Effects of ground improvement on the seismic demand on buildings
DOI:
https://doi.org/10.5459/bnzsee.1717Abstract
This paper explores the influence of ground improvement on building seismic demands through parametric site response analyses of low-to-mid-rise buildings supported on mat foundations. A set of soil profiles, containing liquefiable strata, and two building archetypes are analysed using two-dimensional finite element models, both with and without improved zones underneath the buildings. The densification/stiffness of the improved zone and the depth of the improvement is varied as part of the parametric study. The seismic demand on the buildings and foundations for the unimproved and improved sites is assessed. The results show that ground improvement effectively reduces foundation displacements but often increases base shear and inter-storey drift demands. Under total stress conditions, amplified structural seismic demands show a good correlation with increases in shear-wave velocity of the improved ground. However, when liquefiable soil behaviour is modelled, the ratio of the depth of improvement to the depth of the liquefiable stratum (Zi/Zsoft,liq) is a more reliable predictor of seismic demands. When Zi/Zsoft,liq = 0.50, foundation subsidence relative to the adjacent unimproved ground is limited to less than 50 mm in most cases, and rocking drift remains below 0.5%, provided that bearing pressures do not exceed 80 kPa. This improved depth ratio is identified as a good threshold for limiting the potential for damage. However, beyond this threshold, the ability of the building to sustain repairable damage after an ULS earthquake relies on its capacity to accommodate increased flexural drift caused by soil–foundation–structure interaction effects. The trends identified in this study offer valuable insights into how ground improvement influences seismic demand on buildings.
References
1 Japanese Geotechnical Society (1998). “Remedial Measures against Soil Liquefaction from Investigation and Design to Implementation”. Rotterdam: A. A. Balkema.
2 Karimi Z and Dashti S (2016). “Seismic performance of shallow founded structures on liquefiable ground: validation of numerical simulations using centrifuge experiments”. Journal of Geotechnical and Geoenvironmental Engineering, 142(6). https://doi.org/10.1061/(ASCE)GT.1943-5606.0001479
3 Olarte J, Dashti S and Liel AB (2018). “Can ground densification improve seismic performance of the soil‐foundation‐structure system on liquefiable soils?” Earthquake Engineering and Structural Dynamics, 47(5): 1193-1211. https://doi.org/10.1002/eqe.3012
4 Ohsaki Y (1970). “Effects of sand compaction on liquefaction during the Tokachioki earthquake”. Soils and Foundations, 10(2): 112-128. https://doi.org/10.3208/sandf1960.10.2_112.
5 Mitchell JK and Wentz FJ (1991). “Performance of improved ground during the Loma Prieta Earthquake”. Report No. UCB/EERC-91/12, Earthquake Engineering Research Center, University of California at Berkeley, Berkeley, CA. https://nehrpsearch.nist.gov/article/PB93-114791/XAB
6 Hausler EA and Koelling M (2004). “Performance of improved ground during the 2001 Nisqually earthquake”. 5th International Conference on Case Histories in Geotechnical Engineering, New York, NY. https://scholarsmine.mst.edu/icchge/5icchge/session03/18.
