![Furtado A., Rodrigues H., Arêde A., Varum, H. (2015), Modelling of masonry infill walls participation in the seismic behaviour of
RC buildings using OpenSees, International Journal of Advanced Structural Engineering, Vol. 7, Issue 2, pp. 117-127.
In-Plane Calibration • Infilled RC frame – 1 Bay
• Reduced scale - 2/3
• Horizontal hollow clay brick IM wall with no openings
• The characterization material test results were used to
calibrate the numerical model
0.15 0.420.150.42
0.35
0.20
0.165
1.625
4.20
[ m ]
Felicita Pires (1999)
IM wall numerical model
Previous Research](https://image.slidesharecdn.com/presentationfurtadorodriguesardevarum-170704232626/85/Simplified-macro-modelling-approach-for-infill-masonry-wall-in-plane-and-out-of-plane-behaviour-using-OpenSees-14-320.jpg)
Simplified macro-modelling approach for infill masonry wall in-plane and out-of-plane behaviour using OpenSees
- 1. André Furtado, H. Rodrigues, A. Arêde, H. Varum afurtado@fe.up.pt Simplified macro-modelling approach for infill masonry wall in-plane and out-of- plane behaviour using OpenSees elemento Não-Linear Bielas
- 2. Greece Athens – September 7, 1999 Magnitude 6.0 143 deaths and 50,000 homeless Economic loss of $3,000M US Turkey Kocaeli – August 17, 1999 Magnitude 7.5 17,127 deaths and 300,000 homeless Economic loss of $23,000M US Duzce – November 12, 1999 Magnitude 7.2 894 deaths and 24,000 homeless Economic loss $40M US Van – October 23, 2011 Magnitude 7.1 604 deaths and 60,000 homeless Economic loss of $2,000M US Italy L’Aquila – April 6, 2009 Magnitude 6.3 308 deaths and 65,000 homeless Economic loss of $10,000M US Bologna – May 20, 2012 Magnitude 6.1-5.8 26 deaths and 43,000 homeless Economic loss of $13,000M US Spain Lorca – May 11, 2011 Magnitude 5.1 9 deaths and 5,000 homeless Economic loss of $99M US Only in these earthquakes (20 years)! ~20,000 deaths ~550,000 homeless >50,000 million USD of losses Influence of infill masonry walls in buildings’ response
- 3. Influence of infill masonry walls in buildings’ response • Infill masonry (IM) walls are usually considered on the design of new RC building structures, as well as on the assessment of existing ones, as non-structural elements (only gravity load) • Common IM walls can modify drastically the global structural behavior, leading to unexpected behavior/response and collapse mechanisms • IM panels may change considerably: the global lateral stiffness and strength of building structures their natural frequencies and vibration modes the energy dissipation capacity a brittle behavior and failure mechanism Background
- 4. Diagonal cracking; detachment between the panel and surrounding RC frame OOP collapse; etc. Influence of infill masonry walls in buildings’ response Typical damages – IP and OOP lateral loadings
- 5. Influence of infill masonry walls in buildings’ response Soft-storey mechanism due to: vertical irregularities; existence of open ground-storeys for commercial purposes or for garages Typical damages – IP and OOP lateral loadings
- 6. Influence of infill masonry walls in buildings’ response Current practice nowadays
- 7. IM walls modelling strategies Macro-models: • More simplified than the micro-models • Allow for a representation of the global behavior of the infill masonry panels and of their influence in the buildings response • Equivalent strut model is the most used Infilled frames are complex structural systems and exhibit a highly nonlinear behavior. This fact complicates the analysis and explains why infill panels has been considered as "non-structural elements", despite their strong influence on the global response of buildings. Micro-models: • Detailed modeling • Allow interpretation of the behavior at local level • Allow to obtain the cracking pattern, the ultimate load, and the collapse mechanisms • High computational effort • Need for a large number of parameter • Useful for the calibration of global models Micro-modelling vs Macro-modelling
