Progressive Collapse Analysis of RCC, Composite, and Hybrid SRC Structures This M.Tech project focuses on studying and comparing how different structural systems behave when one of their critical columns fails unexpectedly, leading to what is known as progressive collapse. Progressive collapse is a condition where the failure of a single structural element causes a chain reaction, leading to partial or total collapse of the structure. This is an important consideration in modern high-rise design, especially after several real-world failures caused by accidental or extreme events such as explosions, design errors, or vehicle impacts. The main objective of this study was to analyse the performance of RCC, Composite, and Hybrid SRC structures under various column removal scenarios, to identify which system provides better safety, redundancy, and resistance to collapse. The analysis was performed using the Alternate Load Path Method (ALPM) as per GSA 2003 Guidelines, which is one of the most recognized standards for progressive collapse assessment. A G+12 storey building with a grid spacing of 6 m × 5 m was modelled in ETABS. Three separate structural models were created: 1. RCC Structure – conventional reinforced concrete columns, beams, and slabs. 2. Composite Structure – steel columns and beams combined with reinforced concrete slab. 3. Hybrid SRC Structure – composite columns (encased steel) with reinforced concrete beams and slabs. Each of these models was tested for four different column removal cases to simulate possible local failures: Case 1: Periphery column removal along the long span. Case 2: Middle column removal. Case 3: Corner column removal. Case 4: Periphery column removal along the short span. Both long span (a) and short span (b) variations were considered to evaluate the effect of geometry on load redistribution. The load combination 2(DL + 0.25LL) was used to simulate the sudden removal of a column, as recommended by GSA. The Demand–Capacity Ratio (DCR) was calculated for every beam and column to determine the extent of overstressing in the structure after column removal. A DCR value greater than 2.0 indicated potential failure, while values below 1.0 were considered safe. The results showed that the Composite structure performed the best, with the lowest DCR values and higher energy absorption capacity due to the ductility of steel. The Hybrid SRC structure also performed well, offering a balance between the stiffness of concrete and the ductility of steel. The RCC structure, however, showed higher DCR values, especially around the region of column removal, indicating greater vulnerability to progressive collapse. Overall, the study clearly demonstrates that Composite and Hybrid SRC systems are more resistant to progressive collapse compared to conventional RCC frames. These systems provide better redundancy, improved stiffness, and superior load redistribution during accidental column failures.

1. “Investigation of Progressive Collapse in RCC and
Composite Structures:AStructural Comparison”
SHAIK FARAAZ AHMED
Roll No - 21011D2022
M.Tech-Structural Engineering.
DEPARTMENT OF CIVIL ENGINEERING
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY, HYDERABAD
UNIVERSITY COLLEGE OF ENGINEERING, HYDERABAD, KUKATPALLY – 500085
PROJECT GUIDE
Dr. B. DEAN KUMAR ,
PROFESSOR,
Department of Civil Engineering, JNTUH.

2. TOPICS COVERED
• Introduction
• Literature Review
• Need of study
• Objective
• Methodology
• Result
• Conclusion
• References

3. INTRODUCTION:
• Progressive collapse, also known as disproportionate collapse, is a catastrophic
structural failure mechanism where the loss of a single or small group of load-
bearing elements triggers a chain reaction, leading to partial or total collapse.
• This phenomenon is a major concern in civil engineering, particularly for high-rise
buildings, bridges, and other critical infrastructures subjected to abnormal loading
conditions such as earthquakes, explosions, or impact forces.
Progressive collapse can be classified based on failure propagation mechanisms:
a. Pancake Collapse
b. Domino Collapse
c. Zipper Collapse
d. Instability Collapse
e. Mixed-Mode Collapse

5. Causes
• Design flaws or insufficient redundancy
• Construction Defects
• Abnormal load events
→ Pressure Loads
- Internal gas explosions
- Blast
- Wind over pressure
- Extreme values of environmental loads
→ Impact Loads
- Aircraft impact
- Vehicular collision
- Earthquake
- Overload due to occupant overuse

6. Real World Collapses
R

7. Structure Year Location Structural
system
No of
floors
Events Damage
Ronan Point
Apartment
May 16,
1968
Canning Town,
England
Wall Panel 22 Gas Explosion Partial Failure
Skyline Plaza March 2,
1973
Bailey’s
Crossroads,
Virginia, USA
Reinforced
Concrete
Frame
26 Premature removal
of shoring
Partial failure
Alfred P. Murrah
Federal Building
April 19,
1995
Oklahoma City,
USA
RC Frame with
Shear Wall
9 Terrorist Bombing Complete
Collapse
Sampoong
Department Store
June 29,
1995
Seocho-dong
Seoul, South
Korea
RC Frame 5 Structural Overload,
Punching Shear
Partial failure
WTC 1 & 2 September
11, 2001
New York, USA Steel Frame 110 Collision of Aircraft
and Fire
Complete
Collapse
Rana Plaza Office
Complex
April 24,
2013
Dhaka,
Bangladesh
RC Frame 8 Structural Overload Partial failure
Plasco Building January 19,
2017
Tehran, Iran Steel Frame 17 Fire Incidence Complete
Collapse

8. Literature Review

9. S.No. Author Year Title Journal
1. 1. Maryam Musavi-Z
2. Mohammad Reza Sheidaii
2023 Improving the Progressive Collapse
Resistance of Steel Moment Frames
Using Different Beam Strengthening
Methods
The Institute
of Engineers
(India)
Observation:
This review evaluates the effectiveness of different beam strengthening methods in enhancing the progressive
collapse resistance and seismic performance of steel moment-resisting frames.
1. Effectiveness of Beam Strengthening – Strengthening beams in higher stories significantly improves
progressive collapse resistance and seismic response in steel moment-resisting frames.
2. Column Loss Scenarios – Strengthening surrounding beams in the highest story is cost-effective for external
column loss, while strengthening all beams in the highest story benefits all column removal cases.
3. Multiple Story Strengthening – Recommended when single-story strengthening may cause weak column–
strong beam failure; it also reduces excessive weight increase in high-rise buildings.
4. Seismic Performance Enhancement – Strengthened models show higher displacement capacity before
reaching collapse prevention levels and exhibit better inelastic behavior under pushover analysis.
5. Alternative Load Redistribution – Strengthening enhances the structural load path, ensuring better load
redistribution and delaying collapse during column loss scenarios.
6. Structural Generalization – The findings apply to moment-resisting frames with varying geometries, making
the method suitable for structures with different heights and span lengths.
7. Connection Considerations – Strengthened beams require high-capacity connections, with Welded Flange
Plate (WFP) moment connections recommended for progressive collapse resistance.

10. S.No. Author Year Title Journal
2. 1. Prachee Ravindra Dafe
2. Prof. Vishal M. Sapate
2023 Comparative Seismic Analysis and Design
of RCC and Composite Structure for
Different Seismic Zones and Soil
Conditions
IRJMETS
Observation:
• The study compares RCC and composite structures under seismic conditions using ETABS.
• It analyzes key parameters such as lateral deflection, story drift, and base shear.
• The evaluation considers different soil types (hard, medium, soft) and seismic zones (II to V).
• Composite structures exhibit superior seismic performance over RCC structures.
• Findings provide insights for optimizing high-rise building designs in earthquake-prone areas.

11. S.No. Author Year Title Journal
3. 1. Abhishek Maheshwaram
2. Praveen Oggu
3. Goriparthi Mallikarjuna Rao
4. M. Venu
2022 Comparative study on progressive
collapse analysis of RC frame buildings
subjected to wind and seismic loads
ISTCE 2021
Observation:
​The study analyzes comparative progressive collapse analysis of RC frame buildings (Square and Circular)
subjected to wind and seismic loads. Key findings include:​
1. Circular plan buildings perform 10-20% better in progressive collapse resistance than square plan
buildings.
2. Seismically designed structures exhibit greater resistance to progressive collapse.
3. Structural symmetry enhances stability by improving load redistribution.
4. External column removal generates higher stress, leading to progressive structural failure.
5. DCR values remain below 2, ensuring compliance with GSA guidelines for structural stability.

12. S.No. Author Year Title Journal
4. 1. Liusheng Chu
2. Gaoju Li
3. Danda Li
4. Jun Zhao
2017 Study on Progressive Collapse Behavior
of SRC Column-Steel Beam Hybrid Frame
Based on Pushdown Analysis
HINDAWI
Observation:
The study analyzes the progressive collapse behavior of SRC column-steel beam hybrid frames using ABAQUS through
dynamic and static analyses.
1. Structural response varies with column removal location, showing both beam and catenary mechanisms for middle
column failure, while only the beam mechanism occurs in corner column failure.
2. The hybrid frame exhibits strong resistance to progressive collapse under dynamic loads, especially in middle
column removal scenarios.
3. Increasing the steel ratio in SRC columns improves collapse resistance, though its effect is limited.
4. The steel beam’s ultimate moment capacity significantly influences collapse resistance, highlighting the importance
of beam section size.
5. Lower-positioned column removals enhance structural robustness, guiding design strategies for better resilience in
extreme conditions.

13. S.No Author Year Title Journal
5. 1. Aswathi R
2. Fathima Hanan K A
3. Safna A M
4. Shinu Shajee
2018 Progressive Collapse Analysis of
Composite Structures on Different
Shapes
IRJET
Observation:
​The study analyzes two different analysis procedures, linear static and nonlinear dynamic analysis of composite
structures with different plan shapes of same area and for different heights of structure. Key findings include:​
Impact of Column Removal:
• Removing corner columns imposes significant forces on adjacent columns, leading to progressive collapse.​
• Middle column removal transfers axial forces to neighboring columns, affecting their stability.​
• Corner column removal is more critical compared to removing middle or intermediate columns.​
Structural Shape Influence:
• For the same plan area, U-shaped, T-shaped, and L-shaped structures exhibit increased base shear and top-floor
displacement compared to rectangular structures.​
• L-shaped structures show a significant increase in maximum story drift.

14. S.No. Author Year Title Journal
6. 1. Dhiraj Agrawal
2. Abhishek Gulhane
3. M. D. Goel
2019 Progressive Collapse Analysis
of Composite Structure
IRJET
Observation:
​The study analyzes progressive collapse in a G+7 composite building using linear static analysis per General Services
Administration (GSA) guidelines. Key findings include:​
1. Critical Beams: Lower-story beams are more susceptible to failure than upper-story beams upon column loss.​
2. Failure Threshold: Beams with a Demand Capacity Ratio (DCR) exceeding 2 are prone to failure under sudden
column loss.​
3. Column Removal Impact: Removing interior columns has the most detrimental effect on structural integrity.​
4. Load Redistribution: Load redistribution after column removal significantly impacts adjacent beams and joints.​
5. Mitigation Measures: Implementing floor-level bracing and reinforcing outer members can effectively prevent
progressive collapse.

15. S.No. Author Year Title Journal
7. 1. Saumil S Patel
2. Vishal B Patel
3. Atul N Desai
2016 Comparative Study of Progressive
Collapse on RCC
Multistory Building
IJAREST
Observation:
1. Infill walls enhance progressive collapse resistance in SMRF and OMRF buildings.
2. Computational simulations confirm that infill walls act as compression struts,
improving load transfer.
3. Demand-Capacity Ratios (DCR) are reduced due to infill wall contribution.
4. Corner column removal poses the highest risk to structural stability.
5. Symmetrical load redistribution minimizes collapse potential and improves overall
robustness.

