1. A summary of essential
differences between EC2 and
BS8110
Prof Tan Kang Hai
Email: [email protected]
Director of Protective Technology Research Centre (PTRC)
School of Civil & Environmental Engineering All the rights of 11 lecture materials belong to Tan Kang Hai
1
Outline
Similarities and differences of BS8110 and EC2
Influence of material behaviour
Basis of design and load combination
Global geometric imperfections
Nonlinear versus linear elastic analysis
Shear design of beams and slabs
Design of columns
Detailing of members
2
Outline
Similarities and differences of BS8110 and EC2
Influence of material behaviour
Basis of design and load combination
Global geometric imperfections
Nonlinear versus linear elastic analysis
Shear design of beams and slabs
Design of columns
Detailing of members
3
- Ultimate limit state and serviceability limit state
- Permanent actions, imposed loads and wind loads
- Plane strain assumption for design of beams,
slabs, columns, and walls
- Linear elastic analysis
- Linear elastic analysis with limited distribution
- Plastic analysis
Similarities
of BS8110 and EC2
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
4
• EC2 is phenomenon-based code unlike the BS8110
• Entire code is based on reliability index
• Based on Model Concrete Code 1978 and 1990
1. Influence of material behaviour
2. Basis of design and load combination
3. Global geometric imperfections
4. Nonlinear versus linear elastic analysis
5. Shear design of beams and slabs
6. Design of columns
7. Detailing of members
Differences
between BS8110 and EC2 Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
5
Outline
Similarities and differences of BS8110 and EC2
Influence of material behaviour
Basis of design and load combination
Global geometric imperfections
Nonlinear versus linear elastic analysis
Shear design of beams and slabs
Design of columns
Detailing of members
6
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
max stress level for idealized curve must be below the max stress
of the schematic diagram for the same area under the curve
(3.15)
The design value of concrete compressive strength fcd is given by:
Where the factor allows for the difference between the
bending strength and the cylinder crushing strength of concrete,
and is the concrete material partial safety factor.
EC2 stress-strain relationships of
concrete under compression
7
ckck
c
ckcccd f
fff 567.0
5.1
85.0
5.1c
Class 1 Class 2 Class 3
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Table 3.1 Strength and deformation
characteristics for concrete
8
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
EC2 stress-strain relationships of
reinforcing steel
k=ft/fy indicates ductility; the greater the k value, the longer is the
plateau or the plastic zone uk.
The design value of the modulus of elastic Es is 200 GPa. In
the ultimate limit state calculation, by taking a partial safety
factor of , design values of yield strength fyd and
yield strain of reinforcing steel are respectively computed as:
9
15.1s
y
yk
yk
yd ff
f 87.015.1
00217.0
1020015.1
105006
3
ss
yk
yE
f
10
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Table C.1: Properties of reinforcement
Product form Bars and de-coiled
rods
Wire Fabrics Requirement or
quantile value (%)
Class A B C A B C -
Characteristic yield
strength fyk or f0.2k (MPa)
400 to 600
5.0
Minimum value of
k = (ft/fy)k
≥1.05
≥1.08
≥1.15
<1.35
≥1.05
≥1.08
≥1.15
<1.35
10.0
Characteristic strain at
maximum force, (%)
≥2.5
≥5.0
≥7.5
≥2.5
≥5.0
≥7.5
10.0
Bendability Bend/Rebend test -
Shear strength - 0.3 A fyk (A is area of wire) Minimum
Maximum
deviation
from nominal
mass
(individual
bar of wire)
(%)
Nominal
bar size
(mm)
≤8
>8
± 6.0
± 4.5
5.0
11
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
7.2.3 Tensile properties
The specified values for the tensile properties
are given in Table 4.
Table 4 – Characteristic tensile properties
Yield strength,
Re
MPa
Tensile/yield strength ratio,
Rm/Re
Total elongation at
maximum force, Agt
%
B500A 500 1.05a 2.5b
B500B 500 1.08 5.0
B500C 500 ≥1.15,<1.35 7.5
a Rm/Re characteristics is 1.02 for sizes below 8mm. b Agt characteristics is 1.0% for sizes below 8mm.
Values of Re specified are characteristic with p = 0.95.
Values of Rm/Re and Agt specified are characteristic with p = 0.90.
Calculate the values of Rm and Re using the nominal cross sectional area.
The absolute maximum permissible value of yield strength is 650 MPa.
