This document discusses earthquake analysis and design of multi-storey frames. It begins with definitions and causes of earthquakes, including plate tectonics and the elastic rebound theory. It then covers earthquake measurement in terms of magnitude, intensity, and location of the focus and epicenter. Methods of seismic analysis are described, including linear static, linear dynamic using response spectrum and time history methods, and non-linear methods. Indian codes for earthquake resistant design are also discussed. The document provides information on seismic zoning in India and the methodology for earthquake load design using the static equivalent method. Key concepts in ductile design such as strong-column weak-beam and ductile detailing requirements are covered.
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.
Analysis and design of pre engineered building using is 800:2007 and Internat...Pratik R. Atwal
Abstract: In this report, comparison is made between IS800:2007 & International standards. The entire range of preengineered building is studied while doing this comparison. A school building is designed using IS800:2007 & International standards by keeping the loading parameters similar, all the loads are applied accordance with Indian codes. An attempt is made to study the variation in tonnage as per IS800:2007 & International standards & possible reasons for variation in respective results.
ANALYSIS AND DESIGN OF HIGH RISE BUILDING BY USING ETABSila vamsi krishna
RESULT OF ANALYSIS:
https://www.slideshare.net/ilavamsikrishna/results-of-etabs-on-high-rise-residential-buildings
ANALYSIS AND DESIGN OF BUILDING BY USING STAAD PRO PPT link :
https://www.slideshare.net/ilavamsikrishna/analysis-and-design-of-mutistoried-residential-building-by-using-staad-pro
FOR FULL REPORT:
vamsiila@gmail.com
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.
Seismic analysis of multi storey reinforced concrete buildings frame”ankialok
The opinion that designing new buildings to be Earthquake resistant will cause substantial additional costs is still among the constructional professionals. In a country of moderate seismicity adequate seismic resistance of new buildings may be achieved at no or no significant additional cost however the expenditure needed to ensure adequate seismic resistance may depend strongly on the approach selected during the conceptual design phase and the relevant design method. Regarding the conceptual design phase early collaboration between the architect and civil engineering is crucial.
ANALYSIS AND DESIGN OF RESIDENTIAL TOWER BY DYNAMIC ANALYSIS USING RESPONSE S...Ijripublishers Ijri
This Project Named As “Analysis And Design Of Residential Tower (2basemetns+Stilt+31 Upper Floors)By Dynamic Analysis
Using Response Spectrum Method” Involves The Analysis And Design Of Residential Tower 3-D Frames Of Uniform
Floor heights for typical floors using very popular software tool ETABS 9.7.2.
The main thesis of this Project is to achieve the following:
1).To arrive at minimum number of modes required to get modal mass participating ratio more than 90% by dynamic
analysis using Response Spectrum Method.
2). To limit the lateral deflection at the top of the tower less than H/250(Where H = Height of the tower till terrace) for
seismic load.
3). To limit the Inter Storey Deflection(Storey Drift) in any storey due to the minimum specified design lateral force,
with factor of 1.0 less than 0.004 times the storey height.
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.
Analysis and design of pre engineered building using is 800:2007 and Internat...Pratik R. Atwal
Abstract: In this report, comparison is made between IS800:2007 & International standards. The entire range of preengineered building is studied while doing this comparison. A school building is designed using IS800:2007 & International standards by keeping the loading parameters similar, all the loads are applied accordance with Indian codes. An attempt is made to study the variation in tonnage as per IS800:2007 & International standards & possible reasons for variation in respective results.
ANALYSIS AND DESIGN OF HIGH RISE BUILDING BY USING ETABSila vamsi krishna
RESULT OF ANALYSIS:
https://www.slideshare.net/ilavamsikrishna/results-of-etabs-on-high-rise-residential-buildings
ANALYSIS AND DESIGN OF BUILDING BY USING STAAD PRO PPT link :
https://www.slideshare.net/ilavamsikrishna/analysis-and-design-of-mutistoried-residential-building-by-using-staad-pro
FOR FULL REPORT:
vamsiila@gmail.com
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.
