Blind Prediction of SMART 2008 Seismic Structural Response Test Results

2008 ◽  
Author(s):  
Pentti Varpasuo ◽  
Jukka Ka¨hko¨nen
Keyword(s):  
Numerical Simulation ◽  
Reinforced Concrete ◽  
Structural Response ◽  
Response Spectra ◽  
Test Results ◽  
Base Excitation ◽  
Structural Dynamic ◽  
Blind Prediction ◽  
Floor Response Spectra ◽  
Best Estimate

This paper describes the numerical simulation contribution of Fortum Nuclear Services Ltd. to the round-robin blind prediction of SMART 2008 seismic structural response tests to be conducted by Commissariat Energie Atomique in France in spring 2008. In order to assess the seismic tri-dimensional effects (such as torsion) and non-linear response of reinforced concrete buildings, a reduced scaled model (scale of 1/4th) of a nuclear reinforced concrete building is going to be tested in 2008 on AZALEE shaking table at Commissariat a` l’Energie Atomique (CEA Saclay, France). This test, supported by Commissariat a` l’Energie Atomique (CEA) and Electricite´ de France (EDF), will be part of the “SMART-2008” project (Seismic design and best-estimate Methods Assessment for Reinforced concrete buildings subjected to Torsion and non-linear effects). The first part of the project is a blind prediction of the structure behavior under different seismic loadings. It is presented as a contest, opened to teams from the practicing structural engineering as well as the academic and research community, worldwide. This phase will result in the creation of a predictive benchmark, which should allow us to compare and validate approaches used for the dynamic responses evaluation of reinforced concrete structures subjected to earthquake and exhibiting both 3-D and nonlinear behaviors. The objectives of the predictive benchmark are to: 1) Assess different conventional design methods of structural dynamic analyses, including floor response spectra evaluation; 2) Compare best-estimate methods for structural dynamic response and floor response spectra evaluation. In the next analytical phase to be carried out during the year 2009, the prediction contest will be compared to test results at various levels of seismic excitation (including ‘under-design’ and high ‘over-design’ levels), in order to: 1) Quantify variability in the seismic response of the structure and identify contribution coming from uncertainties in input parameters and random variables; 2) Investigate and compare different methods for fragility curves elaboration. The numerical simulation gives the best estimate values for acceleration response spectra values in five specified response points of the model in two perpendicular horizontal directions for base excitation values from 0.05g up to 0.8 g. Also the maximum and minimum values of the stresses and strains in the concrete and in the reinforcement of four vertical walls of the model are to be simulated as well as the acceleration and displacement response time histories at the top of the model for base excitation values from 0.05g up to 0.8 g.

Inelastic Analysis of Reinforced Concrete Shear Wall Structures Under Seismic Excitation

1993 ◽  
Author(s):  
Ming L. Wang
Keyword(s):  
Reinforced Concrete ◽  
Response Spectra ◽  
Shear Wall ◽  
Stiffness Degradation ◽  
Structural Stiffness ◽  
Hysteresis Model ◽  
Safety Equipment ◽  
Floor Response Spectra ◽  
Wall Structures ◽  
Degradation Models

Abstract During strong ground motions, members of reinforced concrete structures undergo cyclic deformations and experience permanent damage. Members may lose their initial stiffness as well as strength. Recently, Los Alamos National Laboratory has performed experiments on scale models of shear wall structures subjected to recorded earthquake signals. In general, the results indicated that the measured structural stiffness decreased with increased levels of excitation in the linear response region. Furthermore, a significant reduction in strength as well as in stiffness was also observed in the inelastic range. Since the in-structure floor response spectra, which are used to design and qualify safety equipment, have been based on calculated structural stiffness and frequencies, it is possible that certain safety equipment could experience greater seismic loads than specified for qualification due to stiffness reduction. In this research, a hysteresis model based on the concept of accumulated damage has been developed to account for this stiffness degradation both in the linear and inelastic ranges. Single and three degrees of freedom seismic Category I structures were analyzed and compared with equivalent linear stiffness degradation models in terms of maximum displacement responses, permanent displacement, and floor response spectra. The results indicate significant differences in responses between the hysteresis model and equivalent linear stiffness degradation models. The hysteresis model is recommended in the analysis of reinforced concrete shear-wall structures to obtain the in-structure floor response spectra for equipment qualification. Results of both cumulative and one shot tests are compared.