- 8. IM walls modelling strategies The equivalent strut model was suggested by Poliakov and implemented by Holmes and Stafford Smith in the 1960s. Later, many researchers improved this basic model. Today, the strut model is accepted as a simple and rational way to represent the effect of the masonry infill panel in the global response of buildings. The main advantage of the multi-strut models, in spite of the increase of complexity, is the ability to represent the actions in the frame more accurately. Macro-modelling: Strut models
- 9. IM wall numerical model Previous Research • Simplified global macro-model • Represents the infill panel behaviour and its influence in the building response to seismic loadings • An upgrading of the bi-diagonal strut model • Considers the strength and stiffness degradation interaction in both directions of loading • 4 strut elements with rigid linear behaviour that support a central element where the non- linear behaviour is concentrated • Non-linear behaviour characterized by a monotonic curve with 5 branches for each loading direction, and corresponding hysteretic rules elemento Não-Linear Bielas F K0 K1 + K2 + K3 + K4 + u F2 + F1 + F3 + u1 + u2 + u3 + u4 + 1 2 3 4 5 Rodrigues, H.; Varum, H.; Costa, A. (2010) - Simplified macro-model for infill masonry panels - Journal of Earthquake Engineering, Vol. 14, Issue 3, March 2010, pp. 390-416. General description
- 10. IM wall numerical model Previous Research OpenSees Implementation BeamwithHinges Elements Strut behavior in plane Residual stiffness in the OP direction non-linearBeamColumn Only with axial Non-linear behavior Pinching4
- 11. OpenSees Implementation BeamwithHinges Elements Strut behavior in plane Residual stiffness in the OP direction non-linearBeamColumn Only with axial Non-linear behavior Pinching4 IM wall numerical model Previous Research
- 12. The uniaxial material Pinching 04 was adopted to represent the hysteretic rule i) Cracking (cracking force Fc, cracking displacement dFC) ii) Yielding (yielding force Fy, yielding displacement dFY) iii) Maximum strength corresponding to the beginning of crushing (Fmax and corresponding displacement dFmax) iv) Residual strength (Residual strength Fu and residual displacement dFU) Furtado A., Rodrigues H., Arêde A., Varum, H. (2015), Modelling of masonry infill walls participation in the seismic behaviour of RC buildings using OpenSees, International Journal of Advanced Structural Engineering, Vol. 7, Issue 2, pp. 117-127. (Mpa) In-Plane Calibration IM wall numerical model Previous Research Fmax Fy Fc Fu dc dy dFmax
- 13. Furtado A., Rodrigues H., Arêde A., Varum, H. (2015), Modelling of masonry infill walls participation in the seismic behaviour of RC buildings using OpenSees, International Journal of Advanced Structural Engineering, Vol. 7, Issue 2, pp. 117-127. In-Plane Calibration IM wall numerical model Previous Research )11(818.0 2 1 1 max ++ ×× ×= C C ftL F tpin Lin h' t '1 925.1 h L C in = i) Fc/Fmax=0.55 and dc~0,075%-0,12% ii) Fy is determined as an intermediate point between the cracking displacement (Fc, dc) and the maximum one (Fmax, dmax) iii) dmax ~0,25%-0,55% iv) Fu=20%Fmax and du=5 x dFmax
- 14. Furtado A., Rodrigues H., Arêde A., Varum, H. (2015), Modelling of masonry infill walls participation in the seismic behaviour of RC buildings using OpenSees, International Journal of Advanced Structural Engineering, Vol. 7, Issue 2, pp. 117-127. In-Plane Calibration • Infilled RC frame – 1 Bay • Reduced scale - 2/3 • Horizontal hollow clay brick IM wall with no openings • The characterization material test results were used to calibrate the numerical model 0.15 0.420.150.42 0.35 0.20 0.165 1.625 4.20 [ m ] Felicita Pires (1999) IM wall numerical model Previous Research
- 15. Furtado A., Rodrigues H., Arêde A. (2017), Calibration of a simplified macro-model for infilled frames with openings, Journal of Structural Engineering, In Press In-Plane Calibration (with openings) Kakaletsis et al. (2004) • Infilled RC frame – 1 Bay • Reduced scale - 1/3 • Vertical hollow clay brick IM wall with 3 different configurations: 1) No openings 2) Central window 3) Central door 0.50.80.2 0.25 0.15 1.2 0.15 0.25 A A' B B' IM wall numerical model Previous Research
