A. Rashidi Alashti
Analysis
method
 Nonlinear static analysis for progressive collapse under seismic loading
 3-D and 2-D models of SMRF were considered for push over analysis (ETABS)
Lateral
Loading
pattern
 Triangular load pattern
 Uniform load pattern
Capacity curve for both the pattern in determined
Column
Removal
 Critical column is made to lose 40%, 70% and 100% of effective area.
Capacity curve for each cases are determined and compared.
To
Determine
Robustness indicator
Ductility ratio
Plastic hinge rotation
Conclusion  Number of stories and bays are Increased capacity of the structure to resist
progressive collapse under lateral loading also increased.
 Increasing the number of bays and stories, induces a higher level of robustness
index.

13. 3-D Nonlinear Static Progressive Collapse Analysis of Multi-story Steel Braced Buildings
H.R. Tavakoli, A. Rashidi Alashti & G.R. Abdollahzadeh
Building
description
 Special dual system SMRF with concentrically X braces
 CASE I - 5 stories buildings with 4 spans
 CASE II - 15 stories buildings with 6 spans
Lateral load
patterns
 Uniform pattern +ve and –ve
 Triangular pattern +ve and -ve
To
Determine
Robustness indicator
Ductility ratio
Plastic hinge rotation
Conclusion Triangular pattern induce the least capacity curve for intact and damage
structure
Robustness index in uniform and triangular pattern is almost the same.
Number of stories and bays are increased larger capacity to resist
progressive collapse under lateral loading and higher level of robustness
index obtained.

14. Progressive Collapse Assessment of RC Structures under Instantaneous and
Gradual Removal of Columns
A.R. Rahai, M. Banazadeh, M.R. Seify Asghshahr & H. Kazem
Building
description
5 story RC structure model with RC resisting moment frames at either
side was designed using a high ductility level.
Column
removal
scenario
Three columns are removed,
 Instantaneously
 Gradually
Analysis
method
 For instantaneous removal method static analysis is performed
 In gradual reduction method concrete strength reduction factor is determined
Modeling 3D model of the RC structure was developed using Opensees software
Results  Instantaneous removal
- 4 sec once column C1 was removed
- Maximum vertical displacement is
1.411 m occurring at t=1.19 sec.
 Gradual removal
- 34200 sec once column C1 was removed
- Maximum vertical displacement is 1.03m.

15. Progressive Collapse Analysis Of Building
Miss. Preeti K. Morey Prof S.R.Satone
Mathematical
modeling
Using STADD Pro software 3d model of a frame is
analyzed
DCR ( Acceptance
Criteria)
For typical structure (symmetrical structure) = DCR≤ 2.0
For typical structure (unsymmetrical structure) = DCR≤ 1.5
DCR= M max / Mp
Performance
analysis
 C1 , C3 is removed and critical column is identified for both
static and seismic case.
 Result of column wise DCR of Linear Static analysis and
linear dynamic analysis for both static and seismic case is
considered.
CONCLUSION  Case II - RC Frame with removal of column c3 has highest
DCR value in comparison with case I.
 DCR of column c3 is 1.98 which is less than 2 i.e. GSA
criteria. Hence the frame is less vulnerable to progressive
collapse.

16. Analytical Study of Seismic Progressive Collapse in one-Story Steel Building
F. Nateghi Alahi
Introduction  Corner-column building was weakened to navigate the
initial damage toward a certain part of the structure.
 Nonlinear static analysis was carried out
FEM GSA progressive collapse guidelines were applied
Numerical
Analysis
 Combination of gravity loads was applied to the structure and
then the push-over analysis was carried
 Plastic hinges of Damaged and primary model was compared.
 Push over curve indicates that damaged model has less secondary
stiffness than the primary one.
Conclusion  Collapse pattern is in a way that the deformation of damaged
frame increases near the failed column and further away from it,
deformation of the frames decreases.
 So during an earthquake progressive collapse gets started from
damaged frames then passes through the others beside it.

