Transcript Slide 1

T10. ECCENTRICALLY COMPRESSED WALLS
+ PREFABRICATED REINFORCED CONCRETE FLOOR
Masonry structure + pre-fabricated R.C. floor with
type „E” pre-stressed R.C. beams
Floor plan
Example: Checking pre-fabricated reinforced concrete beams
Checking axially compressed masonry walls F2
Design of axially compressed masonry wall F4
(next class: bracing system contains F1-F2-F3 walls)
T10. Eccentrically compressed walls
page 1.
I. Design of pre-fabricated reinforced concrete floor
I.1. Geometry, model, loads
I.1.1. Model, Geometry: pre-fabricated r.c. floor constructions with beams type E:
Always simple supported! beam
(SR. p.55. and 56.)
Minimal bearing is 10 cm below clear span 4,8 m, above it is 12 cm
min
here : l beam

Required beam type: E7-60
Data of pre-stressed concrete floor beams type E:
Jel
E7-24
E7-30
E7-36
E7-42
E7-48
E7-54
E7-60
E7-66
Jel
E7-24
E7-30
E7-36
E7-42
E7-48
E7-54
E7-60
E7-66
leff
cm
252
312
372
432
492
558
618
678
19 cm high concrete floor blocks
19 cm magas béléstest
MRd
qRD
Mqp
qqp
kNm
kN/m
kNm
kN/m
20,00
20,77
14,15
17,83
20,00
16,10
14,15
11,63
20,00
11,56
14,15
8,18
20,00
8,57
14,15
6,07
20,00
6,61
14,15
4,68
20,00
5,14
14,15
3,64
20,00
4,19
14,15
2,96
20,00
3,48
14,15
2,46
Mfr
kNm
17,60
17,60
17,60
17,60
17,60
17,60
17,60
17,60
qfr
kN/m
22,17
14,46
10,17
7,54
5,82
4,52
3,69
3,06
leff
cm
252
312
372
432
492
558
618
678
24 cm24
high
floor
blocks
cmconcrete
magas
béléstest
MRd
qRD
Mqp
qqp
kNm
kN/m
kNm
kN/m
24,70
20,77
16,20
20,41
24,70
16,10
16,20
13,31
24,70
13,14
16,20
9,37
24,70
10,59
16,20
6,94
24,70
8,16
16,20
5,35
24,70
6,35
16,20
4,16
24,70
5,17
16,20
3,39
24,70
4,30
16,20
2,82
Mfr
kNm
20,70
20,70
20,70
20,70
20,70
20,70
20,70
20,70
qfr
kN/m
26,08
17,01
11,97
8,87
6,84
5,32
4,34
3,60
page 2.
T10. Eccentrically compressed walls
I.1.1. Loads: floor
Dead load
 kN 
gK  2 
m 
 g ,sup  1.35
-Self-weight:
Floor layers:
2 cm glued ceramics
6 cm concrete topping
3 cm floating layer
(EPS) + foil
Prefabricated floor
Σ
g Kfloor 
Live load: Variable load:
qKfloor 
load of light partition walls:
qK 
 q  1.5
floor
.pEd 
Design value of the load of one beam (concrete floor blocks 60 cm):
60
p beam

Ed
Double beam with 24 cm high concrete floor blocks:
60
p beam

Ed
page 3.
T10. Eccentrically compressed walls
II. Checking axially compressed wall F1
II.1. Geometry, model, loads, internal forces
II.1.1. Model, Geomety:
h=3.00 m
t=300 mm
II.1.1. Loads, internal forces:
PEdfloor 
g wall

Ed
II.2. Material properties
inhomogenous, anizotropic, linear elastic material model, without tensile strength,
compressive strength:
f k  K fb0.7 f m0.3
where f b is thecompressive strengthof brick, for Porotherm30 f b 
f m is thecompressive strengthof masonrymortar,for masonrymortarM3 f m 
is thefunctionof thegroup of masonry,typeof mortarand typeof bonding, for Porothermmasonry: K 
K
fk 
Safety factor: Attestation of conformity: category: 3, material of masonry: class I,

  2.2
M

fd 
fk
M
T10. Eccentrically compressed walls

page 4.
II.3. Ultimate limit state: strength analysis
Axially compressed wall is also eccentrically compressed!
eccentricity :
ez 
M zd
M
 einit  0.05t here: zd  0
N zd
N zd
einit  h0 /450initialeccentricity (secondeffect,construction inaccuracy... )
ez  einit 
No tensile strength, plastic strength analysis
(at the top and at the bottom of the wall):
N 1Rd,3, y  (t  2e1,3, z ) f d 
N 1Rd,3, y  N Edmax  N 3Ed 
or : N 1Rd,3, y  (1 - 2
e1,3,z
)tf d  1,3, y tf d
t
II.4. Stability analysis
N Rd , y   y t f d  N Ed
calculation of  based on the slenderness of wall and the eccetricity of loads:
slenderness of wall :
h0  h 
, t

h0 / t 
Capacity reduction factor at the midheight of the wall : 2, y e2 , h0 / t   0.84 (Table)
N Rd2 , y  2, y tf d 
T10. Eccentrically compressed walls
 N Ed2 
page 5.
III. Design of axially compressed wall F4
III.1. Geometry, model, loads, internal forces
3,00 m
l= ?
30
B
P1
Monolithic RC
beam
h=
leff
leff
t
N
B ger
t=
ger
p Edföd 
g Edger 
B ger
g Edfal 
B ger


10 föd

p  g Edger l eff 
8 Ed
III.2. Material properties
See previous example
B ger
g Edfal
km
469.87 kN
1
475.25 kN
2
481.18 kN
3
fd 
page 6.
T10. Eccentrically compressed walls
II.3. Strength analysis
Eccentricity :
M zd
 0  ez  einit  h0 / 450  0.05t
N zd
ez 
Plastic analysis (at top and at bottom of wall: c-s 1,3):
N 1Rd,3, y  (t  2e1,3, z )lf d 
N 1Rd,3, y  N Edmax

lszüks 
II.4. Stability analysis
NRd , y   y t l f d  N Ed
h0  h 
t
h0 / t 
lalk 
ez / t 
At midheight of wall (c-s 2): 2, y ez / t, h0 / t  
N Rd2 , y  2, y t l f d  N Ed2

lszüks 
IV. Eccentrically loaded masonry walls
380
190
190
fal
PEd
100
280
140
140
PEdföd
ez
7. page
T10. Eccentrically compressed walls