This document provides an overview of a performance-based seismic analysis conducted on a reinforced concrete building. It describes the modeling approach used, which involved defining plastic hinges in beams and columns to capture nonlinear behavior. Both pushover analysis and time history analysis were performed. The pushover analysis generated a capacity curve and identified performance points for two performance levels under the design basis earthquake and maximum considered earthquake. Time history analysis involved applying 7 sets of ground motion records scaled to target displacements. Results from the nonlinear analyses were used to evaluate response parameters like base shear, roof displacement, and interstory drift ratios to assess the building's performance.
The Pushover Analysis from basics - Rahul LeslieRahul Leslie
Pushover analysis has been in the academic-research arena for quite long. The papers published in this field usually deals mostly with proposed improvements to the approach, expecting the reader to know the basics of the topic... while the common structural design practitioner, not knowing the basics, is left out from participating in those discussions. Here I’m making an effort to bridge that gap by explaining the Pushover analysis, from basics, in its simplicity.
A write up on this topic can be found at http://rahulleslie.blogspot.in/p/blog-page.html, though does not cover the full spectrum presented in this slide show.
Pushover is a static-nonlinear analysis method where a structure is subjected to gravity loading and a monotonic displacement-controlled lateral load pattern which continuously increases through elastic and inelastic behavior until an ultimate condition is reached. Lateral load may represent the range of base shear induced by earthquake loading, and its configuration may be proportional to the distribution of mass along building height, mode shapes, or another practical means.
The static pushover analysis is becoming a popular tool for seismic performance evaluation of existing and new structures. The expectation is that the pushover analysis will provide adequate information on seismic demands imposed by the design ground motion on the structural system and its components. The purpose of the paper is to summarize the basic concepts on which the pushover analysis can be based, assess the accuracy of pushover predictions, identify conditions under which the pushover will provide adequate information and, perhaps more importantly, identify cases in which the pushover predictions will be inadequate or even misleading.
The Pushover Analysis from basics - Rahul LeslieRahul Leslie
Pushover analysis has been in the academic-research arena for quite long. The papers published in this field usually deals mostly with proposed improvements to the approach, expecting the reader to know the basics of the topic... while the common structural design practitioner, not knowing the basics, is left out from participating in those discussions. Here I’m making an effort to bridge that gap by explaining the Pushover analysis, from basics, in its simplicity.
A write up on this topic can be found at http://rahulleslie.blogspot.in/p/blog-page.html, though does not cover the full spectrum presented in this slide show.
Pushover is a static-nonlinear analysis method where a structure is subjected to gravity loading and a monotonic displacement-controlled lateral load pattern which continuously increases through elastic and inelastic behavior until an ultimate condition is reached. Lateral load may represent the range of base shear induced by earthquake loading, and its configuration may be proportional to the distribution of mass along building height, mode shapes, or another practical means.
The static pushover analysis is becoming a popular tool for seismic performance evaluation of existing and new structures. The expectation is that the pushover analysis will provide adequate information on seismic demands imposed by the design ground motion on the structural system and its components. The purpose of the paper is to summarize the basic concepts on which the pushover analysis can be based, assess the accuracy of pushover predictions, identify conditions under which the pushover will provide adequate information and, perhaps more importantly, identify cases in which the pushover predictions will be inadequate or even misleading.
Part-II: Seismic Analysis/Design of Multi-storied RC Buildings using STAAD.Pr...Rahul Leslie
For novice, please continue from "Modelling Building Frame with STAAD.Pro & ETABS" (http://www.slideshare.net/rahulleslie/modelling-building-frame-with-staadpro-etabs-rahul-leslie).
This is a presentation covering almost all aspects of Seismic analysis & design of Multi-storied RC Structures using the Indian code IS:1893-2016 (New edition), with references to IS:13920-2015 (Code for ductile detailing) & IS:16700-2017 (code for design of tall buildings) where relevant; following for each aspect of the code, (1) The clause/formula (2) It's explanation/theory (3) How it is/can be implemented in the software packages of (i) STAAD.Pro and (ii) ETABS
This is the latest edition of the earlier slides based on IS:1893-2002 which this one supersedes. This is Part-II of a two part series.
Dhruvin Goyani
M.Tech Structural
This PPT is For All the Civil Engineering Students and Specially for M.tech Students Who Trying To Learn Something New on Earthquake and its Resisting Methods and also For Seismic Analysis
Quality Control in Concrete and Durability factors : An overviewbybyRAJESH PRASAD,IRSE, CPM/M, RVNL. KOLKATA. An interesting and informative presentation....
The dynamic behavior of structures is an important topic in many fields. Aerospace engineers must understand dynamics to simulate space vehicles and airplanes, while mechanical engineers must understand dynamics to isolate or control the vibration of machinery. In civil engineering, an understanding of structural dynamics is important in the design and retrofit of structures to withstand severe dynamic loading from earthquakes, hurricanes, and strong winds, or to identify the occurrence and location of damage within an existing structure.
Design of Reinforced Concrete Structure (IS 456:2000)MachenLink
This is the 1st Lecture Series on Design Reinforced Cement Concrete (IS 456 -2000).
In this video, you will learn about the objective of structural designing and then basic properties of concrete and steel.
Concrete properties like...
1. Grade of Concrete
2. Modulus of Elasticity
3. Characteristic Strength
4. Tensile Strength
5. Creep and Shrinkage
6. Durability
Reinforced Steel Properties....
