尊敬的 微信汇率:1円 ≈ 0.046374 元 支付宝汇率:1円 ≈ 0.046466元 [退出登录]
SlideShare a Scribd company logo
Compression Members
• Vertical Structural members
• Transmits axial compressive loads with or
without moment
• Design considerations
– Strength
– Buckling
• Examples : Pedestal, column, wall and strut
1/6/2024 1
• Effective length
– The vertical distance between the points of
inflection of the compression member in the
buckled configuration in a plane is termed as
effective length le of that compression member in
that plane. If l is the unsupported length, then
– Clause 25.2 of IS 456:2000 stipulates the effective
lengths of compression members
le = kl
1/6/2024 2
IS-456: Table 28:Effective length of
compression member
1/6/2024 3
IS-456: Table 28:Effective length of
compression member- Continue
1/6/2024 4
Major and Minor axis of Column
Major Axis : Axis about which the moment of Inertia of column is
more than the moment of inertia about other perpendicular axis
Minor Axis : Axis about which the moment of Inertia of column is less
than the moment of inertia about other perpendicular axis
1/6/2024 5
Compression Members
• Pedestal (IS 456:2000 cl. 26.5.3)
– l <= 3 times least horizontal dimension, say b
– other horizontal dimension <= 4 times b
• Column (IS 456:2000 cl. 25.3)
– unsupported length, l <= 60 times least
dimension, if restrained at both ends
• Wall (IS 456:2000 cl. 32.2.3)
– Effective height to thickness ratio <= 30
1/6/2024 6
Classification of columns based on
types of reinforcement
Column with transverse
(lateral ties) reinforcement Column with helical
reinforcement
Composite columns
with steel sections
1/6/2024 7
Classification of columns based on
loadings
Axial loading (concentric)
Axial loading with
uniaxial bending
Axial loading with
biaxial bending
1/6/2024 8
Column with axial loading (concentric)
Column with axial loads and uniaxial bending
Column with axial loads and biaxial bending
1/6/2024 9
Classification of columns based on
slenderness ratio
Mode Failure
Mode 1
Compression
Failure
• Occurs in short column
• No lateral deformation
• collapse due to material failure
Mode 2
Combine
compression
and bending
Failure
• Short column – combined effects of axial
load and bending
• Slender column – beam-column effect
under axial load
Mode 3
Buckling
Failure
• Failure due to elastic instability under
small loads without yielding of material
1/6/2024 10
Classification of columns based on
slenderness ratio
According to code (Cl.25.1.2)
•Short Column – (Lex/D) & (Ley/b) < 12
•Long Column – (Lex/D) OR (Ley/b) ≥ 12
Lex = Effective length in respect of the major axis
D = Depth w.r.t. major axis
Ley = Effective length in respect of the minor axis
b = Width of the member
1/6/2024 11
• cl. 25.3.1 the maximum unsupported length between
two restraints of a column to sixty times its least
lateral dimension.
l/d ≤ 60
• For cantilever columns, when one end of the column
is unrestrained, the unsupported length is restricted
to 100b2/D where b and D are as defined earlier
cl.25 Compression members
1/6/2024 12
Code Requirements on Reinforcement
and Detailing
Longitudinal reinforcement (cl.26.5.3.1)
• The minimum amount of steel should be at least 0.8% of the
gross cross-sectional area of the column required.
• The maximum amount of steel should be 4% of the gross
cross-sectional area of the column so that it does not exceed
6 per cent when bars from column below have to be lapped
with those in the column under consideration.
• Four and six are the minimum number of longitudinal bars in
rectangular and circular columns, respectively.
• The diameter of the longitudinal bars should be at least 12
mm.
1/6/2024 13
Code Requirements on Reinforcement
and Detailing
• Columns having helical reinforcement shall have at
least six longitudinal bars within and in contact with
the helical reinforcement. The bars shall be placed
equidistant around its inner circumference.
• The bars shall be spaced not exceeding 300 mm
along the periphery of the column.
• The amount of reinforcement for pedestal shall be at
least 0.15 per cent of the cross-sectional area
provided
1/6/2024 14
Code Requirements on Reinforcement
and Detailing
Transverse reinforcement (cl.26.5.3.2)
• A reinforced concrete compression member shall have transverse or
helical reinforcement so disposed that every longitudinal bar nearest
to the compression face has effective lateral support against
buckling subject to provisions given in cl.26.5.3.2(b)(Arrangement
of transverse reinforcement). The effective lateral support is given
by transverse reinforcement either in the form of circular rings or by
polygonal links (lateral ties) with internal angles not exceeding 1350.
• The pitch or spacing of lateral ties is limited to the least of:
– the least lateral dimension of the compression members;
– sixteen times the smallest diameter of the longitudinal reinforcement bar to
be tied; and
– 300 mm.
1/6/2024 15
