Assessment of steel load-bearing structures - Assessment and Refurbishment of Steel Structures - page 78

The methods and purposes of various measurements and most important instrument
equipment needed are described in Table 3.1. While particular types of instruments are
given in the table, it is necessary to bear in mind the rapid development of current
measuring technology.

3.4.1 Measurement of the geometric shape of a structure

The purpose of measuring geometric shape is to obtain the background data needed for
verifying the behaviour of the structure, taking into consideration the influ-
Table 3.1 Instruments and equipment for
assessment

Measurement
aim

Type of
assessment

Purpose Methods Instruments

Geometric
shape

Periodic assessment,
asssessment
prompted by user

Reference
systems

Geodetic:
• Intersection forward
• Measuring of length
(mechanical, optical,
electric)
• Measuring space grid
of direction in rows and
groups
• Determining
inaccessible distances

Aids for mechanical
implementation of
straight lines

Tensioned invar
wire, plumbline

Photogrametric
methods

Phototheodolite

Accurate
comparator

Recording device

Preventive
assessment,
assessment before
refurbishment

Position of
constructional
parts

Measuring distances,
space grids for
determination of
inaccessible distances,
intersection forward

Steel gauge with
millimetre division,
theodolite electronic
distance finder

Assessment
prompted by user,
Assessment before
refurbishment

Shape and
dimensions of
constructional
parts

Dimension
measurement

Invar bands, vernier
micrometric bolts,
ultrasound thickness
gauge

Measurement of
gradients

Shim gauge, level
with micrometric
bolt