Seismic analysis of multi storey reinforced concrete buildings frame”ankialok
The opinion that designing new buildings to be Earthquake resistant will cause substantial additional costs is still among the constructional professionals. In a country of moderate seismicity adequate seismic resistance of new buildings may be achieved at no or no significant additional cost however the expenditure needed to ensure adequate seismic resistance may depend strongly on the approach selected during the conceptual design phase and the relevant design method. Regarding the conceptual design phase early collaboration between the architect and civil engineering is crucial.
ANALYSIS AND DESIGN OF RESIDENTIAL TOWER BY DYNAMIC ANALYSIS USING RESPONSE S...Ijripublishers Ijri
This Project Named As “Analysis And Design Of Residential Tower (2basemetns+Stilt+31 Upper Floors)By Dynamic Analysis
Using Response Spectrum Method” Involves The Analysis And Design Of Residential Tower 3-D Frames Of Uniform
Floor heights for typical floors using very popular software tool ETABS 9.7.2.
The main thesis of this Project is to achieve the following:
1).To arrive at minimum number of modes required to get modal mass participating ratio more than 90% by dynamic
analysis using Response Spectrum Method.
2). To limit the lateral deflection at the top of the tower less than H/250(Where H = Height of the tower till terrace) for
seismic load.
3). To limit the Inter Storey Deflection(Storey Drift) in any storey due to the minimum specified design lateral force,
with factor of 1.0 less than 0.004 times the storey height.
Design and Analysis of a Multistory Reinforced Concrete Frame in Different Se...ijtsrd
This study work focuses on the analysis of a structural system to determine the deformations and comparison of steel quantity of seismic zones. In this study, we have taken G 12 multi storied RC moment resisting framed structure building with the shear wall by analyzing the structure for gravity load, wind load and seismic loads for different cities. By Selecting four different cities on the basis of seismic zones zone II, zone III, zone IV, zone V and also considering that the basic wind speed. We have mainly focus on the structural system to determine the deformations and also forces induced by applied loads or ground excitation is an essential step in the design of a structure to resist earthquake. The analysis and design for all the cities are carried out using STAAD Pro' and STAAD Foundation' software which are industry standard software the world over. The wind resistant design is carried out as per IS 875 Part 3 1987 and the earthquake resistant design is carried out as per IS 1893 Part 1 2002. Analysis and design of beams, columns and shear wall have been done in STAAD Pro and the foundation is done in STAAD Foundation. We have also checked the design of some beams, columns, and footings manually and find correct. Design of RCC slabs is carried out manually for which an excel sheet is developed for working out moment coefficients for different edge conditions as per IS code. In this study work, we design and analyze a reinforced concrete frame structure in various seismic zones and we observing the variation in the behavior of the structure in various loading conditions. Priyatam Kumar | Vikash Kumar Singh "Design and Analysis of a Multistory Reinforced Concrete Frame in Different Seismic Zone" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-5 , August 2019, URL: https://www.ijtsrd.com/papers/ijtsrd26688.pdfPaper URL: https://www.ijtsrd.com/engineering/civil-engineering/26688/design-and-analysis-of-a-multistory-reinforced-concrete-frame-in-different-seismic-zone/priyatam-kumar
Seismic Analysis of Structures under Different Soil ConditionsIJERA Editor
In India, multi-storied buildings are usually constructed due to high cost and scarcity of land. In order to utilize maximum land area, builders and architects generally propose asymmetrical plan configurations. These asymmetrical plan buildings, which are constructed in seismic prone areas, are likely to be damaged during earthquake. Earthquake is a natural phenomenon which can generate the most destructive forces on structures. Buildings should be made safe for lives by proper design and detailing of structural members in order to have a ductile form of failure. The concept of earthquake resistant design is that the building should be designed to resist the forces, which arises due to Design Basis Earthquake, with only minor damages and the forces, which arises due to Maximum Considered Earthquake, with some accepted structural damages but no collapse. This project report comprises of seismic analysis and design of an five-storied R.C. building with asymmetrical plan in different soil conditions. The building is modelled as a 3D space frame with six degrees of freedom at each node using the software SAP2000 v 14. Building is analyzed using Response Spectrum method. The Response Spectra as per IS 1893 (Part 1): 2002 for