BS 4449:2005
+A2:2009
12
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
7.2.3 Tensile properties
BS 8666:2005 - Scheduling, dimensioning, bending and cutting of steel
reinforcement for concrete — Specification has been revised to incorporate:
(i) Shape codes available under BS EN ISO 3766:2003; (ii) Revised
notation in accordance with BS 4449:2005 and BS EN 10080:2005; (iii)
Revisions to BS 4449:2005 (including the omission of grade 250 and grade
460 reinforcement)
.
13
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
BS system:
notation is T
Similar to BS specification
Outline
Similarities and differences of BS8110 and EC2
Influence of material behaviour
Basis of design and load combination
Global geometric imperfections
Nonlinear versus linear elastic analysis
Shear design of beams and slabs
Design of columns
Detailing of members
14
15
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Leading variable action and accompanying variable action:
Comparison of partial factors for loading
Design situations BS 8110 EC2
With one variable action
(Live load) 1.4DL + 1.6LL 1.35Gk + 1.5Qk
With one variable action
(Wind load) 1.4DL + 1.6W 1.35Gk + 1.5Wk
With two variable
actions
(leading and
accompanying)
(Wind & live loads)
1.2DL + 1.2LL +
1.2W
1.35 Gk + 1.5 Qk + 0.75Wk
Or 1.35 Gk + 1.05 Qk + 1.5Wk
0.7x1.5Qk for office or
residential buildings
0.5x1.5Wk
(6.10)
Load combinations
according to EC0
16
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Ultimate states Combinations of actions
Eq. (6.10)
For EQU, STR,
GEO
1.35 Gk + 1.5 Qk + 1.5*0.5Wk
Or 1.35 Gk + 1.05 Qk + 1.5Wk
Eq. (6.10a)
For STR, GEO
1.35 Gk + 1.5*0.5Wk +1.5*0.7 Qk
1.35 Gk + 1.5*0.5Wk
Eq. (6.10b)
For STR, GEO
0.925*1.35Gk + 1.5Wk +1.5*0.7 Qk
Or 0.925*1.35 Gk + 1.5Wk
To be applied together
(6.10a)
(6.10b)
For unfavourable
permanent
actions – single
source principle
in EC0 - Table
A1.2 (B) Set B
Load combinations
according to EC0
17
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Instantaneous value of Q
t2 t3
Combination value 0Qk
Characteristic value Qk
Frequent value 1Qk
Time
Quasi-permanent value 2Qk
t1
Fig. Representative values of variable actions
Load combinations
according to EC0
18
Combination Value 0Qk
Frequent Value 1Qk
Quasi-permanent Value 2Qk
OTHER REPRESENTATIVE VALUES OF VARIABLE ACTIONS:
For:
1) ULS and
2) Irreversible SLS
3) Apply to non-leading variable
actions
(consider the reduced probability of
simultaneous occurrences of two or
more independent variable actions.)
For:
1) ULS involving accidental actions,
and
2) Reversible SLS
3) Apply to leading variable actions
(e.g. for buildings, the frequent value is
chosen so that the time it is exceeded is
0.01 of the reference period of 50
years)
For:
1) ULS involving accidental
actions, and
2) Reversible SLS
3) Used for calculation of long-
term effects.
(e.g. for loads on building floors, the
quasi-permanent value is chosen
so that the proportion of the time it
is exceeded is 0.50 of the reference
period.)
1. BS EN 1990:2002 (EC0)
19
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Combinations of actions for the Serviceability Limit State
Combination Permanent action
Gd
Variable action Qd
Leading Others
Characteristic Gk,j Qk,1 0,iQk,i
Frequent Gk,j 1,1Qk,1 2,iQk,i
Quasi-
permanent Gk,j 2,1Qk,1 2,iQk,i
Load combinations
according to EC0
20
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Load combinations
according to EC0
Exposure Reinforced members and
prestressed members
without bonded tendons
(quasi-permanent load
combination)
Prestressed
members with
bonded tendons
(frequent load
combination)
X0, XC1 0.3a 0.2
XC2, XC3, XC4 0.3 0.2b
XD1, XD2, XD3, XS1, XS2,
XS3
0.2 and decompressionc
a For X0, XC1 exposure classes, crack width has no influence on durability and this limit is set to produce
acceptable appearance. In the absence of specific requirements for appearance this limit may be relaxed.
b For these exposure classes, in addition, decompression should be checked under the quasi-permanent
combination of loads.
c wmax = 0.2 mm applies to parts of the member that do not have to be checked for decompression.
