1 of 78

Seismic Performance Assessment and Improvement�of Reinforced Concrete Buildings with Vertical Irregularity�（鉛直方向の不整形性を有する鉄筋コンクリート造建物の耐震性能評価と性能改善）

In fulfillment of the requirement for the degree of:

Doctor of Philosophy (Engineering)

1

Taufiq Ilham Maulana – D199504

Supervisor: Prof. Dr. Taiki SAITO

�Earthquake Disaster Engineering Laboratory

Department of Architecture and Civil Engineering

Toyohashi University of Technology, Japan

2 of 78

Chapter 1 – Background – a

Irregularity in building is unavoidable
One type of irregularity in single system frame: Setback
Setback: discontinuities mass, stiffness, and strength distribution
Understanding the seismic performance behavior of RC frame building with� setback is important

2

Source: rehouse.co.jp, 2022

Rivera Marks Residential Building

Source: Syamsi et al., 2021

Academic Building, UMY

Fukuoka International Hall

Source: stirworld.com, 2020

3 of 78

Chapter 1 – Background – a

To study further, numerical analysis must be established
STERA_3D, a software developed by Supervisor is utilized
Perform analytical study and verify its accuracy, by using previous� experimental test data

3

Source: Wood 1986

Previous Experimental Tests

Numerical Analysis

4 of 78

Chapter 1 – Background – b

4

Setback existance

Building Damage Degree

Building seismic responses

Represented as Irregularity indices, 𝜑_𝑏 and 𝜑_𝑠

Represented as Park-Ang Damage Index: DI

For setback building: DI ratio

Seismic

Proposed formulas to determine damage distribution of setback building

based on geometric measure without conducting nonlinear dynamic analyses

Stepped

Towered

require to perform nonlinear dynamic analysis

Tower part

Base part

5 of 78

Chapter 1 – Background – c

Single system

(Moment Resisting Frame)

Dual System

(MRF with Shear walls)

Ground

Source: Estekanchi et al, 2018

Seismic

Ground

Frame-Curtailed Wall

Ground

Shear force and bending moment diagram

Ground

Frame-Curtailed Wall

Frame only

Frame with wall

Vertical irregularity appears

Understanding the seismic performance behavior of frame with curtailed wall is important

Chapter 2 and 3 discussed mainly about vertical irregularity in single system, which is moment resisting frame, however, vertical irregularity could also appear in dual system. Let me show you an illustration.
This figure is single system, supported only by frame
The next figure is a dual system, consist of frame, supported with shear wall, installed along the building height.
Previous study showed, when a wall-frame is loaded laterally, lower part deflects in a flexural shape and the upper part deflects in a shear shape.
Which means the lower part and upper part react contrarily.
The shear force and bending moment diagram showed the region above the point inflection respond in the negative way,
thus the upper part of walls will result a negative force, and the forces in the upper part are caried by columns.
To avoid this, some study suggest to remove the wall at the upper stories and create a new type of structure: curtailed wall
Therefore the are sudden change of mass and stiffness at the level where the wall coverage stops
Understanding the seismic performance of these structures is important

6 of 78

Chapter 1 – Background – c

To study further, numerical analysis must be established
STERA_3D, a software developed by Supervisor is utilized
Perform analytical study and verify its accuracy, by using previous� experimental test data

Source: Wood 1986

Previous Experimental Tests

Numerical Analysis

Source: Moehle & Sozen, 1980

7 of 78

Chapter 1 – Background – d

Under nonlinear dynamic analyses, significant responses of the drift at the upper region without wall coverage are observed.
Improvement structural configuration is proposed by using Buckling-restrained braces BRBs
Determination of number of BRBs is by using Genetic Algorithm (GA) approach

Ground

Frame only

Frame with wall

8 of 78

Chapters Organization

8

Chapter 1

(Introduction)

Chapter 2

Chapter 3

Chapter 4

Chapter 5

Chapter 6

(Conclusion and Future Work)

Part 1: Vertical Irregularity in single system

(frame only with setback)

Frame only

Part 2: Vertical Irregularity in dual system

(frame-curtailed wall, with BRBs)

Frame with walls

9 of 78

Thesis organization

Chapter 1 – Overview
Chapter 2 – Seismic Performance Assessment of RC Buildings with Setback
Chapter 3 – Proposal of Damage Index Ratio for RC Buildings with Setback
Chapter 4 – Seismic Performance of RC Frame with Different� Shear Walls Height
Chapter 5 – Seismic Performance Improvement of� RC Frame – Curtailed Shear Walls using BRBs
Chapter 6 – Conclusion

9

10 of 78

Chapter 1 – Background – e, Research Gaps, Novelty, and Contributions

Previous research related to Part 1 (Chapter 2 & 3):

Habibi & Asadi (2017): Developed equation for overall Park-Ang damage index, containing:

overall drift (ratio of maximum roof displacement to frame total height),
natural period, and irregularity indices of the building.