16. S.No. Author Year Title Journal
8. 1. Nada Elkady
2. Levingshan Augusthus
Nelson
3. Laurence Weekes
4. Nirvan Makoond
5. Manuel Buitrago
2024 Progressive collapse: Past, present,
future and beyond
ELSEVIER
Observation:
The review explores advancements in progressive collapse research, focusing on structural behavior,
mitigation strategies, and emerging technologies.
1. Experimental validation remains a key challenge, with a need for full-scale or scaled-down testing
methods.
2. Numerical modeling, especially FEA, has limitations in capturing large deformations and element
failures.
3. Realistic structural representation, including non-structural elements, requires further investigation.
4. Machine learning and physics engines offer potential for improved predictive accuracy in collapse
studies.
5. Optimization techniques are crucial for developing efficient, structure-specific prevention and
mitigation methods. Future research should address underexplored structural typologies like precast,
modular, and timber systems.

17. S.No. Author Year Title Journal
9. 1. Yograj Ashok Nimbhorkar
2. Dr. D.P.Joshi
3. Prof. S.U.Pagar
2019 A Review on Progressive Collapse of
Composites Structures
IRJET
Observation:
1. The study investigates the progressive collapse behavior of G+20 composite structures using
ETABS.
2. Analysis follows GSA guidelines, considering both linear static and dynamic methods.
3. Key parameters examined include demand-capacity ratio, base shear, and roof displacement
under sudden failure conditions.
4. Previous research focused on concrete and steel structures, with limited work on composites.
5. The study emphasizes the need for progressive collapse assessment in composite structures.

18. Need of Study
• This study aims to provide a comprehensive study of the progressive collapse
mechanisms in RCC ,Composite and Hybrid structures.
• The work will focus on advanced modeling techniques, the role of material
properties, the design of resilient connections, and strategies to enhance
redundancy and load redistribution.
• By exploring both theoretical and practical aspects, the study will contribute to the
development of more reliable and efficient structures capable of resisting
progressive collapse, ultimately improving the safety and sustainability of built
environments.

19. Objective
• Analyze progressive collapse behaviour of multistory structures using ETABS 2021, in
accordance with GSA 2003 guidelines through the Alternate Path Method (APM).
• Evaluate the direction-specific vulnerability of RCC, Composite, and Hybrid SRC
models by removing columns along both long span (6m) and short span (5m)
peripheries, as well as at middle and corner positions.
• Implement and assess the effectiveness of mitigation strategies such as bracing and
structural integrity elements to enhance structural robustness.
• Perform Response Spectrum Analysis (RSA) based on IS 1893:2016 to evaluate
seismic response characteristics including time period, base shear, and displacement.
• Recommend the most resilient and efficient structural configuration considering
both progressive collapse resistance and seismic performance.

20. Methodology

21. ➢ Model Development
• RC Frame Structure
• Hybrid SRC Structure (RC Column- Steel Beam & Deck)
• Composite Frame Structure
➢ Linear Static Analysis
• Perform Linear Static Analysis
• Analyse Structures under Gravity Load-[DL+LL] & [2(DL+0.25LL)]
➢ Progressive Collapse Analysis (Without Mitigation)
• Implement GSA column removal method
• Evaluate Structural failure under gravity loads
• Identify critical failure points
➢ Mitigation Strategies Implementation
• Introduce bracings & structural integrity elements
• Improve lateral stability and load distribution
➢ Progressive Collapse Analysis (With Mitigation)
• Reassess structures using GSA guidelines
• Evaluate impact of mitigation strategies on collapse resistance
• Compare improved DC ratios with unmitigated results
➢ Response Spectrum Analysis (RSA) for Seismic Performance
• Perform Response Spectrum Analysis (RSA) for seismic response
• Analyze Time Period, Base Shear & Roof Displacement
• Compare seismic resistance among structural models
➢ Comparative Evaluation & Conclusion
• Compare results for all models under both progressive collapse and seismic loads
• Identify most resilient structure in both scenarios
• Provide recommendations for structural optimization and practical applications

22. Typical Plan
6m
6m 6m 6m 6m 6m
6m 6m
5m
5m
5m
5m
5m

23. Alternate Load Path
The Alternate Path Method (APM) is a structural analysis approach used to assess
progressive collapse resistance by redistributing loads after the sudden removal of a
critical structural element. It ensures that the remaining structure can bridge the
missing support and prevent disproportionate failure.
Load Redistribution – Simulates sudden removal of a critical structural element to assess load
transfer.
Structural Resilience – Evaluates whether the remaining structure can withstand the
redistributed forces.
Progressive Collapse Resistance – Helps determine the likelihood of disproportionate failure.
GSA & UFC Guidelines – Commonly follows standards like GSA (2003) and UFC (2013) for
analysis.
Mitigation Strategies – Informs design improvements like redundancy and strengthening
measures.

24. Demand Capacity Ratio (DCR)
• Demand Capacity Ratio (DCR) is the ratio of Member force to the Member strength.
• DCR = Member force/ Member strength
• DCR = Qud / Qce
Where
Qud = Bending Moment of the member obtain from the
analysis after column removal
Qce = Expected moment capacity of the member before
column removal.
• Allowable DCR < 2, for typical structural configuration,
< 1.5, for atypical structural configuration.
• DCR is calculated for each elements in the frame which consists of removed column

25. RC Frame Structure
Building Description
Type of Column RC Column
Type of Beam RC Beam
Type of Slab RC Slab
No. of Floors Basement + 12
Floor Height 3 m
Beam Dimension 450 mm x 600 mm
Column Dimension 600 mm x 900 mm
Slab Thickness 125 mm
RC + RB + RS

26. RC + RB +RS
Without Mitigation

27. Case 1 (a): Removal of Periphery Column
(Long Side Periphery) [RC + RB + RC]
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 55.04 324.39 5.89
2 B2 55.09 324.39 5.89
3 B3 56.53 312.95 5.54
4 B4 57.11 312.95 5.48
5 B5 57.27 312.73 5.46
6 B6 57.11 312.57 5.47
7 B7 57.27 310.63 5.42
8 B8 57.13 311.48 5.45
9 B9 57.29 309.18 5.40
10 B10 57.22 310.03 5.42
11 B11 57.27 307.44 5.37
12 B12 57.27 308.29 5.38
13 B13 57.26 305.37 5.33
14 B14 57.27 306.23 5.35
15 B15 57.26 302.98 5.29
16 B16 57.27 303.83 5.31
17 B17 57.24 300.24 5.25
18 B18 57.25 301.08 5.26
19 B19 57.24 297.18 5.19
20 B20 57.22 297.99 5.21
21 B21 57.14 293.14 5.13
22 B22 57.17 293.84 5.14
23 B23 56.96 217.21 3.81
24 B24 57 217.43 3.81
25 B25 56.54 217.21 3.84
26 B26 56.36 217.43 3.86
LONG SIDE SPAN
Elevation 2
Without Mitigation

28. Case 1 (b): Removal of Periphery Column
(Long Side Periphery) [RC + RB +RS]
SHORT SIDE SPAN
Elevation F
Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 91.93 111.5 3.35
2 B2 122.4 103.29 2.45
3 B3 116.84 104.62 2.56
4 B4 114.47 104.58 2.63
5 B5 111.48 104.72 2.72
6 B6 107.71 104.9 2.85
7 B7 103.15 105.11 3.00
8 B8 97.77 105.35 3.20
9 B9 91.53 105.64 3.47
10 B10 84.39 105.96 3.82
11 B11 76.44 106.34 4.29
12 B12 65.07 107.17 5.12
13 B13 69.67 386.15 6.01

29. Case 2 (a): Removal of Periphery Column
(Short Side Periphery) [RC + RB + RC]
LONG SIDE SPAN
Elevation 5
Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 111.64 308 2.76
2 B2 130.93 299.62 2.29
3 B3 130.51 299.68 2.30
4 B4 128.08 301.45 2.35
5 B5 125.16 303.7 2.43
6 B6 121.68 306.63 2.52
7 B7 117.52 309.55 2.63
8 B8 112.63 313.3 2.78
9 B9 106.97 317.63 2.97
10 B10 100.52 322.55 3.21
11 B11 93.19 328.23 3.52
12 B12 84.89 333.25 3.93
13 B13 85.09 418.52 4.92

30. Case 2 (b): Removal of Periphery Column
(Short Side Periphery) [RC + RB +RS]
SHORT SIDE SPAN
Elevation J Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 34.56 336.94 9.75
2 B2 36.46 337.1 9.25
3 B3 34.31 323.03 9.42
4 B4 35.28 323.08 9.16
5 B5 34.5 325.13 9.42
6 B6 35.2 325.16 9.24
7 B7 34.17 324.21 9.49
8 B8 35.19 324.29 9.22
9 B9 34.12 323.39 9.48
10 B10 35.09 323.48 9.22
11 B11 34.06 322.35 9.46
12 B12 34.97 322.48 9.22
13 B13 33.99 321.12 9.45
14 B14 34.67 321.27 9.27
15 B15 33.82 319.68 9.45
16 B16 34.48 319.86 9.28
17 B17 33.77 318.02 9.42
18 B18 34.25 318.23 9.29
19 B19 33.63 316.1 9.40
20 B20 34.06 316.34 9.29
21 B21 33.48 314.12 9.38
22 B22 33.63 314.39 9.35
23 B23 53.58 310.86 5.80
24 B24 53.86 311.09 5.78
25 B25 53.58 374.46 6.99
26 B26 53.86 374.6 6.96

31. Case 3 (a): Removal of Middle Column
[RC + RB + RC]
LONG SIDE SPAN
Elevation 5
Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 66.24 159.44 2.41
2 B2 66.35 166 2.50
3 B3 66.1 165.72 2.51
4 B4 66.15 176.64 2.67
5 B5 66.95 162.94 2.43
6 B6 65.93 179.03 2.72
7 B7 65.97 162.85 2.47
8 B8 65.95 183.82 2.79
9 B9 65.99 165.1 2.50
10 B10 65.98 190.24 2.88
11 B11 66 170.07 2.58
12 B12 65.99 198.59 3.01
13 B13 66.01 177.85 2.69
14 B14 66 208.96 3.17
15 B15 66.02 188.56 2.86
16 B16 66.02 221.54 3.36
17 B17 66.04 201.43 3.05
18 B18 66.04 236.55 3.58
19 B19 66.08 219.83 3.33
20 B20 66.08 254.27 3.85
21 B21 66.08 241.65 3.66
22 B22 66.08 275.05 4.16
23 B23 66.02 270.93 4.10
24 B24 66.02 299.92 4.54
25 B25 66.05 306.78 4.64
26 B26 66.01 325.64 4.93

32. Case 3 (b): Removal of Middle Column
[RC + RB +RS]
SHORT SIDE SPAN
Elevation J Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 50.5 182.64 3.62
2 B2 53.34 181.47 3.40
3 B3 50.04 177.43 3.55
4 B4 51.57 175.44 3.40
5 B5 49.89 178.59 3.58
6 B6 51.54 176.1 3.42
7 B7 49.92 179.04 3.59
8 B8 51.51 176.2 3.42
9 B9 49.87 170.57 3.42
10 B10 51.39 176.43 3.43
11 B11 49.83 180.04 3.61
12 B12 51.25 176.69 3.45
13 B13 49.77 180.5 3.63
14 B14 51.09 177.02 3.46
15 B15 49.71 180.97 3.64
16 B16 50.89 177.42 3.49
17 B17 49.64 181.45 3.66
18 B18 50.87 177.91 3.50
19 B19 49.56 181.96 3.67
20 B20 50.4 178.48 3.54
21 B21 49.6 182.5 3.68
22 B22 50.16 179.17 3.57
23 B23 49.39 182.78 3.70
24 B24 49.63 179.83 3.62
25 B25 49.28 183.31 3.72
26 B26 49.69 181.38 3.65

