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Author (up) Parra, P.F.; Arteta, C.A.; Moehle, J.P.
Title Modeling criteria of older non-ductile concrete frame-wall buildings Type
Year 2019 Publication Bulletin Of Earthquake Engineering Abbreviated Journal Bull. Earthq. Eng.
Volume 17 Issue 12 Pages 6591-6620
Keywords Non-ductile buildings; Nonlinear analysis; Plastic collapse mechanism; Base shear strength; Hazard levels
Abstract The purpose of seismic provisions included in modern building codes is to obtain a satisfactory structural performance of buildings during earthquakes. However, in the United States and elsewhere, there are large inventories of buildings designed and constructed several decades ago, under outdated building codes. Some of these buildings are classified as non-ductile buildings. Currently, under the ATC-78 project, a methodology is being developed to identify seismically hazardous frame-wall buildings through a simple procedure that does not require full nonlinear analyses by the responsible engineer. This methodology requires the determination of the controlling plastic collapse mechanism, the base shear strength, and the ratio between the story drift ratio and the roof drift ratio, called parameter alpha, at collapse level. The procedure is calibrated with fully inelastic nonlinear analyses of archetype buildings. In this paper we first introduce an efficient scheme for modeling frame-wall buildings using the software OpenSees. Later, the plastic collapse mechanism, the base shear strength, and values of alpha are estimated from nonlinear static and dynamic analyses considering a large suite of ground-motion records that represent increasing hazard levels. The analytical experiment included several frame-wall combinations in 4 and 8-story buildings, intended to represent a broad range of conditions that can be found in actual buildings, where the simplified methodology to evaluate the risk of collapse can be applicable. Analysis results indicate that even walls of modest length may positively modify the collapse mechanism of nonductile bare frames preventing soft story failures.
Address [Parra, P. F.] Univ Adolfo Ibanez, Fac Ingn & Ciencias, Diagonal Las Torres 2700, Santiago, Chile, Email: pablo.parra@uai.cl
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1570-761x ISBN Medium
Area Expedition Conference
Notes WOS:000496337400011 Approved
Call Number UAI @ eduardo.moreno @ Serial 1072
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Author (up) Parra, P.F.; Moehle, J.P.
Title Effects of strain gradients in the onset of global buckling in slender walls due to earthquake loading Type
Year 2020 Publication Bulletin Of Earthquake Engineering Abbreviated Journal Bull. Earthq. Eng.
Volume 18 Issue 7 Pages 3205-3221
Keywords Walls; Global buckling; Reinforced concrete; Earthquake
Abstract Global buckling of slender walls, reported only in a few laboratory tests before 2010, became a critical issue in design of reinforced concrete buildings after it was observed following the 2010 Mw 8.8 Chile earthquake and the 2011 Mw 6.3 New Zealand earthquake. Researchers have proposed theoretical buckling models based on prismatic columns subjected to uniform tension/compression cycles, where the key parameters are slenderness ratio, number of curtains of reinforcement, and maximum tensile strain before buckling during load reversal. These models have shown sufficient accuracy in comparison with laboratory tests on columns under such loading conditions. However, buckling in walls is more complex because of variation of strains through the wall depth and variation of moment along the wall height. Nonlinear finite elements are used to evaluate the effects of these more complex loadings on buckling of wall boundary elements. Analyses showed that the maximum tensile strain (averaged over the wall out-of-plane unsupported height) required to buckle the wall during load reversal does not depend on the moment variation along the wall height. Moreover, for typical wall lengths, the wall boundary behaves like an isolated column subjected to axial force cycles, with minimal apparent bracing provided by the wall web. This allows to analyze a broad range of practical cases for buckling susceptibility using simplified approaches based on buckling models of axially loaded columns.
Address [Parra, P. F.] Univ Adolfo Ibanez, Fac Ingn & Ciencias, Diagonal Torres 2700, Santiago, Chile, Email: pablo.parra@uai.cl
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1570-761x ISBN Medium
Area Expedition Conference
Notes WOS:000520685900004 Approved
Call Number UAI @ eduardo.moreno @ Serial 1157
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Author (up) Ugalde, D.; Lopez-Garcia, D.; Parra, P.F.
