Nonlinear Structural Analysis for Seismic Design
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Using Opensees for Analyzing a 9- Story Steel Building Under Post- Earthquake Fires
Tenth U.S. National Conference on Earthquake Engineering Frontiers of Earthquake Engineering July 21-25, 2014 10NCEE Anchorage, Alaska USING OPENSEES FOR ANALYZING A 9- STORY STEEL BUILDING UNDER POST- EARTHQUAKE FIRES N. Elhami Khorasani1 and M. E. M. Garlock2 ABSTRACT Post-earthquake fires are major hazards with possible intense consequences. Civil engineering design is moving towards the concept of resilient cities, which requires buildings with structural systems to perform adequately after extreme hazards and ensure human safety. Current codes and standards in fire engineering are mainly based on design at the component level and deterministic approaches, where uncertainties in variables are not directly incorporated in the design process. Reliability-based approaches offer better means of evaluating resilience in the face of extreme hazards. But to measure resilience in an earthquake-fire multi-hazard scenario, uncertainties in the system must be captured, and nonlinear analyses must seamlessly transfer from seismic to fire analysis. This paper discusses the successes and challenges of this seamless analysis using the open source software OpenSees. A 9-story steel building with moment resisting frames is subject to fire following earthquake while being modeled in OpenSees. With the newly added fire module in OpenSees, the software has the capacity to perform structural analysis for both seismic and thermal loads. This way, system-level analysis is performed in one software and interaction of members with each other, under both seismic and fire events, is then considered together. The current constitutive material model for steel at elevated temperature does not properly capture behavior in fire following earthquake scenario. -
3 Concepts of Stress Analysis
FEA Concepts: SW Simulation Overview J.E. Akin 3 Concepts of Stress Analysis 3.1 Introduction Here the concepts of stress analysis will be stated in a finite element context. That means that the primary unknown will be the (generalized) displacements. All other items of interest will mainly depend on the gradient of the displacements and therefore will be less accurate than the displacements. Stress analysis covers several common special cases to be mentioned later. Here only two formulations will be considered initially. They are the solid continuum form and the shell form. Both are offered in SW Simulation. They differ in that the continuum form utilizes only displacement vectors, while the shell form utilizes displacement vectors and infinitesimal rotation vectors at the element nodes. As illustrated in Figure 3‐1, the solid elements have three translational degrees of freedom (DOF) as nodal unknowns, for a total of 12 or 30 DOF. The shell elements have three translational degrees of freedom as well as three rotational degrees of freedom, for a total of 18 or 36 DOF. The difference in DOF types means that moments or couples can only be applied directly to shell models. Solid elements require that couples be indirectly applied by specifying a pair of equivalent pressure distributions, or an equivalent pair of equal and opposite forces at two nodes on the body. Shell node Solid node Figure 3‐1 Nodal degrees of freedom for frames and shells; solids and trusses Stress transfer takes place within, and on, the boundaries of a solid body. The displacement vector, u, at any point in the continuum body has the units of meters [m], and its components are the primary unknowns. -
Structural Analysis
Module 1 Energy Methods in Structural Analysis Version 2 CE IIT, Kharagpur Lesson 1 General Introduction Version 2 CE IIT, Kharagpur Instructional Objectives After reading this chapter the student will be able to 1. Differentiate between various structural forms such as beams, plane truss, space truss, plane frame, space frame, arches, cables, plates and shells. 2. State and use conditions of static equilibrium. 3. Calculate the degree of static and kinematic indeterminacy of a given structure such as beams, truss and frames. 4. Differentiate between stable and unstable structure. 5. Define flexibility and stiffness coefficients. 6. Write force-displacement relations for simple structure. 1.1 Introduction Structural analysis and design is a very old art and is known to human beings since early civilizations. The Pyramids constructed by Egyptians around 2000 B.C. stands today as the testimony to the skills of master builders of that civilization. Many early civilizations produced great builders, skilled craftsmen who constructed magnificent buildings such as the Parthenon at Athens (2500 years old), the great Stupa at Sanchi (2000 years old), Taj Mahal (350 years old), Eiffel Tower (120 years old) and many more buildings around the world. These monuments tell us about the great feats accomplished by these craftsmen in analysis, design and construction of large structures. Today we see around us countless houses, bridges, fly-overs, high-rise buildings and spacious shopping malls. Planning, analysis and construction of these buildings is a science by itself. The main purpose of any structure is to support the loads coming on it by properly transferring them to the foundation. -