7 Wotherspoon LM, Orense RP, Jacka M, Green RA, Cox BR and Wood CM (2014). “Seismic performance of improved ground sites during the 2010–2011 Canterbury earthquake sequence”. Earthquake Spectra, 30(1): 111-129. https://doi.org/10.1193/082213EQS236M
8 Elgamal A, Lu J and Yang Z (2005). “Liquefaction-induced settlement of shallow foundations and remediation: 3D numerical simulation”. Journal of Earthquake Engineering, 9: 17-45. https://doi.org/10.1080/13632460509350578
9 Liu L and Dobry R (1997). “Seismic response of shallow foundation on liquefiable sand”. Journal of Geotechnical and Geoenvironmental Engineering, 123(6): 557-567. https://doi.org/10.1061/(ASCE)1090-0241(1997)123:6(557)
10 Karamitros DK, Bouckovalas GD and Chaloulos YK (2013). “Insight into the seismic liquefaction performance of shallow foundations”. Journal of Geotechnical and Geoenvironmental Engineering, 139(4): 599-607. https://doi.org/10.1061/(ASCE)GT.1943-5606.000079
11 Bray JD and Macedo J (2017). “6th Ishihara Lecture: Simplified procedure for estimating liquefaction-induced building settlement”. Soil Dynamics and Earthquake Engineering, 102: 215-231. https://doi.org/10.1016/j.soildyn.2017.08.026
12 Shahir H, Pak A and Ayoubi P (2016). “A performance-based approach for design of ground densification to mitigate liquefaction”. Soil Dynamics and Earthquake Engineering, 90: 381-394. https://doi.org/10.1016/j.soildyn.2016.09.014
13 Hwang YW, Bullock Z, Dashti S and Liel A (2022). “A probabilistic predictive model for foundation settlement on liquefiable soils improved with ground densification”. Journal of Geotechnical and Geoenvironmental Engineering. https://doi.org/10.1061/(ASCE)GT.1943-5606.0002768
14 NZGS and MBIE (2016). “Earthquake Geotechnical Engineering Practice in New Zealand – Module 4: Earthquake resistant foundation design. New Zealand”. Geotechnical Society and Ministry of Business Innovation & Employment. https://www.building.govt.nz/building-code-compliance/b-stability/b1-structure/module-4-earthquake-foundation-design
15 Kramer SL (2008). “Performance-based earthquake engineering: Opportunities and implications for geotechnical engineering practice”. Geotechnical Earthquake Engineering and Soil Dynamics, IV: 1-32. https://doi.org/10.1061/40975(318)213
16 Standards New Zealand (2004). "NZS1170.5: Structural Design Actions. Part 5: Earthquake Actions ‐ New Zealand”. Standards New Zealand, Wellington, 76pp. https://www.standards.govt.nz/sponsored-standards/building-standards/NZS1170-5
17 Brown LJ and Weeber JH (1995). “Geology of Christchurch, New Zealand”. Environmental and Engineering Geoscience. https://doi.org/10.2113/gseegeosci.I.4.427
18 Cubrinovski M, Bradley B, Wotherspoon L, Green R, Bray J, Wood C, Pender M, Allen J, Bradshaw A, Rix G and Taylor M (2011). “Geotechnical aspects of the 22 February 2011 Christchurch earthquake”. Bulletin of the New Zealand Society for Earthquake Engineering. 44(4): 205-226. https://doi.org/10.5459/bnzsee.44.4.205-226
19 Lin YC, Joh SH and Stokoe K (2014). “Analysis of the UTexas 1 surface wave dataset using the SASW methodology”. in: Geo-Congress Technical Papers, GSP 234: 830–839. https://doi.org/10.1061/9780784413272.081
20 McGann CR, Bradley BA and Cubrinovski M (2017). “Development of a regional Vs30 model and typical Vs profiles for Christchurch, New Zealand from CPT data and region-specific CPT-Vs correlation”. Soil Dynamics and Earthquake Engineering, 95: 48-60. https://doi.org/10.1016/j.soildyn.2017.01.032
21 Standards New Zealand (2025). “TS 1170.5 Supp 1:2025, New Zealand Technical Specification. Commentary to Structural Design Actions Part 5: Earthquake Actions – New Zealand”. https://www.standards.govt.nz/shop/snz-ts-1170-5-supp-12025
22 Idriss IM and Boulanger RW (2008). “Liquefaction during Earthquakes”. Earthquake Engineering Research Institute, Oakland, CA.
23 McKenna F (2011). “OpenSees: A framework for earthquake engineering simulation”. Computing in Science & Engineering, 13(4): 58-66. http://opensees.berkeley.edu/
24 Yang Z, Lu J and Elgamal A (2008). “OpenSees soil models and solid-fluid fully coupled elements”. User's Manual. Version 1, 27.
25 Prevost JH (1985). “A simple plasticity theory for frictional cohesionless soils”. Soil Dynamics and Earthquake Engineering, 4(1): 9-17. https://doi.org/10.1016/0261-7277(85)90030-0.
26 Parra-Colmenares EJ (1996). “Numerical modeling of liquefaction and lateral ground deformation including cyclic mobility and dilation response in soil systems”. PhD Dissertation, Department of Civil Engineering, Rensselaer Polytechnic Institute, Troy, NY.
27 Kondner RL and Zelasko JS (1963). “Hyperbolic stress-strain formulation for sands”. 2nd Pan American Conference on Soil Mechanics and Foundation Engineering (ISSMGE). 289–324. https://cir.nii.ac.jp/crid/1572261549806272256
28 Darendeli MB (2001). “Development of a New Family of Normalized modulus reduction and material damping curves”. PhD Dissertation, Department of Civil Engineering, University of Texas at Austin, TX.
