Program Plan for the Development of Collapse Assessment and Mitigation Strategies for Existing Reinforced Concrete Buildings
Size: 5.9 MB | Format:PDF | Quality:Unspecified | Publisher: NEHRP Consultants Joint Venture A partnership of the Applied Technology Council and the Consortium of Universities for Research in Earthquake Engineering | Year: 2010 | pages: 100
Reinforced concrete buildings designed and constructed prior to the introduction of seismic design provisions for ductile response (commonly referred to as nonductile concrete buildings) represent one of the largest seismic safety concerns in the United States and the world. The need for improvement in collapse assessment technology for existing nonductile concrete buildings has been recognized as a high-priority
because: (1) such buildings represent a significant percentage of the vulnerable building stock across the United States; (2) failure of such buildings can involve total collapse, substantial loss of life, and significant economic loss; (3) at present, the
ability to predict collapse thresholds for different types of older reinforced concrete buildings is limited; (4) recent research has focused on older West Coast concrete buildings; and, (5) full advantage has not yet been taken of past research products
(ATC, 2003). The National Science Foundation awarded a George E. Brown, Jr. Network for Earthquake Engineering Simulation (NEES) Grand Challenge project to the Pacific
Earthquake Engineering Research (PEER) Center to develop comprehensive strategies for identifying seismically hazardous older concrete buildings, enable prediction of the collapse of such buildings, and to develop and promote costeffective
hazard mitigation strategies for them. Products from this important research effort are expected to soon be available, creating an opportunity for transferring past and present research results into design practice. Recognizing this opportunity, the National Institute of Standards and Technology
(NIST) has initiated a multi-phase project with the primary objective being the development of nationally accepted guidelines for assessing and mitigating the risk of
collapse in older nonductile concrete buildings. This report summarizes efforts to define the scope and content of recommended guidance documents, the necessary
analytical studies, and estimated schedule and budget needed for their development. Based on limitations in current seismic evaluation and rehabilitation practice in the United States (Chapter 2), a review of information currently being developed in the NEES Grand Challenge project (Chapter 3), and an understanding of common deficiencies found in nonductile concrete buildings (Chapter 4), the following critical needs for addressing the collapse risk associated with older concrete construction have been identified:
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Guideline for Post-Earthquake Damage Evaluation And Rehabilitation of RC Buildings in Japan
Author: *Yoshiaki NAKANO1 Institute of Industrial Science, The University of Tokyo, Tokyo, Japan Masaki MAEDA2 Department of Architecture and Building Science, Tohoku University, Sendai, Japan Hiroshi KURAMOTO;nternational Cooperation Center of Engineering Education Development, Toyohashi University of Technology, Toyohashi, Japan Masaya MURAKAMI4 Waseda University, Tokyo, Japan | Size: 938 KB | Format:PDF | Quality:Unspecified | Publisher: Proceedings of The 2nd Korea-Japan Workshop on New Direction for Enhancement of Structural Performance - Formulation, Verification, and Its Application - held at Suzukake Hall, Tokyo Institute of Technology, Yokohama, Japan, August 18-19, 20 | Year: 2003 | pages: 17
Presented in this paper is the basic concept of the Guideline for Post-earthquake Damage Evaluation and Rehabilitation of RC buildings in Japan. This paper discusses the damagerating procedure based on the residual seismic capacity index that is consistent with the Japanese Standard for Seismic Evaluation of Existing RC Buildings, their validity through calibration with observed damage due to the 1995 Hyogoken-Nambu (Kobe) earthquake, the decision policy and criteria to determine necessary actions through comparison between experienced earthquake intensity and damage rate.
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Geotechnical aspects of sabkha at Jubail, Saudi Arabia
Author: A. N. James, A. L. Little | Size: 200 KB | Format:PDF | Quality:Unspecified | Publisher: Quarterly Journal of Engineering Geology and Hydrogeology - Q J ENG GEOL HYDROGEOL 01/1994 | Year: 1994.027.P2.03 | pages: 27(2): 83-121
Article/eBook Full Name: Finite Element Analysis: Theory and Application with ANSYS
Author(s): Saeed Moaveni
Edition: (4th Edition)
Publish Date: 2014
ISBN: 0133840808
Related Links:
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Bentley GeoStructural Finite Element Analysis v17.00.33.00
Size: 256 mb MB
The GeoStructural Finite Element Analysis suite contains tools for performing Finite Element modeling for a range of geotechnical problems including excavation, slope stability, foundation beams, settlement, tunneling, and more.