Simulation of a Reinforced Concrete Slab Punching Impact

2012 ◽  
Author(s):  
Jukka Kähkönen ◽  
Pentti Varpasuo
Keyword(s):  
Reinforced Concrete ◽  
Impact Velocity ◽  
Concrete Slab ◽  
Test Results ◽  
Concrete Wall ◽  
Reinforced Concrete Slab ◽  
Simply Supported ◽  
Blind Prediction ◽  
Reinforced Concrete Wall

Reinforced concrete wall subjected to an impact by a hard steel missile with a mass of 47 kg and an impact velocity of 135 m/s was one case study in the IRIS 2010 benchmark exercise in OECD/NEA/CSNI/IAGE framework. The wall had dimensions of 2m × 2m × 0.25m and it was simply supported. The perforation of the missile was expected. Fortum Power and Heat Ltd. participated in the benchmark. In this paper, we present our modeling and blind prediction of the benchmark case. The test results of the benchmark were released after the predictions were made. Based on the result comparison, we concluded that our model gave conservative results.

Numerical Simulation on the Behaviors of Post-Embedded Bars in Reinforced Concrete

2012 ◽  
Vol 598 ◽  
pp. 454-458
Author(s):  
Jian Hua Yang
Keyword(s):  
Numerical Simulation ◽  
Reinforced Concrete ◽  
Slip Model ◽  
Test Results ◽  
One Dimensional ◽  
Pull Out ◽  
Interface Slip ◽  
Experimental Values ◽  
Anchor Design ◽  
Good Agreement

Prism pull-out test results was used to build anchorage bonding interface slip model(ABISM), with this model, the behaviors of post-embedded bars in reinforced concrete with different anchorage depth were analyzed by one-dimensional numerical method, and the calculation values was compared with the experimental values. The results showed that: the calculated value is in good agreement with the experimental values. this model can provides an important reference for anchor design.

Application of a Reinforced Self-Compacting Concrete Jacket in Damaged Reinforced Concrete Beams under Monotonic and Repeated Loading

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Constantin E. Chalioris ◽  
Constantin P. Papadopoulos ◽  
Constantin N. Pourzitidis ◽  
Dimitrios Fotis ◽  
Kosmas K. Sideris
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Small Diameter ◽  
Structural Response ◽  
Reinforced Concrete Beams ◽  
Repeated Loading ◽  
Test Results ◽  
Self Compacting Concrete ◽  
Loading Test ◽  
Flexural Response

This paper presents the findings of an experimental study on the application of a reinforced self-compacting concrete jacketing technique in damaged reinforced concrete beams. Test results of 12 specimens subjected to monotonic loading up to failure or under repeated loading steps prior to total failure are included. First, 6 beams were designed to be shear dominated, constructed by commonly used concrete, were initially tested, damaged, and failed in a brittle manner. Afterwards, the shear-damaged beams were retrofitted using a self-compacting concrete U-formed jacket that consisted of small diameter steel bars and U-formed stirrups in order to increase their shear resistance and potentially to alter their initially observed shear response to a more ductile one. The jacketed beams were retested under the same loading. Test results indicated that the application of reinforced self-compacting concrete jacketing in damaged reinforced concrete beams is a promising rehabilitation technique. All the jacketed beams showed enhanced overall structural response and 35% to 50% increased load bearing capacities. The ultimate shear load of the jacketed beams varied from 39.7 to 42.0 kN, whereas the capacity of the original beams was approximately 30% lower. Further, all the retrofitted specimens exhibited typical flexural response with high values of deflection ductility.

Use of RVT for Computation of In-Structure Response Spectra and Peak Responses and Comparison to Time History and Response Spectrum Analysis

2018 ◽  
Vol 34 (4) ◽  
pp. 1913-1930 ◽  
Author(s):  
Irmela Zentner
Keyword(s):  
Response Spectrum ◽  
Structural Response ◽  
Time History ◽  
Strong Motion ◽  
Response Spectra ◽  
Combination Rules ◽  
Floor Response Spectra ◽  
Power Spectral ◽  
Time Histories ◽  
Definition Of

The random vibration theory offers a framework for the conversion of response spectra into power spectral densities (PSDs) and vice versa. The PSD is a mathematically more suitable quantity for structural dynamics analysis and can be straightforwardly used to compute structural response in the frequency domain. This allows for the computation of in-structure floor response spectra and peak responses by conducting only one structural analysis. In particular, there is no need to select or generate spectrum-compatible time histories to conduct the analysis. Peak response quantities and confidence intervals can be computed without any further simplifications such as currently used in the response spectrum method, where modal combination rules have to be derived. In contrast to many former studies, the Arias intensity-based definition of strong-motion duration is adopted here. This paper shows that, if the same definitions of strong-motion duration and modeling assumptions are used for time history and RVT computations, then the same result can be expected. This is illustrated by application to a simplified model of a reactor building.