Varadharajan et al. (2013, 2014): Estimated Park-Ang damage index using:

ratio of modal participation factor between irregular and regular buildings,
beam to column stiffness ratio, and
displacement ductility

Hait et al. (2020a, 2020b): Predict Park-Ang damage index (using regression and ANN approaches) using criteria derived from dynamic analyses:

maximum inter-story drift,
peak roof displacement,
maximum joint rotation of the members

10

Source: 3darchidesigner.com

derived from dynamic analyses

Contribution: Estimate damage distribution by using damage index ratio, and propose relationship of DI ratio to irregularity indices without dynamic analyses

11 of 78

Chapter 1 – Background – e, Research Gaps, Novelty, and Contributions

Previous research related to Part 2 (Chapter 4 & 5):

Estekanchi et al. (2018), Xia et al. (2019), Bhatta et al. (2017), Bhatt et al. (2017)

Results showed that installing shear walls up to top floor in dual system frame is ineffective, due to predominant bending deformation against lateral linear static loads.
No non-linear dynamic analyses are found in the studies.

Rathi et al. (2019), Nollet et al. (1991,1994), and Atik et al. (2010,2014)

These studies proposed optimal height of shear walls, depends on several parameters:

ratio of wall flexural rigidity to frame shear rigidity,
axial stiffness coefficient, and
building's top deflection

Analyses ignored nonlinear dynamic behaviour, only in static linear loading.

11

Source: 3darchidesigner.com

12 of 78

Chapter 1 – Background – e, Research Gaps, Novelty, and Contributions

Previous research related to Part 2 (Chapter 4 & 5):

Costa et al. (1988), Paulay and Priestley (1992)

Structure above the curtailed walls showed a large inter-story drift response.
There is no solution proposed to decrease significant amount of inter-story drift.

Farhat et al. (2009), Oxborrow and Richards (2009), Oxborrow (2009), Park et al. (2015), Mohammadi et al. (2019), Tu et al. (2020), Fujishita et al. (2016), and Terazawa and Takeuchi (2018,2019)

All mentioned methods to improve seismic performance of frame structure using BRBs.
The determination of number and location is based on optimization analyis using Genetic Algoritm.
The studies are limited only to the frame structures, and have not been implemented for dual system with vertical irregularity.

12

Source: 3darchidesigner.com

Contribution: Propose new structural configuration of frame-curtailed wall improved with BRBs, and its determination is based on Genetic Algoritm optimization

13 of 78

Chapter 1 – Background – f, List of Publications

International journal papers

Chapter 2 and 3

Taufiq Ilham Maulana, Badamkhand Enkhtengis, Taiki Saito. “Proposal of Damage Index Ratio for Low-to Mid-Rise Reinforced Concrete Moment-Resisting Frame with Setback Subjected to Uniaxial Seismic Loading,” Applied Sciences, Vol. 11, 2021. (16 pages) [Published, July 2021]

Chapter 4 and 5

Taufiq Ilham Maulana, Patricia Angelica de Fatima Fonseca, Taiki Saito. “Application of Genetic Algorithm to Optimize Location of BRB for Reinforced Concrete Frame with Curtailed Shear Wall,” Applied Sciences, Vol. 12, 2022. (23 pages) [Published, February 2022]

International Conference paper

Taufiq Ilham Maulana and Taiki Saito, “Numerical Analysis for Progressive Collapse of Reinforced Concrete Campus Building in Yogyakarta,” 17th World Conference on Earthquake Engineering, 17WCEE, Sendai, Japan, September 27th to October 2nd, 2021.