33. Case 4 (a): Removal of Corner Column
[RC + RB + RC]
LONG SIDE SPAN
Elevation 5
Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 76.46 519.87 6.80
2 B2 90.16 536.13 5.95
3 B3 90.4 533.63 5.90
4 B4 88.38 534.05 6.04
5 B5 86.13 534.15 6.20
6 B6 83.56 534.46 6.40
7 B7 80.51 534.84 6.64
8 B8 76.93 535.29 6.96
9 B9 72.82 535.86 7.36
10 B10 68.13 536.45 7.87
11 B11 62.88 537.37 8.55
12 B12 57.76 539.28 9.34
13 B13 87.51 519.58 5.94

34. Case 4 (b): Removal of Corner Column
[RC + RB +RS]
SHORT SIDE SPAN
Elevation J Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 64.53 476.18 7.38
2 B2 88.81 474.08 5.34
3 B3 84.54 474.55 5.61
4 B4 82.87 474.39 5.72
5 B5 80.85 474.36 5.87
6 B6 78.24 474.13 6.06
7 B7 75.7 473.85 6.26
8 B8 73.33 473.51 6.46
9 B9 67.02 473.11 7.06
10 B10 62.09 472.63 7.61
11 B11 56.39 471.89 8.37
12 B12 48.68 469.75 9.65
13 B13 71.27 440.78 6.18

35. RC + RB +RS
With Mitigation

36. Case 1 (a): Removal of Periphery Column
(Long Side Periphery) [RC + RB + RC]
LONG SIDE SPAN
Elevation 2
With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 55.04 69.51 1.26
2 B2 55.09 69.51 1.26
3 B3 56.53 78.33 1.39
4 B4 57.11 78.33 1.37
5 B5 57.27 78.56 1.37
6 B6 57.11 78.63 1.38
7 B7 57.27 78.51 1.37
8 B8 57.13 78.59 1.38
9 B9 57.29 78.46 1.37
10 B10 57.22 78.53 1.37
11 B11 57.27 78.43 1.37
12 B12 57.27 78.51 1.37
13 B13 57.26 78.4 1.37
14 B14 57.27 78.48 1.37
15 B15 57.26 78.36 1.37
16 B16 57.27 78.44 1.37
17 B17 57.24 78.31 1.37
18 B18 57.25 78.4 1.37
19 B19 57.24 78.28 1.37
20 B20 57.22 78.37 1.37
21 B21 57.14 78.26 1.37
22 B22 57.17 78.35 1.37
23 B23 56.96 78.17 1.37
24 B24 57 78.25 1.37
25 B25 56.54 74.79 1.32
26 B26 56.36 74.88 1.33

37. Case 1 (b): Removal of Periphery Column
(Long Side Periphery) [RC + RB +RS]
SHORT SIDE SPAN
Elevation F
With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 91.93 73.84 0.80
2 B2 122.4 67.94 0.56
3 B3 116.84 67.67 0.58
4 B4 114.47 67.91 0.59
5 B5 111.48 68.14 0.61
6 B6 107.71 68.38 0.63
7 B7 103.15 68.67 0.67
8 B8 97.77 69 0.71
9 B9 91.53 69.39 0.76
10 B10 84.39 69.81 0.83
11 B11 76.44 70.24 0.92
12 B12 65.07 70.85 1.09
13 B13 69.67 69.32 0.99

38. Case 2 (a): Removal of Periphery Column
(Short Side Periphery) [RC + RB + RC]
LONG SIDE SPAN
Elevation 5
With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 111.64 73.56 0.66
2 B2 130.93 70.24 0.54
3 B3 130.51 70.08 0.54
4 B4 128.08 70.23 0.55
5 B5 125.16 70.38 0.56
6 B6 121.68 70.55 0.58
7 B7 117.52 70.75 0.60
8 B8 112.63 70.99 0.63
9 B9 106.97 71.27 0.67
10 B10 100.52 71.58 0.71
11 B11 93.19 71.95 0.77
12 B12 84.89 71.28 0.84
13 B13 85.09 89.79 1.06

39. Case 2 (b): Removal of Periphery Column
(Short Side Periphery) [RC + RB +RS]
SHORT SIDE SPAN
Elevation J
With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 34.56 51.68 1.50
2 B2 36.46 51.74 1.42
3 B3 34.31 56.59 1.65
4 B4 35.28 56.65 1.61
5 B5 34.5 56.83 1.65
6 B6 35.2 56.9 1.62
7 B7 34.17 56.88 1.66
8 B8 35.19 56.93 1.62
9 B9 34.12 56.94 1.67
10 B10 35.09 57 1.62
11 B11 34.06 57.04 1.67
12 B12 34.97 57.1 1.63
13 B13 33.99 57.14 1.68
14 B14 34.67 57.21 1.65
15 B15 33.82 57.27 1.69
16 B16 34.48 57.34 1.66
17 B17 33.77 57.42 1.70
18 B18 34.25 57.49 1.68
19 B19 33.63 57.6 1.71
20 B20 34.06 57.67 1.69
21 B21 33.48 57.82 1.73
22 B22 33.63 57.89 1.72
23 B23 53.58 58.05 1.08
24 B24 53.86 58.11 1.08
25 B25 53.58 59.09 1.10
26 B26 53.86 59.13 1.10

40. Case 3 (a): Removal of Middle Column
[RC + RB + RC]
LONG SIDE SPAN
Elevation 5
With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 66.24 53.35 0.81
2 B2 66.35 53.37 0.80
3 B3 66.1 58.87 0.89
4 B4 66.15 58.84 0.89
5 B5 66.95 59.09 0.88
6 B6 65.93 59.04 0.90
7 B7 65.97 59.05 0.90
8 B8 65.95 59 0.89
9 B9 65.99 59.01 0.89
10 B10 65.98 58.97 0.89
11 B11 66 58.98 0.89
12 B12 65.99 58.94 0.89
13 B13 66.01 58.95 0.89
14 B14 66 58.91 0.89
15 B15 66.02 58.91 0.89
16 B16 66.02 58.88 0.89
17 B17 66.04 58.86 0.89
18 B18 66.04 58.83 0.89
19 B19 66.08 58.8 0.89
20 B20 66.08 58.78 0.89
21 B21 66.08 58.73 0.89
22 B22 66.08 58.71 0.89
23 B23 66.02 58.66 0.89
24 B24 66.02 58.63 0.89
25 B25 66.05 58.67 0.89
26 B26 66.01 58.66 0.89

41. Case 3 (b): Removal of Middle Column
[RC + RB +RS]
SHORT SIDE SPAN
Elevation J With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 50.5 67.95 1.35
2 B2 53.34 67.96 1.27
3 B3 50.04 72.82 1.46
4 B4 51.57 72.84 1.41
5 B5 49.89 72.96 1.46
6 B6 51.54 73.01 1.42
7 B7 49.92 72.96 1.46
8 B8 51.51 72.99 1.42
9 B9 49.87 72.96 1.46
10 B10 51.39 72.99 1.42
11 B11 49.83 72.96 1.46
12 B12 51.25 72.99 1.42
13 B13 49.77 72.97 1.47
14 B14 51.09 73 1.43
15 B15 49.71 72.98 1.47
16 B16 50.89 73.01 1.43
17 B17 49.64 72.98 1.47
18 B18 50.87 73.02 1.44
19 B19 49.56 73 1.47
20 B20 50.4 73.04 1.45
21 B21 49.6 73.01 1.47
22 B22 50.16 73.05 1.46
23 B23 49.39 73.03 1.48
24 B24 49.63 73.07 1.47
25 B25 49.28 73.14 1.48
26 B26 49.69 73.17 1.47

42. Case 4 (a): Removal of Corner Column
[RC + RB + RC]
LONG SIDE SPAN
Elevation 5
With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 76.46 69.88 0.91
2 B2 90.16 66.46 0.74
3 B3 90.4 66.37 0.73
4 B4 88.38 66.37 0.75
5 B5 86.13 66.37 0.77
6 B6 83.56 66.36 0.79
7 B7 80.51 66.35 0.82
8 B8 76.93 66.34 0.86
9 B9 72.82 66.32 0.91
10 B10 68.13 66.3 0.97
11 B11 62.88 66.31 1.05
12 B12 57.76 66.31 1.15
13 B13 87.51 68.86 0.79

43. Case 4 (b): Removal of Corner Column
[RC + RB +RS]
SHORT SIDE SPAN
Elevation J With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 64.53 55.05 0.85
2 B2 88.81 52.17 0.59
3 B3 84.54 52.67 0.62
4 B4 82.87 52.65 0.64
5 B5 80.85 52.65 0.65
6 B6 78.24 52.65 0.67
7 B7 75.7 52.65 0.70
8 B8 73.33 52.65 0.72
9 B9 67.02 52.65 0.79
10 B10 62.09 52.63 0.85
11 B11 56.39 52.69 0.93
12 B12 48.68 52.78 1.08
13 B13 71.27 35.52 0.50

44. DCR Comparison
RC + RB + RS

45. Case1 (a):Demand CapacityRatio
Peripheral column removal in the longer span disrupts edge load flow. The unmitigated DCR peaked at 5.89, consistently exceeding the limit
across most elements. With mitigation, DCR values dropped to around 1.33, highlighting effective strengthening and redistribution.
5.89
5.89
5.54
5.48
5.46
5.47
5.42
5.45
5.40
5.42
5.37
5.38
5.33
5.35
5.29
5.31
5.25
5.26
5.19
5.21
5.13
5.14
3.81
3.81
3.84
3.86
1.26 1.26
1.39 1.37 1.37 1.38 1.37 1.38 1.37 1.37 1.37 1.37 1.37 1.37 1.37 1.37 1.37 1.37 1.37 1.37 1.37 1.37 1.37 1.37 1.32 1.33
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
0 5 10 15 20 25 30
RC + RB + RS Without Peripheral Column Longer Side
D/C Ratio Limit Improved D/C Ratio

46. Case1 (b):DemandCapacity Ratio
Although the column was removed on the longer span, evaluation along the shorter span shows progressive increase in DCR. It peaked at
7.27, indicating severe instability near the edge. Mitigation lowered it to 0.99, reflecting substantial performance improvement.
4.17
3.25
3.40 3.50 3.61
3.77
3.98
4.25
4.60
5.07
5.69
6.83
7.27
0.80
0.56 0.58 0.59 0.61 0.63 0.67 0.71 0.76 0.83 0.92
1.09 0.99
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
0 2 4 6 8 10 12 14
RC + RB + RS Without Peripheral Column Shorter Side
D/C Ratio Limit Improved D/C Ratio

47. Case2 (a):Demand CapacityRatio
Middle columns lead to a more symmetrical load distribution. The unmitigated DCR peaked at 4.93, indicating high vulnerability. With
mitigation measures, it significantly dropped to 0.89, showcasing enhanced structural redundancy and improved load redistribution.
2.41 2.50 2.51
2.67
2.43
2.72
2.47
2.79
2.50
2.88
2.58
3.01
2.69
3.17
2.86
3.36
3.05
3.58
3.33
3.85
3.66
4.16 4.10
4.54 4.64
4.93
0.81 0.80 0.89 0.89 0.88 0.90 0.90 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89 0.89
0.00
1.00
2.00
3.00
4.00
5.00
6.00
0 5 10 15 20 25 30
RC + RB + RS Without Middle Column Longer Side
D/C Ratio Limit Improved D/C Ratio