Toppling Fragility of Unrestrained Equipment

1998 ◽  
Vol 14 (4) ◽  
pp. 695-711 ◽  
Author(s):  
Z. Y. Zhu ◽  
T. T. Soong
Keyword(s):  
Fragility Curves ◽  
Response Spectra ◽  
Static Friction ◽  
Block Type ◽  
Base Excitation ◽  
Loss Of Function ◽  
Floor Response Spectra ◽  
Rocking Motion ◽  
Design Earthquake ◽  
Supporting Base

Block-type equipment without restraining devices and under earthquake loads can effectively be modeled as freestanding rigid blocks resting on supporting bases subjected to base excitations. Once the peak values of base excitation levels, the aspect ratio of the bock, and the static friction coefficient between the block and the supporting base are known, the motion type of the block that will be initiated under base excitation can be determined. One of the possible motion types is rocking. When rocking is initiated, the block may topple and suffer severe damage and permanent loss of function. The emphasis of this study is placed on quantifying the possibility of toppling of a rigid block during rocking motion given its geometry and design earthquake environment. Using floor response spectra to characterize excitation inputs, results are given in the form of toppling fragility curves, i.e., probability of toppling as a function of peak ground accelerations. Parametric sensitivity studies are also carried out to show the effects of several key parameters on the fragility results.

Stochastic Floor Response Spectra for an Actively-Controlled Secondary System

2011 ◽  
Author(s):  
Takashi Mochio
Keyword(s):  
Structural Response ◽  
Response Spectra ◽  
Value Theory ◽  
Secondary System ◽  
Linear Quadratic ◽  
Gaussian Random Process ◽  
Floor Response Spectra ◽  
Active Mass Damper ◽  
State Space System ◽  
Response Amplification

The purpose of this paper is to propose a newly floor response spectra (FRS) in order to evaluate simply the structural response of the actively-controlled secondary system subjected to earthquake. This paper adopts a linear single-degree-of-freedom system as a main structure and an active mass damper (AMD) system as the active control technology. Also, the earthquake wave is modeled as product of a non-stationary envelope function and a stationary Gaussian random process of which power spectral density is equal to the Kanai-Tajimi spectrum. The control design is executed by using linear quadratic Gaussian control strategy against an enlarged state space system. Finally, the response amplification factor is given by the combination of the obtained statistical response values and the extreme value theory. Analytical results are compared with numerical simulations, and both show a good agreement. As a result, it seems that the validity of the proposed technique is confirmed.

Structural Response under Blast Loads - Simplified Numerical Analysis

2015 ◽  
Vol 782 ◽  
pp. 13-26
Author(s):  
Hong Hao ◽  
Jun Li
Keyword(s):  
Numerical Simulation ◽  
Experimental Study ◽  
Safety Concern ◽  
Structural Response ◽  
Experimental Tests ◽  
Material Model ◽  
Element Model ◽  
Structural Dynamic ◽  
Inelastic Material ◽  
Blast Loadings

Efficiently and accurately predicting structural dynamic response and damage to external blast loading is a big challenge to both structural engineers and researchers. Theoretical investigation on this problem is complex as it involves non-linear inelastic material properties, effect of time varying strain rates, uncertainties of blast load calculations and the time-dependent structural deformations. Experimental investigation can provide valuable data for locating the damage and establishing the damage criteria. The damage curves generated from the extensive experimental study can provide quick assessment of the structural status. However, such blast experiments always involve safety concern and can be beyond the affordability. Besides this, the correlation of the experimental data with predictive method is difficult since it requires a large number of tests to generate damage curves. Compared with the theoretical and experimental study, numerical simulation does not involve any safety concern and is cost-effective. With verified material model and element model, numerical simulation could be powerful supplement to the experimental tests. However, numerical simulation of structural responses under blast and impact loading could be time and resource consuming. Even with modern computer technology and computational mechanics method, detailed modelling and numerical simulation of responses of structures subjected to blast loadings are still often prohibitive. To address this issue, in the present study, an efficient numerical method is proposed to reliably calculate structural response and damage to blast loadings.

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