N G NEERS AND R K TECTS CO PARTNERSHIP
Page: 1
101 HIGH STREET PEVERILL DORSET
Made by: DWB/IFB
JOB: NEW CIVIC CENTRE
Date: 07.07.07
ANCILLARY BUILDING
Ref No: C702
───────────────────────────────────────────────────────────────────────
Office: 6527
Location: Ex1 - 8 metre span arch
─────────────────────────────────
Assessment of Masonry Arch Bridges by the Modified MEXE Method
──────────────────────────────────────────────────────────────
Departmental Standard BD 21/01 and Advice Note BA 16/97
───────────────────────────────────────────────────────
Calculations are in accordance with "The Assessment of Highway
Bridges and Structures" as described in the following documents:
■ Departmental Standard BD 21/01
■ Departmental Advice Note BA 16/97 incorporating Amendment No. 2.
NOTE: Unless otherwise noted references are to sections of BA 16/97.
├─────────────────────────────────────────────────────┤
≈ ░░░░ road surfacing ░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░░ ≈
├─────────────────────────────────────────────────────┤
│
│
│
■ ┬ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─ ─│─
│
■
│d
■
│
│
■
■ ┼
■
│
≈
■
■┬
│rc
■
■
≈
│
■
■
│rq
│
■
■
│
│
■ ─ ─ ─ ┴ ─ ─ ─ ─ ┴
■
│
│
│
L/4
│
│
│
│<──────>
│
│
│
│
L
│
│
│
│<───────────────────────────────>│
│
├────@────┤
├────@────┤
Span of arch
Rise of barrel at crown
Rise of barrel at quarter points
Thickness of barrel adjacent to keystone
Average depth of fill between the road
surface and the arch barrel at the crown
L=
rc=
rq=
d=
4 m
1 m
0.5 m
0.305 m
h=
0.5 m
┬
│
│ h
│
┴
*************************** WARNING ***********************************
Depth of fill is greater than barrel thickness at crown. Results should
be confirmed using an alternative method ( BD 21/01 Clause 6.17 ).
Span/rise factor ( 3.11 and Figure 3/3 ):
Span/rise ratio
Span/rise factor
srr=L/rc=4/1=4
Fsr=-0.00225*srr^3+0.05425*srr^2-0.4955*srr+2.256
=-0.00225*4^3+0.05425*4^2-0.4955*4+2.256
=0.998
Profile factor ( 3.12 and Figure 3/4 )
Ratio of rq/rc
rr=rq/rc=0.5/1=0.5
The ratio rq/rc is less than or equal to 0.75
Profile factor
Fp=1.0
Barrel factor ( Table 3/1 )
Fb=1.2
Joint factor ( 3.16 ):
N G NEERS AND R K TECTS CO PARTNERSHIP
Page: 2
101 HIGH STREET PEVERILL DORSET
Made by: DWB/IFB
JOB: NEW CIVIC CENTRE
Date: 07.07.07
ANCILLARY BUILDING
Ref No: C702
───────────────────────────────────────────────────────────────────────
Office: 6527
Joint factor = width factor * mortar factor * depth factor
Width factor ( Table 3/3 )
Fw=0.9
Mortar factor ( Table 3/4 )
Fmo=0.9
Pointed joints in good condition.
Depth factor ( 3.16 )
Fd=1.0
Gross barrel thickness
dr=d=0.305 m
Joint factor (3.16 )
Fj=Fw*Fd*Fmo=0.9*1*0.9=0.81
Fill factor ( Table 3/2 )
Ff=0.7
Material Factor ( 3.13 ) = MF
(barrel factor*barrel thickness)+(fill factor*fill depth)
MF = ─────────────────────────────────────────────────────────
total thickness of barrel and fill at crown
Material factor
Fm=(Fb*dr+Ff*h)/(dr+h)
=(1.2*0.305+0.7*0.5)/(0.305+0.5)
=0.88944
Condition factor ( 3.17 )
FcM=0.9
Provisional axle load ( 3.10 )
PAL=740*(dr+h)^2/L^1.3
=740*(0.305+0.5)^2/4^1.3
=79.094 tonnes
The provisional axle load is limited to 70 tonnes. ( 3.23 )
Revised provisional axle load
PAL=70 tonnes
The modified axle load represents the allowable loading on the arch
from an axle forming part of a double axled bogie configuration with
no lift-off from any axle. ( 3.24 ).