1. Grade and types of steel
2. Yield Strength of Mild Steel and HYSD Bars
Kittelson's Brian Ray and special guest Dr. John M. Mason, PhD presented this topic at a workshop on 4/15/10. It focused on how industry trends in performance based design can support practical design-based project solutions. Brian and John provided a summary of current and emerging tools that can aid professionals in evaluating, screening, and selecting project alternative concepts. For more information contact Brian 800-878-5230.
Part-II: Seismic Analysis/Design of Multi-storied RC Buildings using STAAD.Pr...Rahul Leslie
For novice, please continue from "Modelling Building Frame with STAAD.Pro & ETABS" (http://www.slideshare.net/rahulleslie/modelling-building-frame-with-staadpro-etabs-rahul-leslie).
This is a presentation covering almost all aspects of Seismic analysis & design of Multi-storied RC Structures using the Indian code IS:1893-2016 (New edition), with references to IS:13920-2015 (Code for ductile detailing) & IS:16700-2017 (code for design of tall buildings) where relevant; following for each aspect of the code, (1) The clause/formula (2) It's explanation/theory (3) How it is/can be implemented in the software packages of (i) STAAD.Pro and (ii) ETABS
This is the latest edition of the earlier slides based on IS:1893-2002 which this one supersedes. This is Part-II of a two part series.
Dhruvin Goyani
M.Tech Structural
This PPT is For All the Civil Engineering Students and Specially for M.tech Students Who Trying To Learn Something New on Earthquake and its Resisting Methods and also For Seismic Analysis
Quality Control in Concrete and Durability factors : An overviewbybyRAJESH PRASAD,IRSE, CPM/M, RVNL. KOLKATA. An interesting and informative presentation....
The dynamic behavior of structures is an important topic in many fields. Aerospace engineers must understand dynamics to simulate space vehicles and airplanes, while mechanical engineers must understand dynamics to isolate or control the vibration of machinery. In civil engineering, an understanding of structural dynamics is important in the design and retrofit of structures to withstand severe dynamic loading from earthquakes, hurricanes, and strong winds, or to identify the occurrence and location of damage within an existing structure.
Design of Reinforced Concrete Structure (IS 456:2000)MachenLink
This is the 1st Lecture Series on Design Reinforced Cement Concrete (IS 456 -2000).
In this video, you will learn about the objective of structural designing and then basic properties of concrete and steel.
Concrete properties like...
1. Grade of Concrete
2. Modulus of Elasticity
3. Characteristic Strength
4. Tensile Strength
5. Creep and Shrinkage
6. Durability
Reinforced Steel Properties....
1. Grade and types of steel
2. Yield Strength of Mild Steel and HYSD Bars
Kittelson's Brian Ray and special guest Dr. John M. Mason, PhD presented this topic at a workshop on 4/15/10. It focused on how industry trends in performance based design can support practical design-based project solutions. Brian and John provided a summary of current and emerging tools that can aid professionals in evaluating, screening, and selecting project alternative concepts. For more information contact Brian 800-878-5230.
Modelling Building Frame with STAAD.Pro & ETABS - Rahul LeslieRahul Leslie
A basic tutorial to learn the concepts of modelling RC building in an Analysis/Design package -- STAAD.Pro & ETABS are in focus here, but concepts are applicable for any package. Good for novice in structural designing, and also B.Tech / BE / BSc (Engg) / BS students wising to do 'design of multi-storied RC building' as their final year project.
A Picture Album of the Finite Element MethodRahul Leslie
FEM is still taught in some parts of the world as a dry subject: the faculty, after dealing with the Riley-Ritz, Galerkin’s and other numerical approaches, draws a small rectangle on the board, introduces it to the students as ‘this is an element’ and then quickly rushes into the derivations: polynomial representation, shape functions, strain energy equations, Gaussian quadrature, etc.
In those universities/colleges, the students might given a hands of experience in ANSYS or the like, for name sake, demonstrating the ‘plate with a hole’ sample (or the like, and may be a cantilever beam too), leaving the students unaware of the greater wider world of FEM (of course, unless the student is a web-miner, digging up and reading all those extra stuff, downloading some FE software himself, installing, and trying it out)
Here an effort is being made to present a “A Picture Album of the Finite Element Method”, so to say, which any FEM tutor can present to his class and introduce the range of applications that makes FEM such a wonderful tool, explaining each at his own capacity (which I’m confident of), before going into the dull ordeal of the underlying derivations. Such an introduction is sure to make the dull latter phase interesting to the students.
I’m also of the belief that hands of experience with an FEM package dealing with a range of problems, intending to give the student a deeper view into the versatility of FEM and the nearly unlimited things one can do with it makes it of interest enough, that I’m sure many of them will proclaim FEM to be ‘My hobby’ – at least some of the students.
Rahul Leslie
Jan ‘17
Book for Beginners, RCC Design by ETABSYousuf Dinar
Advancement of softwares is main cause behind comparatively quick and simple
design while avoiding complexity and time consuming manual procedure. However
mistake or mislead could be happened during designing the structures because of not
knowing the proper procedure depending on the situation. Design book based on
manual or hand design is sometimes time consuming and could not be good aids with
softwares as several steps are shorten during finite element modeling. This book may
work as a general learning hand book which bridges the software and the manual
design properly. The writers of this book used linear static analysis under BNBC and
ACI code to generate a six story residential building which could withstand wind load
of 210 kmph and seismic event of that region. The building is assumed to be designed
in Dhaka, Bangladesh under RAJUK rules to get legality of that concern organization.