13

Source: 3darchidesigner.com

14 of 78

Chapter 2 – Seismic Performance Assessment of RC Buildings with Setback

14

15 of 78

Chapter 2 – Building specimen description

15

Towered setback type

Source: Wood 1986

Database source: datacenterhub.org

16 of 78

Chapter 2 – Building specimen description

16

17 of 78

Chapter 2 – Building specimen description

17

18 of 78

Chapter 2 – Building specimen description

18

19 of 78

Chapter 2 – STERA_3D modelling

19

Towered setback type

Source: Wood 1986

Further detail can be freely accessed here: http://www.rc.ace.tut.ac.jp/saito/software_sample_EX02-e.html

20 of 78

20

Chapter 2 – Comparison seismic responses

21 of 78

Chapter 2 – Building specimen description

21

Stepped setback type

Source: Shahrooz & Moehle, 1987

Database source: datacenterhub.org

22 of 78

Chapter 2 – Building specimen description

22

Stepped setback type

23 of 78

Chapter 2 – Building specimen description

23

24 of 78

Chapter 2 – Building weight and input motion

24

25 of 78

Chapter 2 – STERA_3D modelling

25

Source: Wood 1986

Further detail can be freely accessed here: http://www.rc.ace.tut.ac.jp/saito/software_sample_EX02-e.html

26 of 78

Chapter 2 – Comparison seismic responses

26

27 of 78

Chapter 2 – Summary

27

The result shows that there are only slight differences between experiment and simulation in both acceleration and displacement response.
Therefore, STERA_3D program is adequate for further analyses especially in vertical irregular buildings.

28 of 78

Chapter 3 – Proposal of Damage Index Ratio for RC Buildings with Setback

28

29 of 78

Chapter 3 – Park-Ang damage index, 1985 (for beam, column)

29

Where

Degree of Damage

30 of 78

Chapter 3 – Park-Ang damage index, 1985 (for beam, column)

30

Park & Ang, 1985

is taken as 15, for assumption the structural elements failed by flexural

31 of 78

Chapter 3 – Park-Ang damage index, 1985 (for story)

31

32 of 78

Chapter 3 – Irregularity indices

32

Originally introduced by Mazzolani & Piluso (1996), and

developed by Karavasilis et al. (2008)

33 of 78

Chapter 3 – Irregularity indices

33

If the all stories have same height, and all bays have same length,

therefore:

34 of 78

Chapter 3 – Generated 2D frame (stepped+towered)

34

Source: Wood 1986

35 of 78

Chapter 3 – Generated 2D frame (stepped+towered)

35

Source: Wood 1986

36 of 78

Chapter 3 – Structural Details

36

Source: Wood 1986

37 of 78

Chapter 3 – Input earthquakes

37

38 of 78

Chapter 3 – Damage Index ratio

38

Calculation example

Tower part

Base part

Calculated for 20 models of stepped type and 15 models of towered type, and then�conducted regression analyses and proposed formulas to determine Damage Index ratio

39 of 78

Chapter 3 – Damage Index ratio

39

Stepped setback type

40 of 78

Chapter 3 – Damage Index ratio

40

Towered setback type

41 of 78

Chapter 3 – Validation Damage Index Ratio

41

42 of 78

Chapter 3 – Summary

42

Damage Index ratio can be used to estimate damage concentration for reinforced concrete with setback, by using only geometrical indices.
The accuracy of the proposed method can still be improved, but currently is adequate

43 of 78

Chapter 4 – Seismic Performance of RC Frame with Different Shear Walls Height

43

44 of 78

Chapter 4 – Building specimen description

44

Source: Moehle & Sozen, 1980

Database source: datacenterhub.org

45 of 78

Chapter 4 – Building specimen description

45

46 of 78

Chapter 4 – Building specimen description

46

47 of 78

Chapter 4 – Building specimen description

47

48 of 78

Chapter 4 – Weight and input motions

48

49 of 78

Chapter 4 – STERA_3D modelling

49

Source: Wood 1986

Further detail can be freely accessed here: http://www.rc.ace.tut.ac.jp/saito/software_sample_EX01-e.html

50 of 78

Chapter 4 – Comparison seismic responses

50

51 of 78

Chapter 4 – Summary

51

the experimental and computational of seismic responses results were quite close
STERA_3D is adequate to be used for further nonlinear responses analyses of frame building with curtailed shear walls.

52 of 78

Chapter 5 – Seismic Performance Improvement of RC Frame – Curtailed Shear Walls using BRBs

52

53 of 78

Chapter 5 – Six Generated Specimens

53

The model is designed to satisfy the Japanese design standard criteria
Inter-story height = 3000 mm
Story weight = 3000 kN/level
Fyl = 490 MPa for main rebar
Fyt =295 MPa for shear rebar
f ^’_c = 36 – 48 MPa