17. Linear and nonlinear analysis of progressive collapse for seismic designed steel
moment frames.
M. A. Hadianfard & M. Wassegh
 Structural
model
3-story and 6-story SMRF designed for medium level and very
high level seismic zones
 Analysis -Linear static analysis & Non Linear static analysis carried out
as per 1. GSA 2003, 2. UFC 2009
- Push down curves are determined
 Conclusions - potential of progressive collapse decreases with increasing the height of
the structures
- In short steel structures steel structures designed for higher seismicity,
there is less possibility of occurrence of progressive collapse.
- In LSA, the resisting-capacity of progressive collapse of UFC 2009 is less
than the GSA 2003. And for NLSA it is vice versa
- For mitigating progressive collapse, the gravity loads should not have
one-way patterns, so that gravity loads will not be concentrated in some
elements and the potential of progressive collapse can be decreased in the
structure.

18. Progressive Collapse Analysis of an RC Building with Exterior Non-Structural Walls
MENG-HAO TSAI*, TSUEI-CHIANG HUANG
Types of Exterior Non-
Structural Walls
Parapet-type wall, Wing-type wall , Panel-type wall.
 Building description
 Column loss scenario
 Elastic displacement
 Progressive Collapse
Analysis
 10-story, MRRC building with a 2-story basement
 In 1st storey at 3 different location columns are removed
(Case 1A, 1B, 2A)
 RC frame > parapet walls >wing walls >panel walls
 linear static analysis and Non linear static analysis
Conclusion Linear static analysis results - DCRs of beams are
generally reduced with consideration of the exterior walls
Nonlinear static analysis results - collapse resistance of
the RC building subjected to column loss may be
significantly increased with the wing-type walls

19. Fragility Assessment of Progressive Collapse Buildings
Kuan-Hsoung Chen
Objective
Modeling
- To identify the progressive damage by the nonlinear
pushover analysis.
- 2D nine-story, 3bay MRF building
 Column loss
scenario
 Capacity curves
- 8 cases were considered
- T of various locations of column removal scenarios were
determined
Nonlinear pushover analysis
-capacity of column loss in 1st story is 3 times greater than
column in roof story.
- Strength of removal interior columns are greater than
corner column loss.
 Nonlinear hinges plastic hinges is generated from lower story to higher story
with an increase of incremental vertical loadings
 Conclusions - Ground level column loss activate the damage above the
column removal and don’t propagate to its neighboring
spans.
- The roof level column loss only leads to local damage

20. Assessment of progressive collapse-resisting capacity of steel
moment frames
Jinkoo Kima, Taewan Kimb
Analysis procedure
Acceptance criterion
(as per GSA2003)
procedure for linear static
analysis
Applied loads for static and
dynamic analyses
-DCR vary from 1.25 to 3.0
- Remove column , carry linear static analysis
- Check DCR in each structural member
- At each inserted hinge, equal but opposite moments are applied
-Steps are repeated until DCR of any member does not exceed the limit
- For static analysis both the GSA 2003 and the DoD 2005 use dynamic
amplification factor of 2.0 in load combination
Analysis of model Open sees software
- Linear dynamic and Non linear dynamic analysis is carried out
Conclusion - SMRF designed for lateral load is less vulnerable for progressive
collapse.
-potential for progressive collapse was highest when a corner column
was suddenly removed.
- progressive collapse potential decreased as the number of story
increased.

21. Design of steel moment frames considering progressive collapse
Jinkoo Kim and Junhee Park
Analysis of
structure
• 3x3 bay and 9-story. Span length are varied as 6 m, 9 m, and 12m.
• Nonlinear dynamic analysis using the program code OpenSees
Progressive
collapse
potential.
- Vertical deflection as bay width and girder size decreases .
- beam size may lead to strong beam weak Column.
- Weak story is prevented if summation of plastic moment capacity of
columns > than beam.
Plastic
design
- vertical deflection if damping ratio and stiffness ratio
Conclusion Structures redesigned by plastic design method to prevent progressive
collapse turned out to satisfy the given failure criterion in most of the
model structures.

