Broadway Road Overbridge (A322)
Collision Assessment Review Report
October 2017
Notice
This document and its contents have been prepared and are intended solely for Surrey County Council and
use in relation to the collision assessment of Broadway Road Overbridge (A322).
Atkins Highways and Transportation assumes no responsibility to any other party in respect of or arising out
of or in connection with this document and/or its contents.
Document History
JOB NUMBER: 5158836
DOCUMENT REF: Broadway Road Overbridge Pier
Collision Review
2.0
2nd Issue
19/10/17
1.0
Preliminary Issue
17/10/17
Revision
Purpose Description
Originated
Checked
Reviewed
Authorised
Date
Document Reference:
Broadway Road Overbridge (A322)
Collision Assessment Review Report
Contents
Chapter
Pages
1.
Introduction
1
2.
Structural Description
2
2.1.
Typical section
2
2.2.
Superstructure
2
2.3.
Substructure
2
3.
Overview of the Assessment
3
3.1.
Collision load
3
3.2.
Superstructure dead load
5
3.3.
Material property and Material factors
5
3.4.
Loads and Load factors
5
3.5.
Assessment result
6
4.
Conclusion
7
5.
References
8
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Broadway Road Overbridge (A322)
Collision Assessment Review Report
2.
Structural Description
2.1.
Typical section
A typical section of the bridge is shown below.
Figure 3.
Typical section of the structure
2.2.
Superstructure
The bridge superstructure incorporates a voided post-tensioned concrete deck, continuously
supported over intermediate piers. The total width of the deck slab is 10.8m and supports a 6.0m
carriageway, two 2.0m footpaths and two 0.4m parapet upstands. The superstructure is
supported by bearings at all support locations.
2.3.
Substructure
The bridge incorporates reinforced concrete abutments at both ends, plus two intermediate piers.
The piers have two discrete columns respectively. Columns are 1.1m diameter reinforced
concrete circular type. Both abutments have pile foundations and the piers are supported on
spread footings.
2
Broadway Road Overbridge (A322)
Collision Assessment Review Report
4.
Conclusion
Broadway Road Overbridge (A322) was assessed for the collision load. The result concluded that
column is adequate to the assumed collision load. As the assessment results passed,
strengthening works is not considered necessary. However concrete repairs should be
undertaken as soon as possible.
It is noted the columns have been assessed as inadequate for collision loading in accordance
with BD 48/93. The shear resistance tabulated above is considered conservative (as based on
shear resistance of the concrete only). However, the columns are overstressed in bending. This
result takes account of the beneficial effect of compression in the column due to permanent
loads. As such the pier should be protected with a high containment safety barrier. This is
especially important during the concrete repairs as this will result in temporary reduction in
capacity. It is also recommended a lane closure is implemented during the repair works to further
mitigate the risk of an errant vehicle incursion.
7
Broadway Road Overbridge (A322)
Collision Assessment Review Report
5.
References
Highways England Standards:
-
BA 48/93 The assessment and strengthening of highway bridge supports
-
BD 44/15 The assessment of concrete highway bridges and structures
-
BS6779-1 Highway parapets for bridges and other structures
8