Design of axially loaded columns
rm = 1.5 for Concrete
Stress = 0.67fck/1.5 = 0.446 fck
rm = 1.15 for Steel
Stress = fy/1.5 = 0.87fy
1/6/2024 16
• The stress corresponding to 0.002 strain in steel bars are as follows:
Grade of Steel Stress
Corresponding to
0.002 Strain
Fe250 0.87 fy
Fe 415 0.79 fy
Fe 500 0.75 fy
1/6/2024 17
Design of axially loaded columns
• The code adopts the critical value of 0.75 fy
for all grades of steel for finding out the pure
axial load carrying capacity of the column
Pu = 0.446 fck Ac + 0.75 fy As………….(1)
1/6/2024 18
Design of axially loaded columns
• Due to Rigid frame action, lateral loadings and
practical aspects of construction axially loaded
columns are subjected to bending moments.
• Minimum eccentricity as specified in code
(Clause 25.4) need to be considered
• emin Should be Greater of
– (unsupported length/500 + lateral dimension/30)
– 20 mm
1/6/2024 19
Design of axially loaded columns
• When emin does not exceed 0.05 times the lateral
dimension, code permits the use of following
simplified formula obtained by reducing Pu (Given in
equation 1 ) by approx. 10% (cl. 39.3)
Pu = 0.4 fck Ac + 0.67 fy As
1/6/2024 20
𝑃𝑢 = 0.40𝑓𝑐𝑘𝐴𝑐 + 0.67𝑓𝑦𝐴𝑠
𝑃𝑢 = 0.40𝑓𝑐𝑘(𝐴𝑔−𝐴𝑠) + 0.67𝑓𝑦𝐴𝑠
𝑃𝑢 = 0.40𝑓𝑐𝑘𝐴𝑔(1 − 𝑝) + 0.67𝑓𝑦𝑝𝐴𝑔
• 𝐴𝑔= gross area of the section
• 𝑝= percentage of steel reinforcement
Design of axially loaded columns
1/6/2024 21
Compression Member with Helical
Reinforcement
• The strength of compression
members with helical reinforcement
shall be taken as 1.05 times the
strength of similar member with
lateral ties.
Pu = 1.05*(0.4 fck Ac + 0.67 fy As)
•The ratio of the volume of helical
reinforcement to the volume of the
core shall not be less than
0.36(Ag/Ac-1)*fck/fy
1/6/2024 22
• 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 ℎ𝑒𝑙𝑖𝑐𝑎𝑙 𝑟𝑒𝑖𝑛𝑓𝑜𝑟𝑐𝑒𝑚𝑒𝑛𝑡
𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑐𝑜𝑟𝑒(𝑉𝑐)
≥ 0.36
𝐴𝑔
𝐴𝑐
− 1 ∗
𝑓𝑐𝑘
𝑓𝑦
• 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 ℎ𝑒𝑙𝑖𝑐𝑎𝑙 𝑟𝑒𝑖𝑛𝑓𝑜𝑟𝑐𝑒𝑚𝑒𝑛𝑡 =
𝜋(𝐷𝑐−𝜑𝑠𝑝
)∗asp
• 𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑐𝑜𝑟𝑒 = 𝜋
4
∗ Dc2 ∗ 𝑆𝑣
•
𝜋(𝐷𝑐−𝜑𝑠𝑝
)∗asp
𝜋
4
∗Dc2∗Sv
≥ 0.36
𝐴𝑔
𝐴𝑐
− 1 ∗
𝑓𝑐𝑘
𝑓𝑦
Dc = Dia. of core
𝜑𝑠𝑝 = Dia. of spiral reinforcement
asp = Area of cross section of spiral reinforcement
Sv = pitch of spiral reinforcement
1/6/2024 23
Detailing of Reinforcement in Column
1/6/2024 24
Q. Design the reinforcement in a column of size 400 mm x 600 mm
subjected to an axial load of 2000 KN under service dead load and
live load. The column has an unsupported length of 4.0 m and
effectively held in position and restrained against rotation in both
ends. Use M 25 concrete and Fe 415 steel.
Slenderness Check
𝑙𝑒𝑥/𝐷𝑥 = 2600/600=4.33 < 12
𝑙𝑒𝑦/𝐷𝑦 = 2600/400=6.5 < 12
Hence it is a short column
Minimum Eccentricity
ex min = Greater of (lx/500+D/30) and 20 mm
= Greater of (4000/500 + 600/30) and 20 mm
= 28 mm and 20 mm => 28 mm
As per IS-456: Table 28,
Theoretical value = 0.5L
Recommended value =0.65L
=0.65*4000=2600
1/6/2024 25
ey min = Greater of (ly/500+Dy/30) and 20 mm
= Greater of (4000/500 + 400/30) and 20 mm
= 21.33 mm and 20 mm => 21.33 mm
0.05*Dx = 0.05*600 =30 mm > ex min (28mm)
0.05*Dy = 0.05*400 = 20 mm ~ ey min (21.33 mm)
• When emin does not exceed 0.05 times the lateral
dimension, code permits the use of simplified
formula.
1/6/2024 26
𝑃𝑢 = 0.40𝑓𝑐𝑘𝐴𝑐 + 0.67𝑓𝑦
𝑃𝑢 = 0.40𝑓𝑐𝑘(𝐴𝑔 − 𝐴𝑠) + 0.67𝑓𝑦𝐴𝑠
3000*103 = 0.4 *25*(400 *600- As) + 0.67*415*As
As = 2238.39 mm2
Provide #6 Nos. 20 mm dia. Bars and #2 Nos. 16 mm dia. Bars
Hence Area provided = 2287 mm2
% Reinforcement Pt = (As/bd)*100
Pt = 0.953 > 0.8% & < 4% (cl. 26.5.3.2)……..OK.
Lateral Ties
Not less than…… i. φ/4 and
ii. 6 mm
Here φ is the largest bar diameter in the longitudinal reinforcement
Consider 8 mm dia. lateral ties which is currently being used in
field.
1/6/2024 27
Pitch ……. cl.26.5.3.2
i. the least lateral dimension of the column = 400 mm
ii. sixteen times the smallest diameter of longitudinal
reinforcement bar to be tied = 16(16) = 256 mm
iii. 300 mm
Use a pitch of 250 mm
1/6/2024 28
Design a reinforced concrete spiral column of 390
mm diameter subjected to an axial factored load of
1750 kN. The column is braced against side sway and
has unsupported length of 3.3 m. The concrete mix
and steel to be used in construction are of grades M25
and Fe415, respectively.
1/6/2024 29
1/6/2024 30
Design of Spiral steel
Conside a bar dia. Of 8 mm and pitch Sv
Dia. Of the Core Dc = 390-40-40 = 310 mm
Dia. Of the helix Dsp = 390-40-40-8 = 302 mm
As per cl. 39.4.1
𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 ℎ𝑒𝑙𝑖𝑐𝑎𝑙 𝑟𝑒𝑖𝑛𝑓𝑜𝑟𝑐𝑒𝑚𝑒𝑛𝑡
𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑐𝑜𝑟𝑒(𝑉𝑐)
≥ 0.36
𝐴𝑔
𝐴𝑐
− 1 ∗
𝑓𝑐𝑘
𝑓𝑦
𝜋(𝐷𝑐−𝜑𝑠𝑝
)∗asp
𝜋
4
∗Dc2∗Sv
≥ 0.36
𝐴𝑔
𝐴𝑐
− 1 ∗
𝑓𝑐𝑘
𝑓𝑦
Dc = Dia. of core
φsp = Dia. of spiral reinforcement
asp = Area of cross section of spiral reinforcement
Sv = pitch of spiral reinforcement
1/6/2024 31
1/6/2024 32
Detailing of Reinforcement
1/6/2024 33