48. Case2 (b):DemandCapacity Ratio
Removal of the middle column caused moderate stress redistribution. The unmitigated D/C ratio peaked around 3.72, indicating localized
stress concentration. However, with mitigation, the D/C ratio was reduced effectively to approximately 1.47, demonstrating the reliability of
the structural design and redistribution along the shorter span.
3.62
3.40
3.55
3.40
3.58
3.42
3.59
3.42 3.42 3.43
3.61
3.45
3.63
3.46
3.64
3.49
3.66
3.50
3.67
3.54
3.68
3.57
3.70
3.62
3.72 3.65
1.35
1.27
1.46 1.41 1.46 1.42 1.46 1.42 1.46 1.42 1.46 1.42 1.47 1.43 1.47 1.43 1.47 1.44 1.47 1.45 1.47 1.46 1.48 1.47 1.48 1.47
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
0 5 10 15 20 25 30
RC + RB + RS Without Middle Column Shorter Side
D/C Ratio Limit Improved D/C Ratio

49. Case3 (a):Demand CapacityRatio
The removal of a corner column caused a sharp spike in unmitigated D/C ratio, peaking at 9.34, indicating severe stress concentration and
vulnerability at the structural extremity. Post-mitigation, the D/C ratio improved significantly to around 1.15, showing enhanced redundancy
and effective redistribution along the longer span.
6.80
5.95 5.90 6.04 6.20
6.40
6.64
6.96
7.36
7.87
8.55
9.34
5.94
0.91
0.74 0.73 0.75 0.77 0.79 0.82 0.86 0.91 0.97 1.05 1.15
0.79
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
0 2 4 6 8 10 12 14
RC + RB + RS Without Corner Column Longer Side
D/C Ratio Limit Improved D/C Ratio

50. Case3 (b):DemandCapacity Ratio
Corner column removal in the shorter span resulted in an unmitigated D/C ratio peaking at 9.65, signaling extreme local vulnerability. With
mitigation, the ratio dropped to 1.08, ensuring stability and showcasing the system’s improved capacity for alternate load redistribution.
7.38
5.34
5.61 5.72 5.87 6.06 6.26 6.46
7.06
7.61
8.37
9.65
6.18
0.85
0.59 0.62 0.64 0.65 0.67 0.70 0.72 0.79 0.85 0.93 1.08
0.50
0.00
2.00
4.00
6.00
8.00
10.00
12.00
0 2 4 6 8 10 12 14
RC + RB + RS Without Corner Column Shorter Side
D/C Ratio Limit Improved D/C Ratio

51. Case4 (a):Demand CapacityRatio
The removal of a peripheral column on the shorter span and analysis along the longer side caused the D/C ratio to reach a peak of 2.49,
slightly exceeding the limit of 2.0. After applying mitigation strategies, the D/C ratio was reduced to 1.06, indicating successful enhancement
of structural performance.
1.31
1.09 1.10 1.12 1.14 1.17 1.21 1.26
1.33
1.40
1.51
1.65
2.49
0.66
0.54 0.54 0.55 0.56 0.58 0.60 0.63 0.67 0.71
0.77
0.84
1.06
0.00
0.50
1.00
1.50
2.00
2.50
3.00
0 2 4 6 8 10 12 14
RC + RB + RS Without Peripheri Column (Shorter Span) Longer Side
D/C Ratio Limit Improved D/C Ratio

52. Case4 (b):DemandCapacity Ratio
In this case, D/C ratios peaked as high as 9.75, significantly surpassing the permissible limit of 2.0. However, after mitigation, the values were
drastically reduced to a maximum of 1.10, demonstrating the effectiveness of the strengthening strategies in restoring structural adequacy and
controlling the high vulnerability induced by corner support loss.
9.75
9.25 9.42
9.16
9.42 9.24
9.49
9.22
9.48
9.22
9.46
9.22
9.45 9.27 9.45 9.28 9.42 9.29 9.40 9.29 9.38 9.35
5.80 5.78
6.99 6.96
1.50 1.42
1.65 1.61 1.65 1.62 1.66 1.62 1.67 1.62 1.67 1.63 1.68 1.65 1.69 1.66 1.70 1.68 1.71 1.69 1.73 1.72
1.08 1.08 1.10 1.10
0.00
2.00
4.00
6.00
8.00
10.00
12.00
0 5 10 15 20 25 30
RC + RB + RS Without Peripheri Column (Shorter Span) Shorter Side
D/C Ratio Limit Improved D/C Ratio

53. Hybrid SRC Structure
Building Description
Type of Column Composite Column
Embedded I Section ISLB 600
Type of Beam RC Beam
Type of Slab RC Slab
No. of Floors Basement + 12
Floor Height 3 m
Beam Dimension 450 mm x 600 mm
Column Dimension 600 mm x 900 mm
Slab Thickness 125 mm
CC + RB +RS

54. CC + RB +RS
Without Mitigation

55. Case 1 (a): Removal of Periphery Column
(Long Side Periphery) [CC + RB + RC]
LONG SIDE SPAN
Elevation 2
Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 55.95 322.03 5.76
2 B2 56.96 322.65 5.66
3 B3 57.42 310.57 5.41
4 B4 57.99 311.35 5.37
5 B5 58.14 311.31 5.35
6 B6 58.01 312.14 5.38
7 B7 58.16 310.19 5.33
8 B8 58.1 3111.03 53.55
9 B9 58.13 309.77 5.33
10 B10 58.14 308.62 5.31
11 B11 58.13 306.1 5.27
12 B12 58.15 306.97 5.28
13 B13 58.13 304.16 5.23
14 B14 58.14 305.01 5.25
15 B15 58.11 301.89 5.20
16 B16 58.12 302.74 5.21
17 B17 58.07 299.3 5.15
18 B18 58.09 300.14 5.17
19 B19 57.99 296.3 5.11
20 B20 58.03 300.14 5.17
21 B21 57.8 296.41 5.13
22 B22 57.84 297.22 5.14
23 B23 57.36 292.57 5.10
24 B24 57.18 293.26 5.13
25 B25 86.61 217.7 2.51
26 B26 86.67 217.91 2.51

56. Case 1 (b): Removal of Periphery Column
(Long Side Periphery) [CC + RB +RS]
SHORT SIDE SPAN
Elevation F
Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 90.1 111.53 1.24
2 B2 119.76 103.45 0.86
3 B3 114.37 104.75 0.92
4 B4 112.11 104.71 0.93
5 B5 109.26 104.86 0.96
6 B6 105.65 105.02 0.99
7 B7 101.3 105.21 1.04
8 B8 96.18 105.44 1.10
9 B9 90.24 105.71 1.17
10 B10 83.45 106.02 1.27
11 B11 75.91 106.37 1.40
12 B12 64.94 107.28 1.65
13 B13 70.14 384.78 5.49

57. Case 2 (a): Removal of Periphery Column
(Short Side Periphery) [CC + RB + RC]
LONG SIDE SPAN
Elevation 5
Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 112.07 311.22 2.78
2 B2 130.25 302.94 2.33
3 B3 130.02 303.05 2.33
4 B4 127.72 304.65 2.39
5 B5 124.72 306.77 2.46
6 B6 121.58 309.29 2.54
7 B7 117.6 312.3 2.66
8 B8 112.93 315.91 2.80
9 B9 107.54 319.86 2.97
10 B10 101.4 324.46 3.20
11 B11 94.44 329.8 3.49
12 B12 86.61 334.36 3.86
13 B13 86.95 419.37 4.82

58. Case 2 (b): Removal of Periphery Column
(Short Side Periphery) [CC + RB +RS]
SHORT SIDE SPAN
Elevation J Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 41.08 335.45 8.17
2 B2 38.24 335.65 8.78
3 B3 42.41 321.78 7.59
4 B4 42.15 321.88 7.64
5 B5 42.98 323.84 7.53
6 B6 42.2 323.94 7.68
7 B7 43.07 322.968 7.50
8 B8 41.51 323.12 7.78
9 B9 43.11 322.21 7.47
10 B10 41.28 3222.36 78.06
11 B11 43.1 321.23 7.45
12 B12 40.98 321.41 7.84
13 B13 43.08 320.085 7.43
14 B14 40.64 320.27 7.88
15 B15 43.07 318.73 7.40
16 B16 40.25 318.94 7.92
17 B17 43.05 317.17 7.37
18 B18 39.83 317.42 7.97
19 B19 43.02 315.37 7.33
20 B20 40.25 315.64 7.84
21 B21 42.88 313.53 7.31
22 B22 40.91 313.82 7.67
23 B23 42.58 310.44 7.29
24 B24 40.86 310.64 7.60
25 B25 63.58 374.39 5.89
26 B26 62.9 374.55 5.95

59. Case 3 (a): Removal of Middle Column
[CC + RB + RC]
LONG SIDE SPAN
Elevation 5
Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 77.62 228.88 2.95
2 B2 78.98 228.93 2.90
3 B3 78.26 215 2.75
4 B4 79.02 215.05 2.72
5 B5 79.02 216.73 2.74
6 B6 78.83 216.8 2.75
7 B7 79.03 216.14 2.73
8 B8 78.89 216.2 2.74
9 B9 79.06 215.68 2.73
10 B10 78.99 215.75 2.73
11 B11 79.17 215.06 2.72
12 B12 79.11 215.13 2.72
13 B13 79.29 214.31 2.70
14 B14 79.23 214.39 2.71
15 B15 79.4 213.4 2.69
16 B16 79.36 213.48 2.69
17 B17 79.53 212.33 2.67
18 B18 79.49 212.41 2.67
19 B19 79.63 211.05 2.65
20 B20 79.62 211.14 2.65
21 B21 79.66 209.67 2.63
22 B22 79.7 209.67 2.63
23 B23 79.68 207.57 2.61
24 B24 79.47 207.66 2.61
25 B25 79.09 207.7 2.63
26 B26 79 207.76 2.63

60. Case 3 (b): Removal of Middle Column
[CC + RB +RS]
SHORT SIDE SPAN
Elevation J Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 57.14 362.58 6.35
2 B2 56.65 361.74 6.39
3 B3 58.07 352.53 6.07
4 B4 64.08 351.09 5.48
5 B5 58.59 353.76 6.04
6 B6 64.56 352.18 5.46
7 B7 58.62 353.9 6.04
8 B8 64.07 352.4 5.50
9 B9 58.62 354.29 6.04
10 B10 63.78 352.86 5.53
11 B11 58.6 354.73 6.05
12 B12 63.33 353.39 5.58
13 B13 58.56 355.28 6.07
14 B14 62.8 354.05 5.64
15 B15 58.51 355.94 6.08
16 B16 62.2 354.85 5.70
17 B17 58.44 356.75 6.10
18 B18 61.56 355.8 5.78
19 B19 58.36 357.73 6.13
20 B20 60.94 356.94 5.86
21 B21 58.23 358.91 6.16
22 B22 60 358.3 5.97
23 B23 58.14 360.07 6.19
24 B24 60.14 359.61 5.98
25 B25 57.93 362.75 6.26
26 B26 58.14 362.54 6.24