Key Features
Leverage a database of material models to accurately represent soil or rock mass properties
Model ground water conditions by defining the ground water table (GWT) or the pore water pressure distribution
Construct problems in axisymmetric or plane strain space
Utilize time-saving input of project information using DXF file format and automatic mesh generator
Generate boundary conditions automatically or through individual specification
Specify analysis for stress distribution, stability, fluid flow, and tunnels
Specify regional design standards for concrete (e.g., ACI) and steel structures
Accurately model complex multi-stage construction projects
Analyze an unlimited number of anchor, geogrid, and geotextile elements
Analyze an unlimited number of surcharge loads
Analyze project for stability throughout construction sequence to identify safety concerns
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Advance Steel is a modeling package that accelerates the creation of general arrangement drawings, fabrication drawings, list of materials and NC files.
From the model, Advance Steel creates all fabrication drawings and offers a large selection of tools for automated detail creation, dimension, annotations, symbols and drag and drop printing layouts.
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Author: C. O. CIOFLAN, A. MÃRMUREANU, GH. MÃRMUREANU National Institute for Earth Physics, Romania Received January 19, 2009 | Size: 602 KB | Format:PDF | Quality:Unspecified | Year: 2009 | pages: 10
The seismic hazard of Romania has been the object of several studies based on probabilistic or deterministic methods (1). Details of the resulted hazard maps are still a controversial issue that leads to an innovative approach: a combined analysis of the available records and macroseismic information completed with numerical simulations since the strong motion records are rather scarce. The main purpose of this paper is to add new features regarding site effects evaluation and its role in seismic hazard analyses at regional and/or local scale. This study is focusing on nonlinear aspects of seismic ground motion and presents new results related to site effects induced by strong Vrancea intermediate events.
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A FIBER BEAM-COLUMN ELEMENT FOR SEISMIC RESPONSE ANALYSIS OF REINFORCED CONCRETE STRUCTURES
Author: Fabio F. Taucer Research Assistant Enrico Spacone Doctoral Student and Filip C. Filippou Associate Professor Department of Civil Engineering | Size: 2.6 MB | Format:PDF | Quality:Unspecified | Publisher: Report No. UCB/EERC-91/17 Earthquake Engineering Research Center College of Engineering University of California, Berkeley | Year: 1991 | pages: 140
This study proposes a reliable and computationally efficient beam-column finite element model for the analysis of reinforced concrete members under cyclic loading conditions that induce biaxial bending and axial force. The element is discretized into longitudinal steel and concrete fibers such that the section force-deformation relation is derived by integration of the stress-strain relation of the fibers. At present the nonlinear behavior of the element derives entirely from the nonlinear stress-strain relation of the steel and concrete fibers.
The proposed beam-column element is based on the assumption that deformations are small and that plane sections remain plane during the loading history. The formulation of the
element is based on the mixed method: the description of the force distribution within the element by interpolation functions that satisfy equilibrium is the starting point of the
formulation. Based on the concepts of the mixed method it is shown that the selection of flexibility dependent shape functions for the deformation field of the element results in
considerable simplification of the final equations. With this particular selection of deformation shape functions the general mixed method reduces to the special case of the
flexibility method. The mixed method formalism is, nonetheless, very useful in understanding the proposed procedure for the element state determination. A special flexibility based state determination algorithm is proposed for the computation of the stiffness matrix and resisting forces of the beam-column element. The proposed nonlinear algorithm for the element state determination is general and can be used with any nonlinear section force-deformation relation. The procedure involves an element iteration scheme that converges to a state that satisfies the material constitutive relations within the specified tolerance. During the element iterations the equilibrium and the compatibility of the element are always satisfied in a strict sense by the assumed force and deformation interpolation functions. The proposed method proved to be computationally stable and robust, while being able to describe the complex hysteretic behavior of reinforced concrete members, such as strain hardening, "pinching" and softening under cyclic nodal and element loads.