54 of 78

Chapter 5 – Six Generated Specimens

54

55 of 78

Chapter 5 – Input earthquakes

55

56 of 78

Chapter 5 – Input earthquakes

56

57 of 78

Chapter 5 – Inter-story drift responses to scaled earthquakes

57

58 of 78

Chapter 5 – Inter-story drift responses to scaled earthquakes

58

59 of 78

Chapter 5 – Genetic Algorithm – Population Preparation

59

60 of 78

Chapter 5 – Genetic Algorithm

60

61 of 78

Chapter 5 – Genetic Algorithm

61

1. Initial Population

2. Fitness Function

62 of 78

Chapter 5 – Genetic Algorithm

62

63 of 78

Chapter 5 – Profile of BRBs

Chapter 5 – Summary

72

The genetic algorithm is used to discover the optimal position of BRBs by taking into account three parameters in fitness function: the inter-story drift responses, beam damage index, and total number of BRBs installed.
Under ten selected seismic motions, the optimal placement of BRBs is determined to be unique for each motion. Therefore, a simple probabilistic technique is used to determine the best final location of BRBs.
The result shows that by implementing the optimized BRBs locations, the average inter-story drift at upper story could be reduced from 1/75 to 1/100 of inter-story height

73 of 78

Chapter 6 – Conclusion

73

Chapter 2 : For setback building, numerical study matched with the experimental test
Chapter 3 : Damage Index ratio is proposed to determine the damage concentration of� setback building and it can be estimated with the proposed equation by relying� only on geometrical indices, without nonlinear dynamic analyses
Chapter 4 : For frame-curtailed wall building, numerical study matched with experimental test
Chapter 5 : The seismic performance of upper structure with no wall in frame-curtailed wall� structures can be improved by installing BRBs and the consideration is based on� GA optimization

74 of 78

Chapter 6 – Future works

74

Improvement of model to make the building responses closer to the experimental results
Broaden the parametrical study of setback building with more buildings, bays, and stories.
Find out and compare other available faster optimization method to determine number and location of BRBs
Consider three dimensional axis and other effects, such as torsion
Determine the BRBs strength and stiffness also base on the optimization

75 of 78

References

75

https://www.stirworld.com/think-columns-acros-fukuoka-prefectural-international-hall-by-emilio-ambasz-turns-25, accessed on July 2022
Syamsi, M. I., Maulana, T. I., Widyantama, H., Ian, M. R., & Lesmana, R. I. (2021). Comparative Study of Indonesian Seismic Codes Applied on Vertically Irregular RC Building in High Seismicity Region. International Journal of Integrated Engineering, 13(3), 158-167.
https://www.rehouse.co.jp/mansionlibrary/ABM0019528/, accessed on July 2022
Habibi, A.; Asadi, K. Development of drift-based damage index for reinforced concrete moment resisting frames with set-back. Int. J. Civ. Eng. 2017, 15, 487-498.
Park, Y. -J.; Ang, A.H.-S. Mechanistic seismic damage model for reinforced concrete. J. Struct. Eng. 1985, 111, 722-739.
Karavasilis, T.L.; Bazeos, N.; Beskos, D.E. Seismic response of plane steel MRF with setbacks: Estimation of inelastic defor-mation demands. J. Constr. Steel Res. 2008, 64, 644-654.
Varadharajan, S.; Sehgal, V.K.; Saini, B. Determination of inelastic seismic demands of RC moment resisting setback frames. Arch. Civ. Mech. Eng. 2013, 13, 370-393.
Varadharajan, S.; Sehgal, V.K.; Saini, B. Seismic behavior of multistory RC building frames with vertical setback irregulari-ty. Struct. Des. Tall. Spec. Build. 2014, 23, 1345-1380.
Hait, P.; Sil, A.; Choudhury, S. Damage assessment of low to mid rise reinforced concrete buildings considering planner irregularities. Int. J. Comput. Methods Eng. Sci. Mech. 2020, 22, 150-168.
Hait, P.; Sil, A.; Choudhury, S. Seismic damage assessment and prediction using artificial neural network of RC building considering irregularities. Int. J. Struct. Integr. Maint. 2020, 5, 51-69.

76 of 78

References

76

Wood, S.L. Experiments to Study the Earthquake Response of Reinforced Concrete Frames with Setbacks. Doctoral disserta-tion, University of Illinois at Urbana-Champaign, IL, USA, 1985.
Shahrooz, B.M.; Moehle, J.P. Experimental study of seismic response of RC setback buildings; National Science Foundation Report; UCB: CA, USA, 1987.
Mazzolani, F.; Piluso, V. Theory and design of seismic resistant steel frames; E & FN Spon, London, UK, 1996.
Saito, T. Structural Earthquake Response Analysis, STERA_3D Version 10.8. Available online: http://www.rc.ace.tut.ac.jp/saito/software-e.html (accessed on 1 October 2020).
Moehle, J.P.; Sozen, M. Experiment to study earthquake response of R/C structures with stiffness interruptions; National Science Foundation Report; University of Illinois at Urbana-Champaign: IL, USA, 1980.
Estekanchi, H. E.; Harati, M.; Mashayekhi, M. R. An investigation on the interaction of moment‐resisting frames and shear walls in RC dual systems using endurance time method. Struct. Des. Tall. Spec. Build. 2018, 27, 1-16.
Xia, G.; Shu, W.; Stanciulescu, I. Efficient analysis of shear wall-frame structural systems. Eng. Comp. 2019, 36, 2084-2110.
Bhatta, B. D.; Vimalanandan, G.; Senthilselvan, S. Analytical study on effect of curtailed shear wall on seismic performance of high-rise building. Int. J. Civ. Eng. Tech. 2017, 8. 511-519.
Bhatt, G.; Titiksh, A.; Rajepandhare, P. Effect of Curtailment of Shear Walls for Medium Rise Structures. The 2nd International Conference on Sustainable Computing Techniques in Engineering, Science and Management (SCESM-2017), Belagavi, Karnataka, India, 27-28 January 2017; 501-507.
Rathi, N.; Muthukumar, G.; Kumar, M. Influence of Shear Core Curtailment on the Structural Response of Core-Wall Structures. In Lecture Notes in Civil Engineering: Recent Advances in Structural Engineering; Springer: Singapore, Singapore, 2019; 1, 207-215.
Nollet, M. J.; Stafford Smith, B. Behavior of curtailed wall-frame structures. J. Struct. Eng. 1993, 119. 2835-2854.
Nollet, M. J. Behaviour of wall-frame structures: a study of the interactive behaviour of continuous and discontinuous wall-frame structures. Doctoral thesis, McGill University, Canada, 1991.

77 of 78

References

77

Moehle, J.P.; Sozen, M. Experiment to study earthquake response of R/C structures with stiffness interruptions; National Science Foundation Report; University of Illinois at Urbana-Champaign: IL, USA, 1980.
Atik, M.; Badawi, M. M.; Shahrour, I.; Sadek, M. Optimum level of shear wall curtailment in wall-frame buildings: The continuum model revisited. J. Struct. Eng., 2019, 140, 1–4.
Atik, M. The effect of curtailed walls in wall-frame structures to resist lateral loads. Master T., University of Aleppo, Syria, 2010.
Costa, A. G.; Oliveira, C. S.; Duarte, R. T. Influence of vertical irregularities on seismic response of buildings. The 9th World Conference on Earthquake Engineering (9th WCEE), Tokyo-Kyoto, Japan, 2-9 August 1988; 491-496.
Paulay, T.; Priestley, M. J. N. Seismic Design of Reinforced Concrete and Masonry Buildings, 1st ed.; Wiley-Interscience: New York, USA, 1992; 500-531.
Farhat, F.; Nakamura, S.; Takahashi, K. Application of genetic algorithm to optimization of buckling restrained braces for seismic upgrading of existing structures. Comput. Struct., 2009, 87, 110-119.
Oxborrow, G. T.; Richards, P. Optimized distribution of strength in tall buckling-restrained brace frames. In Behaviour of Steel Structures in Seismic Areas; CRC Press: London, U.K., 2009, 1, 819-824.
Oxborrow, G. T. Optimized distribution of strength in buckling-restrained brace frames in tall buildings. Master thesis, Brigham Young University, USA, 2009.
Fujishita, K.; Sutcu, F.; Matsui, R.; Takeuchi, T. Optimization of Damper Arrangement with Hybrid GA using Elasto-plastic Response Analysis on Seismic Response Control Retrofit. J. Struct. Constr. Eng., 2016, 81, 537-546.
Terazawa, Y.; Takeuchi, T. Generalized response spectrum analysis for structures with dampers. Earthq. Spectra, 2018, 34, 1459-1479.
Terazawa, Y.; Takeuchi, T. Optimal damper design strategy for braced structures based on generalized response spectrum analysis. Japan Archit. Rev., 2018, 2, 477-493.
Naqi, A.; Saito, T. (2021). Performance of a BRB RC High-rise Buildings Under Successive Application of Wind-Earthquake Scenarios. The 1st Croatian Conference on Earthquake Engineering (1st CroCEE), Zagreb: Croatia, 22-24 March 2021; 909-919.

78 of 78

Thank you so much for your attention.

78

どもありがとうございます。

TAUFIQ ILHAM MAULANA