More Related Content

Similar to RCC column_Shortly Axially Loaded column.pptx

CE 72.52 - Lecture6 - Member Behavior
CE 72.52 - Lecture6 - Member BehaviorCE 72.52 - Lecture6 - Member Behavior
CE 72.52 - Lecture6 - Member Behavior
Fawad Najam
 
Columns rajeevan sir
Columns rajeevan sirColumns rajeevan sir
Columns rajeevan sir
SHAMJITH KM
 
Calulation of deflection and crack width according to is 456 2000
Calulation of deflection and crack width according to is 456 2000Calulation of deflection and crack width according to is 456 2000
Calulation of deflection and crack width according to is 456 2000
Vikas Mehta
 
Column uniaxial axial loaded column design
Column  uniaxial axial loaded column designColumn  uniaxial axial loaded column design
Column uniaxial axial loaded column design
UmarSaba1
 
Compression member
Compression memberCompression member
Compression member
Vikas Mehta
 
Design of concrete structure.
Design of concrete structure.Design of concrete structure.
Design of concrete structure.
M M ALAMGIR HOSSAIN
 
Chapter 6 column
Chapter 6   columnChapter 6   column
Chapter 6 column
Simon Foo
 
Introduction to design of rcc column
Introduction to design of rcc columnIntroduction to design of rcc column
Introduction to design of rcc column
PHURTSHERINGSHERPA
 
Columns lecture#1
Columns lecture#1Columns lecture#1
Columns lecture#1
Irfan Malik
 
Column
ColumnColumn
Ductile detailing
Ductile detailingDuctile detailing
Ductile detailing
Binay Shrestha
 
M10l21
M10l21M10l21
M10l21
imaduddin91
 
Sd i-module4- rajesh sir
Sd i-module4- rajesh sirSd i-module4- rajesh sir
Sd i-module4- rajesh sir
SHAMJITH KM
 
chapter 4 flexural design of beam 2021.pdf
chapter 4 flexural design of beam 2021.pdfchapter 4 flexural design of beam 2021.pdf
chapter 4 flexural design of beam 2021.pdf
AshrafZaman33
 
Design of torsion reinforcement
 Design of torsion reinforcement Design of torsion reinforcement
Design of torsion reinforcement
MuskanDeura
 
Div_Syd_detailing_of_reinforcement_in_concrete_structures.pdf
Div_Syd_detailing_of_reinforcement_in_concrete_structures.pdfDiv_Syd_detailing_of_reinforcement_in_concrete_structures.pdf
Div_Syd_detailing_of_reinforcement_in_concrete_structures.pdf
LandelSmith1
 
Presentation on Slab, Beam, Column, and Foundation/Footing
Presentation on Slab,  Beam, Column, and Foundation/FootingPresentation on Slab,  Beam, Column, and Foundation/Footing
Presentation on Slab, Beam, Column, and Foundation/Footing
Dhaka University of Engineering & Technology, Gazipur
 
Connections
Connections Connections
Connections
kamariya keyur
 
Design of columns axial load as per IS 456-2000
Design of columns  axial load as per IS 456-2000Design of columns  axial load as per IS 456-2000
Design of columns axial load as per IS 456-2000
PraveenKumar Shanmugam
 
DSR chap4 shear and bond pdf.pptxxxxxxxxxxxxxxxxxxxxxx
DSR chap4 shear and bond pdf.pptxxxxxxxxxxxxxxxxxxxxxxDSR chap4 shear and bond pdf.pptxxxxxxxxxxxxxxxxxxxxxx
DSR chap4 shear and bond pdf.pptxxxxxxxxxxxxxxxxxxxxxx
ADITYAPILLAI29
 