rocky or hard soil and soft soil is used. Dynamic response of a structure resting on soft soils in particular, may differ substantially in amplitude and frequency content from the response of an identical structure supported on a very stiff soil or rock. However, data on many failure examples of rigid structures resting on flexible soils and intensive analytical studies in recent years have made considerable advances in the field of soil-structure interaction and analytical techniques are now available. This interaction phenomenon is principally affected by the mechanism of energy exchanged between soil and the structure. Considering the soil – structure interaction effect which is mainly due to the fact that buildings with high stiffness on loose soils behave differently. Base shears have shown significant variation with high values for structures resting on loose soils and low values in case of hard rock. This attributes mainly due to more absorbing energy capacity of soils when compared to rock materials
The objective of the paper is to show the effect of the earthquake on different types of foundations such as shallow, mat/raft, pile and structures like gravity dam, arch dam etc. The reaction of soil to the loading of the building when a building undergoes an earthquake disturbance as a behaviour of deflection is known as the soil structure interaction. The movement of ground during the Earthquake induces kinematic and inertial loading which decreases the bearing capacity and increments the settlement of shallow foundations. In seismic regions, where kinematic interactions have been observed, the mat foundations experiences overturning moments. Pile foundations are influenced by both kinematic and inertial interactions which causes many failures. The convoluted oscillating arrangement of acceleration and ground motion in a gravity dam, developing ephemeral dynamic loads because of inertia of dam and confined water is the seismic activity generated in these dams. The arch dam foundations undergoes effects of inertia and flexibility due to the propagation of seismic waves.
An earthquake (also known as a quake, tremor or temblor) is the perceptible shaking of the surface of the Earth, which can be violent enough to destroy major
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Sachpazis:Terzaghi Bearing Capacity Estimation in simple terms with Calculati...Dr.Costas Sachpazis
Terzaghi's soil bearing capacity theory, developed by Karl Terzaghi, is a fundamental principle in geotechnical engineering used to determine the bearing capacity of shallow foundations. This theory provides a method to calculate the ultimate bearing capacity of soil, which is the maximum load per unit area that the soil can support without undergoing shear failure. The Calculation HTML Code included.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
6th International Conference on Machine Learning & Applications (CMLA 2024)ClaraZara1
6th International Conference on Machine Learning & Applications (CMLA 2024) will provide an excellent international forum for sharing knowledge and results in theory, methodology and applications of on Machine Learning & Applications.
CW RADAR, FMCW RADAR, FMCW ALTIMETER, AND THEIR PARAMETERSveerababupersonal22
It consists of cw radar and fmcw radar ,range measurement,if amplifier and fmcw altimeterThe CW radar operates using continuous wave transmission, while the FMCW radar employs frequency-modulated continuous wave technology. Range measurement is a crucial aspect of radar systems, providing information about the distance to a target. The IF amplifier plays a key role in signal processing, amplifying intermediate frequency signals for further analysis. The FMCW altimeter utilizes frequency-modulated continuous wave technology to accurately measure altitude above a reference point.
2. What is an Earthquake ?
Sudden movement of the earth’s crust
90% of all earthquakes result from movements on geological
faults – tectonic earthquakes
Earthquakes are generally natural disasters of unpredictable
nature.
But due to human activity such as construction of large dams
and reservoirs, mine blasts, nuclear tests, etc earthquake may be
generated.
4. Theory of Plate Tectonics
The lithosphere if fragmented
into seven major tectonic
plates and many smaller
ones.
Due to convection current in
viscous mantle these plates
move in different directions and
at different speeds from those of
the neighbouring ones.
5. Elastic Rebound Theory
Most boundaries of the plates have irregularities and this
leads to a form of stick-slip behaviour.
Once the boundary has locked, continued relative motion
between the plates leads to increasing stress and stored strain
energy in the volume around the fault surface.
This continues until the stress has risen sufficiently to
overcome the strength of the rock, suddenly allowing sliding
over the locked portion of the fault, releasing the stored
energy that spreads out through seismic waves that causes
earthquakes.
6.
7. Focus and Epicentre
The point within the earth from which
the earthquake originates is the Focus
or Hypocenter.
The point on the earth’s surface lying
vertically above the focus is the
Epicenter.
Distance from epicenter to any point of
interest is called epicentral distance.
The depth of focus from the epicenter,
is the Focal Depth, shallow focus
earthquakes with focal depths less than
about 70km are the most damaging.
8. How are Earthquakes Located?
P wave travels faster than S wave.
The difference in arrival time between the two
types of seismic waves can be used to
calculate the distance of the earthquake's
epicentre from the measuring station.
DE = DeltaT x (VP VS) / (VP - VS)
where
DE = Distance to epicentre (km)
DeltaT = Difference between P and S-wave
arrival time (s)
VP = P-wave velocity (km/s)
VS = S-wave velocity (km/s)
9. A circle with a radius equal to
the distance to the epicentre is
plotted around the seismograph
station. This is then repeated for
the other two stations and the
point where the three circles
intersect is the location of the
earthquake’s epicentre.
10. Measerement of earthquake(Magnitude &Intensity)
Magnitude is a quantitative measure of the size of an earthquake. There is only
one magnitude per earthquake.
Richter defined the magnitude of an earthquake as the logarithm to base 10 of the
maximum seismic wave amplitude (in microns) recorded on a standard
seismograph at a distance of 100 km from the epicentre
An increase in magnitude (M) by 1.0 means that the amplitude of the earthquake
waves increases 10 times.
Earthquake magnitude is related to the amount of energy released in the
earthquake.
log10 E = 11.8 + 1.5M, where, energy, E, is in ergs
Other magnitude scales are Surface wave magnitude, Body wave magnitude,
Duration magnitude and Moment Magnitude (MW).
11. Intensity of an Earthquake
Intensity is a qualtitative measure of the severity of shaking at a location during
an earthquake. The severity of shaking is much higher near the epicenter than
farther away.
Intensity scales are -
Rossi-Forel intensity scale (developed in the late 19th century) – ten stages
Mercalli intensity scale (1902) – twelve stages
Modified Mercalli Intensity (MMI) scale (1931)
Medvedev-Spoonheuer-Karnik (MSK) intensity scale (1964)
Both scales are quite similar and range from I (least perceptive) to XII (most
severe).
17. So the social consequences of earthquakes, in terms of
human casualties and injuries and direct and indirect
economic losses justify the need to be prepared for
earthquakes.
Earthquakes are still difficult to predict
So,we should prepare for earthquake by making our
buildings with proper structural design procedure.
18. Indian Codes relevant to Earthquake Engineering
IS 1893 - 2002: Criteria for earthquake resistant design of structures.
IS 13920 - 1993: Code of practice for ductility detailing of reinforced
concrete structures subjected to Seismic forces.
IS 4326 - 1993: Earthquake resistant design and construction of
buildings code of practice.
IS 13828 - 1993: Improving Earthquake resistance of low strength
masonry buildings - Guidelines.
IS 13827 - 1993: Guidelines for improving earthquake resistance -
Earthen Buildings.
Among these codes in our project we have used IS 1893-
2002,IS13920-1993 and IS 875.
19. Method of seismic Analysis
1. Linear static analysis (or equivalent static analysis) :–
Applicable for regular structures and low rise buildings.
2. Linear dynamic analysis :-–
can be performed either by
response spectrum method (mode superposition method like
SRSS,CQC) or by elastic time history method.
3. Non-linear static analysis:-
4. Non-linear dynamic analysis:-
Describe the actual behaviour of the structure during an
earthquake.
20. • Slabs forces the beam
to bend with it when
horizontal forces act.
21. The philosophy of earthquake
design for structures is:
In frequent, minor ground shaking -
Main structural members should
not be damaged, other building parts may
have repairable damage
In occasional, moderate ground
shaking -
Main structural members may
sustain reparable damage, other building
parts may have to be replaced
In rare, major ground shaking –
Structural members may be
irreparably damaged but the structure
should not collapse
General Goals in Seismic-Resistant Design and Construction
Courtesy: IITK-BMTPC EQ. Tips
22. After minor shaking, the building will be fully operational within a short time and the
repair costs will be small.
After moderate shaking, the building will be operational once the repair and
strengthening of the damaged main members are completed.
After a strong earthquake, the building may become unsuitable for further use, but will
stand so that inhabitants can be evacuated.
Important buildings, like hospitals and fire stations, play a critical role in post-
earthquake activities and must remain functional immediately after the earthquake.
Collapse of dams during earthquakes can cause flooding.
Damage to sensitive facilities like nuclear power plant, chemical plants, etc. can cause
a further disaster.
These structures must sustain very little damage and should be designed for a higher
level of earthquake protection.
23. Seismic Zoning Map of India
In 1935, GSI prepared a seismic hazard map of three zones depicting
likely damage scenario (severe, moderate, light).
By evaluating peak horizontal ground acceleration based on
earthquake data from 1904-1950, Jai Krishna developed a 4-zone
seismic map in 1958. The Indian peninsular regions were not given
any seismic consideration as it was considered to be a stable plateau.
BIS provided a seismic zone map in IS: 1893-1962 with seven zones
based on isoseismals of major earthquakes and average intensity
attenuation relationship. Past smaller earthquakes, trend of principal
tectonic features and local ground conditions were also considered.
For Zone 0 (intensity less than V) seismic loading on the
structure need not be considered.
24. Koyna earthquake of 1967 (magn. 6.5) in Peninsular India caused the
revision of the seismic zone map in IS: 1893-1970. Number of zones
was reduced to five (based on five seismo-tectonic units of the
country).
Due to the Latur earthquake (magn. 6.2) in 1993, the seismic status of
the Indian peninsular shield was again reviewed.
The IS 1893-2002 map has only four zones. Zone I has been
enhanced to Zone II.
Enhanced extent of Zone III (Chennai is now in Zone III, previously
in Zone II).
This 2002 seismic zone map is not the final word on the seismic
hazard of the country, and hence there can be no sense of
complacency in this regard!
The decision of the BIS is to have a new revised zoning map using
probabilistic framework.
To account for new available information, the shapes of some of the
isoseismals were changed and the extent of Zone 0 in the southern part of the
Indian Peninsula was reduced in the seismic zone map of IS: 1893-1966
30. EARTHQUKE LOAD DESIGN (STATIC EQUIVALENT METHOD)
Z = zone factor = 0.16 (zone-3)
I = importance factor = 1.5
The structure is a special RC moment resisting frame (SMRF)
R = Response reduction factor = 5
Factored dead load on each floor = 3.725 kN/m2
Live load on each floor = 4 kN/m2
EQ in X direction,
Ta = 0.508. For type – 3 Soil, Sa/g = 2.5.
Dead Load from beam on each floor = 434.49 kN
Dead Load from column on each floor = 205.8 kN
Dead load from column on ground level = 176.4 kN
Dead load from wall (2nd from 6th floor) = 1556.526 kN
Dead load from wall (ground floor) = 778.31 kN
Dead load from wall (roof level) = 862.31 kN
31. DEAD LOAD ON ROOF
Dead Load from Slab = 3.445 kN/m2
Dead Load from column = 102.9 kN
Total Load,
On Ground Level = 3040.40 kN
On Floor level (2nd to 6th) = 3846.20 kN
On Roof level (7th) = 2393.90 kN
Horizontal Acceleration (Ah) = (1.5/5) x (0.16/2) x (2.5) = 0.06
Total weight of ll the floor = 28510.9 kN
DESIGN BASE SHEAR
V b = Ah x W = (0.06 x 28510.9) kN = 1710.65 kN
EQ in Z direction,
d = 14.5, Ta = 0.638,
Horizontal Acceleration (Ah) = (1.5/5) x (0.16/2) x (2.13) = 0.05112
DESIGN BASE SHEAR
V b = Ah x W = (0.05112 x 28510.9) KN = 1457.47 kN
32.
33.
34.
35.
36.
37.
38.
39.
40. 40
A plot of the peak value of a response quantity to a ground motion time
history, as a function of the natural vibration period, Tn, or natural frequency,
wn, of the system is called the response spectrum for that quantity.
Each such plot is for SDOF systems having a fixed damping ratio, z, and
several such plots for different values of z are included together in one graph
to cover the range of z values for real structures.
What is Response Spectrum ?
zz
zz
zz
,,max,
,,max,
,,max,
nno
nno
nno
TtuTu
TtuTu
TtuTuD
42. 42
Response Spectra (z = 2%) for
El Centro ground motion
Deformation Response Spectrum
Pseudo-velocity Response Spectrum
Pseudo-acceleration Response
Spectrum
43. 43
Why do we need three spectra when each of them contains the same
information ?
Each spectrum provides a physically meaningful quantity.
Deformation spectrum – provides peak deformation
Pseudo-velocity spectrum – directly related to peak strain energy of the system
Pseudo-acceleration spectrum – directly related to the peak equivalent static force and
base shear
47. Masses are connected to each other and to a
supporting point by linear springs and viscous dashpots.
48. 48
Each characteristic deflected shape Mode Shape
So for a N-DOF system there exist ‘N’ mode shapes and ‘N’ natural frequencies.
Note: Any ith mode shape has (i-1) nodes (points of zero displacement).
NODE
49. 49
Modal Combination Rules
The maximum or peak of the desired response quantity is first obtained for each mode and then
these modal maxima are combined according to a modal combination rule.
1.Square Root of Sum of Squares (SRSS) Method:-
Assumed that the modes achieve peak responses at randomly distributed time instants.
It provides a very good approximation of the peak response for modes with well-separated
natural frequencies but fails for closely spaced modes
2.Complete Quadratic Combination (CQC) Method:-
Based on the use of cross-modal coefficients, it is an improvement over the SRSS
method and applicable to a wide class of structures.
In this method all possible quadratic combinations are incorporated.
60. 60
Ductility is the ability of a member to deform beyond its
elastic limit without failure.
Ductility
Concrete and masonry
are brittle.
Steel is ductile.
Courtesy: IITK-BMTPC EQ. Tips
62. 62
Ductile Chain design
As more and more force is applied, the chain will eventually
break when the weakest link in it breaks.
If the ductile link is the weak one (i.e., its capacity to take load is
less), then the chain will show large final elongation.
Instead, if the brittle link is the
weak one, then the chain will fail
suddenly and show small final
elongation.
Thus, to design a ductile chain, the
ductile link has to be made the
weakest link.
Courtesy: IITK-BMTPC EQ. Tips
63. 63
Strong-Column Weak-Beam Design
The beams should be made the ductile weak link in the chain
and not the columns because the failure of a column affects the
stability of the whole building while the failure of a beam has a
localized effect.
Strong-Column Weak-Beam
Design Method
Courtesy: IITK-BMTPC EQ. Tips
64. 64
Design Provisions for Ductility
IS codes (such as IS 13920 : 1993) enforce ductility
specifications with the following objectives:
Provide large capacity for inelastic deformations.
Prescribe relative strengths of different members to control
failure mechanism at joints.
Permit structure to undergo large inelastic deformations
before collapse – “fail-safe” design philosophy.
65. Clause 7.4.5 :-Special confining reinforcement shall be provided over the full height of column
which has significant variation in stiffness along its height.
This clause deals with short column effect.
70. Earthquake resisting materials1.Masonry
Masonry is made up of burnt clay bricks and cement or mud mortar.
Masonry can carry loads that cause compression (i.e. pressing together) but
can hardly take load that causes tension (i.e. pulling apart). Masonry is a brittle
material, these walls develop cracks once their ability to carry horizontal load is
exceeded.
2.Concrete
Concrete is another material that has been popularly used in building
construction particularly over the last four decades. Cement concrete is made
of crushed stone pieces (called aggregate), sand, cement and water mixed in
appropriate proportions. Concrete is much stronger than masonry under
compressive loads, but again its behavior in tension is poor.