22. METHODOLOGY
Detailed study of literature review
G+8 RCC building is taken for Project
Prepare AUTO CAD plan for G+8 structure
Modeling in ETABS
Non linear static analysis is carried out
Identification of critical column
Removal of critical column to initiate
progressive collapse
DCR, Robustness indicator are determined
Result comparison – before & after
progressive collapse
check for acceptance criteria as per
GSA 2003 guidelines
By this evaluation a building can be assessed
whether it can withstand progressive collapse

23. AUTO CAD DRAWINGS

27. ETABS Modeling

28. Front and side elevation of building

29. Non Linear static analysis
Steps to be followed:
 Preliminary Pushover Analysis
Procedure:
- Modeling of structure is carried out
- Load cases are defined
- Loads are assigned
- Load combinations are provided as per IS 875 part 5
Seismic load case:
Response spectrum user defined file
ELX Res spec x
ELY Res spec y
Wind load case:
Applied as point load in floor diaphragms
WLX Wind load along X direction
WLY Wind load along Y direction
Gravity load case:
DL Self weight
DI Super imposed load
LL 1 live load greater that 3
LL 2 live load lesser than 3

30. Load combination as per IS 875 part 5
DL – Dead load, DI – Dead Imposed, WLX- Wind load in direction, WLY – Wind load in Y direction,
EQX,EQY – Seismic load in X&Y direction
Basic Load Case
COMB001 - 1.5 DL + 1.5 DL1 + 1.5 DL2 + 1.5 LL1 + 1.5 LL2 + 1.5 LL3
Seismic Load Cases
COMB002 - 1.2 DL + 1.2 DL1 + 1.2 DL2 + 0.6 LL1 + 0.3 LL2 + 1.2 ELX
COMB003 - 1.2 DL + 1.2 DL1 + 1.2 DL2 + 0.6 LL1 + 0.3 LL2 + 1.2 ELY
COMB004 - 1.5 DL + 1.5 DL1 + 1.5 DL2 + 1.5 ELX
COMB005 - 1.5 DL + 1.5 DL1 + 1.5 DL2 + 1.5 ELY
COMB006 - 0.9 DL + 0.9 DL1 + 0.9 DL2 + 1.5 ELX
COMB007 - 0.9 DL + 0.9 DL1 + 0.9 DL2 + 1.5 ELY
Wind Load Cases
COMB008 - 1.2 DL + 1.2 DL1 + 1.2 DL2 + 1.2 LL1 + 1.2 LL2 + 1.2 LL3 + 1.2 WLX
COMB009 - 1.2 DL + 1.2 DL1 + 1.2 DL2 + 1.2 LL1 + 1.2 LL2 + 1.2 LL3 - 1.2 WLX
COMB010 - 1.2 DL + 1.2 DL1 + 1.2 DL2 + 1.2 LL1 + 1.2 LL2 + 1.2 LL3 + 1.2 WLY
COMB011 - 1.2 DL + 1.2 DL1 + 1.2 DL2 + 1.2 LL1 + 1.2 LL2 + 1.2 LL3 - 1.2 WLY
COMB012 - 1.5 DL + 1.5 DL1 + 1.5 DL2 + 1.5 WLX
COMB013 - 1.5 DL + 1.5 DL1 + 1.5 DL2 - 1.5 WLX
COMB014 - 1.5 DL + 1.5 DL1 + 1.5 DL2 + 1.5 WLY
COMB015 - 1.5 DL + 1.5 DL1 + 1.5 DL2 - 1.5 WLY
COMB016 - 0.9 DL + 0.9 DL1 + 0.9 D + 1.5 WLX
COMB017 - 0.9 DL + 0.9 DL1 + 0.9 DL - 1.5 WLX
COMB018 - 0.9 DL + 0.9 DL1 + 0.9 DL2 + 1.5 WLY
COMB019 - 0.9 DL + 0.9 DL1 + 0.9 DL2 - 1.5 WLY
Load combination as per GSA Guidelines
For static Analysis
2 ( LL + 0.25 DL)

31. Maximum displacement occurs for the combination 1.5DL+ 1.5DI + 1.5WLY
For this combination the bending moment action and axial force on the columns in
the ground floors were compared to identify the critical members