Similar to RCC column_Shortly Axially Loaded column.pptx (20)

CE 72.52 - Lecture6 - Member Behavior
CE 72.52 - Lecture6 - Member BehaviorCE 72.52 - Lecture6 - Member Behavior
CE 72.52 - Lecture6 - Member Behavior
 
Columns rajeevan sir
Columns rajeevan sirColumns rajeevan sir
Columns rajeevan sir
 
Calulation of deflection and crack width according to is 456 2000
Calulation of deflection and crack width according to is 456 2000Calulation of deflection and crack width according to is 456 2000
Calulation of deflection and crack width according to is 456 2000
 
Column uniaxial axial loaded column design
Column  uniaxial axial loaded column designColumn  uniaxial axial loaded column design
Column uniaxial axial loaded column design
 
Compression member
Compression memberCompression member
Compression member
 
Design of concrete structure.
Design of concrete structure.Design of concrete structure.
Design of concrete structure.
 
Chapter 6 column
Chapter 6   columnChapter 6   column
Chapter 6 column
 
Introduction to design of rcc column
Introduction to design of rcc columnIntroduction to design of rcc column
Introduction to design of rcc column
 
Columns lecture#1
Columns lecture#1Columns lecture#1
Columns lecture#1
 
Column
ColumnColumn
Column
 
Ductile detailing
Ductile detailingDuctile detailing
Ductile detailing
 
M10l21
M10l21M10l21
M10l21
 
Sd i-module4- rajesh sir
Sd i-module4- rajesh sirSd i-module4- rajesh sir
Sd i-module4- rajesh sir
 
chapter 4 flexural design of beam 2021.pdf
chapter 4 flexural design of beam 2021.pdfchapter 4 flexural design of beam 2021.pdf
chapter 4 flexural design of beam 2021.pdf
 
Design of torsion reinforcement
 Design of torsion reinforcement Design of torsion reinforcement
Design of torsion reinforcement
 
Div_Syd_detailing_of_reinforcement_in_concrete_structures.pdf
Div_Syd_detailing_of_reinforcement_in_concrete_structures.pdfDiv_Syd_detailing_of_reinforcement_in_concrete_structures.pdf
Div_Syd_detailing_of_reinforcement_in_concrete_structures.pdf
 
Presentation on Slab, Beam, Column, and Foundation/Footing
Presentation on Slab,  Beam, Column, and Foundation/FootingPresentation on Slab,  Beam, Column, and Foundation/Footing
Presentation on Slab, Beam, Column, and Foundation/Footing
 
Connections
Connections Connections
Connections
 
Design of columns axial load as per IS 456-2000
Design of columns  axial load as per IS 456-2000Design of columns  axial load as per IS 456-2000
Design of columns axial load as per IS 456-2000
 
DSR chap4 shear and bond pdf.pptxxxxxxxxxxxxxxxxxxxxxx
DSR chap4 shear and bond pdf.pptxxxxxxxxxxxxxxxxxxxxxxDSR chap4 shear and bond pdf.pptxxxxxxxxxxxxxxxxxxxxxx
DSR chap4 shear and bond pdf.pptxxxxxxxxxxxxxxxxxxxxxx
 

Recently uploaded

Applications of artificial Intelligence in Mechanical Engineering.pdf
Applications of artificial Intelligence in Mechanical Engineering.pdfApplications of artificial Intelligence in Mechanical Engineering.pdf
Applications of artificial Intelligence in Mechanical Engineering.pdf
Atif Razi
 
一比一原版(爱大毕业证书)爱荷华大学毕业证如何办理
一比一原版(爱大毕业证书)爱荷华大学毕业证如何办理一比一原版(爱大毕业证书)爱荷华大学毕业证如何办理
一比一原版(爱大毕业证书)爱荷华大学毕业证如何办理
nedcocy
 
一比一原版(USF毕业证)旧金山大学毕业证如何办理
一比一原版(USF毕业证)旧金山大学毕业证如何办理一比一原版(USF毕业证)旧金山大学毕业证如何办理
一比一原版(USF毕业证)旧金山大学毕业证如何办理
uqyfuc
 
Call For Paper -3rd International Conference on Artificial Intelligence Advan...
Call For Paper -3rd International Conference on Artificial Intelligence Advan...Call For Paper -3rd International Conference on Artificial Intelligence Advan...
Call For Paper -3rd International Conference on Artificial Intelligence Advan...
ijseajournal
 
SMT process how to making and defects finding
SMT process how to making and defects findingSMT process how to making and defects finding
SMT process how to making and defects finding
rameshqapcba
 
This study Examines the Effectiveness of Talent Procurement through the Imple...
This study Examines the Effectiveness of Talent Procurement through the Imple...This study Examines the Effectiveness of Talent Procurement through the Imple...
This study Examines the Effectiveness of Talent Procurement through the Imple...
DharmaBanothu
 
3rd International Conference on Artificial Intelligence Advances (AIAD 2024)
3rd International Conference on Artificial Intelligence Advances (AIAD 2024)3rd International Conference on Artificial Intelligence Advances (AIAD 2024)
3rd International Conference on Artificial Intelligence Advances (AIAD 2024)
GiselleginaGloria
 
