scholarly journals Seismic Response of Nonseismically Designed Reinforced Concrete Low Rise Buildings

2018 ◽  
Vol 24 (4) ◽  
pp. 112
Author(s):  
Thamir K. Mahmoud ◽  
Hayder A. Al-Baghdadi
Keyword(s):  
Reinforced Concrete ◽  
Numerical Model ◽  
Three Dimensional ◽  
Nonlinear Dynamic Analysis ◽  
Time History ◽  
Inelastic Behavior ◽  
Base Shear ◽  
Earthquake Excitation ◽  
Inelastic Responses ◽  
Concrete Damage

In this paper, the time-history responses of a square plan two-story reinforced concrete prototype building, considering the elastic and inelastic behavior of the materials, were studied numerically. ABAQUS software was used in three-dimensional (3D) nonlinear dynamic analysis to predict the inelastic response of the buildings. Concrete Damage Plasticity Model (CDPM) has been used to model the inelastic behavior of the reinforced concrete building under seismic excitation. The input data included geometric information, material properties, and the ground motion. The building structure was designed only for gravity load according to ACI 318 with non-seismically detailing requirements. The prototype building was subjected to El Centro 1940 NS earthquake at different amplitudes (PGA=0.05g, PGA=0.15g, and PGA=0.32g). The elastic and inelastic responses of the 3D numerical model of the same building were evaluated. The differences between the elastic and inelastic displacements and base shear forces were analyzed. It was found from the results that base shear responses are significantly more sensitive to the numerical model of analysis than displacement responses. The evaluation showed that the base shear force and displacement responses of a two-story R.C. building subjected to severe earthquake excitation are very sensitive to the numerical model used whether it is elastic or inelastic.  

Inelastic analysis of a reinforced concrete shear wall building according to the National Building Code of Canada 2005

2006 ◽  
Vol 33 (7) ◽  
pp. 854-871 ◽  
Author(s):  
M Panneton ◽  
P Léger ◽  
R Tremblay
Keyword(s):  
Reinforced Concrete ◽  
Three Dimensional ◽  
Time History ◽  
Shear Walls ◽  
Shear Wall ◽  
Fundamental Period ◽  
Building Code ◽  
Base Shear ◽  
Inelastic Analysis ◽  
The Impact

An eight-storey reinforced concrete shear wall building located in Montréal and designed according to the 1995 National Building Code of Canada (NBCC) and the Canadian Standards Association standard CSA-A23.3-94 is studied to evaluate the impact of new requirements for inclusion in new editions of the NBCC and CSA-A23.3. Static and modal analyses were conducted according to the 2005 NBCC (draft 2003) and CSA-A23.3-04 (draft 4) procedures, and three-dimensional dynamic inelastic time history analysis was performed using three earthquake records. The building is braced by four flat shear walls and three cores. Various estimates of the fundamental period of vibration based on empirical expressions presented in the literature or structural models with different stiffness assumptions were examined. The analysis also permitted the study of the displacement and force demand on the lateral load resisting system. It was found that the base shear from the 2005 NBCC is 29% higher than the 1995 NBCC value when code empirical formulae are used for the fundamental period of vibration.Key words: building, shear wall, inelastic seismic response, NBCC, CSA-A23.3 design of concrete structures.

Seismic Performance of a Concrete Highway Tunnel Using a Concrete Damage Plasticity Model

2016 ◽  
Vol 711 ◽  
pp. 966-973
Author(s):  
Joanna M. Dulinska ◽  
Izabela J. Murzyn
Keyword(s):  
Time History ◽  
Fe Model ◽  
Plasticity Model ◽  
Inelastic Behavior ◽  
Ground Acceleration ◽  
Highway Tunnel ◽  
Tunnel Section ◽  
Concrete Damage ◽  
Concrete Damage Plasticity ◽  
The Impact