For easy and explained understanding the book chapters are oriented in 2 parts. Part A
is concern about modeling and analysis which completed in only one chapter. Part B
is organized with 8 chapters. From chapter 1 to 7 the writers designed the model
building and explained with references how to consider during design so that
creativity of readers could not be threated. Chapter 8 is dedicated for estimation. As a
whole the book will help the readers to experience a building construction related all
facts and how to progress in design. Although the volume I is limited to linear static
analysis, upcoming volume will eventually consider dynamic facts to perform
dynamic analysis. Implemented equations are organized in the appendix section for
easy memorizing.
BNBC and other codes are improving and expending day by day, by covering new
and improved information as civil engineering is a vast field to continue the research.
Before designing something or taking decision judge the contemporary codes and
choose data, equations, factors and coefficient from the updated one.
Book for Beginners series is basic learning book of YDAS outlines. Here only
rectangular grid system modeling and a particular model is shown. Round shape grid
is avoided to keep the study simple. No advanced analysis is described and it is kept
simple for beginners. Only two way slab is elaborated with direct design method,
avoiding other procedures. In case of beam, only flexural and shear designs are made.
T- Beam, L- Beam or other shapes are not shown as rectangular beam was enough for
this study. Bi-axial column and foundation design is not shown. During column and
foundation design only pure axial load is considered. Use of interaction diagram is not
shown in manual design. Load centered isolated and combined footing designs are
shown, avoiding eccentric loading conditions. Pile and pile cap design, Mat
foundation design, strap footing design and sand pile concept are not included in this
Non linear static pushover analysis of irregular space frame structure with a...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Assessing Uncertainty of Pushover Analysis to Geometric ModelingIDES Editor
Pushover Analysis a popular tool for seismic
performance evaluation of existing and new structures and is
nonlinear Static procedure where in monotonically increasing
loads are applied to the structure till the structure is unable
to resist the further load .During the analysis, whatever the
strength of concrete and steel is adopted for analysis of
structure may not be the same when real structure is
constructed and the pushover analysis results are very sensitive
to material model adopted, geometric model adopted, location
of plastic hinges and in general to procedure followed by the
analyzer. In this paper attempt has been made to assess
uncertainty in pushover analysis results by considering user
defined hinges and frame modeled as bare frame and frame
with slab modeled as rigid diaphragm and results compared
with experimental observations. Uncertain parameters
considered includes the strength of concrete, strength of steel
and cover to the reinforcement which are randomly generated
and incorporated into the analysis. The results are then
compared with experimental observations.
Effect of variation of plastic hinge length on the results of non linear anal...eSAT Journals
Abstract The nonlinear Static procedure also well known as pushover analysis is method where in monotonically increasing loads are applied to the structure till the structure is unable to resist any further load. It is a popular tool for seismic performance evaluation of existing and new structures. In literature lot of research has been carried out on conventional pushover analysis and after knowing deficiency efforts have been made to improve it. But actual test results to verify the analytically obtained pushover results are rarely available. It has been found that some amount of variation is always expected to exist in seismic demand prediction of pushover analysis. Initial study is carried out by considering user defined hinge properties and default hinge length. Attempt is being made to assess the variation of pushover analysis results by considering user defined hinge properties and various hinge length formulations available in literature and results compared with experimentally obtained results based on test carried out on a G+2 storied RCC framed structure. For the present study two geometric models viz bare frame and rigid frame model is considered and it is found that the results of pushover analysis are very sensitive to geometric model and hinge length adopted. Keywords: Pushover analysis, Base shear, Displacement, hinge length, moment curvature analysis
Abstract: In the recent years, natural disasters are recognized to be the cause of considerable human and socioeconomic losses, particularly in modern, infrastructure-dependent societies. For example, the 2011 earthquake and tsunami in Japan have been one of the most devastating disasters of the past decades. Likewise, the Katrina hurricane in the US east coast in 2005. In this context, the concepts of “structural robustness” and
“resilience of urban areas” and “resilient community”, have gathered the attention of researchers. On top of that, more recently, anti-fragile design came as an evolution of design for resilience (intended as the capacity to recover), or for robustness (a main dimension of resilience, intended as the ability of a structure to withstand events without being damaged to an extent disproportionate to the original cause). This study focuses on a modern approach in disaster resilience - including anti-fragile design and structural robustness - providing insight for a preliminary framework on important modelling aspects.
Keywords: resilience, robustness, antifragility, structural engineering, structural design, urban design.
Look also to: http://www.dcee2016.eu/
Seismic Vulnerability of RC Building With and Without Soft Storey Effect Usi...IJMER
A soft storey is one which has less resistance to earthquake forces than the other storeys;
Buildings containing soft stories are extremely vulnerable to earthquake collapses, since one floor is
flexible compared to others. Vulnerability of buildings is important in causing risk to life hence special
consideration is necessary for such soft storey RC buildings. In the present study, analytical
investigation of a RC building by considering the effect of soft storey situated in seismic Zone-V of
India, in accordance with IS 1893-2002 (part-1), is taken as an example and the various analytical
approaches (linear static and nonlinear static analysis) are performed on the building to identify the
seismic demand and also pushover analysis is performed to determine the performance levels, and
Capacity spectrum of the considered, also Storey Shear is compared for 3 models by using Finite
Element Software Package ETAB’s 9.7.4 version.
Performance of Flat Slab Structure Using Pushover AnalysisIOSR Journals
Performance Based Seismic Engineering is the modern approach to earthquake resistant design. It
is a limit-state based design approach extended to cover complex range of issues faced by structural engineers.
Flat slabs are becoming popular and gaining importance as they are economical as compared to beam-column
connections in conventional slab. Many existing flat slabs may not have been designed for seismic forces so it is
important to study their response under seismic conditions and to evaluate seismic retrofit schemes. In this
paper we have discussed the results obtained by performing push over analysis on flat slabs by using most
common software SAP2000. A (G+7) frame having 5 bays is considered for analysis. It is observed that the
performance point of flat slab is more as compared to conventional building.