SEISMIC DESIGN RESPONSE by an ALTERNATIVE SRSS RULE By
SEISMIC DESIGN RESPONSE BY AN ALTERNATIVE SRSS RULE by Mahendra Pw Singh and K. B. Mehta A Technical Report of the Research Supported by The National Science Foundation Under Grant No. PFR-8023978 Department of Engineering Science &Mechanics Virginia Polytechnic Institute &State University Blacksburg, VA 24061 March 1983 BIBLIOGRAPHIC DATA 11. Report No. ' SHEET VPI-E-83~12 4. Title and Subtitle 5. Report Da'te'" v ~iJ 0 SEISMIC DESIGN RESPONSE BY AN ALTERNATIVE SRSS RULE March 1983 6. 7. Author(s) 8. Performing Organization Rept. M. P. Singh and K. B. Mehta No. 9. Performinl! Organization Name and Address 10. Project/Task/Work Unit No. Dept. of Engineering Science &Mechanics Virginia Polytechnic Institute &State Univ. 11. Contract/Grant No. 225 Norri s Hall Blacksburg, VA 24061 PFR-8023978 12. Sponsoring Organization Name and Address 13. Type of Report & Period Covered National Science Foundation Washington, D.C. 20550 14. 15. Supplementary r-.;otes 16. Abstracts The Square Root of the Sum of the Squares (SRSS) procedures are often used to obtain seismic design response. The design inputs for such procedures are usually defined in terms of psuedo velocity or acceleration response spectra. Erroneous results have been obtained with these existing SRSS procedures, especially in the calculation of response where high frequency effects dominate. Here an alternative SRSS pro cedure is developed using the so-called mode acceleration approach of structural dynamics. The design input in this procedure is defined in terms of, though, pri marily relative acceleration spectra but also relative velocity spectra. The rela tive spectra can be related to psuedo spectra. -
Module Code CE7S02 Module Name Advanced Structural Analysis ECTS
Module Code CE7S02 Module Name Advanced Structural Analysis 1 ECTS Weighting 5 ECTS Semester taught Semester 1 Module Coordinator/s Module Coordinator: Assoc. Prof. Dermot O’Dwyer ([email protected]) Module Learning Outcomes with reference On successful completion of this module, students should be able to: to the Graduate Attributes and how they are developed in discipline LO1. Identify the appropriate differential equations and boundary conditions for analysing a range of structural analysis and solid mechanics problems. LO2. Implement the finite difference method to solve a range of continuum problems. LO3. Implement a basic beam-element finite element analysis. LO4. Implement a basic variational-based finite element analysis. LO5. Implement time-stepping algorithms and modal analysis algorithms to analyse structural dynamics problems. L06. Detail the assumptions and limitations underlying their analyses and quantify the errors/check for convergence. Graduate Attributes: levels of attainment To act responsibly - ho ose an item. To think independently - hoo se an item. To develop continuously - hoo se an it em. To communicate effectively - hoo se an item. Module Content The Advanced Structural Analysis Module can be taken as a Level 9 course in a single year for 5 credits or as a Level 10 courses over two years for the total of 10 credits. The first year of the module is common to all students, in the second year Level 10 students who have completed the first year of the module will lead the work groups. The course will run throughout the first semester. The aim of the course is to develop the ability of postgraduate Engineering students to develop and implement non-trivial analysis and modelling algorithms. -
Seismic Analysis of Industrial Structure Using Bracings and Dampers
International Journal of Recent Technology and Engineering (IJRTE) ISSN: 2277-3878, Volume-7, Issue-6C2, April 2019 Seismic Analysis of Industrial Structure Using Bracings and Dampers B. Ravali, P. Poluraju Abstract: Resistance of structures against earthquake plays an shear, lateral displacement). Dampers are more economical extensive role in construction industry. A structure should consist than bracings [1]. Aspect ratio plays a vital role in of strength, stability and ductility to accommodate both performance of structure. As aspect ratio increases, there horizontal and vertical loadings. Horizontal loading leads to the will be reduction in base shear carrying capacity and roof production of sway and further results in vibration and storey drift. Strength and stiffness are two major keys for any structure displacement of steel frame with aspect ratio 1 [2]. Arranged to resist gravity and lateral loads. Provision of bracings or bracings to the structure should be of buckling resistant. dampers to any structure contributes to lateral stability. After Buckling restrained frames with special concentric bracings assigning dampers or bracings, the general system changes to have effective performance than moment resisting and lateral load resisting system (LLRS). However, this involves high conventional frames [3]. economy, it is only suitable for high rise, important buildings Based on the arrangement of bracing, there are concentric which are suspected to be affected by lateral load and structures damaged by lateral load. The present work involves in proposing and eccentric bracings. Concentric bracing system is the suitability of type of damper or bracing for controlling the effective in reducing storey displacement, storey drift, and seismic activity on industrial structures in respective seismic base shear than without bracing system [4]. -