In the paper a non-linear dynamic response of a concrete highway tunnel to a natural earthquake is presented. The acceleration time history of the registered shock was applied as seismic excitation acting in three directions. The peak ground acceleration (PGA) of the shock was 0.5 g. A three-dimensional FE model of the concrete tunnel section (600 m long) and surrounding soil layers was created with the ABAQUS software. To represent the inelastic behavior of the tunnel under the earthquake, a concrete damage plasticity model was assumed as a constitutive model for the concrete. A model of spatially varying ground motion, which takes so called “wave passage effect” was implemented for the dynamic analysis. Two velocities of seismic wave propagation were assumed: 500 and 1000 m/s. These velocities are typical for soft and stiff bedrock, respectively. It turned out that in case of stiffer bedrock, in which seismic waves propagate faster, the damage pattern shows less cracking than in case of soft bedrock. The distribution of plastic and damage computed indices also allowed to assess the impact of the shock on the structure. It turned out that the analyzed shock with PGA of 0.5 g was strong enough to cause severe destruction (cracking) in the tunnel lining. Finally, the transverse pattern of cracks, that was obtained from the calculations, was in good agreement with damages observed during severe earthquakes.

INFLUENCE OF HIGH INITIAL ISOLATOR STIFFNESS ON THE SEISMIC RESPONSE OF A BASE-ISOLATED BENCHMARK BUILDING

2011 ◽  
Vol 11 (06) ◽  
pp. 1201-1228 ◽  
Author(s):  
AJAY SHARMA ◽  
R. S. JANGID
Keyword(s):  
Degrees Of Freedom ◽  
Base Isolation ◽  
Near Field ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Time History ◽  
Base Shear ◽  
Isolation System ◽  
Base Displacement ◽  
Floor Acceleration

The influence of high initial isolator stiffness on the response of a base-isolated benchmark building is investigated. The base-isolated building is modeled as a three-dimensional linear-elastic structure having three degrees-of-freedom at each floor level. The time-history analysis of this building is carried out by solving the governing equations of motion using Newmark-beta method along with an iterative predictor–corrector approach. The force–deformation behavior of the isolation system is modeled by a bilinear law, which can be effectively used to model all isolation systems in practice. Three near-field earthquakes with bidirectional ground motions are considered. Structural response parameters such as absolute top floor acceleration, base shear, and base displacement are chosen for investigating the effects of high initial isolator stiffness. It was observed that the high initial isolator stiffness of the isolation system excites the higher modes in the base-isolated building and increases the top floor acceleration. Such a phenomenon can be detrimental to the sensitive instruments placed in the isolated structure. On the other hand, both the base displacement and base shear reduce marginally due to increase in the initial isolator stiffness. Further, the influences of high initial isolator stiffness are found to dependent on the period and characteristic strengths of the base isolation system.

scholarly journals Three dimensional numerical simulations for non-breaking solitary wave interacting with a group of slender vertical cylinders

2009 ◽  
Vol 1 (1) ◽  
Author(s):  
Weihua Mo ◽  
Philip L.-F. Liu
Keyword(s):  
Free Surface ◽  
Numerical Model ◽  
Dynamic Pressure ◽  
Laboratory Data ◽  
Three Dimensional ◽  
Time History ◽  
Surface Displacement ◽  
Numerical Results ◽  
Finite Volume Scheme ◽  
Free Surface Displacement

AbstractIn this paper we validate a numerical model for-structure interaction by comparing numerical results with laboratory data. The numerical model is based on the Navier-Stokes(N-S) equations for an incompressible fluid. The N-S equations are solved by two-step projection finite volume scheme and the free surface displacements are tracked by the slender vertical piles. Numerical results are compared with the laboratory data and very good agreement is observed for the time history of free surface displacement, fluid particle velocity and force. The agreement for dynamic pressure on the cylinder is less satisfactory, which is primarily caused by instrument errors.

scholarly journals Cost effectiveness of code base shear requirements for reinforced concrete frame structures