- 16. Furtado A., Rodrigues H., Arêde A. (2017), Calibration of a simplified macro-model for infilled frames with openings, Journal of Structural Engineering, In Press In-Plane Calibration (with openings) Kakaletsis et al. (2004) • Infilled RC frame – 1 Bay • Reduced scale - 1/3 • Hollow clay brick masonry infill wall with 3 different configurations: 1) No openings 2) Central window 3) Central door IM wall numerical model Previous Research 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 0 0.2 0.4 0.6 0.8 1 1.2 1.4 Strength(MPa) Drift (%) Full infill Infill with window Infill with door
- 17. IM wall numerical model proposal Out-of-plane modelling - Assumptions The modelling of this particular behaviour through simplified macro-models is difficult, because: i) reduced experimental data available; ii) big number of variables and other relevant parameters; iii) in-plane and out-of-plane interaction. Simplified assumptions were considered: • The IM walls’ out-of-plane behaviour is considered with linear elastic behaviour • Distribution of the infill panel mass at the central nodes, which can be calculated as 0.81 M, where M is the total mass of the infill panel and is divided by two (equal value for each node of 0.405 M) • The infill panel bending stiffness was calculated following the recommendations of FEMA-356 and ASCE-41 and the suggestions of Mosalam and Gunay
- 18. The OOP inertia panel characteristics can be determined by Equations 1 and 2: inf 3 inf 3 644.1 I h L I diag eq × = Equation 1 12 3 infinf inf Lt I × = Equation 2 In order to obtain a realistic representation of the infills behaviour when subjected to biaxial loadings, an element removal algorithm developed by Mosalam and Gunay was introduced The IM walls are removed when it is reached the in-plane and out-of-plane interaction drift limits. The IP and OOP interaction curve needs experimental data to be calibrated …. (Future work…) IM wall numerical model proposal Out-of-plane modelling - Assumptions
- 19. Furtado A., Rodrigues H., Arêde A. and Varum, H. (2016) - Simplified macro-model for infill masonry walls considering the out- of-plane behaviour, Earthquake Engineering and Structural Dynamics, doi 10.1080/13632460903086044, Vol. 45, pp. 507-524. IM wall numerical model proposal In-plane and out-of-plane interaction
- 20. Schematic layout IM wall numerical model proposal
- 21. Case Study General description 3D View RC structure designed according to the Portuguese codes Representative of Portuguese building stock: • 8 Storeys • 3 bays (YY) x 5 bays (XX) • 3 Numerical models: - Bare frame (BF) - With infill In-plane (IP) - With infill In-plane and Out-of-plane (IP_OP) Plan View RC material properties: C20/25 and A500 Infill mechanical properties: Fwh (MPa) Fwv (MPa) Fwu (MPa) Fwu (MPa) Ewh (MPa) Ews (MPa) G (MPa) W (kN/m3 ) 1.18 2.02 0.44 0.55 991 1873 1089 6.87
- 22. Case Study Seismic safety assessment methodology A total of 20 ground motion records were selected from real previous seismic events were progressive scaled: 0 0.5 1 1.5 2 2.5 3 3.5 4 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Damage state Inter-storey drift (%) Slight 0.05 Light 0.08 Moderate 0.30 Extensive 1.15 Partial collapse 2.80 Collapse >4.40 • Maximum inter-storey drifts; • Maximum base shear; • Inter-storey drifts envelopes • Fragility curves
- 23. Case Study Main Results – Inter-storey drift profile 0 1 2 3 4 5 6 0 1 2 3 4 5 6 7 8 BF IP IP_OOP StoreyNumber Max. Inter-storey Drift (%) pga=0.15g 0 1 2 3 4 5 6 0 1 2 3 4 5 6 7 8 BF IP IP_OOP StoreyNumber Max. Inter-storey Drift (%) pga=0.30g 0 1 2 3 4 5 6 0 1 2 3 4 5 6 7 8 BF IP IP_OOP StoreyNumber Max. Inter-storey Drift (%) pga=0.50g • Different response obtained by all the models, in particular difference between the IP and IP_OOP model is notorious • For pga=0.30g the IP_OOP model show 2.5 times higher inter-storey drift than BF model • IP and IP_OOP models show slight differences for pga<0.15g, however for larger pga demand it is observed different responses • For pga=0.5 g the most vulnerable model is IP_OOP, with the collapse of storeys 1 and 5
