Civil Engineering Reference
In-Depth Information
Bond
condition
Bar diameter (mm)
Reinforcement in
compression
8
10
12
16
20
25
32
40
Anchorage
length, l
bd
Good
230
320
410
600
780
1010
1300
1760
41
ϕ
Straight bars
Poor
320
450
580
850
1120
1450
1850
2510
58
ϕ
Good
320
410
490
650
810
1010
1300
1760
41
ϕ
Other bars
Poor
460
580
700
930
1160
1450
1850
2510
58
ϕ
Lap length, l
0
33% lapped in
one location
Good
260
360
470
690
900
1170
1490
2020
47
ϕ
Poor
370
520
670
980
1280
1660
2130
2890
67
ϕ
Good
310
440
570
830
1090
1420
1810
2460
57
ϕ
50% lapped in
one location
Poor
450
630
820
1190
1560
2020
2590
3520
81
ϕ
Good
340
470
610
890
1170
1520
1940
2640
61
ϕ
100% lapped
in one location
Poor
480
680
870
1270
1670
2170
2770
3770
87
ϕ
Notes:
1. Nominal cover to all sides
≥
25 mm.
2. Distance between bars
≥
50 mm.
3.
α
1
=
α
3
=
α
4
=
α
5
ɪ
= 1.0.
4. Design stress has been taken as 435 MPa. Where the stress is less than 435 MPa, the fi gures in this table can be factored by
σ
sd
/ 435, subject to the minimum lap lengths
given in Cl. 8.7.3 of Eurocode 2.
5. The anchorage and lap lengths have been rounded up to the nearest 10 mm.
6. The fi gures in this table have been prepared for concrete class C25/30, for other concrete class the following factors can be applied:
C30/37 0.89
C35/45 0.80
C40/50 0.73
C50/60 0.63
Table 17.12 Recommended minimum lap and anchorage lengths (mm)
40
f
ck
= 20
ck
= 20
f
ck
= 25
ck
= 25
35
f
ck
= 30
ck
= 30
f
ck
= 35
ck
= 35
30
f
ck
= 40
ck
= 40
f
ck
= 45
ck
= 45
25
f
ck
= 50
ck
= 50
20
15
10
0.20%
0.40%
0.60%
0.80%
1.00%
1.20%
1.40%
1.60%
1.80%
2.00%
Percentage of tension reinforcement (
A
s,req
/
bd
)
bd
)
Figure 17.8 Span-to-depth ratio for checking defl ection