Crack width limit
UK Annex Table NA.4 Recommended values of wmax (mm)
maxw w
21
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Failure conditions under ULS
according to EC0
1.35Gk
1.35Gk + 1.5Qk
1.35Gk + 1.5Qk
1.0Gk
1.35Gk 1.35Gk
1.35Gk + 1.5Qk
Single source for Gk
1.4Gk + 1.6Qk
1.4Gk + 1.6Qk
1.4Gk + 1.6Qk
22
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Load combinations
according to EC2 Cl 5.1.3
1.35Gk + 1.5Qk
1.0Gk 1.0Gk
Outline
Similarities and differences of BS8110 and EC2
Influence of material behaviour
Basis of design and load combination
Global geometric imperfections
Nonlinear versus linear elastic analysis
Shear design of beams and slabs
Design of columns
Detailing of members
23
24
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
• In EC2, there is no notional
horizontal load.
• Global geometric imperfections due
to out-of-plumbness of vertical
elements must be modelled by
equivalent loads in two design
situations:
Persistent design situations:
Possible extreme loading condition
of wind, imposed loads.
Accidental design situations: fire,
impact.
When to consider
geometric imperfections?
25
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
• Imperfection loads are quantified by three considerations:
Global analysis of building structures.
Analysis of isolated vertical members.
Analysis of floor diaphragms as horizontal elements
transferring forces to bracing members.
Only imperfection loads in global analysis are similar to
notional horizontal loads, although they are very different in
the way to be considered.
• Imperfections need not be considered for serviceability limit
states.
When to consider
geometric imperfections?
26
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
• The structure is assumed with inclination θl, given by:
where: θ0 is the basic value (θ0 = 1/200)
• αh is the reduction factor for height
• αm is the reduction factor for number of members:
where m is the number of vertically continuous members
in the storey contributing to total horizontal forces on the
floor.
How to consider
geometric imperfections?
27
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members • The imperfection on each floor may be represented by a
force acting on the floor where Na and Nb are the factored
axial forces above and below the floor considered. (see
EC3 Figure 5.3)
To design for slab
(member transferring
forces to bracing
elements)
How to consider
geometric imperfections?
28
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Lateral load case: in BS 8110: Hdesign = Max(HN, 1.2Wk)
However, in EC 2: Hdesign = 1.0 Hi + FWk
where Hi is horizontal loads for geometric imperfection
How to consider
geometric imperfections?
Outline
Similarities and differences of BS8110 and EC2
Influence of material behaviour
Basis of design and load combination
Global geometric imperfections
Nonlinear versus linear elastic analysis
Shear design of beams and slabs
Design of columns
Detailing of members
29
30
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
First order elastic analysis: represents conditions at
normal service loads very well (Section 5.4)
First order elastic analysis with limited redistribution:
excluded nonlinearity, represents conditions at normal
service loads very well (Section 5.5)
First order inelastic analysis: Plastic analysis with no
geometrical nonlinearity (Section 5.6)
Second order elastic analysis: Effects of finite
deformation considered. Good representation of P- effect
(Section 5.7)
Second order inelastic analysis: Both geometrical and
material nonlinearities are considered. Model can faithfully
reflect the behavior of structures up to ultimate limit state
Different types of analysis
31
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Source: Fig. 8.1 of Matrix Structural Analysis, Second Edition, William
McGuire, Richard H. Gallagher and Ronald D. Ziemian, John Wiley & Sons, Inc,
2000, ISBN 0-471-12918-6
e
Different types of analysis
32
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Taken from EC2
Local second order effects
Cl 5.8.7 or Cl 5.8.8
33
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
States that if there are additional action effects caused by
structural deformations under the influence of significant axial
load, second order effects should be considered.
Local second order effect
on isolated members (P-)
Global second order effect
on whole structure (P-)
Local second order effects
Cl 5.8.7 or Cl 5.8.8
How to account for second order effects?
Local second order effects
- Method based on nominal stiffness (EC2 Clause 5.8.7)
- Method based on nominal curvature (EC2 Clause 5.8.8)
Local second order effects
Cl 5.8.7 or Cl 5.8.8 Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Outline
Similarities and differences of BS8110 and EC2
Influence of material behaviour
Basis of design and load combination
Global geometric imperfections
Nonlinear versus linear elastic analysis
Shear design of beams and slabs
Design of columns
Detailing of members
35
36
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Methodology
DC : the concrete acts as the
diagonal struts;
VT: the stirrups act as the
vertical ties;
BT: the tension reinforcement
forms the bottom chord;
TC: the compression
steel/concrete forms the top
chord.