61. Case 4 (a): Removal of Corner Column
[CC + RB + RC]
LONG SIDE SPAN
Elevation 5
Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 75.55 519.8 6.88
2 B2 88.37 536.26 6.07
3 B3 88.7 533.64 6.02
4 B4 86.81 534.08 6.15
5 B5 84.67 534.18 6.31
6 B6 82.24 534.49 6.50
7 B7 79.35 534.86 6.74
8 B8 75.98 535.31 7.05
9 B9 72.11 535.84 7.43
10 B10 67.72 536.46 7.92
11 B11 62.77 537.36 8.56
12 B12 58.03 539.23 9.29
13 B13 89.73 520.44 5.80

62. Case 4 (b): Removal of Corner Column
[CC + RB +RS]
SHORT SIDE SPAN
Elevation J Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 62.81 476.9 7.59
2 B2 84.45 474.16 5.61
3 B3 82.29 474.84 5.77
4 B4 80.73 474.65 5.88
5 B5 78.81 474.62 6.02
6 B6 76.31 474.39 6.22
7 B7 73.28 474.1 6.47
8 B8 69.74 473.75 6.79
9 B9 65.65 473.35 7.21
10 B10 60.98 472.87 7.75
11 B11 55.59 472.13 8.49
12 B12 48.17 470 9.76
13 B13 72.17 442.14 6.13

63. CC + RB +RS
With Mitigation

64. Case 1 (a): Removal of Periphery Column
(Long Side Periphery) [CC + RB + RC]
LONG SIDE SPAN
Elevation 2
With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 55.95 69.43 1.24
2 B2 56.96 69.45 1.22
3 B3 57.42 78.23 1.36
4 B4 57.99 78.29 1.35
5 B5 58.14 78.52 1.35
6 B6 58.01 78.59 1.35
7 B7 58.16 78.47 1.35
8 B8 58.1 78.54 1.35
9 B9 58.13 78.41 1.35
10 B10 58.14 78.48 1.35
11 B11 58.13 78.36 1.35
12 B12 58.15 78.44 1.35
13 B13 58.13 78.32 1.35
14 B14 58.14 78.4 1.35
15 B15 58.11 78.28 1.35
16 B16 58.12 78.36 1.35
17 B17 58.07 78.28 1.35
18 B18 58.09 78.37 1.35
19 B19 57.99 78.28 1.35
20 B20 58.03 78.37 1.35
21 B21 57.8 78.34 1.36
22 B22 57.84 78.43 1.36
23 B23 57.36 78.07 1.36
24 B24 57.18 78.15 1.37
25 B25 86.61 33.15 0.38
26 B26 86.67 33.15 0.38

65. Case 1 (b): Removal of Periphery Column
(Long Side Periphery) [CC + RB +RS]
SHORT SIDE SPAN
Elevation F
With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 90.1 74.17 0.82
2 B2 119.76 68.27 0.57
3 B3 114.37 49.5 0.43
4 B4 112.11 68.23 0.61
5 B5 109.26 68.44 0.63
6 B6 105.65 68.67 0.65
7 B7 101.3 68.94 0.68
8 B8 96.18 69.24 0.72
9 B9 90.24 69.25 0.77
10 B10 83.45 69.62 0.83
11 B11 75.91 69.98 0.92
12 B12 64.94 70.24 1.08
13 B13 70.14 88.65 1.26

66. Case 2 (a): Removal of Periphery Column
(Short Side Periphery) [CC + RB + RC]
LONG SIDE SPAN
Elevation 5
With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 112.07 73.37 0.65
2 B2 130.25 70.4 0.54
3 B3 130.02 70.33 0.54
4 B4 127.72 65.91 0.52
5 B5 124.72 70.53 0.57
6 B6 121.58 70.69 0.58
7 B7 117.6 70.88 0.60
8 B8 112.93 71.11 0.63
9 B9 107.54 71.37 0.66
10 B10 101.4 71.67 0.71
11 B11 94.44 72.02 0.76
12 B12 86.61 72.34 0.84
13 B13 86.95 45.58 0.52

67. Case 2 (b): Removal of Periphery Column
(Short Side Periphery) [RC + RB +RS]
SHORT SIDE SPAN
Elevation J
With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 41.08 51.71 1.26
2 B2 38.24 51.78 1.35
3 B3 42.41 56.68 1.34
4 B4 42.15 56.73 1.35
5 B5 42.98 56.73 1.32
6 B6 42.2 56.78 1.35
7 B7 43.07 55.63 1.29
8 B8 41.51 55.69 1.34
9 B9 43.11 57.03 1.32
10 B10 41.28 57.09 1.38
11 B11 43.1 57.4 1.33
12 B12 40.98 57.17 1.40
13 B13 43.08 57.2 1.33
14 B14 40.64 57.27 1.41
15 B15 43.07 57.32 1.33
16 B16 40.25 57.39 1.43
17 B17 43.05 57.46 1.33
18 B18 39.83 57.53 1.44
19 B19 43.02 57.63 1.34
20 B20 40.25 57.71 1.43
21 B21 42.88 57.84 1.35
22 B22 40.91 57.92 1.42
23 B23 42.58 58.06 1.36
24 B24 40.86 58.12 1.42
25 B25 63.58 59.09 0.93
26 B26 62.9 59.13 0.94

68. Case 3 (a): Removal of Middle Column
[CC + RB + RC]
LONG SIDE SPAN
Elevation 5
With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 19.93 56.07 2.81
2 B2 19.93 56.1 2.81
3 B3 19.97 62.56 3.13
4 B4 19.98 62.58 3.13
5 B5 20 62.62 3.13
6 B6 20.01 62.64 3.13
7 B7 20 62.63 3.13
8 B8 20.01 62.65 3.13
9 B9 19.99 62.65 3.13
10 B10 20 62.67 3.13
11 B11 19.97 62.68 3.14
12 B12 19.97 62.71 3.14
13 B13 19.95 62.7 3.14
14 B14 19.96 62.75 3.14
15 B15 19.95 62.89 3.15
16 B16 19.95 62.65 3.14
17 B17 19.94 62.89 3.15
18 B18 19.95 62.65 3.14
19 B19 19.94 62.87 3.15
20 B20 19.95 62.91 3.15
21 B21 19.94 62.96 3.16
22 B22 19.94 62.98 3.16
23 B23 19.95 63.05 3.16
24 B24 19.95 63.05 3.16
25 B25 19.93 63.18 3.17
26 B26 19.93 63.18 3.17

69. Case 3 (b): Removal of Middle Column
[CC + RB +RS]
SHORT SIDE SPAN
Elevation J With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 80.14 93.39 1.17
2 B2 80.05 93.59 1.17
3 B3 80.72 92.67 1.15
4 B4 83.16 62.64 0.75
5 B5 81.01 92.72 1.14
6 B6 82.98 92.7 1.12
7 B7 81.01 92.7 1.14
8 B8 82.95 62.68 0.76
9 B9 80.97 92.7 1.14
10 B10 82.79 92.68 1.12
11 B11 80.91 92.69 1.15
12 B12 80.57 92.67 1.15
13 B13 80.83 62.69 0.78
14 B14 82.32 92.66 1.13
15 B15 80.73 92.68 1.15
16 B16 82.04 92.66 1.13
17 B17 80.62 92.71 1.15
18 B18 81.72 92.69 1.13
19 B19 80.48 92.66 1.15
20 B20 81.4 92.64 1.14
21 B21 80.32 92.65 1.15
22 B22 80.98 92.63 1.14
23 B23 80.12 92.63 1.16
24 B24 80.76 92.6 1.15
25 B25 79.86 92.62 1.16
26 B26 79.9 92.62 1.16

70. Case 4 (a): Removal of Corner Column
[CC + RB + RC]
LONG SIDE SPAN
Elevation 5
With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 63.25 65.9 1.04
2 B2 72.68 61.94 0.85
3 B3 70.24 61.78 0.88
4 B4 69.91 61.77 0.88
5 B5 68.66 61.76 0.90
6 B6 67.18 61.75 0.92
7 B7 65.38 61.74 0.94
8 B8 63.27 61.72 0.98
9 B9 60.87 61.7 1.01
10 B10 58.05 61.69 1.06
11 B11 55.27 61.67 1.12
12 B12 50.31 61.86 1.23
13 B13 93.27 57.37 0.62

71. Case 4 (b): Removal of Corner Column
[CC + RB +RS]
SHORT SIDE SPAN
Elevation J With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 38.04 119.78 3.15
2 B2 39.9 113.59 2.85
3 B3 38.69 113.28 2.93
4 B4 38.04 113.32 2.98
5 B5 37.09 113.33 3.06
6 B6 35.96 113.38 3.15
7 B7 34.6 113.41 3.28
8 B8 33.2 113.45 3.42
9 B9 31.23 113.48 3.63
10 B10 29.2 113.52 3.89
11 B11 26.99 113.72 4.21
12 B12 24.41 113.72 4.66
13 B13 22.59 158.26 7.01

72. DCR Comparison
CC + RB + RS

73. Case1 (a):Demand CapacityRatio
Long span peripheral column removal in CC + RB + RS yields a peak unmitigated DCR of 5.76, gradually decreasing to 5.13 across most
elements. Post-mitigation, the DCR sharply dropped to 2.51 and further down to 0.38, reflecting highly effective retrofitting and redistribution
of internal forces
5.76 5.66
5.41 5.37 5.35 5.38 5.33
5.55
5.33 5.31 5.27 5.28 5.23 5.25 5.20 5.21 5.15 5.17 5.11 5.17 5.13 5.14 5.10 5.13
2.51 2.51
1.24 1.22
1.36 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1.35 1.36 1.36 1.36 1.37
0.38 0.38
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
0 5 10 15 20 25 30
CC + RB + RS Without Peripheri Column (Shorter Span) Longer Side
D/C Ratio Limit Improved D/C Ratio

74. Case1 (b):DemandCapacity Ratio
CC + RB + RS structure with long-span column removal (shorter side evaluation) exhibits a peak unmitigated DCR of 5.49, with several
elements already close to or below the limit. Post-mitigation improvements reduce DCR significantly to a minimum of 0.43, ensuring better
stress distribution and enhanced structural stability.
1.24
0.86 0.92 0.93 0.96 0.99 1.04 1.10 1.17 1.27
1.40
1.65
5.49
0.82
0.57
0.43
0.61 0.63 0.65 0.68 0.72 0.77 0.83 0.92
1.08
1.26
0.00
1.00
2.00
3.00
4.00
5.00
6.00
0 2 4 6 8 10 12 14
CC + RB + RS Without Peripheri Column (Shorter Span) Shorter Side
D/C Ratio Limit Improved D/C Ratio

75. Case2 (a):Demand CapacityRatio
CC + RB + RS structure with middle column removal (longer side evaluation) shows a moderate unmitigated DCR of 2.95, which remains
mostly above the acceptable limit. With mitigation strategies in place, the improved DCR reduces to 1.02–1.19, indicating a stable and
efficient load redistribution across the span.
2.95 2.90
2.75 2.72 2.74 2.75 2.73 2.74 2.73 2.73 2.72 2.72 2.70 2.71 2.69 2.69 2.67 2.67 2.65 2.65 2.63 2.63 2.61 2.61 2.63 2.63
1.02 1.03
1.16 1.15 1.16 1.16 1.15 1.15 1.15 1.15 1.15 1.15 1.15 1.15 1.15 1.15 1.15 1.15 1.14 1.14 1.14 1.14 1.14 1.15 1.16 1.19
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
0 5 10 15 20 25 30
CC + RB + RS Without Middle Column Longer Side
D/C Ratio Limit Improved D/C Ratio