A performance-based Analysis is aimed at controlling the structural damage based on precise estimations of proper response parameters. Performance-based seismic design explicitly evaluates how a building is likely to perform; given the potential hazard it is likely to experience, considering uncertainties inherent in the quantification of potential hazard and uncertainties in assessment of the actual building response. It is an iterative process that begins with the selection of performance objectives, followed by the development of a preliminary design, an assessment as to whether or not the design meets the performance objectives, and finally redesign and reassessment, if required, until the desired performance level is achieved. In this present study three new R.C.C buildings unsymmetrical in plan (L-shape) (designed according to IS 456:2000) is taken for analysis: 4, 8 and 20 storey to cover the broader spectrum of low rise, medium rise & high rise building construction. Different modelling issues were incorporated through six model for each building were; bare frame (without infill), having infill as membrane, replacing infill as an equivalent strut in previous model. The pushover analysis has been carried out using ETABS, a product of Computers and Structures International. Buildings located in Zone-III have been analyzed Comparative study made for bare frame (without infill), having infill as membrane, replacing infill as an equivalent strut. The results of analysis are compared in terms of Base Shear, Storey Displacement and Drift Ratio.
Analysis of Multi Storey Building using Structural Software MIDAS Generalijtsrd
Earthquakes are known to produce one of the most destructive forces on earth. It has been seen that during past earthquakes many of the buildings were collapsed. Therefore, realistic method for analysis and design are required. Performance Based Design is the modern approach for earthquake resistant design. It is an attempt to predict the performance of buildings under expected seismic event. A structure designed with Performance Based Design PBD concept does not developed undesirable failure mechanism during earthquake. The analysis can be performed on new as well as existing buildings and the performance of buildings in future earthquake can be evaluated. In this research we apply different type type of analysis method on the 30 storey building plan and compare the result. Priyank H. Patel | Jenish M. Mistry | Vishal N. Patel "Analysis of Multi- Storey Building using Structural Software MIDAS General" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-4 | Issue-4 , June 2020, URL: https://www.ijtsrd.com/papers/ijtsrd30961.pdf Paper Url :https://www.ijtsrd.com/engineering/civil-engineering/30961/analysis-of-multi-storey-building-using-structural-software-midas-general/priyank-h-patel
International Refereed Journal of Engineering and Science (IRJES)irjes
International Refereed Journal of Engineering and Science (IRJES) is a leading international journal for publication of new ideas, the state of the art research results and fundamental advances in all aspects of Engineering and Science. IRJES is a open access, peer reviewed international journal with a primary objective to provide the academic community and industry for the submission of half of original research and applications
International Refereed Journal of Engineering and Science (IRJES)irjes
International Refereed Journal of Engineering and Science (IRJES) is a leading international journal for publication of new ideas, the state of the art research results and fundamental advances in all aspects of Engineering and Science. IRJES is a open access, peer reviewed international journal with a primary objective to provide the academic community and industry for the submission of half of original research and applications
Seismic performance of r c buildings on sloping grounds with different types ...eSAT Journals
Abstract
Structure are highly susceptible to serve damages in earthquake scenario, so choosing an appropriate lateral force resisting
bracing systems will have a significant effect on performance of the structure. So this present study is aimed at evaluating and
comparing various types of eccentric steel bracings for 12 storey RC frame building resisting on sloping ground configurations.
For this 5 types of bracing systems like X-Bracing, Diagonal bracing, K- bracing, V-bracing and inverted V bracing are
considered on the outer periphery of the buildings with step back and set back – step back type configurations are modeled and
analyzed. The models are compared for different aspects within the structure, such as the maximum storey displacement, base
shear, storey drift and storey shear, the structure is analyzed for seismic zone V and medium soil condition as per IS 1893:2002
using ETABS software. Results conclude that on sloping ground due to irregularity on ground surface, the structures are more
vulnerable to earthquakes. Hence use of eccentric steel bracing is an effective and economical way to resist earthquake forces,
Inverted V type bracing performs well compared to other bracing types. By using inverted V type bracing in step back buildings
types maximum storey displacement of 70% and storey drift of 66% are obtained. Similarly for setback – step back configuration
maximum storey displacement of 74% and storey drift of 70% are obtained respectively.
Keywords: X-Bracing, Diagonal Bracing, K- Bracing, V-Bracing and Inverted V Bracing
Performance evaluation of a multi storey car parking structure under strength...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
IRJET- Effect of Vertical Irregularities in R.C Frame Structures on Accuracy ...
Performance Based Design Presentation By Deepak Bashetty
1. 1
DEPARTMENT OF CIVIL ENGINEERING
MANIPAL INSTITUTE OF TECHNOLOGY
Deepak S Bashetty
Reg.No:060918003
PERFORMANCE BASED SEISMIC
ANALYSIS OF RC BUILDINGS
Under the Guidance of
Mr.S.VEERAMANI Dr.KRISHNAMOORTHY
Chief Engineering Manager (Civil) Professor,
Engineering Design Research Centre Department of Civil Engineering
(Building & Factories Sector) Manipal Institute of Technology,
ECC Division L&T, Chennai – 600089 Manipal –576 104
External Guide Internal Guide
4. 4
Performance-based Design
The basic concept of performance based seismic
design is to provide engineers with the capability to
design buildings that have a predictable and reliable
performance in earthquakes.
Thus the Performance-based seismic design is a
process that permits design of new buildings or
upgrade of existing buildings with a realistic
understanding of the risk of life, occupancy and
economic loss that may occur as a result of future
earthquakes.
5. 5
Performance-based design begins with the selection
of design criteria stated in the form of one or more
performance objectives. Each performance objective
is a statement of the acceptable risk of incurring
specific levels of damage, and the consequential
losses that occur as a result of this damage, at a
specified level of seismic hazard.
7. 7
Selecting Performance Present
Generation
Beer!Beer!
Food!
Operational
Operational – negligible impact on building
Beer!Beer!
Food!Food!
Joe’s
Beer!Beer!
Food!Food!
Beer!Beer!
Food!
Joe’s
Immediate
Occupancy
Immediate Occupancy – building is safe to occupy but
possibly not useful until cleanup and repair has occurred
Beer!Beer!
Food!Food!
Joe’s
Beer!Beer!
Food!Food!
Beer!Beer!
Food!
Life
Safety
Life Safe – building is safe during event but possibly not
afterward
Collapse
Prevention
CollapsePrevention–building is onvergeof
collapse, probabletotal loss
8. 8
Performance based design
Performance Levels
Building Damage States
Immediate
occupancy
Life
safety
Collapse
prevention
Displacement
parameter
Force
parameter
Demand for specific hazard level
9. 9
A simple flow chart explaining the
“Performance based design”
11. 11
Generally, a team of decision makers, including the
building owner, design professionals, and
building officials, will participate in the selection
of performance objectives for a building.
Once the performance objectives are set, a series
of simulations (analyses of building response to
loading) are performed to estimate the probable
performance of the building under various
design scenario events.
If the simulated performance meets or exceeds the
performance objectives, the design is complete
otherwise it has to be redesigned.
12. 12
Advantages of Performance
Based Seismic Design
Systematic methodology for assessing the performance capability of a building
Design individual buildings with a higher level of confidence
Design individual buildings to achieve higher performance and lower potential
losses.
Design individual buildings that fall outside of code-prescribed limits with
regard to configuration, materials, and systems to meet the performance
intended by present building codes
Assess the potential seismic performance of existing structures and estimate
potential losses in the event of a seismic event.
Performance-based seismic design offers society the potential to be both more
efficient and effective in the investment of financial resources to avoid future
earthquake losses
13. 13
Differences between traditional approach
and performance based approach
1) Conventional limit-states design is typically a two-level design
approach having concern for the service operational and
ultimate-strength limit states for a building, performance-
based design can be viewed as a multi-level design approach
that additionally has explicit concern for the performance of a
building at intermediate limit states related to such issues as
occupancy and life-safety standards.
2) The performance based analysis is based on quantifying
the deformation of the members and the building as a whole,
under the lateral forces of an earthquake of a certain level of
seismic hazard. Traditional Approach-Force based Design
has no measure of the deformation capability of members or
of building.
14. 14
3) The deformation or strains are better quantities to assess
damage than stress or forces. Since the deformation are
expected to go beyond the elastic values.
4) The performance based analysis gives the analyst more
choice of ‘performance’ of the building as compared to the
limit states of collapse and serviceability in a design based
on limit state method.
5)Traditional based design uses Elastic behavior where as
Performance based design uses inelastic behavior
16. 16
Methods of analysis
Generally for analyzing the structure the following analysis
methods are used depending upon the requirements.
1) Linear static procedure
2) Linear dynamic procedure
3) Nonlinear static procedure
1. Pushover analysis
2. Capacity spectrum method
4) Nonlinear dynamic procedure
1. Time history Analysis
Push-over and Time History analyses tools to perform non-linear
analysis are considered.
17. 17
pushover analysis is the one which is suitable for the
performance based seismic design, because elastic
analyses are insufficient, therefore they cannot realistically
predict the force and deformation distributions after the
initiation of damage in the building.
Inelastic analytical procedures become necessary to
identify the modes of failure and the potential for
progressive collapse.
Inelastic time-history analysis are most realistic analytical
approach for evaluating the performance of a building.
However, the inelastic time-history analysis is usually too
complex and time- consuming in the design of most
buildings.
18. 18
What is Push-Over Analysis?
• Push-over analysis is a technique by which a computer model of the
building is subjected to a lateral load of a certain shape (i.e., parabolic,
inverted triangular or uniform).
• Building is pushed in one horizontal direction. The intensity of the lateral
load is slowly increased and the sequence of cracks, yielding, plastic
hinge formations, and failure of various structural components is recorded.
• Proportion of applied force on each floor is constant , only its magnitude
is increased gradually (i.e., Load pattern may be 1st mode shape,
parabolic, uniform, inverted triangular etc.).
• Material nonlinearity is modeled by inserting plastic hinge at potential
location.
19. 19
Continued…
• A series of iterations are usually required during which, the structural
deficiencies observed in one iteration, are rectified and followed by
another.
• This iterative analysis and design process continues until the design
satisfies a pre-established performance criteria.
• The performance criteria for push-over analysis is generally established
as the desired state of the building given a roof-top or spectral
displacement amplitude.
• Push over analysis requires a large number of assumptions and
member response curves are to be provided to the program before it
can analyze.
21. 21
Why Push-Over Analysis?
• Static Nonlinear Analysis technique, also known as sequential yield
analysis, or simply "push-over" analysis.
• To get the performance level of structure in case of seismic load.
• Elastic analysis cannot predict failure mechanism and account for
redistribution of forces during progressive yielding.
• The use of inelastic procedure for design and evolution is an attempt to
help engineer better understand how structures will behave when
subjected to major EQ, where it is assumed that the elastic capacity of
the structure will be exceeded.
22. 22
What is Time History Analysis?