= 21.80 ÷ 450 (strut angle)
(EC2 6.2.3(2))
(a) Beam and reinforcement
(b) Analogous truss
• EC2 uses The Variable Strut Inclination Method for shear
design.
• BS 8110 uses Truss Analogy with truss angle = 450
37
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Comparison of shear design
• BS 8110
1. = 45o
2. BS 8110 compares shear
stresses.
3. The maximum shear
stress is limited to 5
N/mm2 or 0.8fcu,
whichever is the lesser.
4. The design shear force
must be less than the
sum of the shear
resistance of concrete
plus shear links.
• EC2
1. = 21.8o ÷ 45o
2. EC 2 compares shear forces.
3. The maximum shear capacity
of concrete VRd,max cannot be
exceeded.
4. Where the applied shear
exceeds the min shear
resistance of concrete VRd,c,
the shear reinforcement
should be capable of resisting
all the shear forces.
38
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Punching shear design of slabs
Control perimeters
Basic control perimeter u1:
Control perimeters
39
For slabs with a rectangular column with a rectangular head
with lH < 2hH, the value rcont may be taken as the lesser of:
1 2 12 0.56 and 2 0.69 cont cont
r d l l r d l
1 1 1 2 2 2 1 22 ; 2 ;
H Hl c l l c l l l
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Control perimeters
40
For slabs with enlarged column heads where lH > 2hH, the
control sections both within the head and in the slab should
be checked. For circular columns:
cont,ext
cont,int
2 0.5
2 0.5
H
H
r l d c
r d h c
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Punching shear stress VEd
41
(EC2 6.4.3 (3))
How to calculate b?
For rectangular columns:
221
1 1 2 2 14 16 2
2
cW c c c d d dc
1
1
1 Ed
Ed
M uk
V Wb
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Outline
Similarities and differences of BS8110 and EC2
Influence of material behaviour
Basis of design and load combination
Global geometric imperfections
Nonlinear versus linear elastic analysis
Shear design of beams and slabs
Design of columns
Detailing of members
42
43
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Differences in symbols
44
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Differences in symbols
45
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Differences in design
46
Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
Differences in design
Outline
Similarities and differences of BS8110 and EC2
Influence of material behaviour
Basis of design and load combination
Global geometric imperfections
Nonlinear versus linear elastic analysis
Shear design of beams and slabs
Design of columns
Detailing of members
47
48
Minimum cover due to
environmental conditions cmin,dur Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
49
Minimum cover due to
environmental conditions cmin,dur Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
50
Minimum cover due to
environmental conditions cmin,dur Similarities and
differences of
BS8110 and EC2
Influence of
material behaviour
Basis of design
and load
combination
Global geometric
imperfections
Nonlinear versus
linear elastic
analysis
Shear design of
beams and slabs
Design of columns
Detailing of
members
DESIGN ANCHORAGE LENGTH
For the effect of the form of the
bars assuming adequate cover
1=0.7~1.0 (in comp. is 1.0)
For the effect of concrete minimum
cover 2=0.7~1.0 (in comp. is 1.0)
For the effect of confinement by tied
transverse bars along the design anc.
length 3=0.7~1.0 (in comp. is 1.0)
For the effect of confinement by welded
transverse bars along the design anc. length
4=0.7
For the effect of confinement by transverse
pressure along the design anc. length 5=0.7
Basic anchorage length
Design stress of the bar:
Design ultimate stress:
For the quality of bond condition 1=0.7
(poor) - 1=1.0 (good)
For the bar diameter 2=1.0 for ≤32mm
2=(132-)/100 for >32mm
The design concrete tensile strength (<C60/75)
fctd=fctk,0.05/c
Detailing of members
51
DESIGN ANCHORAGE LENGTH lbd
Detailing of members
52
• Complex load combinations due to leading and accompanying
variable load cases;
• In EC0 - Eq 6.10 compared with Eq 6.10(a) and Eq 6.10(b).
• Definition of member types and the choice of suitable elements;
• Represent global geometrical imperfection load by horizontal
loads and consider in all ULS;
• Need to consider global second order effect unless structure
satisfies Clause 5.8.3.3;
• Calculation model should reflect realistic global and local
behaviour of the designed RC structure
• High strength concrete is permitted (above 50 MPa till 90 MPa);
SUMMARY on Differences between BS and EC
53
Thank You!
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