Call Girls Chennai +91-8824825030 Vip Call Girls Chennai
Call Girls Chennai +91-8824825030 Vip Call Girls ChennaiCall Girls Chennai +91-8824825030 Vip Call Girls Chennai
Call Girls Chennai +91-8824825030 Vip Call Girls Chennai
paraasingh12 #V08
 
Blood finder application project report (1).pdf
Blood finder application project report (1).pdfBlood finder application project report (1).pdf
Blood finder application project report (1).pdf
Kamal Acharya
 
Accident detection system project report.pdf
Accident detection system project report.pdfAccident detection system project report.pdf
Accident detection system project report.pdf
Kamal Acharya
 
Call Girls Goa (india) ☎️ +91-7426014248 Goa Call Girl
Call Girls Goa (india) ☎️ +91-7426014248 Goa Call GirlCall Girls Goa (india) ☎️ +91-7426014248 Goa Call Girl
Call Girls Goa (india) ☎️ +91-7426014248 Goa Call Girl
sapna sharmap11
 
Asymmetrical Repulsion Magnet Motor Ratio 6-7.pdf
Asymmetrical Repulsion Magnet Motor Ratio 6-7.pdfAsymmetrical Repulsion Magnet Motor Ratio 6-7.pdf
Asymmetrical Repulsion Magnet Motor Ratio 6-7.pdf
felixwold
 
Tools & Techniques for Commissioning and Maintaining PV Systems W-Animations ...
Tools & Techniques for Commissioning and Maintaining PV Systems W-Animations ...Tools & Techniques for Commissioning and Maintaining PV Systems W-Animations ...
Tools & Techniques for Commissioning and Maintaining PV Systems W-Animations ...
Transcat
 
Open Channel Flow: fluid flow with a free surface
Open Channel Flow: fluid flow with a free surfaceOpen Channel Flow: fluid flow with a free surface
Open Channel Flow: fluid flow with a free surface
Indrajeet sahu
 
Lateral load-resisting systems in buildings.pptx
Lateral load-resisting systems in buildings.pptxLateral load-resisting systems in buildings.pptx
Lateral load-resisting systems in buildings.pptx
DebendraDevKhanal1
 
Northrop Grumman - Aerospace Structures Overvi.pdf
Northrop Grumman - Aerospace Structures Overvi.pdfNorthrop Grumman - Aerospace Structures Overvi.pdf
Northrop Grumman - Aerospace Structures Overvi.pdf
takipo7507
 
Sri Guru Hargobind Ji - Bandi Chor Guru.pdf
Sri Guru Hargobind Ji - Bandi Chor Guru.pdfSri Guru Hargobind Ji - Bandi Chor Guru.pdf
Sri Guru Hargobind Ji - Bandi Chor Guru.pdf
Balvir Singh
 
UNIT 4 LINEAR INTEGRATED CIRCUITS-DIGITAL ICS
UNIT 4 LINEAR INTEGRATED CIRCUITS-DIGITAL ICSUNIT 4 LINEAR INTEGRATED CIRCUITS-DIGITAL ICS
UNIT 4 LINEAR INTEGRATED CIRCUITS-DIGITAL ICS
vmspraneeth
 
Prediction of Electrical Energy Efficiency Using Information on Consumer's Ac...
Prediction of Electrical Energy Efficiency Using Information on Consumer's Ac...Prediction of Electrical Energy Efficiency Using Information on Consumer's Ac...
Prediction of Electrical Energy Efficiency Using Information on Consumer's Ac...
PriyankaKilaniya
 
Flow Through Pipe: the analysis of fluid flow within pipes
Flow Through Pipe:  the analysis of fluid flow within pipesFlow Through Pipe:  the analysis of fluid flow within pipes
Flow Through Pipe: the analysis of fluid flow within pipes
Indrajeet sahu
 

Recently uploaded (20)

Applications of artificial Intelligence in Mechanical Engineering.pdf
Applications of artificial Intelligence in Mechanical Engineering.pdfApplications of artificial Intelligence in Mechanical Engineering.pdf
Applications of artificial Intelligence in Mechanical Engineering.pdf
 
一比一原版(爱大毕业证书)爱荷华大学毕业证如何办理
一比一原版(爱大毕业证书)爱荷华大学毕业证如何办理一比一原版(爱大毕业证书)爱荷华大学毕业证如何办理
一比一原版(爱大毕业证书)爱荷华大学毕业证如何办理
 
一比一原版(USF毕业证)旧金山大学毕业证如何办理
一比一原版(USF毕业证)旧金山大学毕业证如何办理一比一原版(USF毕业证)旧金山大学毕业证如何办理
一比一原版(USF毕业证)旧金山大学毕业证如何办理
 
Call For Paper -3rd International Conference on Artificial Intelligence Advan...
Call For Paper -3rd International Conference on Artificial Intelligence Advan...Call For Paper -3rd International Conference on Artificial Intelligence Advan...
Call For Paper -3rd International Conference on Artificial Intelligence Advan...
 
SMT process how to making and defects finding
SMT process how to making and defects findingSMT process how to making and defects finding
SMT process how to making and defects finding
 
This study Examines the Effectiveness of Talent Procurement through the Imple...
This study Examines the Effectiveness of Talent Procurement through the Imple...This study Examines the Effectiveness of Talent Procurement through the Imple...
This study Examines the Effectiveness of Talent Procurement through the Imple...
 