Modified axle load
MAL=Fsr*Fp*Fm*Fj*FcM*PAL
=0.998*1*0.88944*0.81*0.9*70
=45.297 tonnes
Centrifugal effects not considered.
Centrifugal effect factor
Fa=1.0
Axle lift-off ( 3.27 ):
Axle factors - no lift-off case ( Figure 3/5a )
Single axle
Afsanl=TABLE 1 for L=4
=1
Double axle
Afdanl=1.0
Triple axle
Aftanl=TABLE 2 for L=4
=1
Allowable axle loads - no lift-off case
Single axle
sanlo=MAL*Afsanl/Fa=45.297*1/1
=45.297 tonnes
Double axle
danlo=MAL*Afdanl/Fa=45.297*1/1
=45.297 tonnes
Triple axle
tanlo=MAL*Aftanl/Fa=45.297*1/1
=45.297 tonnes
N G NEERS AND R K TECTS CO PARTNERSHIP
Page: 3
101 HIGH STREET PEVERILL DORSET
Made by: DWB/IFB
JOB: NEW CIVIC CENTRE
Date: 07.07.07
ANCILLARY BUILDING
Ref No: C702
───────────────────────────────────────────────────────────────────────
Office: 6527
DESIGN SUMMARY
──────────────
Allowable axle loads are rounded off to the nearest 0.5 tonnes
Rounded values of allowable axle loads - no lift-off case
Single axle
45.5 tonnes
Double axle
45.5 tonnes
Triple axle
45.5 tonnes
Weight Restrictions and Permitted Vehicles ( 3.30 )
┌──────────┬─────────────────────┬───────────┬─────────────╥─────────┐
│ Type of │ Allowable Axle Load │ Max Gross │
Weight
║ Vehicle │
│ Vehicle │ (tonnes) per axle
│ Vehicle │ Restriction ║Permitted│
├──────────┼───────┬──────┬──────┤ Weight
│ (tonnes)
║
│
│
│Single │Double│Triple│ (tonnes) │
║
│
├──────────┼───────┼──────┼──────┼───────────┼─────────────╫─────────┤
│HGV axles │
│
│
│
│
║
│
├──────────┼───────┼──────┼──────┼───────────┼─────────────╫─────────┤
│5 or 6
│ 11.5 │ 10.0 │ 8.0 │ 40/44
│
N/A
║ Yes
│
├──────────┼───────┼──────┼──────┼───────────┼─────────────╫─────────┤
│4
│ 11.5 │ 9.5 │
│ 32
│
33
║ Yes
│
├──────────┼───────┼──────┼──────┼───────────┼─────────────╫─────────┤
│3
│ 11.5 │ 9.5 │
│ 26
│
26
║ Yes
│
├──────────┼───────┼──────┼──────┼───────────┼─────────────╫─────────┤
│2
│ 11.5 │
│
│ 18
│
18
║ Yes
│
├──────────┼───────┼──────┼──────┼───────────┼─────────────╫─────────┤
│2
│ 9.0 │
│
│ 13
│
13
║ Yes
│
├──────────┼───────┼──────┼──────┼───────────┼─────────────╫─────────┤
│2
│ 7.0 │
│
│ 10
│
10
║ Yes
│
├──────────┼───────┼──────┼──────┼───────────┼─────────────╫─────────┤
│LGV
│ 5.5 │
│
│
7.5
│
7.5
║ Yes
│
├──────────┼───────┼──────┼──────┼───────────┼─────────────╫─────────┤
│Car/Van
│ 2.0 │
│
│
3
│
3
║ Yes
│
├──────────┼───────┼──────┼──────┼───────────┼─────────────╫─────────┤
│Fire Eng. │
│
│
│
│
║
│
├──────────┼───────┼──────┼──────┼───────────┼─────────────╫─────────┤
│Group 1
│ 10.0 │
│
│
│
║ Yes
│
├──────────┼───────┼──────┼──────┼───────────┼─────────────╫─────────┤
│Group 2
│ 5.0 │
│
│
│
║ Yes
│
└──────────┴───────┴──────┴──────┴───────────┴─────────────╨─────────┘