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EVALUATION OF SEISMIC DEFORMATION DEMANDS USING NON- LINEAR PROCEDURES IN MULTISTORY STEEL AND CONCRETE MOMENT FRAMES
Author: Sashi K. Kunnath and Erol Kalkan Department of Civil and Environmental Engineering University of California at Davis | Size: 271 KB | Format:PDF | Quality:Unspecified | Publisher: SET Journal of Earthquake Technology, Paper No. 445, Vol. 41, No. 1, March 2004, pp. 159-181 | Year: 2004 | pages: 23
A key component of performance-based seismic evaluation is the estimation of seismic demands. In FEMA-356 (FEMA, 2000b), which is now recognized as the model for future performance-based seismic codes in the US, these demands are evaluated at the component level in terms of ductility demands or plastic rotations when using non-linear procedures. Since acceptance criteria for various performance objectives are assessed in terms of local component demands, it is essential that a rational basis be established for determining such demands. Of the non-linear procedures advocated in FEMA-356,
pushover procedures are becoming increasingly popular in engineering practice. However, there are still several unresolved issues in identifying appropriate lateral load patterns to be used in a pushover procedure. This paper investigates the correlation between demand estimates for various lateral load patterns used in non-linear static analysis. It also examines the rationale for using component demands over story and system demands. Results reported in the paper are based on a comprehensive set of pushover and non-linear time-history analyses carried out on eight- and twelve-story steel and concrete moment frames. Findings from this study point to inconsistencies in the demands predicted by different
lateral load patterns when using pushover analysis and also highlight some issues in the current understanding of local demand estimates using FEMA-based procedures.
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Nonlinear Soil-Site Effects in Probabilistic Seismic-Hazard Analysis
Author: Paolo Bazzurro and C. Allin Cornell | Size: 250 KB | Format:PDF | Quality:Unspecified | Publisher: Bulletin of the Seismological Society of America, Vol. 94, No. 6, pp. 2110–2123, December 2004 | Year: 2004 | pages: 14
This study presents effective probabilistic procedures for evaluating ground-motion hazard at the free-field surface of a nonlinear soil deposit located at a specific site. Ground motion at the surface, or at any depth of interest within the
soil formation (e.g., at the structure foundation level), is defined here in terms either of a suite of oscillator-frequency-dependent hazard curves for spectral acceleration,
, or of one or more spectral acceleration uniform-hazard spectra, each associated with a given mean return period. It is presumed that similar information is available
for the rock-outcrop input. The effects of uncertainty in soil properties are directly included.
This methodology incorporates the amplification of the local soil deposit into the framework of probabilistic seismic hazard analysis (PSHA). The soil amplification is characterized by a frequency-dependent amplification function, AF( f ), where f is a generic oscillator frequency. AF( f ) is defined as the ratio of to the spectral acceleration at the bedrock level, . The estimates of the statistics of the ampli-fication function are obtained by a limited number of nonlinear dynamic analyses of the soil column with uncertain properties, as discussed in a companion article in this issue (Bazzurro and Cornell, 2004). The hazard at the soil surface (or at any desired
depth) is computed by convolving the site-specific hazard curve at the bedrock level
with the probability distribution of the amplification function.
The approach presented here provides more precise surface ground-motion-hazard estimates than those found by means of standard attenuation laws for generic soil conditions. The use of generic ground-motion predictive equations may in fact lead
to inaccurate results especially for soft-clay-soil sites, where considerable amplification is expected at long periods, and for saturated sandy sites, where high-intensity
ground shaking may cause loss of shear strength owing to liquefaction or to cyclic mobility. Both such cases are considered in this article. In addition to the proposed procedure, two alternative, easier-to-implement but approximate techniques for obtaining hazard estimates at the soil surface are also briefly discussed. One is based on running a conventional PSHA with a rockattenuation relationship modified to include the soil response, whereas the other consists of using a simple, analytical, closed-form solution that appropriately modifies the hazard results at the rock level.
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