3rd International Conference on Artificial Intelligence Advances (AIAD 2024)
3rd International Conference on Artificial Intelligence Advances (AIAD 2024)3rd International Conference on Artificial Intelligence Advances (AIAD 2024)
3rd International Conference on Artificial Intelligence Advances (AIAD 2024)
 
Call Girls Chennai +91-8824825030 Vip Call Girls Chennai
Call Girls Chennai +91-8824825030 Vip Call Girls ChennaiCall Girls Chennai +91-8824825030 Vip Call Girls Chennai
Call Girls Chennai +91-8824825030 Vip Call Girls Chennai
 
Blood finder application project report (1).pdf
Blood finder application project report (1).pdfBlood finder application project report (1).pdf
Blood finder application project report (1).pdf
 
Accident detection system project report.pdf
Accident detection system project report.pdfAccident detection system project report.pdf
Accident detection system project report.pdf
 
Call Girls Goa (india) ☎️ +91-7426014248 Goa Call Girl
Call Girls Goa (india) ☎️ +91-7426014248 Goa Call GirlCall Girls Goa (india) ☎️ +91-7426014248 Goa Call Girl
Call Girls Goa (india) ☎️ +91-7426014248 Goa Call Girl
 
Asymmetrical Repulsion Magnet Motor Ratio 6-7.pdf
Asymmetrical Repulsion Magnet Motor Ratio 6-7.pdfAsymmetrical Repulsion Magnet Motor Ratio 6-7.pdf
Asymmetrical Repulsion Magnet Motor Ratio 6-7.pdf
 
Tools & Techniques for Commissioning and Maintaining PV Systems W-Animations ...
Tools & Techniques for Commissioning and Maintaining PV Systems W-Animations ...Tools & Techniques for Commissioning and Maintaining PV Systems W-Animations ...
Tools & Techniques for Commissioning and Maintaining PV Systems W-Animations ...
 
Open Channel Flow: fluid flow with a free surface
Open Channel Flow: fluid flow with a free surfaceOpen Channel Flow: fluid flow with a free surface
Open Channel Flow: fluid flow with a free surface
 
Lateral load-resisting systems in buildings.pptx
Lateral load-resisting systems in buildings.pptxLateral load-resisting systems in buildings.pptx
Lateral load-resisting systems in buildings.pptx
 
Northrop Grumman - Aerospace Structures Overvi.pdf
Northrop Grumman - Aerospace Structures Overvi.pdfNorthrop Grumman - Aerospace Structures Overvi.pdf
Northrop Grumman - Aerospace Structures Overvi.pdf
 
Sri Guru Hargobind Ji - Bandi Chor Guru.pdf
Sri Guru Hargobind Ji - Bandi Chor Guru.pdfSri Guru Hargobind Ji - Bandi Chor Guru.pdf
Sri Guru Hargobind Ji - Bandi Chor Guru.pdf
 
UNIT 4 LINEAR INTEGRATED CIRCUITS-DIGITAL ICS
UNIT 4 LINEAR INTEGRATED CIRCUITS-DIGITAL ICSUNIT 4 LINEAR INTEGRATED CIRCUITS-DIGITAL ICS
UNIT 4 LINEAR INTEGRATED CIRCUITS-DIGITAL ICS
 
Prediction of Electrical Energy Efficiency Using Information on Consumer's Ac...
Prediction of Electrical Energy Efficiency Using Information on Consumer's Ac...Prediction of Electrical Energy Efficiency Using Information on Consumer's Ac...
Prediction of Electrical Energy Efficiency Using Information on Consumer's Ac...
 
Flow Through Pipe: the analysis of fluid flow within pipes
Flow Through Pipe:  the analysis of fluid flow within pipesFlow Through Pipe:  the analysis of fluid flow within pipes
Flow Through Pipe: the analysis of fluid flow within pipes
 