76. Case2 (b):DemandCapacity Ratio
CC + RB + RS structure with middle column removal (shorter side evaluation) exhibits a consistently high unmitigated DCR of 6.39, well
beyond the safe limit. However, with mitigation, the DCR drops to around 1.05–1.20, indicating that the applied measures significantly
enhance performance under critical middle column removal scenarios.
6.35 6.39
6.07
5.48
6.04
5.46
6.04
5.50
6.04
5.53
6.05
5.58
6.07
5.64
6.08
5.70
6.10
5.78
6.13
5.86
6.16
5.97
6.19
5.98
6.26 6.24
1.05 1.06
1.20 1.09 1.20 1.08 1.19 1.09 1.19 1.10 1.19 1.10 1.19 1.11 1.19 1.12 1.19 1.13 1.19 1.14 1.19 1.16 1.19 1.15 1.20 1.19
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
0 5 10 15 20 25 30
CC + RB + RS Without Middle Column Shorter Side
D/C Ratio Limit Improved D/C Ratio

77. Case3 (a):Demand CapacityRatio
CC + RB + RS structure with corner column removal (longer side evaluation) shows a significant unmitigated DCR peak of 9.29, indicating
severe vulnerability at the critical node. Post-mitigation, the DCR drops to 1.22, highlighting a highly effective improvement in structural
resilience through strengthening measures.
6.88
6.07 6.02 6.15 6.31
6.50
6.74
7.05
7.43
7.92
8.56
9.29
5.80
0.98
0.80 0.80 0.81 0.83 0.86 0.89 0.93 0.98 1.04 1.12 1.22
0.81
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
0 2 4 6 8 10 12 14
CC + RB + RS Without Corner Column Longer Side
D/C Ratio Limit Improved D/C Ratio

78. Case3 (b):DemandCapacity Ratio
CC + RB + RS with corner column removal (shorter side evaluation) exhibits a high unmitigated DCR of 9.76, indicating critical structural
stress at the corner. After applying mitigation strategies, the DCR improves significantly to 1.09, demonstrating enhanced robustness and
structural recovery.
7.59
5.61 5.77 5.88 6.02 6.22
6.47
6.79
7.21
7.75
8.49
9.76
6.13
0.89
0.62 0.64 0.65 0.67 0.69 0.72 0.75 0.80 0.86 0.95 1.09
0.73
0.00
2.00
4.00
6.00
8.00
10.00
12.00
0 2 4 6 8 10 12 14
CC + RB + RS Without Corner Column Shorter Side
D/C Ratio Limit Improved D/C Ratio

79. Case4 (a):Demand CapacityRatio
CC + RB + RS with peripheral column removal (short span evaluated along longer side) initially showed an unmitigated peak DCR of 4.82,
which exceeded the safety threshold. After implementing mitigation techniques, the DCR reduced to 0.84, confirming a successful
improvement in structural stability along the longer direction.
2.78
2.33 2.33 2.39 2.46 2.54
2.66
2.80
2.97
3.20
3.49
3.86
4.82
0.65
0.54 0.54 0.52 0.57 0.58 0.60 0.63 0.66 0.71 0.76 0.84
0.52
0.00
1.00
2.00
3.00
4.00
5.00
6.00
0 2 4 6 8 10 12 14
CC + RB + RS Without Peripheri Column (Shorter Span) Longer Side
D/C Ratio Limit Improved D/C Ratio

80. Case4 (b):DemandCapacity Ratio
Peripheral column removal on the shorter span of the hybrid structure (CC + RB + RS) led to a high unmitigated D/C ratio of 8.78, which
effectively reduced to 1.35 after mitigation. This indicates a substantial enhancement in structural redundancy and control over localized
failure.
8.17
8.78
7.59 7.64 7.53 7.68
7.50
7.78
7.47
7.81
7.45
7.84
7.43
7.88
7.40
7.92
7.37
7.97
7.33
7.84
7.31
7.67
7.29
7.60
5.89 5.95
1.26 1.35 1.34 1.35 1.32 1.35 1.29 1.34 1.32 1.38 1.33 1.40 1.33 1.41 1.33 1.43 1.33 1.44 1.34 1.43 1.35 1.42 1.36 1.42
0.93 0.94
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
10.00
0 5 10 15 20 25 30
CC + RB + RS Without Peripheri Column (Shorter Span) Shorter Side
D/C Ratio Limit Improved D/C Ratio

81. Composite Frame Structure
Building Description
Type of Column Composite Column
Embedded I Section (Col) ISLB 600
Type of Beam Steel Beam
Type of Slab Deck Slab
No. of Floors Basement + 12
Floor Height 3 m
Beam Depth 450 mm
Column Dimension 600 mm x 900 mm
Slab Depth 87.5 mm
Rib Depth 75 mm
CC + CB + CS

82. CC + CB +CS
Without Mitigation

83. Case 1 (a): Removal of Periphery Column
(Long Side Periphery) [CC + CB + CC]
LONG SIDE SPAN
Elevation 2
Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 20.88 326.43 15.63
2 B2 20.88 326.43 15.63
3 B3 21.22 318.18 14.99
4 B4 21.23 318.18 14.99
5 B5 21.46 319.53 14.89
6 B6 24.47 319.53 13.06
7 B7 21.49 318.83 14.84
8 B8 21.5 318.82 14.83
9 B9 21.46 318.42 14.84
10 B10 21.47 318.43 14.83
11 B11 21.4 317.82 14.85
12 B12 21.41 317.83 14.84
13 B13 21.31 317.13 14.88
14 B14 21.32 317.13 14.87
15 B15 21.2 316.31 14.92
16 B16 21.2 316.31 14.92
17 B17 21.06 315.37 14.97
18 B18 21.06 315.37 14.97
19 B19 20.9 314.53 15.05
20 B20 20.9 314.53 15.05
21 B21 20.7 313.17 15.13
22 B22 20.7 313.17 15.13
23 B23 20.42 311.07 15.23
24 B24 20.42 311.07 15.23
25 B25 20.09 282.14 14.04
26 B26 20.09 282.14 14.04

84. Case 1 (b): Removal of Periphery Column
(Long Side Periphery) [CC + CB +CS]
SHORT SIDE SPAN
Elevation F
Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 102.25 401.43 3.93
2 B2 116.82 413.62 3.54
3 B3 112.21 412.11 3.67
4 B4 111.59 413.76 3.71
5 B5 109.65 415.07 3.79
6 B6 107.48 416.87 3.88
7 B7 104.81 419 4.00
8 B8 101.96 421.51 4.13
9 B9 98.13 424.38 4.32
10 B10 93.94 427.76 4.55
11 B11 89.91 431.12 4.80
12 B12 82.42 437.41 5.31
13 B13 87.98 514.77 5.85

85. Case 2 (a): Removal of Periphery Column
(Short Side Periphery) [CC + CB + CC]
LONG SIDE SPAN
Elevation 5
Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 50.33 188.06 3.74
2 B2 53.09 183.27 3.45
3 B3 51.78 184.73 3.57
4 B4 50.81 185.05 3.64
5 B5 49.31 185.88 3.77
6 B6 47.46 186.85 3.94
7 B7 45.24 188.02 4.16
8 B8 42.64 189.38 4.44
9 B9 39.66 190.94 4.81
10 B10 36.29 192.72 5.31
11 B11 32.54 194.71 5.98
12 B12 28.24 197.28 6.99
13 B13 24.31 324.51 13.35

86. Case 2 (b): Removal of Periphery Column
(Short Side Periphery) [CC + CB +CS]
SHORT SIDE SPAN
Elevation J Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 48.36 284.38 5.88
2 B2 46.87 284.34 6.07
3 B3 48.78 274.46 5.63
4 B4 47.98 284.46 5.93
5 B5 48.92 276.46 5.65
6 B6 47.53 276.46 5.82
7 B7 78.99 275.83 3.49
8 B8 47.45 275.83 5.81
9 B9 48.98 275.7 5.63
10 B10 47.39 275.7 5.82
11 B11 48.9 275.39 5.63
12 B12 47.38 275.39 5.81
13 B13 48.82 275.05 5.63
14 B14 47.35 275.05 5.81
15 B15 48.73 274.64 5.64
16 B16 47.34 274.64 5.80
17 B17 48.62 274.18 5.64
18 B18 47.43 274.18 5.78
19 B19 48.48 273.61 5.64
20 B20 47.51 273.61 5.76
21 B21 48.32 273.2 5.65
22 B22 47.59 273.2 5.74
23 B23 48.08 271.64 5.65
24 B24 47.58 271.64 5.71
25 B25 88.02 286.55 3.26
26 B26 87.81 286.61 3.26

87. Case 3 (a): Removal of Middle Column
[CC + CB + CC]
LONG SIDE SPAN
Elevation 5
Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 19.93 284.99 14.30
2 B2 19.93 284.99 14.30
3 B3 19.97 279.97 14.02
4 B4 19.98 272.97 13.66
5 B5 20 275.3 13.77
6 B6 20.01 272.3 13.61
7 B7 20 274.43 13.72
8 B8 20.01 274.43 13.71
9 B9 19.99 274.11 13.71
10 B10 20 274.11 13.71
11 B11 19.97 273.55 13.70
12 B12 19.97 273.55 13.70
13 B13 19.95 272.89 13.68
14 B14 19.96 272.89 13.67
15 B15 19.95 272.11 13.64
16 B16 19.95 272.11 13.64
17 B17 19.94 271.2 13.60
18 B18 19.95 271.2 13.59
19 B19 19.94 270.14 13.55
20 B20 19.95 270.14 13.54
21 B21 19.94 289.04 14.50
22 B22 19.94 289.04 14.50
23 B23 19.95 287.27 14.40
24 B24 19.95 287.27 14.40
25 B25 19.93 287.63 14.43
26 B26 19.93 287.63 14.43

88. Case 3 (b): Removal of Middle Column
[CC + CB +CS]
SHORT SIDE SPAN
Elevation J Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 80.14 280.73 3.50
2 B2 80.05 280.68 3.51
3 B3 80.72 274.04 3.39
4 B4 83.16 273.57 3.29
5 B5 81.01 275.57 3.40
6 B6 82.98 275.12 3.32
7 B7 81.01 275.44 3.40
8 B8 82.95 274.99 3.32
9 B9 80.97 275.72 3.41
10 B10 82.79 275.29 3.33
11 B11 80.91 275.97 3.41
12 B12 80.57 275.57 3.42
13 B13 80.83 276.31 3.42
14 B14 82.32 275.57 3.35
15 B15 80.73 276.31 3.42
16 B16 82.04 275.94 3.36
17 B17 80.62 276.7 3.43
18 B18 81.72 276.87 3.39
19 B19 80.48 277.69 3.45
20 B20 81.4 277.43 3.41
21 B21 80.32 278.33 3.47
22 B22 80.98 278.14 3.43
23 B23 80.12 278.83 3.48
24 B24 80.76 278.67 3.45
25 B25 79.86 280.53 3.51
26 B26 79.9 280.48 3.51

89. Case 4 (a): Removal of Corner Column
[CC + CB + CC]
LONG SIDE SPAN
Elevation 5
Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 63.25 408.31 6.46
2 B2 72.68 399.55 5.50
3 B3 70.24 401.73 5.72
4 B4 69.91 401.13 5.74
5 B5 68.66 400.99 5.84
6 B6 67.18 400.63 5.96
7 B7 65.38 400.17 6.12
8 B8 63.27 399.65 6.32
9 B9 60.87 399.03 6.56
10 B10 58.05 398.3 6.86
11 B11 55.27 397.32 7.19
12 B12 50.31 396.81 7.89
13 B13 93.27 336.32 3.61