“Linear Buckling” Analysis Branch
Appendix A Eigenvalue Buckling Analysis 16.0 Release Introduction to ANSYS Mechanical 1 © 2015 ANSYS, Inc. February 27, 2015 Chapter Overview In this Appendix, performing an eigenvalue buckling analysis in Mechanical will be covered. Mechanical enables you to link the Eigenvalue Buckling analysis to a nonlinear Static Structural analysis that can include all types of nonlinearities. This will not be covered in this section. We will focused on Linear buckling. Contents: A. Background On Buckling B. Buckling Analysis Procedure C. Workshop AppA-1 2 © 2015 ANSYS, Inc. February 27, 2015 A. Background on Buckling Many structures require an evaluation of their structural stability. Thin columns, compression members, and vacuum tanks are all examples of structures where stability considerations are important. At the onset of instability (buckling) a structure will have a very large change in displacement {x} under essentially no change in the load (beyond a small load perturbation). F F Stable Unstable 3 © 2015 ANSYS, Inc. February 27, 2015 … Background on Buckling Eigenvalue or linear buckling analysis predicts the theoretical buckling strength of an ideal linear elastic structure. This method corresponds to the textbook approach of linear elastic buckling analysis. • The eigenvalue buckling solution of a Euler column will match the classical Euler solution. Imperfections and nonlinear behaviors prevent most real world structures from achieving their theoretical elastic buckling strength. Linear buckling generally yields unconservative results -
Structural Analysis (Statics & Mechanics)
APPLIED ARCHITECTURAL STRUCTURES: STRUCTURAL ANALYSIS AND SYSTEMS Structural Requirements ARCH 631 • serviceability DR. ANNE NICHOLS FALL 2013 – strength – deflections lecture two • efficiency – economy of materials • construction structural analysis • cost (statics & mechanics) • other www.pbs.org/wgbh/buildingbig/ Analysis 1 Applied Architectural Structures F2009abn Analysis 2 Architectural Structures III F2009abn Lecture 2 ARCH 631 Lecture 2 ARCH 631 Structure Requirements Structure Requirements • strength & • stability & equilibrium stiffness – safety – stability of – stresses components not greater – minimum than deflection and strength vibration – adequate – adequate foundation foundation Analysis 3 Architectural Structures III F2008abn Analysis 4 Architectural Structures III F2008abn Lecture 2 ARCH 631 Lecture 2 ARCH 631 1 Structure Requirements Relation to Architecture • economy and “The geometry and arrangement of the construction load-bearing members, the use of – minimum material materials, and the crafting of joints all represent opportunities for buildings to – standard sized express themselves. The best members buildings are not designed by – simple connections architects who after resolving the and details formal and spatial issues, simply ask – maintenance the structural engineer to make sure it – fabrication/ erection doesn’t fall down.” - Onouy & Kane Analysis 5 Architectural Structures III F2008abn Analysis 6 Architectural Structures III F2008abn Lecture 2 ARCH 631 Lecture 2 ARCH 631 Structural Loads - STATIC Structural -
Simulating Sliding Wear with Finite Element Method
Tribology International 32 (1999) 71–81 www.elsevier.com/locate/triboint Simulating sliding wear with finite element method Priit Po˜dra a,*,So¨ren Andersson b a Department of Machine Science, Tallinn Technical University, TTU, Ehitajate tee 5, 19086 Tallinn, Estonia b Machine Elements, Department of Machine Design, Royal Institute of Technology, KTH, S-100 44 Stockholm, Sweden Received 5 September 1997; received in revised form 18 January 1999; accepted 25 March 1999 Abstract Wear of components is often a critical factor influencing the product service life. Wear prediction is therefore an important part of engineering. The wear simulation approach with commercial finite element (FE) software ANSYS is presented in this paper. A modelling and simulation procedure is proposed and used with the linear wear law and the Euler integration scheme. Good care, however, must be taken to assure model validity and numerical solution convergence. A spherical pin-on-disc unlubricated steel contact was analysed both experimentally and with FEM, and the Lim and Ashby wear map was used to identify the wear mech- anism. It was shown that the FEA wear simulation results of a given geometry and loading can be treated on the basis of wear coefficientϪsliding distance change equivalence. The finite element software ANSYS is well suited for the solving of contact problems as well as the wear simulation. The actual scatter of the wear coefficient being within the limits of ±40–60% led to considerable deviation of wear simulation results. These results must therefore be evaluated on a relative scale to compare different design options. 1999 Elsevier Science Ltd. -
Structural Analysis and Design, University of Houston-Downtown
Session 3615 STRUCTURAL ANALYSIS DESIGN: A DISTINCTIVE ENGINEERING TECHNOLOGY PROGRAM Alberto Gomez-Rivas, and George Pincus Professors of Structural Analysis and Design, University of Houston-Downtown Abstract Graduates of the Structural Analysis and Design Engineering Technology program, University of Houston-Downtown, are successful in reaching responsible positions in industry and government. The strong emphasis on computer technology provides an advantage to graduates of the program because they are highly productive. The Structural Analysis Design (SAD) Engineering Technology program, University of Houston-Downtown, is focused on the design of bridges, buildings, towers, offshore platforms and other structures. It is not traditional civil engineering but includes all aspects of structural design, including soil mechanics, foundation design, and construction surveying by GIS-GPS. Students take an intensive course in applications of computers, a visualization course, and two courses in computer-aided design, followed by a course in 3-D modeling including the most common CADD software packages: MicroStation, AutoCAD, and 3D Studio. Structural Analysis deals with application of finite element theory to beams and frames. A second course, Finite Element Analysis, utilizes ANSYS and ROBOT. Since the program focuses on structural analysis and design, students are exposed to several techniques and practices that are taught in schools of civil engineering at the graduate level. Examples include instruction on finite element analysis and use of structural software packages used in industry. Structural Analysis Design – Program Description This program covers the design of structures, bridges, buildings, towers, and offshore platforms and in general what is called civil structures. However, the program is not civil engineering because that field is considered broader. -
Mechanical Properties and Structural Analysis of Coatings and Engineered Surfaces
coatings Editorial Mechanical Properties and Structural Analysis of Coatings and Engineered Surfaces Mattia Merlin * and Annalisa Fortini * Department of Engineering (DE), University of Ferrara, Via Saragat 1, 44122 Ferrara, Italy * Correspondence: [email protected] (M.M.); [email protected] (A.F.) 1. Introduction and Scope The performance improvement in engineering components during operation is a challenging issue and surface engineering methods have been attracting considerable interest in both research and industrial fields. Surface characteristics have a pivotal role in enhancing the life of products since they control the mechanical, electrical, thermal, and electronic properties. Nevertheless, the surface and near-surface properties are cru- cial in failure mechanisms since the loss of performance and failures mostly begin from the surface. In this framework, this Special Issue includes original research papers and a review that covers the latest development in methods for enhancing the life and functionality of engineering components by tuning the physical, chemical, mechanical, and metallur- gical properties of their surfaces. Attention is focused on processing and characterizing methods capable of supporting industrial applications and products to both tackle surface degradation and improve the performance and reliability of components. 2. Contributions Citation: Merlin, M.; Fortini, A. The book collects manuscripts from cutting-edge academic researchers and consists of Mechanical Properties and Structural one review paper regarding the characteristics and mechanical properties of high-velocity Analysis of Coatings and Engineered oxy-fuel (HVOF) cermet coatings [1] and four research papers focused on the effects of Surfaces. Coatings 2021, 11, 875. different treatments and coatings on the mechanical and microstructural properties of the https://doi.org/10.3390/coatings investigated material [2–4]. -
Seismic Retrofitting Manual for Highway Structures: Part 1 – Bridges
Seismic Retrofitting Manual for Highway Structures: Part 1 – Bridges PUBLICATION NO. FHWA-HRT-06-032 JANUARY 2006 Research, Development, and Technology Turner-Fairbank Highway Research Center 6300 Georgetown Pike McLean, VA 22101-2296 Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No. FHWA-HRT-06-032 N/A N/A 4. Title and Subtitle 5. Report Date SEISMIC RETROFITTING MANUAL FOR HIGHWAY January 2006 STRUCTURES: PART 1 – BRIDGES 6. Performing Organization Code N/A 7. Author(s) 8. Performing Organization Report No. Ian Buckle, Ian Friedland, John Mander, Geoffrey Martin, Richard Nutt and Maurice Power 9. Performing Organization Name and Address 10. Work Unit No. Multidisciplinary Center for Earthquake Engineering Research N/A University at Buffalo, State University of New York 11. Contract or Grant No. Red Jacket Quadrangle DTFH61-92-C-00106 Buffalo, NY 14261 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered Office of Infrastructure Research and Development Final Report Federal Highway Administration 14. Sponsoring Agency Code 6300 Georgetown Pike McLean, VA 22101-2296 15. Supplementary Notes: Contracting Officer’s Technical Representatives: James Cooper, P.E., HRDI-03, Wen-huei (Phillip) Yen, Ph.D., P.E., HRDI-07, John D. O’Fallon, P.E., HRDI-07 16. Abstract This report is the first of a two-part publication entitled: Seismic Retrofitting Manual for Highway Structures: Part 1: Bridges Part 2: Retaining Structures, Slopes, Tunnels, Culverts and Roadways. Part 1 of this manual is based on previous Federal Highway Administration (FHWA) publications on this subject including Seismic Retrofitting Manual for Highway Bridges, published in 1995 as report FHWA-RD-94-052.