• Time History analysis is a step by step analysis of the
dynamical response of a structure to a specified loading
that may vary with time.
• The performance analysis may be
– Linear
– Non-linear
23. 23
Why Linear Time History Analysis?
• To get the variation of forces at each time step and to get the maximum
response under the the particular time history.
• To verify the design of structure. If forces in the member are within the
design forces, then no need to do Non- Linear time history analysis.
• If the forces are exceeding the design forces, then Non-Linear time
history analysis is required to understand the performance of structure.
24. 24
Why Non-Linear Time History
Analysis?
• Elastic analysis cannot predict failure mechanism and account
for redistribution of forces during progressive yielding.
• Certain part may yield when subject to major earthquake.
• To get the performance level of structure in case of seismic
load.
• The use of inelastic procedure for design and evolution is an
attempt to help engineer to better understand how the
structures will behave when subjected to major EQ.
25. 25
Pushover Analysis Procedure
Create 2D/3D Model
Assign end offsets
Design Structure
Assign Hinge properties
Beams – M3, V2
Columns –PMM, V2
Define Static Pushover
Cases
Gravity Pushover
(Force controlled)
Lateral Pushover
(Displacement controlled)
Define Load case
(Lateral Load at centre of mass)
Analyze
Run analysis, Run Now
Establish Performance point
Base shear Vs Roof Displacement
Sequential Hinge Formation
26. 26
Performance Analysis
Create Model as Designed
Define Time History Function
Define Linear Time History cases
Analyze
Check
Member Forces ≤ Design Force
Define Non linear Time
History Case
Assign Plastic Hinges
(Material Nonlinearity)
Define Geometric Nonlinearity
Analyze
Results
Check the performance of the
structure and if required, redesign
YESYES
NoNo
Material nonlinearity is modeled by inserting
plastic hinge at potential location.
28. 28
Modeling of Beams and Columns
• 3D Frame Elements
• Cross Sectional dimensions, reinforcement details, material
type
• Effective moment of inertia (As per ATC 40)
Beams
Rectangular 0.5 Ig
T-Beam 0.7 Ig
L-Beam 0.6 Ig
Columns 0.7 Ig
29. 29
Modeling approach
Lp = 0.5H
Location of hinges in beams and columns:
• Beam & column elements - nonlinear frame elements with lumped plasticity -
defining plastic hinges at both ends of the beams and columns.
lcolumn
Dcolumn
lbeam
Dbeam
Moment and shear hinge
Axial-moment and shear hinge
L = Critical distance from critical section of
plastic hinge to point of contra flexure
fye = yield strength of transverse reinforcement
dbl= diameter of transverse reinforcement
30. 30
Modelling Approach
• Plastic hinge is defined in terms of Force-deformation
behaviour of the member.
• Values are depend on type of element, material properties,
longitudinal and transverse steel content - axial load level on
the element.
• For beam, flexural hinge is assigned
• For Column, axial and flexural hinges
are assigned
• A-unloaded condition, B-effective
yield, C-ultimate strength, D- residual
strength and E-maximum deformation
Force-deformation Relationship
of a Typical Plastic Hinge
32. 32
Description of Structure
Building Type
RC frame without brick infill
Concrete compressive
strength
Yield Strength of
reinforcement
– 25 MPa
– 415 MPa
Number of stories Ground + 5 Storey
Plan dimensions 16 m × 12 m
Building height 24.775 m above plinth level
Type of footing Raft footing (fixed)
•Seismic performance - inter-storey drift ratio, ductility, maximum base
shear, roof displacement and plastic hinge formation.
33. 33
Column Dimensions and Area of Longitudinal Reinforcement
Column
Label
Cross
Section
mm x mm
Acol
(mm2
)
1 & 9 300 x 500 5892
2 & 10 300 x 500 4020
3 & 11 300 x 400 3216
4 & 12 300 x 300 3080
21& 23 300 x 300 1232
24& 26 300 x 300 905
27& 29 300 x 300 905
5 650 x 650 14784
6 600 x 600 12744
7 550 x 550 10620
8 500 x 500 7856
22 450 x 450 6372
25 300 x 300 4928
28 300 x 300 804
Acol
= Area of longitudinal reinforcement in column
The beam in all storey levels is of size 300mm x 600mm with tension and
compression reinforcements of 3885mm2 and 2412mm2 respectively. The column
dimensions and area of longitudinal reinforcement (Acol) details are presented in
Table
34. 34
Details of Analysis
• Pushover Analysis
Gravity analysis is an Force controlled.
Pushover analysis is a Displacement controlled.
Behaviour of structure characterized by capacity curve
(base shear force Vs. roof displacement)
• Time-History Analysis
Step by step analysis of the dynamical response of structure
to a time varying load.
7 sets of strong ground motion in the magnitude range of
6.5-7.5 were selected.
The peak displacement from NTH is not correspond to
ultimate displacement from pushover analysis.
To facilitate comparison the ground motion records scaled
according to
peak roof displacement =target displacement
35. 35
Input Ground Motions
EQ
No.
Year Earthquake Recording
Station
Magnit
ude
PGA
in g
EQ. Scale Factor
DBE MCE
1 1979 El Centro Array #7 7.0 0.338 0.45 0.785
2 1999 Duzce Turkey 7.1 0.348 0.8 1.15
3 1971 San Fernando Old Ridge 6.5 0.268 1.7 1.9
4 1995 Kobe KJM 6.9 0.343 0.35 0.5
5 1976 Friuli Tolmezzo 6.5 0.315 0.95 1.2
6 1994 Northridge Arleta 6.7 0.344 0.6 1.0
7 1989 Loma Prieta Gilroy #2 7.1 0.322 0.35 0.515
36. 36
Base shear
• Maximum base shear -
571kN - 10% of seismic
weight - displacement
corresponding to base
shear - 1.02m.
