Civil Engineering Reference
In-Depth Information
where
γ
RE
is 1.0 for a beam on the wall between windows.
b. Checking seismic strength of the wall after retrofitting
Retrofit the wall by adding cement mortar layer with reinforcement mats in one side.
The mat is composed of bi-directional
φ
6@300, thickness of the layer is 30 mm and mortar
strength grade is M7.5. Mortar shear strength of layer is
f
v
1
=1
.
4
√
7
.
5=3
.
83 MPa
When controlled by layer mortar strength:
f
vz
=
nt
1
t
m
f
v
1
+
2
3
f
v
+
0
.
03
nA
sv
1
√
st
m
f
y
30
240
×
3
.
83 +
2
0
.
09 +
0
.
03
×
1
×
28
.
26
=
3
×
√
300
240
×
210
×
=0
.
478 + 0
.
04 + 0
.
06
×
1
.
427 = 0
.
563 MPa
When controlled by reinforcement strength:
f
vz
=
0
.
4
nt
1
t
m
f
v
1
+0
.
26
f
v
+
0
.
35
nA
sv
1
√
st
m
f
y
=0
.
4
×
0
.
478 + 0
.
26
×
0
.
09 + 0
.
35
×
1
.
427 = 0
.
714 MPa
where
f
vz
=0
.
563 MPa is used.
Seismic capacity of brick wall after retrofitting is
(
f
vz
+0
.
7
σ
0
)
A
k
1
.
9
=
0
.
563 + 0
.
7
×
0
.
39
×
2700
×
240
1
.
9
= 285120 N = 285
.
1kN
>V
k
Design value of seismic shear force of retrofitted wall is
V
k
= 216 kN.
4.4
Retrofitting of Brick Columns for Bearing Capacity Deficiency
Those brick columns with inadequate bearing capacity can be retrofitted by augmenting
their sections or utilizing outer packing rolled angles.
4.4.1
Augmenting Sections for Retrofitting Brick Columns
Augmenting section methods for retrofitting brick columns can be done in two ways. One
is covering column with a lateral surface concrete layer (called lateral retrofitting, for short).
And the other way is packing concrete covers or mat reinforced cement mortar covers around
a column, as in Fig. 4.9.
Fig. 4.9
Two augmenting sections method for retrofitting brick columns.