RCC column_Shortly Axially Loaded column.pptx

  • 1. Compression Members • Vertical Structural members • Transmits axial compressive loads with or without moment • Design considerations – Strength – Buckling • Examples : Pedestal, column, wall and strut 1/6/2024 1
  • 2. • Effective length – The vertical distance between the points of inflection of the compression member in the buckled configuration in a plane is termed as effective length le of that compression member in that plane. If l is the unsupported length, then – Clause 25.2 of IS 456:2000 stipulates the effective lengths of compression members le = kl 1/6/2024 2
  • 3. IS-456: Table 28:Effective length of compression member 1/6/2024 3
  • 4. IS-456: Table 28:Effective length of compression member- Continue 1/6/2024 4
  • 5. Major and Minor axis of Column Major Axis : Axis about which the moment of Inertia of column is more than the moment of inertia about other perpendicular axis Minor Axis : Axis about which the moment of Inertia of column is less than the moment of inertia about other perpendicular axis 1/6/2024 5
  • 6. Compression Members • Pedestal (IS 456:2000 cl. 26.5.3) – l <= 3 times least horizontal dimension, say b – other horizontal dimension <= 4 times b • Column (IS 456:2000 cl. 25.3) – unsupported length, l <= 60 times least dimension, if restrained at both ends • Wall (IS 456:2000 cl. 32.2.3) – Effective height to thickness ratio <= 30 1/6/2024 6
  • 7. Classification of columns based on types of reinforcement Column with transverse (lateral ties) reinforcement Column with helical reinforcement Composite columns with steel sections 1/6/2024 7
  • 8. Classification of columns based on loadings Axial loading (concentric) Axial loading with uniaxial bending Axial loading with biaxial bending 1/6/2024 8
  • 9. Column with axial loading (concentric) Column with axial loads and uniaxial bending Column with axial loads and biaxial bending 1/6/2024 9
  • 10. Classification of columns based on slenderness ratio Mode Failure Mode 1 Compression Failure • Occurs in short column • No lateral deformation • collapse due to material failure Mode 2 Combine compression and bending Failure • Short column – combined effects of axial load and bending • Slender column – beam-column effect under axial load Mode 3 Buckling Failure • Failure due to elastic instability under small loads without yielding of material 1/6/2024 10
  • 11. Classification of columns based on slenderness ratio According to code (Cl.25.1.2) •Short Column – (Lex/D) & (Ley/b) < 12 •Long Column – (Lex/D) OR (Ley/b) ≥ 12 Lex = Effective length in respect of the major axis D = Depth w.r.t. major axis Ley = Effective length in respect of the minor axis b = Width of the member 1/6/2024 11
  • 12. • cl. 25.3.1 the maximum unsupported length between two restraints of a column to sixty times its least lateral dimension. l/d ≤ 60 • For cantilever columns, when one end of the column is unrestrained, the unsupported length is restricted to 100b2/D where b and D are as defined earlier cl.25 Compression members 1/6/2024 12
  • 13. Code Requirements on Reinforcement and Detailing Longitudinal reinforcement (cl.26.5.3.1) • The minimum amount of steel should be at least 0.8% of the gross cross-sectional area of the column required. • The maximum amount of steel should be 4% of the gross cross-sectional area of the column so that it does not exceed 6 per cent when bars from column below have to be lapped with those in the column under consideration. • Four and six are the minimum number of longitudinal bars in rectangular and circular columns, respectively. • The diameter of the longitudinal bars should be at least 12 mm. 1/6/2024 13
  • 14. Code Requirements on Reinforcement and Detailing • Columns having helical reinforcement shall have at least six longitudinal bars within and in contact with the helical reinforcement. The bars shall be placed equidistant around its inner circumference. • The bars shall be spaced not exceeding 300 mm along the periphery of the column. • The amount of reinforcement for pedestal shall be at least 0.15 per cent of the cross-sectional area provided 1/6/2024 14
  • 15. Code Requirements on Reinforcement and Detailing Transverse reinforcement (cl.26.5.3.2) • A reinforced concrete compression member shall have transverse or helical reinforcement so disposed that every longitudinal bar nearest to the compression face has effective lateral support against buckling subject to provisions given in cl.26.5.3.2(b)(Arrangement of transverse reinforcement). The effective lateral support is given by transverse reinforcement either in the form of circular rings or by polygonal links (lateral ties) with internal angles not exceeding 1350. • The pitch or spacing of lateral ties is limited to the least of: – the least lateral dimension of the compression members; – sixteen times the smallest diameter of the longitudinal reinforcement bar to be tied; and – 300 mm. 1/6/2024 15