- 24. Case Study Main Results – Maximum inter-storey drift 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 20 IDA curves Longitudinal Direction Pga(g) Maximum inter-storey drift ratio (%) BF model 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 20 IDA curves Longitudinal Direction Pga(g) Maximum inter-storey drift ratio (%) IP model 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 20 IDA curves Transversal Direction Pga(g) Maximum inter-storey drift ratio (%) IP_OOP model • Important differences between the IP model and the IP_OOP model responses • IP model: the infills are protective until 0.2 g. For pga larger than 0.2g due to the infills damage/collapse the inter-storey drift increase • IP_OOP model shows a similar response to BF model, but with higher maximum inter- storey drifts for pga larger than 0.15 g
- 25. Case Study Main Results – Fragility curves 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.0 0.2 0.4 0.6 0.8 1.0 Slight Light Moderate Extensive Part. Collapse Collapse Pga (g) Probabilityofexceedance 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.0 0.2 0.4 0.6 0.8 1.0 Slight Light Moderate Extensive Part. Collapse Collapse Pga (g) Probabilityofexceedance 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.0 0.2 0.4 0.6 0.8 1.0 Slight Light Moderate Extensive Part. Collapse Collapse Pga (g) Probabilityofexceedance BF model IP model IP_OP model • Slight and light damage levels are reached by all numerical models for pga ~0.05–0.12g • Moderate damage state is reached first by BF model (pga=0.15g) and both IP and IP_OOP models for pga ~0.25–0.3g • IP_OOP reached the collapse damage state for lower values than the other numerical models Damage state Inter-storey drift (%) Slight 0.05 Light 0.08 Moderate 0.30 Extensive 1.15 Partial collapse 2.80 Collapse >4.40
- 26. Case Study Main Results 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.0 0.2 0.4 0.6 0.8 1.0 BF IP IP_OOP Pga (g) Probabilityofexceedance Damage state: moderate Damage state: moderate Damage state: extensive 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.0 0.2 0.4 0.6 0.8 1.0 Damage state: Extensive BF IP IP_OOP Pga (g) Probabilityofexceedance Incorrect seismic safety assessment of an infilled RC structures
- 27. Final comments In the assessment of existing buildings, and design of new buildings… • consideration of the masonry infill walls (based on simple checking rules/procedures after the structural design) should be enforced • particular attention should be given to the stiffness differences between the 1st storey and the upper storeys (storey height, dimensions and position of openings, distribution of masonry infill walls) • The large in-plane shear demands that masonry infill walls are subjected to are likely to increase their out-of-plane vulnerability • The OOP collapse of infills can result in serious human and material consequences, as observed in recent earthquakes. So, there is a need to consider the OOP behavior of IM walls in the seismic safety assessment of existing RC infilled structures.
- 28. Acknowledgments Project POCI-01-0145-FEDER-007457 - CONSTRUCT - Institute of R&D in Structures and Construction funded by FEDER funds through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) and by national funds through FCT - Fundação para a Ciência e a Tecnologia, Portugal. Numerical research was developed under financial support provided by FCT - Fundação para a Ciência e Tecnologia, Portugal, namely through the research project P0CI-01-0145-FEDER- 016898 e PTDC/ECM-EST/3790/2014 – ASPASSI - Safety Evaluation and Retrofitting of Infill masonry enclosure Walls for Seismic demands.
- 29. Thanks for your attention! Obrigado