Effects of green roof damping and configuration on structural seismic response

Abstract

Sustainable structures are critical for addressing global climate change. Hence, their structural resilience or ability to recover from natural events must be considered comprehensively. Green roofs are a widely used sustainable feature that improve the environment while providing excellent occupant amenity. To expand their usage, their inherent damping and layout sensitivity to seismic performance are investigated in this study. The soil of a green roof can serve as a damper to dissipate the energy generated by earthquakes or other dynamic events. Results of preliminary analysis show that a green roof soil can increase localized damping by 2.5% under both dry and saturated conditions. Based on these findings, nonlinear time-history analyses are conducted on a three-story building in SAP2000 to monitor the structural behavior with and without a green roof. The increased damping in the green roof soil is beneficial to the structural performance, i.e., it reduces the building displacement and acceleration by 10% and 12%, respectively. Additionally, certain configurations are more effective and beneficial to the structural response than others, which suggests the possibility of design optimization. Based on the findings of this study, new methods of modeling and considering green roofs in structural design are established.

Graphical abstract

Keywords

green infrastructure / green roof / structural resilience / seismic design

References

[1] Jayasooriya V M, Ng A W M, Muthukumaran S, Perera B J C. Green infrastructure practices for improvement of urban air quality. Urban Forestry & Urban Greening, 2017, 21: 34–47

[2] GerrityJHallKLeasiaJRogersDStanleyLvan EppsC. Green Roofing at the University of Michigan. Final Report, 2012

[3] Jaffal I, Ouldboukhitine S E, Belarbi R. A comprehensive study of the impact of green roofs on building energy performance. Renewable Energy, 2012, 43: 157–164

[4] Ascione F, Bianco N, de’ Rossi F, Turni G, Vanoli G P. Green roofs in European climates. Are effective solutions for the energy savings in air-conditioning? Applied Energy, 2013, 104: 845–859

[5] Silva C M, Gomes M G, Silva M. Green roofs energy performance in Mediterranean climate. Energy and Building, 2016, 116: 318–325

[6] Junnila S, Horvath A. Life-cycle environmental effects of an office building. Journal of Infrastructure Systems, 2003, 9(4): 157–166

[7] ThormarkC. Energy and resources, material choice and recycling potential in low energy buildings. In: Proceedings of the International CIB Conference SB07 Sustainable Construction, Materials and Practices. Portugal: IOS, 2007

[8] Departmentof Energy. 2011 Buildings Energy Data Book. MD: D&R International, 2012

[9] Wang J W, Poh C H, Tan C Y T, Lee V N, Jain A, Webb E L. Building biodiversity: Drivers of bird and butterfly diversity on tropical urban roof gardens. Ecosphere, 2017, 8(9): e01905

[10] LiuK K YBaskaranB A. Thermal performance of extensive green roofs in cold climates. In: Proceedings of the 2005 World Sustainable Building Conference. Japan: NRC Publications, 2005

[11] GreenRoofs. Norway: Green Building Alliance, 2021 (Available at the website of Green Roofs)

[12] DinardoK. The Green Revolution Spreading Across Our Rooftops. The New York Times, 2019

[13] Matta E, De Stefano A. Robust design of mass-uncertain rolling-pendulum TMDS for the seismic protection of buildings. Mechanical Systems and Signal Processing. Mechanical Systems and Signal Processing, 2019, 23(1): 127–147

[14] Matta E, de Stefano A. Seismic performance of pendulum and translational roof-garden tmds. Mechanical Systems and Signal Processing, 2009, 23(3): 908–921

[15] CarmodyMJasarevicMOmenzetterPCliftonGFassmanE. Seismic response of green roofs. In: Proceedings of 2009 New Zealand Society for Earthquake Engineering Conference. New Zealand: NZSEE, 2009

[16] Welsh-Huggins S J, Liel A B. A life-cycle framework for integrating green building and hazard-resistant design: Examining the seismic impacts of buildings with green roofs. Structure and Infrastructure Engineering, 2017, 13(1): 19–33

[17] Tam S, Wong J. Seismic performance of green roof structure. Sustainability, 2021, 13(8): 4278

[18] UnitedStates Green Building Council. LEED credit library. Washington, DC: U.S. Green Building Council, 2020 (Available at the website of U.S. Green Building Council)

[19] LandscapeDevelopmentLandscapingResearch Society. Green Roof Guidelines—Guidelines for the Planning. Bonn: Construction and Maintenance of Green Roofs, 2018

[20] Committingto Net-zero. SE2050, 2020 (Available at the website of Structural Engineering Institute SE2050)

[21] CSI. SAP2000 Integrated Software for Structural Analysis and Design. Computers and Structures Inc., 2022

[22] Federal Emergency Management Agency. NEHRP Recommended Seismic Provisions: Design Examples. Green Roof Technology, 2016, 1051: 2015

[23] GreenRoof Technology. Semi-Intensive Green Roofs. Green roof technology, 2021 (Available at the website of Green Roof Technology)

[24] BeresnevI AKuo-LiangW. Nonlinear soil response—A reality? Bulletin of the Seismological Society of America, 1996, 86: 1964–1978

[25] HashashY M AMusgroveM IHarmonJ AIlhanOXingGNumanogluOGroholskiD RPhillipsC AParkD. DeepSoil 7.0, User Manual. Urbana, IL: Board of Trustees of University of Illinois at Urbana-Champaign, 2020

[26] SaidM JBinM. Determination of Shear Wave Velocity and Shear Modulus Estimation of Peat Soil Using Seismic Geophysical Method. University Tun Hussein Onn Malaysia, 2016

[27] Ekwue E I. Organic-matter effects on soil strength properties. Soil & Tillage Research, 1990, 16(3): 289–297

[28] Kallioglou P, Tika T, Koninis G, Papadopoulos S, Pitilakis K. Shear modulus and damping ratio of organic soils. Geotechnical and Geological Engineering, 2009, 27(2): 217–235

[29] Numanoglu O A, Musgrove M, Harmon J A, Hashash Y M A. Generalized non-Masing hysteresis model for cyclic loading. Journal of Geotechnical and Geoenvironmental Engineering, 2018, 144(1): 06017015

[30] Hashash Y M A, Park D. Viscous damping formulation and high frequency motion propagation in nonlinear site response analysis. Soil Dynamics and Earthquake Engineering, 2002, 22(7): 611–624

[31] Park D, Hashash Y M A. Soil damping formulation in nonlinear time domain site response analysis. Journal of Earthquake Engineering, 2004, 8(2): 249–274

[32] PacificEarthquake Engineering Research Center. Peer Strong Ground Motion Databases. Berkeley University of California, 2021

[33] ChopraA K. Dynamics of Structures: Theory and Applications to Earthquake Engineering. 3rd ed. New Jersey: Prentice Hall, 2007

RIGHTS & PERMISSIONS

Higher Education Press