1978 ◽  
Vol 11 (2) ◽  
pp. 85-93
Author(s):  
D. G. Elms ◽  
D. Silvester
Keyword(s):  
Reinforced Concrete ◽  
Time History ◽  
Capital Cost ◽  
Base Shear ◽  
Reinforced Concrete Frame ◽  
Total Cost ◽  
Concrete Frame ◽  
Earthquake Losses ◽  
Frame Buildings ◽  
Code Base

The appropriateness of the overall base shear levels prescribed by
 the New Zealand Loadings Code NZS4203:1976 is investigated for reinforced concrete frame buildings. Six-storey structures were designed to different base shear levels and total costs were computed: total cost takes account of capital cost, averaged direct economic loss due to earthquakes, and indirect earthquake losses. Damage levels were obtained from computer time-history analyses. It is shown that the code base shear levels are
 of the right order of magnitude for reinforced concrete frame buildings, but that the total cost of such buildings is insensitive to design
base shear level. The increase in capital cost of a concrete frame building due to earthquake design requirements is of the order of 4%.

scholarly journals Influence of Superior Vibration Modes on the Seismic Response of Reinforced Concrete Structures with Eigen-Periods Near Code Control Periods

2020 ◽  
Vol 9 (1) ◽  
pp. 108-122
Author(s):  
Savu Adrian-Alexandru
Keyword(s):  
Reinforced Concrete ◽  
Seismic Response ◽  
Seismic Design ◽  
Structural Design ◽  
Control Period ◽  
Three Dimensional ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Base Shear ◽  
Seismic Design Code

Abstract The current paper studies the effect of superior eigen-modes on the seismic response for a series of reinforced concrete structures having eigen-periods near code control periods. Although the structural design is based on Romanian seismic design codes (“P100-1/2013 - Seismic design code - Part 1 - Design provisions for buildings” and “SR-EN 1998/2004 - Design of structures for earthquake resistance”), it carries some importance for other countries with similar seismic design spectra. A total of twenty-four models for structures were considered by varying their location (through control period values), three-dimensional regularity, overall dimensions and height regime. Results were compared and conclusions were drawn based on percentage values of relative displacements (storey drifts) and base shear forces.

Dynamic inelastic analyses of a bridge structure

1981 ◽  
Vol 71 (2) ◽  
pp. 517-530
Author(s):  
A. G. Gillies ◽  
R. Shepherd
Keyword(s):  
Equations Of Motion ◽  
Resistance Mechanism ◽  
Three Dimensional ◽  
Time History ◽  
Bridge Structure ◽  
Three Dimensional Model ◽  
Earthquake Excitation ◽  
Plastic Yield ◽  
Analysis Technique ◽  
Bridge Structures

abstract The necessity for framed structures to be capable of dissipating significant amounts of energy inelastically under severe earthquake excitation is generally acknowledged. Bridge structures differ from buildings in their seismic lateral resistance mechanism in so far as they generally possess a small number of clearly identifiable potential zones in which plastic yield can occur and consequently tend to be amenable to postelastic studies. This paper presents the application of an analysis technique in which the response time history of a bridge structure, treated as a three-dimensional frame, is determined by direct integration of the equations of motion with allowances incorporated for inelastic member behavior. Aspects studied include the differences in responses predicted using a nonlinear three-dimensional model rather than a planar frame idealization and the effect of unequal span lengths or torsional vibrations.

Ground motion sensitivity of a Vancouver-style high rise

2004 ◽  
Vol 31 (2) ◽  
pp. 292-307 ◽  
Author(s):  
Timothy White ◽  
Carlos E Ventura
Keyword(s):  
Reinforced Concrete ◽  
Ground Motion ◽  
Nonlinear Dynamic ◽  
Dynamic Properties ◽  
Three Dimensional ◽  
Nonlinear Dynamic Analysis ◽  
Ground Shaking ◽  
Motion Sensitivity ◽  
High Rise ◽  
Ground Motion Records

The purpose of the study discussed in this paper is to evaluate the seismic response of a modern building, designed according to the current building code and to extreme earthquake earthquakes from two different source mechanisms. To this end, a three-dimensional nonlinear dynamic response of a reinforced concrete high-rise building, typical of the type built in Vancouver, British Columbia, is investigated. According to current design practice, the building has been designed to resist lateral loads with a coupled shearwall system. A comparison of the responses of the building to crustal and subduction type earthquakes of similar magnitudes is presented and discussed. The ground motion records selected for this study were derived from recorded crustal and subduction events, which are both considered to be extreme, and beyond the code-based design requirements of the building. A part of this study includes an evaluation of how the dynamic properties of the building change as the building is being damaged by severe ground shaking. The results of the study show that the crustal earthquake imposes large upper levels displacements, and much plastic hinging near the base because the response of the building is governed mainly by the first mode of the "undamaged" system. The subduction earthquake results in displacements smaller than those from the crustal event and causes plastic hinging at mid-height and near the base as well as large torsional rotations, because the behaviour of the building is greatly influenced by the second mode of the "damaged" system.Key words: nonlinear dynamic analysis, seismic, high rise, reinforced concrete, coupled shearwall.

Seismic Performance of a Six-Story Reinforced Concrete Masonry Building during the Canterbury Earthquake Sequence

2014 ◽  
Vol 30 (1) ◽  
pp. 363-381 ◽  
Author(s):  
Jose Centeno ◽  
Carlos E. Ventura ◽  
Jason M. Ingham
Keyword(s):  
Reinforced Concrete ◽  
Three Dimensional ◽  
Nonlinear Dynamic Analysis ◽  
Masonry Building ◽  
Mechanism Analysis ◽  
Concrete Masonry ◽  
Lateral Resistance ◽  
Lateral Strength ◽  
Canterbury Earthquake Sequence ◽  
Ductility Capacity

During the Christchurch earthquake of February 2011, several midrise reinforced concrete masonry (RCM) buildings showed performance levels that fall in the range of life safety to near collapse. A case study of one of these buildings, a six-story RCM building deemed to have reached the near collapse performance level, is presented in this paper. The RCM walls on the second floor failed due to toe crushing, reducing the building's lateral resistance in the east–west direction. A three-dimensional (3-D) nonlinear dynamic analysis was conducted to simulate the development of the governing failure mechanism. Analysis results showed that the walls that were damaged were subjected to large compression loads during the earthquake, which caused an increase in their in-plane lateral strength but reduced their ductility capacity. After toe crushing failure, axial instability of the model was prevented by a redistribution of gravity loads.

scholarly journals Data set from shake table tests of free-standing rocking bodies

2021 ◽  
pp. 875529302110200
Author(s):  
Michalis F Vassiliou ◽  
Cihan Cengiz ◽  
Matt Dietz ◽  
Luiza Dihoru ◽  
Marco Broccardo ◽  
...  
Keyword(s):  
Earthquake Engineering ◽  
Numerical Models ◽  
Three Dimensional ◽  
Time History ◽  
Stochastic Comparison ◽  
Shake Table ◽  
Free Standing ◽  
Earthquake Excitation ◽  
Shake Table Tests ◽  
Data Set

In earthquake engineering, structural models are validated by performing a time history analysis and comparing its maximum to the maximum response obtained by a shake table test. It has been shown that this is a sufficient (but not a necessary) precondition to accept a numerical model. Numerical models can fail to predict the planar rocking response of a rigid block, but may succeed in predicting the statistics of the response to an ensemble of ground motions. As seismic response is inherently stochastic, comparison of the statistics of the numerically simulated response to the statistics of the experimentally obtained benchmark response for the same ensemble of earthquake excitation is a sufficient (and easier to pass) model validation test. This article describes the publicly available data of a set of 12 free rocking vibration and 115 shake table tests of six three-dimensional rocking and sliding columns, designed at ETH Zurich and performed at EQUALS Laboratory, University of Bristol. The data can be used to statistically validate different approaches that aim to model three-dimensional rocking structures.

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