29 Gingery JR and Elgamal A (2013). “Shear stress-strain curves based on the G/Gmax logic: A procedure for strength compatibility”. IACGE: Challenges and Recent Advances in Geotechnical and Seismic Research and Practices, 721-729. https://doi.org/10.1061/9780784413128.083
30 Haselton CB and Deierlein GG (2007). “Assessing seismic collapse safety of modern reinforced concrete frame buildings”. PEER Report 2007/08, PEER Center, University of California, Berkeley, CA. http://ir.vnulib.edu.vn/handle/123456789/1719
31 Raghunandan M, Liel AB and Luco N (2015). “Collapse risk of buildings in the Pacific northwest region due to subduction earthquakes”. Earthquake Spectra, 31(4): 2087-2115. https://doi.org/10.1193/012114EQS011M
32 AS/NZS 1170.1 (2002). “Structural Design Actions, Part 1: Permanent, Imposed and Other Actions”. Standards Australia/Standards New Zealand, Wellington, New Zealand.
33 Popescu R and Prevost JH (1995). “Comparison between VELACS numerical ‘class A’ predictions and centrifuge experimental soil test results”. Soil Dynamics and Earthquake Engineering, 14(2): 79-92. https://doi.org/10.1016/0267-7261(94)00038-I
34 Adrianopoulos KI, Papadimitriou AG and Bouckovalas GD (2010). “Bounding surface plasticity model for the seismic liquefaction analysis of geostructures”. Soil Dynamics and Earthquake Engineering, 30: 895–911. https://doi.org/10.1016/j.soildyn.2010.04.001
35 Kuhlemeyer RL and Lysmer J (1973). “Finite element method accuracy for wave propagation problems”. Journal of Soil Mechanics and Foundations Division, 99(5): 421-427. https://doi.org/10.1061/JSFEAQ.0001885
36 GNS Science, GeoNet. “Geological Hazard Information for New Zealand”. https://www.geonet.org.nz (Accessed 15 May 2025)
37 Ancheta TD, Darragh RB, Stewart JP, Seyhan E, Silva WJ, Chiou BS, Wooddell KE, Graves RW, Kottke AR and Boore DM (2014). “NGA-West2 Database”. Earthquake Spectra. https://doi.org/10.1193/070913EQS197M
38 Markham C, Bray JD, Macedo J and Luque R. (2016). “Evaluating nonlinear effective stress site response analyses using records from the Canterbury earthquake sequence”. Soil Dynamics and Earthquake Engineering, 82: 84–98. https://doi.org/10.1016/j.soildyn.2015.12.007
39 Luque R and Bray JD (2020). “Dynamic soil-structure interaction analyses of two important structures affected by liquefaction during the Canterbury earthquake sequence”. Soil Dynamics and Earthquake Engineering, 133. https://doi.org/10.1016/j.soildyn.2019.106026
40 Meite R, Wotherspoon L, McGann CR, Green RA and Hayden C (2020). “An iterative linear procedure using frequency-dependent soil parameters for site response analyses”. Soil Dynamics and Earthquake Engineering, 130. https://doi.org/10.1016/j.soildyn.2019.105973
41 FEMA (1997). “NEHRP Guidelines for the Seismic Rehabilitation of Buildings”. FEMA 273, 1997 Edition. Federal Emergency Management Agency, Washington, D.C.
42 Van Ballegooy S, Malan P, Lacrosse V, Jacka ME, Cubrinovski M, Bray JD, O'Rourke TD, Crawford SA and Cowan H (2014). “Assessment of liquefaction-induced land damage for residential Christchurch”. Earthquake Spectra, 30(1): 31-55 https://doi.org/10.1193/031813EQS070M
43 Department of Building and Housing (2010). “Guidance on House Repairs and Reconstruction Following the Canterbury Earthquake”. Paper No. 380. Department of Building and Housing, Wellington. ISBN 978 0 478 34376 2.
44 Meite R, Wotherspoon L and Green R (2022). “Influence of extent of remedial ground densification on seismic site effects via 2-D site response analyses”. Soil Dynamics and Earthquake Engineering, 152. https://doi.org/10.1016/j.soildyn.2021.107041
45 Bowles JE (1996). “Foundation Analysis and Design”. 5th Edition, New York: McGraw‐Hill Companies, Inc.