  • 16. Design of axially loaded columns rm = 1.5 for Concrete Stress = 0.67fck/1.5 = 0.446 fck rm = 1.15 for Steel Stress = fy/1.5 = 0.87fy 1/6/2024 16
  • 17. • The stress corresponding to 0.002 strain in steel bars are as follows: Grade of Steel Stress Corresponding to 0.002 Strain Fe250 0.87 fy Fe 415 0.79 fy Fe 500 0.75 fy 1/6/2024 17
  • 18. Design of axially loaded columns • The code adopts the critical value of 0.75 fy for all grades of steel for finding out the pure axial load carrying capacity of the column Pu = 0.446 fck Ac + 0.75 fy As………….(1) 1/6/2024 18
  • 19. Design of axially loaded columns • Due to Rigid frame action, lateral loadings and practical aspects of construction axially loaded columns are subjected to bending moments. • Minimum eccentricity as specified in code (Clause 25.4) need to be considered • emin Should be Greater of – (unsupported length/500 + lateral dimension/30) – 20 mm 1/6/2024 19
  • 20. Design of axially loaded columns • When emin does not exceed 0.05 times the lateral dimension, code permits the use of following simplified formula obtained by reducing Pu (Given in equation 1 ) by approx. 10% (cl. 39.3) Pu = 0.4 fck Ac + 0.67 fy As 1/6/2024 20
  • 21. 𝑃𝑢 = 0.40𝑓𝑐𝑘𝐴𝑐 + 0.67𝑓𝑦𝐴𝑠 𝑃𝑢 = 0.40𝑓𝑐𝑘(𝐴𝑔−𝐴𝑠) + 0.67𝑓𝑦𝐴𝑠 𝑃𝑢 = 0.40𝑓𝑐𝑘𝐴𝑔(1 − 𝑝) + 0.67𝑓𝑦𝑝𝐴𝑔 • 𝐴𝑔= gross area of the section • 𝑝= percentage of steel reinforcement Design of axially loaded columns 1/6/2024 21
  • 22. Compression Member with Helical Reinforcement • The strength of compression members with helical reinforcement shall be taken as 1.05 times the strength of similar member with lateral ties. Pu = 1.05*(0.4 fck Ac + 0.67 fy As) •The ratio of the volume of helical reinforcement to the volume of the core shall not be less than 0.36(Ag/Ac-1)*fck/fy 1/6/2024 22
  • 23. • 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 ℎ𝑒𝑙𝑖𝑐𝑎𝑙 𝑟𝑒𝑖𝑛𝑓𝑜𝑟𝑐𝑒𝑚𝑒𝑛𝑡 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑐𝑜𝑟𝑒(𝑉𝑐) ≥ 0.36 𝐴𝑔 𝐴𝑐 − 1 ∗ 𝑓𝑐𝑘 𝑓𝑦 • 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 ℎ𝑒𝑙𝑖𝑐𝑎𝑙 𝑟𝑒𝑖𝑛𝑓𝑜𝑟𝑐𝑒𝑚𝑒𝑛𝑡 = 𝜋(𝐷𝑐−𝜑𝑠𝑝 )∗asp • 𝑉𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑐𝑜𝑟𝑒 = 𝜋 4 ∗ Dc2 ∗ 𝑆𝑣 • 𝜋(𝐷𝑐−𝜑𝑠𝑝 )∗asp 𝜋 4 ∗Dc2∗Sv ≥ 0.36 𝐴𝑔 𝐴𝑐 − 1 ∗ 𝑓𝑐𝑘 𝑓𝑦 Dc = Dia. of core 𝜑𝑠𝑝 = Dia. of spiral reinforcement asp = Area of cross section of spiral reinforcement Sv = pitch of spiral reinforcement 1/6/2024 23
  • 24. Detailing of Reinforcement in Column 1/6/2024 24
  • 25. Q. Design the reinforcement in a column of size 400 mm x 600 mm subjected to an axial load of 2000 KN under service dead load and live load. The column has an unsupported length of 4.0 m and effectively held in position and restrained against rotation in both ends. Use M 25 concrete and Fe 415 steel. Slenderness Check 𝑙𝑒𝑥/𝐷𝑥 = 2600/600=4.33 < 12 𝑙𝑒𝑦/𝐷𝑦 = 2600/400=6.5 < 12 Hence it is a short column Minimum Eccentricity ex min = Greater of (lx/500+D/30) and 20 mm = Greater of (4000/500 + 600/30) and 20 mm = 28 mm and 20 mm => 28 mm As per IS-456: Table 28, Theoretical value = 0.5L Recommended value =0.65L =0.65*4000=2600 1/6/2024 25
  • 26. ey min = Greater of (ly/500+Dy/30) and 20 mm = Greater of (4000/500 + 400/30) and 20 mm = 21.33 mm and 20 mm => 21.33 mm 0.05*Dx = 0.05*600 =30 mm > ex min (28mm) 0.05*Dy = 0.05*400 = 20 mm ~ ey min (21.33 mm) • When emin does not exceed 0.05 times the lateral dimension, code permits the use of simplified formula. 1/6/2024 26
  • 27. 𝑃𝑢 = 0.40𝑓𝑐𝑘𝐴𝑐 + 0.67𝑓𝑦 𝑃𝑢 = 0.40𝑓𝑐𝑘(𝐴𝑔 − 𝐴𝑠) + 0.67𝑓𝑦𝐴𝑠 3000*103 = 0.4 *25*(400 *600- As) + 0.67*415*As As = 2238.39 mm2 Provide #6 Nos. 20 mm dia. Bars and #2 Nos. 16 mm dia. Bars Hence Area provided = 2287 mm2 % Reinforcement Pt = (As/bd)*100 Pt = 0.953 > 0.8% & < 4% (cl. 26.5.3.2)……..OK. Lateral Ties Not less than…… i. φ/4 and ii. 6 mm Here φ is the largest bar diameter in the longitudinal reinforcement Consider 8 mm dia. lateral ties which is currently being used in field. 1/6/2024 27
  • 28. Pitch ……. cl.26.5.3.2 i. the least lateral dimension of the column = 400 mm ii. sixteen times the smallest diameter of longitudinal reinforcement bar to be tied = 16(16) = 256 mm iii. 300 mm Use a pitch of 250 mm 1/6/2024 28
  • 29. Design a reinforced concrete spiral column of 390 mm diameter subjected to an axial factored load of 1750 kN. The column is braced against side sway and has unsupported length of 3.3 m. The concrete mix and steel to be used in construction are of grades M25 and Fe415, respectively. 1/6/2024 29
  • 31. Design of Spiral steel Conside a bar dia. Of 8 mm and pitch Sv Dia. Of the Core Dc = 390-40-40 = 310 mm Dia. Of the helix Dsp = 390-40-40-8 = 302 mm As per cl. 39.4.1 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 ℎ𝑒𝑙𝑖𝑐𝑎𝑙 𝑟𝑒𝑖𝑛𝑓𝑜𝑟𝑐𝑒𝑚𝑒𝑛𝑡 𝑣𝑜𝑙𝑢𝑚𝑒 𝑜𝑓 𝑐𝑜𝑟𝑒(𝑉𝑐) ≥ 0.36 𝐴𝑔 𝐴𝑐 − 1 ∗ 𝑓𝑐𝑘 𝑓𝑦 𝜋(𝐷𝑐−𝜑𝑠𝑝 )∗asp 𝜋 4 ∗Dc2∗Sv ≥ 0.36 𝐴𝑔 𝐴𝑐 − 1 ∗ 𝑓𝑐𝑘 𝑓𝑦 Dc = Dia. of core φsp = Dia. of spiral reinforcement asp = Area of cross section of spiral reinforcement Sv = pitch of spiral reinforcement 1/6/2024 31
  翻译: