Handbook for Bridge Inspections - TSP2

All the measurements and materials investigations li sted in Table
7. 1·1 are also described in the "Working procedure Code"
(handbook from NPRA)
Supplementary infonnation can also be found in Chapter 7.2 - 7.8
of this manual. Amongst other things the fo ll owing information
has been detailed:
Purpose of such measurements/investigations
Advantages and disadvantages of the different methods
Requ ired eq uipment
Reference to other manuals which can provide more deta iled
infonnation
7.2 Measurements
7.2.1 Levelling
Purpose
Procedures
To measure settlement, movement and defannation and follow up
possibl e developments.
The need for levelli ng differs fo r new and older bridges, which is
reflected in the need for levelli ng during completion surveys and
other types of inspections.
When measurements are taken on a bridge's superstructure, the
effects of the vibration caused by heavy traffic must be taken into
consideration. If serious vibrations are experienced, measurements
should be taken during periods oflow traffic or while the bridge is
closed for this purpose.
Scope
Acceptance Inspection
For each bridge, levelling should be conducted on all axes and
centrall y in each section.
Levelling bolts require to be installed on bridges with foundations
in weak ground. Regular measurements need not n0011ally be
taken for bridges whose foundations have been sunk into rock;
neither are levell ing bolts requi red.
A decision must be reached as to whether follow·up is to be
undertaken during the operational phase.
Other Inspections
Any fo llow·up inspection in the operational phase stipulated
during a completion survey must be carried Olii.
Levelling must be undertaken in the event of settlement, move·
menl or defonnation. Levell ing can be carried out direct ly on the
relevant clements. However, if developments are to be fo llowed
up over a period, then levelling bolts should be installed.