• Displacement ductility -
2.32.
• Base shear values - DBE
& MCE levels from
Pushover analysis - 116
kN & 171kN
• From NTH - 151kN &
51kN.
• Results from NTH are
23% & 32% higher than
pushover analysis.
37. 37
Target Displacement
• Represent the maximum displacement likely to be experienced
during the design earthquake
• Performance levels are calculated based on equation from
FEMA 356.
C0 = Modification factor to relate spectral displacement of an equivalent SDOF
system to the roof displacement of building MDOF system
C1 = Modification factor to relate expected maximum inelastic displacements to
displacements calculated for linear elastic response
C2 = Modification factor to represent the effect of pinched hysteretic shape,
stiffness degradation and strength deterioration on maximum displacement
response
C3 = Modification factor to represent increased displacements due to dynamic
P- ∆ effects
Te = Effective fundamental period of building, sec
Sa = Response Spectrum Acceleration at effective fundamental period and
damping ratio of building
g
4
T
SCCCC 2
2
e
a3210t
π
=δ
38. 38
Performance Point
• Intersection of capacity & demand spectrum.
• Performance assessed for two levels of performance - Life
Safety (LS) under Design Basis Earthquake (DBE) & Collapse
Prevention (CP) under Maximum Considered Earthquake
(MCE).
• Base shear, roof displacement, spectral acceleration, spectral
displacement, effective time period and effective damping -
performance point - shown.
• Displacement @ performance point in DBE level - 123mm
greater than target displacement 119mm.
• Displacement @performance point in MCE level - 171mm
lesser than target displacement 177mm.
40. 40
• Important indicator of building performance.
• 3rd storey level- the largest interstorey drift values -0.58% and 0.85% at
both DBE and MCE levels.
• Interstorey drift ratio - increased with increase in storey level up to first 4
stories - thereafter - reverse trend at both levels of earthquake.
• DBE level - pushover analysis over-estimated - interstorey drift ratio -
lower storey levels - underestimated - upper storey levels.
• MCE level -pushover analysis -over-estimated - interstorey drift ratio - all
storey levels.
Interstorey Drift
htStoreyHeig
ntfloorsntofadjaceDisplaceme
izontallativedHorRe
ydriftInterstore =
41. 41
0
1
2
3
4
5
6
7
0.00 0.20 0.40 0.60 0.80 1.00
Interstorey drift in %
StoreyLevel
DBE
MCE
(a) Results from Pushover Analysis at DBE &
MCE Levels
0
1
2
3
4
5
6
7
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Intersotrey drift in %
StoreyLevel
NTH-DBE
NSP-MCE
NSP-DBE
NTH-MCE
(b) Comparison between Pushover &
Time-history Results at DBE & MCE Levels
0
1
2
3
4
5
6
7
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
Interstorey Drift Ratio in %
StoreyLevel
Elcentro
Duzce
San Fernando
Friuli,Italy
Kobe
Northridge
LomaPrieta
Average 0
1
2
3
4
5
6
7
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
Interstorey Drift Ratio in %
StoreyLevel
Elcentro
Duzce
San Fernando
Friuli,Italy
Kobe
Northridge
LomaPrieta
Average
(a) Results from Time-history Analysis at DBE
Level
(b) Results from Time-history Analysis at MCE
Level
Figure 8.6 Interstorey Drift Ratios from Time – history Analysis
Figure 8.5 Interstorey Drift Ratios
42. 42
Plastic Hinge Pattern
• Pushover analysis
• Outer columns at all storey level yielded first
• Beams showing hinges in yielding stage at one end only in
the DBE level
• Beams in the MCE Level at all the storey levels except
topmost showing hinges in yielding stage.
• Time History Analysis
• More number of hinges at yielding in beam ends model
compared to pushover analysis at both DBE and MCE
levels.
• At MCE level middle columns in upper stories also yielded;
but in the pushover analysis not showing hinges in any
column.
45. 45
Plastic Hinge Pattern
• Pushover analysis
At final step (frame roof pushed up to
4% of height of frame) - hinge
formation started with yielding in outer
columns at all stories
and yielding of few beam ends in
upper stories.
Middle columns in the upper stories
start yielding with simultaneous
yielding of base columns.
Beams experienced less number of
hinges than columns but shows
significant damage or failure stage.
46. 46
Conclusions
• Base shear from time history analysis are 23% and 32%
higher than pushover analysis at DBE and MCE levels.
• Roof displacement at DBE and MCE levels indicates that
frame satisfies the requirement for Life Safety performance
at DBE level and not satisfies the requirement for Collapse
Prevention performance at MCE level.
• From analyses the middle storey experience the maximum
interstorey drift ratio at both levels.
• Pushover analysis over estimate the interstorey drift ratio
compared with time history analysis
47. 47
• No significant difference of plastic hinge pattern at
DBE and MCE levels from both analyses
• Time-history analysis shows more number of beam
hinges at both levels.
• From time history analysis at MCE level, middle
column shows yielding but not in pushover
analysis.
• The behaviour of frame designed for gravity load
shows column side sway mechanism.
Conclusions
49. 49
Description of Structure
A regular four storeyed (G+3), five storeyed (G+4), six storeyed
(G+5) and a seven storeyed (G+6) building were considered in the
present study. All the buildings are rectangular in plan with same
plan dimensions and storey height. The plan view and sectional
elevation of a G+3 building is shown in Figure.