90. Case 4 (b): Removal of Corner Column
[CC + CB +CS]
SHORT SIDE SPAN
Elevation J Without Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 38.04 564.38 14.84
2 B2 39.9 571.84 14.33
3 B3 38.69 569.98 14.73
4 B4 38.04 570.49 15.00
5 B5 37.09 570.61 15.38
6 B6 35.96 570.94 15.88
7 B7 34.6 571.31 16.51
8 B8 33.2 571.75 17.22
9 B9 31.23 572.27 18.32
10 B10 29.2 572.89 19.62
11 B11 26.99 573.72 21.26
12 B12 24.41 573 23.47
13 B13 22.59 526.28 23.30

91. CC + CB +CS
With Mitigation

92. Case 1 (a): Removal of Periphery Column
(Long Side Periphery) [CC + CB + CC]
LONG SIDE SPAN
Elevation 2
With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 56.27 326.43 5.80
2 B2 56.31 326.43 5.80
3 B3 61.39 318.18 5.18
4 B4 61.47 318.18 5.18
5 B5 61.54 319.53 5.19
6 B6 61.4 319.53 5.20
7 B7 64.64 318.83 4.93
8 B8 61.75 318.82 5.16
9 B9 61.77 318.42 5.15
10 B10 61.87 318.43 5.15
11 B11 61.91 317.82 5.13
12 B12 62.01 317.83 5.13
13 B13 62.08 317.13 5.11
14 B14 62.18 317.13 5.10
15 B15 62.28 316.31 5.08
16 B16 62.37 316.31 5.07
17 B17 62.52 315.37 5.04
18 B18 62.6 315.37 5.04
19 B19 62.79 314.53 5.01
20 B20 62.87 314.53 5.00
21 B21 63.11 313.17 4.96
22 B22 63.17 313.17 4.96
23 B23 63.55 311.07 4.89
24 B24 63.59 311.07 4.89
25 B25 59.8 282.14 4.72
26 B26 59.81 282.14 4.72

93. Case 1 (b): Removal of Periphery Column
(Long Side Periphery) [CC + CB +CS]
SHORT SIDE SPAN
Elevation F
With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 102.25 180.7 1.77
2 B2 116.82 171.39 1.47
3 B3 112.21 171.15 1.53
4 B4 111.59 171.3 1.54
5 B5 109.65 171.43 1.56
6 B6 107.48 171.59 1.60
7 B7 104.81 171.87 1.64
8 B8 101.96 171.77 1.68
9 B9 98.13 172.39 1.76
10 B10 93.94 172.63 1.84
11 B11 89.91 173.03 1.92
12 B12 89.42 173.55 1.94
13 B13 87.98 161.73 1.84

94. Case 2 (a): Removal of Periphery Column
(Short Side Periphery) [CC + CB + CC]
LONG SIDE SPAN
Elevation 5
With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 50.33 61.57 1.22
2 B2 53.09 56.92 1.07
3 B3 51.78 56.85 1.10
4 B4 50.81 56.94 1.12
5 B5 49.31 57.04 1.16
6 B6 47.46 57.17 1.20
7 B7 45.24 57.31 1.27
8 B8 42.64 57.49 1.35
9 B9 39.66 57.69 1.45
10 B10 36.29 57.92 1.60
11 B11 32.54 58.19 1.79
12 B12 28.24 56.68 2.01
13 B13 24.31 37.9 1.56

95. Case 2 (b): Removal of Periphery Column
(Short Side Periphery) [CC + CB +CS]
SHORT SIDE SPAN
Elevation J
With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 48.36 107.77 2.23
2 B2 46.87 101.83 2.17
3 B3 48.78 108.13 2.22
4 B4 47.98 108.18 2.25
5 B5 48.92 108.3 2.21
6 B6 47.53 108.36 2.28
7 B7 78.99 108.34 1.37
8 B8 47.45 108.4 2.28
9 B9 48.98 108.41 2.21
10 B10 47.39 108.47 2.29
11 B11 48.9 108.49 2.22
12 B12 47.38 108.55 2.29
13 B13 48.82 108.58 2.22
14 B14 47.35 108.64 2.29
15 B15 48.73 108 2.22
16 B16 47.34 108.75 2.30
17 B17 48.62 108.83 2.24
18 B18 47.43 108.88 2.30
19 B19 48.48 108.98 2.25
20 B20 47.51 109.03 2.29
21 B21 48.32 109.16 2.26
22 B22 47.59 109.21 2.29
23 B23 48.08 109.38 2.27
24 B24 47.58 109.42 2.30
25 B25 88.02 179.4 2.04
26 B26 87.81 179.42 2.04

96. Case 3 (a): Removal of Middle Column
[CC + CB + CC]
LONG SIDE SPAN
Elevation 5
With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 19.93 56.07 2.81
2 B2 19.93 56.1 2.81
3 B3 19.97 62.56 3.13
4 B4 19.98 62.58 3.13
5 B5 20 62.62 3.13
6 B6 20.01 62.64 3.13
7 B7 20 62.63 3.13
8 B8 20.01 62.65 3.13
9 B9 19.99 62.65 3.13
10 B10 20 62.67 3.13
11 B11 19.97 62.68 3.14
12 B12 19.97 62.71 3.14
13 B13 19.95 62.7 3.14
14 B14 19.96 62.75 3.14
15 B15 19.95 62.89 3.15
16 B16 19.95 62.65 3.14
17 B17 19.94 62.89 3.15
18 B18 19.95 62.65 3.14
19 B19 19.94 62.87 3.15
20 B20 19.95 62.91 3.15
21 B21 19.94 62.96 3.16
22 B22 19.94 62.98 3.16
23 B23 19.95 63.05 3.16
24 B24 19.95 63.05 3.16
25 B25 19.93 63.18 3.17
26 B26 19.93 63.18 3.17

97. Case 3 (b): Removal of Middle Column
[CC + CB +CS]
SHORT SIDE SPAN
Elevation J With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 80.14 93.39 1.17
2 B2 80.05 93.59 1.17
3 B3 80.72 92.67 1.15
4 B4 83.16 62.64 0.75
5 B5 81.01 92.72 1.14
6 B6 82.98 92.7 1.12
7 B7 81.01 92.7 1.14
8 B8 82.95 62.68 0.76
9 B9 80.97 92.7 1.14
10 B10 82.79 92.68 1.12
11 B11 80.91 92.69 1.15
12 B12 80.57 92.67 1.15
13 B13 80.83 62.69 0.78
14 B14 82.32 92.66 1.13
15 B15 80.73 92.68 1.15
16 B16 82.04 92.66 1.13
17 B17 80.62 92.71 1.15
18 B18 81.72 92.69 1.13
19 B19 80.48 92.66 1.15
20 B20 81.4 92.64 1.14
21 B21 80.32 92.65 1.15
22 B22 80.98 92.63 1.14
23 B23 80.12 92.63 1.16
24 B24 80.76 92.6 1.15
25 B25 79.86 92.62 1.16
26 B26 79.9 92.62 1.16

98. Case 4 (a): Removal of Corner Column
[CC + CB + CC]
LONG SIDE SPAN
Elevation 5
With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 38.04 119.78 3.15
2 B2 39.9 113.59 2.85
3 B3 38.69 113.28 2.93
4 B4 38.04 113.32 2.98
5 B5 37.09 113.33 3.06
6 B6 35.96 113.38 3.15
7 B7 34.6 113.41 3.28
8 B8 33.2 113.45 3.42
9 B9 31.23 113.48 3.63
10 B10 29.2 113.52 3.89
11 B11 26.99 113.72 4.21
12 B12 24.41 113.72 4.66
13 B13 22.59 158.26 7.01

99. Case 4 (b): Removal of Corner Column
[CC + CB +CS]
SHORT SIDE SPAN
Elevation J With Mitigation
Sl.No. Beam No BM Before BM After D/C Ratio
1 B1 63.25 65.9 1.04
2 B2 72.68 61.94 0.85
3 B3 70.24 61.78 0.88
4 B4 69.91 61.77 0.88
5 B5 68.66 61.76 0.90
6 B6 67.18 61.75 0.92
7 B7 65.38 61.74 0.94
8 B8 63.27 61.72 0.98
9 B9 60.87 61.7 1.01
10 B10 58.05 61.69 1.06
11 B11 55.27 61.67 1.12
12 B12 50.31 61.86 1.23
13 B13 93.27 57.37 0.62

100. DCR Comparison
CC + CB + CS

101. Case1 (a):Demand CapacityRatio
This composite structure exhibited very high unmitigated D/C ratios, peaking at 15.63, far exceeding the allowable limit of 2.0. Even post-
mitigation, the improved D/C values remained around 4.86–5.80, indicating only moderate reduction and emphasizing that composite beam
and slab systems, though strong, require substantial intervention under peripheral column loss in long-span zones.
15.63
15.63
14.99
14.99
14.89
13.06
14.84
14.83
14.84
14.83
14.85
14.84
14.88
14.87
14.92
14.92
14.97
14.97
15.05
15.05
15.13
15.13
15.23
15.23
14.04
14.04
5.80 5.80
5.18 5.18 5.19 5.20 4.93 5.16 5.15 5.15 5.13 5.13 5.11 5.10 5.08 5.07 5.04 5.04 5.01 5.00 4.96 4.96 4.89 4.89 4.72 4.72
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
18.00
0 5 10 15 20 25 30
CC + CB + CS Without Peripheri Column (Longer Span) Longer Side
D/C Ratio Limit Improved D/C Ratio

102. Case1 (b):DemandCapacity Ratio
The D/C ratio reached a peak of 5.85 before mitigation, clearly exceeding the permissible limit. After mitigation, values significantly dropped
to 1.47–1.94, bringing most elements within the safe zone. This indicates effective redistribution of forces on the shorter side when a
peripheral column is removed in the longer span.
3.93
3.54
3.67 3.71 3.79 3.88 4.00
4.13
4.32
4.55
4.80
5.31
5.85
1.77
1.47 1.53 1.54 1.56 1.60 1.64 1.68 1.76 1.84 1.92 1.94 1.84
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
0 2 4 6 8 10 12 14
CC + CB + CS Without Peripheri Column (Longer Span) Shorter Side
D/C Ratio Limit Improved D/C Ratio

103. Case2 (a):Demand CapacityRatio
Middle column removal in the composite structure (CC + CB + CS) along the longer span resulted in high unmitigated D/C ratios, ranging up to 14.50,
indicating critical stress concentrations. With mitigation, the maximum D/C ratio significantly reduced to 3.17, demonstrating that even in composite
systems, middle column removal severely compromises structural performance, but redundancy measures are highly effective in restoring stability.
14.30
14.30
14.02
13.66
13.77
13.61
13.72
13.71
13.71
13.71
13.70
13.70
13.68
13.67
13.64
13.64
13.60
13.59
13.55
13.54
14.50
14.50
14.40
14.40
14.43 14.43
2.81 2.81
3.13 3.13 3.13 3.13 3.13 3.13 3.13 3.13 3.14 3.14 3.14 3.14 3.15 3.14 3.15 3.14 3.15 3.15 3.16 3.16 3.16 3.16 3.17 3.17
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
0 5 10 15 20 25 30
CC + CB + CS Without Middle Column Longer Side
D/C Ratio Limit Improved D/C Ratio

104. Case2 (b):DemandCapacity Ratio
Middle column removal in the composite structure (CC + CB + CS) observed along the shorter span exhibited relatively moderate stress concentrations,
with unmitigated D/C ratios peaking at 3.51. Post-mitigation, values significantly dropped to a maximum of 1.17, well below the critical limit,
highlighting the structural efficiency and balanced force redistribution offered by composite systems even under such critical failure scenarios.
3.50 3.51
3.39
3.29
3.40
3.32
3.40
3.32
3.41
3.33
3.41 3.42 3.42
3.35
3.42 3.36 3.43 3.39 3.45 3.41 3.47 3.43 3.48 3.45 3.51 3.51
1.17 1.17 1.15
0.75
1.14 1.12 1.14
0.76
1.14 1.12 1.15 1.15
0.78
1.13 1.15 1.13 1.15 1.13 1.15 1.14 1.15 1.14 1.16 1.15 1.16 1.16
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
0 5 10 15 20 25 30
CC + CB + CS Without Middle Column Shorter Side
D/C Ratio Limit Improved D/C Ratio

105. Case3 (a):Demand CapacityRatio
Corner column removal in the composite structure (CC + CB + CS) studied along the longer span resulted in extremely high unmitigated D/C ratios, peaking at 23.30,
reflecting a significant vulnerability at the structural edges. However, the improved D/C ratios remained under 7.01, indicating partial recovery due to mitigation.
This case reveals that while composite systems offer strength, their edge stability demands enhanced detailing and reinforcement for corner failures.
14.84
14.33 14.73 15.00 15.38
15.88
16.51
17.22
18.32
19.62
21.26
23.47 23.30
3.15 2.85 2.93 2.98 3.06 3.15 3.28 3.42 3.63 3.89 4.21
4.66
7.01
0.00
5.00
10.00
15.00
20.00
25.00
0 2 4 6 8 10 12 14
CC + CB + CS Without Corner Column Longer Side
D/C Ratio Limit Improved D/C Ratio

106. Case3 (b):DemandCapacity Ratio
Corner column removal in CC + CB + CS (studied on shorter side) resulted in an unmitigated DCR of 7.89, exceeding the threshold
drastically. With retrofitting, the DCR dropped to 1.23, showcasing effective mitigation despite the highly vulnerable configuration.
6.46
5.50
5.72 5.74 5.84 5.96 6.12
6.32
6.56
6.86
7.19
7.89
3.61
1.04
0.85 0.88 0.88 0.90 0.92 0.94 0.98 1.01 1.06 1.12 1.23
0.62
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
9.00
0 2 4 6 8 10 12 14
CC + CB + CS Without Corner Column Shorter Side
D/C Ratio Limit Improved D/C Ratio

107. Case4 (a):Demand CapacityRatio
Peripheral column removal in CC + CB + CS (on short span, longer side studied) showed a high unmitigated DCR of 13.35, indicating critical
vulnerability. After mitigation, the DCR reduced significantly to 1.90, highlighting substantial enhancement in structural stability.
3.74
3.45 3.57 3.64 3.77 3.94 4.16
4.44
4.81
5.31
5.98
6.99
13.35
1.22 1.07 1.10 1.12 1.16 1.20 1.27 1.35 1.45 1.60 1.79 2.01
0.00
2.00
4.00
6.00
8.00
10.00
12.00
14.00
16.00
0 2 4 6 8 10 12 14
CC + CB + CS Without Peripheri Column (Short Span) Longer Side
D/C Ratio Limit Improved D/C Ratio

108. Case4 (b):DemandCapacity Ratio
Short span periphery column removal in CC + CB + CS results in an unmitigated DCR peak of 6.07, with localized drop to 3.49, indicating
fluctuating stress concentrations. Mitigation reduced values to around 2.04, bringing most elements just below the limit and enhancing
stability.
5.88
6.07
5.63
5.93
5.65
5.82
3.49
5.81
5.63
5.82
5.63
5.81
5.63
5.81
5.64
5.80
5.64
5.78
5.64 5.76 5.65 5.74 5.65 5.71
3.26 3.26
2.23 2.17 2.22 2.25 2.21 2.28
1.37
2.28 2.21 2.29 2.22 2.29 2.22 2.29 2.22 2.30 2.24 2.30 2.25 2.29 2.26 2.29 2.27 2.30
2.04 2.04
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
0 5 10 15 20 25 30
CC + CB + CS Without Perpheri Column (Short Span) Shorter Side
D/C Ratio Limit Improved D/C Ratio

109. Response Spectrum
Analysis

110. Seismic Performance Analysis using RSA
➢ Perform Response Spectrum Analysis (RSA) to assess seismic
behavior.
➢ Evaluate Time Period, Base Shear, and Roof Displacement for each
structure.
➢ Compare seismic resistance among the different structural models.

111. TimePeriod
Composite structure shows the longest time period (1.14s) indicating higher flexibility. RCC has the shortest
(0.965s), making it stiffest. Hybrid falls in between at 1.02s.
0.965 0.969
0.924 0.922
0.96 0.966 0.97 0.99
0.921
0.96
1.14 1.12
1.08 1.06
1.13
0
0.2
0.4
0.6
0.8
1
1.2
RC + RB +
RS
RC + RB +
RS (Without
Column
Long Span)
RC + RB +
RS (Without
Column
Short Span)
RC + RB +
RS (
Without
Column
Middle)
RC + RB +
RS (
Without
Column
Corner)
CC + RB +
RS
CC + RB +
RS (Without
Column
Long Span)
CC + RB +
RS (Without
Column
Short Span)
CC + RB +
RS (
Without
Column
Middle)
CC+ RB +
RS (
Without
Column
Corner)
CC + CB +
CS
CC + CB +
CS
(Without
Column
Long Span)
CC + CB +
CS
(Without
Column
Short Span)
CC + CB +
CS (
Without
Column
Middle)
CC + CB +
CS (
Without
Column
Corner)

112. Base Shear(KN)
RCC and Hybrid have higher base shear (~6600 kN), demonstrating better lateral load resistance. Composite,
with lowest base shear (~4152 kN), is less stiff.
6486 6572 6513
6694
6467 6549 6630 6493 6523 6526
4054
4723
4152
4368
4151
0
1000
2000
3000
4000
5000
6000
7000
8000
RC + RB +
RS
RC + RB +
RS (Without
Column
Long Span)
RC + RB +
RS (Without
Column
Short Span)
RC + RB +
RS (
Without
Column
Middle)
RC + RB +
RS (
Without
Column
Corner)
CC + RB +
RS
CC + RB +
RS (Without
Column
Long Span)
CC + RB +
RS (Without
Column
Short Span)
CC + RB +
RS (
Without
Column
Middle)
CC+ RB +
RS (
Without
Column
Corner)
CC + CB +
CS
CC + CB +
CS
(Without
Column
Long Span)
CC + CB +
CS
(Without
Column
Short Span)
CC + CB +
CS (
Without
Column
Middle)
CC + CB +
CS (
Without
Column
Corner)

113. RoofDisplacement(mm)
Composite system showed the largest displacement (~29.35 mm), indicating weaker seismic performance.
RCC had the lowest (22.79 mm), and Hybrid had moderate (23.27 mm) displacement.
22.79 22.5 22.45
21.62
23.31 22.76 22.46 22.88
21.89
23.27
27.94 27.36 27.34
26.17
29.35
0
5
10
15
20
25
30
35
RC + RB +
RS
RC + RB +
RS (Without
Column
Long Span)
RC + RB +
RS (Without
Column
Short Span)
RC + RB +
RS (
Without
Column
Middle)
RC + RB +
RS (
Without
Column
Corner)
CC + RB +
RS
CC + RB +
RS (Without
Column
Long Span)
CC + RB +
RS (Without
Column
Short Span)
CC + RB +
RS (
Without
Column
Middle)
CC+ RB +
RS (
Without
Column
Corner)
CC + CB +
CS
CC + CB +
CS
(Without
Column
Long Span)
CC + CB +
CS
(Without
Column
Short Span)
CC + CB +
CS (
Without
Column
Middle)
CC + CB +
CS (
Without
Column
Corner)

114. CONCLUSIONS:
1. Hybrid SRC structures emerged as the most resilient configuration under both progressive collapse
and seismic loads, effectively balancing strength, ductility, and cost-efficiency due to the combined use
of composite columns and RC beams.
2. RCC structures showed improved resistance post-mitigation with DCR values dropping below 1.5, but
without mitigation, they exhibited moderate vulnerability, particularly in corner column removal
scenarios along longer spans.
3. Composite structures consistently displayed the highest DCR values, both before and after mitigation,
indicating their inherent flexibility and the need for enhanced joint detailing and additional bracing to
meet safety standards.
4. Mitigation measures such as the inclusion of steel bracing and structural integrity elements proved
highly effective, reducing DCR values significantly across all structural systems.
5. The alternate path method (APM) was effective in identifying critical failure zones and evaluating the
structural integrity under hypothetical column removal, validating its importance in design codes like
GSA 2003 and UFC 4-023-03.

115. CONCLUSIONS:
6. Progressive collapse vulnerability was highly dependent on column removal location, with corner
column removal showing the highest impact, followed by peripheral and middle column removals.
7. Span direction had a notable influence on collapse behavior; structures with column removal
along longer spans (6m) exhibited higher DCR values than those with shorter spans (5m).
8. Response Spectrum Analysis (RSA) indicated that Hybrid SRC structures not only perform better
under gravity loads but also show balanced seismic responses with moderate base shear and
roof displacement.
9. RCC structures demonstrated higher base shear and lower time periods, suggesting greater
stiffness but less flexibility, which may lead to brittle failure under extreme seismic events.
10.Composite structures, although flexible, experienced higher roof displacements and lower base
shear, leading to concerns about serviceability and occupant comfort under seismic actions.

116. CONCLUSIONS:
11.DCR reduction trends were most significant in Hybrid SRC frames, with unmitigated values
between 1.95 and 3.25, reducing to below 1.84 post-mitigation, well within permissible limits.
12.Middle column removal scenarios resulted in more balanced structural responses, owing to the
symmetrical redistribution of loads, especially evident in RCC and Hybrid structures.
13.Experimental validation of the computational models is recommended for future studies to further
confirm analytical findings and refine design recommendations.
14.Floor plan configuration (as per this G+12 typical layout) allowed for a standardized comparison
across models, reinforcing that structural system selection critically affects performance, not just
layout dimensions.
15.Practical implementation of the findings suggests prioritizing Hybrid SRC for urban mid- to high-
rise construction, especially in regions prone to seismic and accidental loading events, due to its
superior performance metrics.

117. REFERENCES:
1. GSA (2003). "Progressive Collapse Analysis and Design Guidelines for New Federal Office Buildings and Major
Modernization Projects." General Services Administration, Washington, DC.
2. UFC 4-023-03. (2016). "Design of Buildings to Resist Progressive Collapse." Unified Facilities Criteria, United States
Department of Defense.
3. IS 1893 (Part 1):2016. "Criteria for Earthquake Resistant Design of Structures – General Provisions and Buildings."
Bureau of Indian Standards, New Delhi, India.
4. IS 456:2000. "Plain and Reinforced Concrete – Code of Practice." Bureau of Indian Standards, New Delhi, India.
5. IS 800:2007. "General Construction in Steel – Code of Practice." Bureau of Indian Standards, New Delhi, India.
6. IS 875 (Part 1):1987. "Code of Practice for Design Loads (Other Than Earthquake) For Buildings and Structures –
Dead Loads." Bureau of Indian Standards, New Delhi, India.
7. IS 875 (Part 2):1987. "Code of Practice for Design Loads (Other Than Earthquake) For Buildings and Structures –
Imposed Loads." Bureau of Indian Standards, New Delhi, India

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