3. Steel
Steel is used in masonry and concrete buildings as reinforcement bars
of diameter ranging from 6mm to 40mm. reinforcing steel can carry both tensile
and compressive loads. Moreover steel is a ductile material.
71.
72.
73.
74.
75.
76.
77.
78. Approaches for Earthquake-Resistant Design of
Structures
First Approach :
Design the structure with sufficient strength, stiffness and inelastic deformation
capacity.
Second Approach :
Use of control devices to reduce the forces acting on the structure.
Control devices may be defined as external structural protective systems that
reduce the energy dissipation demand on primary structural members when the
structure is subjected to external input energy.
80. 1.Passive Control Systems:-
These do not require power to operate – hence termed “passive”
Systems in this category are very reliable since they are unaffected by power outrages, which are
common during earthquakes.
2.Active Control System:-
These require considerable amount of external power, in the order of tens of kilowatts
They are more effective than passive devices because of their ability to adapt to different loading
conditions and to control different modes of vibration
Since the large amount of power required for their operation may not always be available during seismic
events, they are not very reliable.
3. Semi-Active Control Systems:-
cannot inject energy into the controlled system, but their mechanical properties can be adjusted to
improve these performance.
These are often viewed as controllable passive devices.
4. Hybrid Control Systems:-
Combined passive and active control systems – less power and resources are required than active
control systems
82. Types of Passive Control Systems
Base Isolation Systems
Metallic Dampers
Friction Dampers
Viscoelastic Dampers
Fluid Viscous Dampers
Tuned Mass Dampers
Tuned Liquid Dampers
Shape Memory Alloy Dampers
83. Base Isolation Systems
• One of the most powerful tools of earthquake engineering, applicable for
new structures as well as for the retrofit of existing structures.
• It is the only practical way of reducing simultaneously inter-story drift and
floor acceleration
84. 84
Structural Response with and without Base Isolation
Model of a one story building without
base isolation – SDOF system
Model of a one story building with
base isolation – 2-DOF system
c1
c2
85. Base isolation drastically reduces the fundamental
frequency of the system
Fixed Base
Base Isolated
Period
87. 87
Elastomeric Rubber Bearing
Made from natural rubber or neoprene.
Improved by vulcanization bonding of sheets of rubber and thin steel
reinforcing plates or steel shims laminated rubber bearing.
The steel shims reduce the vertical deformation of the bearing and lateral
bulging of the rubber layer.
• Critical damping is of the order of 2% -3% low damping bearing
Easily manufactured at comparatively low cost, are unaffected by time and
resistant to environmental degradation.
.
88. 88
Used as bridge bearing and vibration isolator for buildings
Elastomeric Rubber Bearing….contd.
89. 89
Lead Plug Bearing
Disadvantage of elastomeric bearing’s low damping property can be
overcome by plugging a lead core into the bearing.
A hole is introduced in the center of the elastomeric bearing and a lead
plug is tightly fitted into that hole.
The bearing is designed so that it is very stiff and strong in the vertical
direction but flexible enough in the horizontal direction.
Top and bottom of the bearing are fitted with steel plates which are
used to attach the bearing to building through its foundation.
Critical damping 15% - 35%
91. 91
High Damping Rubber Bearing (HDRB)
Another way to increase the damping is to modify the rubber
compounds. The modification is to add carbon black or other types of
filler material with rubber.
Damping obtained – 10% - 15% of critical.
Super high damping rubber bearing (HDRB-S) has damping 20%
higher than that of conventional HDRB and very stable against cyclic
deformation during a large-scale earthquake.
92. 92
Sliding Systems
This works by limiting the transfer of shear across the isolation
interface.
In China there are at least three buildings on sliding systems that use a
specially selected sand at the sliding interface.
A type of isolation containing a lead-bronze plate sliding on stainless
steel with an elastomeric bearing has been used for a nuclear power
plant in South Africa.
93. CONCLUSION
Earthquake is still unpredictable. So we should
design our structures with proper Earthquake
Codal provisions.Strict laws should be enforced
by the Government for following the codes.
Codes should be revised on the basis of
probabilistic approaches.
So, by using these we can cope up
with earthquake effects.
93