Title Fragility-based analysis of the influence of effective stiffness of reinforced concrete members in shear wall buildings Type
Year 2020 Publication Bulletin Of Earthquake Engineering Abbreviated Journal Bull. Earthq. Eng.
Volume 18 Issue 5 Pages 2061-2082
Keywords Wall buildings; Shear stiffness; Bending stiffness; Fragility curves; Pushover analysis; SPO2FRAG
Abstract When modeling RC shear wall buildings for seismic analysis there is little consensus in the literature on the appropriate value of the wall effective shear stiffness (GA(eff)) and the slab effective bending stiffness (EIeff). A probabilistic analysis based on fragility curves is a robust technique to assess the influence of these parameters on the expected seismic performance, but such studies are scarce because they require computationally expensive analysis such as Incremental Dynamic Analysis (IDA). In this paper, fragility curves are developed following the recently introduced SPO2FRAG procedure, a simplified methodology that does not require IDA but the computationally more affordable incremental static (pushover) analysis. The fragility curves provided by SPO2FRAG are used to evaluate the influence of the values of GA(eff) and EIeff on the analytical seismic response of full 3D nonlinear models of two actual (and representative) residential wall buildings of 17 and 26 stories located in Santiago (Chile). The accuracy of SPO2FRAG is also evaluated through comparisons with empirical fragilities.
Address [Ugalde, David; Lopez-Garcia, Diego] Pontificia Univ Catolica Chile, Dept Struct & Geotech Engn, Av Vicuna Mackenna 4860 Macul, Santiago 7820436, RM, Chile, Email: dgugalde@uc.cl;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1570-761x ISBN Medium
Area Expedition Conference
Notes WOS:000518844200010 Approved
Call Number UAI @ eduardo.moreno @ Serial 1137
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Author (up) Ugalde, D.; Parra, P.F.; Lopez-Garcia, D.
Title Assessment of the seismic capacity of tall wall buildings using nonlinear finite element modeling Type
Year 2019 Publication Bulletin Of Earthquake Engineering Abbreviated Journal Bull. Earthq. Eng.
Volume 17 Issue 12 Pages 6565-6589
Keywords Shear walls; Shear wall buildings; Shear wall models; Seismic response; 2010 Chile earthquake
Abstract Two existing RC shear wall buildings of 17 and 26 stories were analyzed using fully nonlinear finite element models, i.e., models that include nonlinear material behavior and geometric nonlinearities. The buildings are located in Santiago, Chile and are representative of Chilean residential buildings in the sense that they have a large number of shear walls. The buildings withstood undamaged the 2010 Chile earthquake even though they were subjected to demands much larger than the code-specified demand. The approach to model the RC shear walls was validated through comparisons with results experimentally obtained from cyclic static tests conducted on isolated wall specimens. Several pushover analyses were performed to assess the global response of the buildings under seismic actions and to evaluate the influence of several modeling issues. Response history analyses were performed considering a ground motion recorded in Santiago during the 2010 Chile earthquake. In general, results (in terms of both global and local response quantities) are consistent with results given by pushover analysis and with the empirically observed lack of damage, a consistency that was not found in a previous study that considered linearly elastic models. The tangential inter-story drift deformation was found to correlate much better with the lack of observable damage than the total inter-story drift deformation typically considered in practice. The analysis also revealed that foundation uplift is possible but does not seem to significantly influence the response. Other modeling issues that were found to deserve further research are the shear stiffness of the walls and the influence of the slabs.
Address [Ugalde, David; Lopez-Garcia, Diego] Pontificia Univ Catolica Chile, Dept Struct & Geotech Engn, Santiago, Chile, Email: dlg@ing.puc.cl
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1570-761x ISBN Medium
Area Expedition Conference
Notes WOS:000496337400010 Approved
Call Number UAI @ eduardo.moreno @ Serial 1073
Permanent link to this record