50. 50
Figure: Comparison of Variation of
Fundamental Time Period using Time History
Analysis
Figure :Comparison of Variation of
Roof Displacement using Time History Analysis
Results
51. 51
• Analysis results shows that, hinges will be formed earlier
in frames of structures without strut action than frames of
structures with strut action
• It is observed that, in all the cases, the fundamental time
period of the structure with strut action is considerably
less than the structures without strut action.
• Figure, compares the roof displacement of G+3, G+4,
G+5 and G+6 frames with and without strut action.
• The graph shows that roof displacement get
considerably (50%) reduced with strut action.
52. 52
CONCLUSIONS
From the pushover and time-history analyses of 2D RC frames with
infill, the following conclusions are drawn:
• It is found that the fundamental time period of the structure get
considerably reduced due to strut action. This will alter the response
of the structure to lateral loads.
• In addition strut action will considerably reduce the roof
displacement. This will increase the safety level of the structure.
• Hence it is recommended to model infill stiffness using equivalent
diagonal struts for any lateral load analysis.
53. 53
References
1. Ali M. Memari, Shahriar Rafiee, Alireza Y. Motlagh and
Andrew Scanlon (2001), “ComparativeEvaluation of Seismic
Assessment Methodologies Applied to a 32-Story Reinforced
Concrete Office Building”, Journal of Seismology and
Earthquake Engineering, Vol. 3 ,No.1, 31-44.
2. Andreas J. Kappos, Alireza Manafpour (2001), “Seismic
design of R/C buildings with the aid of advanced analytical
techniques”, Engineering Structures, 23, 319–332
3. Chung C. Fu and Hamed AlAyed, “Seismic Analysis of
Bridges Using Displacement-BasedApproach”, 1-20.
4. Federal Emergency Management Agency, Prestandard and
Commentary for the Seismic Rehabilitation of Buildings
(FEMA 356), Washington D.C. November 2000.
54. 54
Contd…
5. IS 456-2000, Indian Standard Plain and Reinforced Concrete - code
of practice, Bureau of Indian Standards.
6. IS 1893 (Part 1) – 2002, Indian Standard Criteria for Earthquake
Resistant Design of Structures, Bureau of Indian Standards.
7. Mehmet Inel, Hayri Baytan Ozmen, (2006) “Effects of plastic hinge
properties in nonlinear analysis of reinforced concrete buildings”,
Engineering Structures, 28, 1494–1502.
8. SAP2000. Linear and nonlinear static and dynamic analysis and
design of structures. Ver.10.0. Berkeley (CA, USA): Computers
and Structures, Inc.
9. Sashi K. Kunnath and Erol Kalkan (2004), “Evaluation of Seismic
Deformation Demands using Nonlinear Procedures in Multistory
Steel and Concrete Moment Frames”, ISET Journal of
Earthquake Technology, Paper No. 445, Vol. 41, No. 1, March
2004, pp. 159-181
10. ATC 40 (1996), “Seismic Evaluation and Retrofit of Concrete
Buildings”, Applied Technology Council, USA, Vol.1.
57. 57
Finding Mcr & Φcr Values
( )
bc
cr
cr
bt
tstt
ckcr
cr
cr
yE
f
yyD
ydmA
D
ybDbDI
ff
y
If
M
=
+=
−+
−+=
=
=
φ
2
2
3
2
7.0
58. 58
Finding M-Φ values
• Assume ec
• Find k1& k2 for corresponding ec
• Assume initially a value for kd , now
• Compare the assumed kd & the calculated kd. If
matching take that value , otherwise try with new kd.
( )
sstck
sss
cs
fAbkdfkk
Ef
kd
kdd
=
=
−
=
31
ε
εε
62. 62
Section considered for calculating M-
Φ relationship
Assumed 25 mm clear cover
All dimensions in mm
63. 63
εc M Φ
start 0 0
cracked 8033504.196 9.74069E-07
0.0005 8283594.419 4.05201E-06
0.001 15378489.83 7.84424E-06
0.0015 21200915.35 1.13588E-05
0.002 25649262.16 1.45742E-05
0.0025 27587840.7 1.85134E-05
0.003 28996952.56 2.22161E-05
0.0035 29959200.87 2.59188E-05
M-Φ values for the section considered
M in Nmm & Φ in rad/mm
M-Phi
0
5000000
10000000
15000000
20000000
25000000
30000000
35000000
0 0.000005 0.00001 0.000015 0.00002 0.000025 0.00003
Phi
M
64. 64
Comparison of M-Φ values for different pt
values.
M in Nmm & Φ in rad/mm
M-Phi
0
5000000
10000000
15000000
20000000
25000000
30000000
35000000
0 5E-06 0.00001 1.5E-05 0.00002 2.5E-05 0.00003 3.5E-05 0.00004 4.5E-05
Phi
M
0.25% 0.50%
0.75% 0.96%
Editor's Notes
<number>
<number>
The damage evaluation procedures are performance-based; that is, they measure acceptability (and changes in acceptability) on the basis of the degree to which a structure achieves one or more performance levels for the hazard posed by one or more hypothetical future earthquakes. A performance level typically is defined by a particular damage state for the components of a building. Commonly-used performance levels, in order of decreasing amounts of damage, are Collapse Prevention, Life Safety, and Immediate Occupancy. Hazards associated with future hypothetical earthquakes commonly are defined in terms of ground shaking intensity with a certain likelihood of being exceeded over a defined time period, or in terms of a characteristic earthquake likely to occur on a given fault. The combination of a performance level and a hazard defines a Performance Objective. For example, a common Performance Objective for a building is that it maintain Life Safety for ground motion with a ten percent chance of exceedance in fifty years.