32. Alternate path method
The ratio of bending moment of the damaged building
to the intact building is calculated to check the
bending moment behavior of the adjacent columns
and adjoining beams of the removed column
Based on this the alternate path for the load flow can
be figured out

33. Bending Moment Behavior of structural elements in
Case1 (for load combination based on IS 875 part 5)
Bending Moment acting on
frame
Bending Moment ratio
(Intact to collapsed frame)

34. Bending Moment Behavior of structural elements in
Case1 (for load combination based on GSA guidelines)
Bending Moment acting on
frame
Bending Moment ratio
(Intact to collapsed frame)

35. Bending Moment Behavior of structural elements in
Case2 (for load combination based on IS 875 part 5)
Bending Moment acting on frame
Bending Moment ratio
(Intact to collapsed frame)

36. Bending Moment Behavior of structural elements in
Case2 (for load combination based on GSA guidelines)
Bending Moment acting on frame
Bending Moment ratio
(Intact to collapsed frame)

37. Bending Moment Behavior of structural elements in
Case3 (for load combination based on IS 875 part 5)
Bending Moment acting on
frame
Bending Moment ratio
(Intact to collapsed frame)

38. Bending Moment Behavior of structural elements in
Case3 (for load combination based on GSA guidelines)
Bending Moment acting on
frame
Bending Moment ratio
(Intact to collapsed frame)

39.  In the case1 the bending moment of the columns in the storeys
above the location of removed column remains unchanged,
where as the bending moment of the columns in the storey
adjacent to either side of the removed column as been increased.
And the bending moments of adjoining beams were also
increased.
 In the case2 also the bending moment of the columns in the
storeys above the location of removed column remains
unchanged and the bending moment of columns in the storey
adjacent to either side of the removed column as been increased.
And the bending moments of adjoining beams were also
increased.
 In the case 3 the bending moment of the columns in the storeys
above the location of the removed column has been reduced and
the bending moments has been increased for the remaining
columns in the ground storey. And the bending moments of
adjoining beams were also increased.

40. Demand Capacity ratio
 Demand Capacity Ratio (DCR) is the ratio of Member force to the
Member strength.
 DCR = Member force/ Member strength
 Allowable DCR < 2, for typical structural configuration,
< 1.5, for atypical structural configuration.
 DCR is calculated for the each elements in the frame which consists of
removed column

41. DCR values for case 1
(for gravity loads) (for gravity loads and lateral
loads)

42. DCR values for case 2
(for gravity loads) (for gravity loads and lateral
loads)

43. DCR values for case 3
(for gravity loads) (for gravity loads and lateral
loads)

44. According to the GSA guideline atypical frame building having DCR values
greater than 1.5 indicate that the portion is severely damaged and have
more damage potential.
It can be seen that in the third case that the demand to capacity
ratio (DCR) values exceeds the acceptance criteria in the first and second
storey beam. But in other spans damage could not propagate.
(for gravity loads) (for gravity loads and lateral
loads)
 The maximum DCR
value experienced by the
frame is 1.71. So in the third
case there is possibility for
the spread of collapse.
 The maximum DCR
value experienced by the
frame is 1.7. So in the third
case there is possibility for
the spread of collapse.

45. Robustness Indicator
Here since the robustness Indicator is almost equal to 1, the structure is
able to provide an alternative load path if the structure is damaged.
Cases Removed
column
V damaged Robustness
indicator
Case1 Middle 6837KN 0.99
Case2 Inner 6837KN 0.99
Case3 Corner 6836KN 0.94

46. Summary
 From Comparing the Bending Moment and shear force
for Intact structure and all the three cases it has been
concluded that in case 3 the bending moment and
shear has been increased more (ie When the corner
column is removed BM and SF increase more
compared to other cases).
 After determining the DCR values for gravity loads
alone and lateral loads, then it is compared.
 Robustness Indicator is calculated for Intact and other
three cases and it is not equal to 0ne expect for intact,
which shows that the building is vulnerable.