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CF change of the initially predicted service conditions (12), CG
environmental actions (5), and CH accidental actions (2).
It is concluded that the main causes of defects are included
in categories CD and CE. Inpidually, the causes that most
contributed to the existence of defectswere installment error CD2
Inappropriate/incorrectly applied complementarymaterials (in 41.2%
of the defects) and lack ofmaintenance error CE3 Exceeded service
life of the joint/wearing material (in 35.6% of the defects). A better
supervision action, in approvingmaterials and following the joints
installment work, as well as a swifter action of the conservation
pision, seem to be the aspects that can be improved to extend
the service life of an expansion joint.
Fig. 7 presents the distribution of the causes identified by
category and joints type, naturally excluding joints types 11 and
12 (not found in the sample) and 9 (no defects detected), and leads
to the following conclusions:
even though most of the types of joints present a distribution
of causes by category close to the overall picture, there are
some exceptions such as buried joints under continuous surfacing
(JOPC), asphaltic plug joints (JBM), and nosing joints with poured
sealant (JSME);
in buried joints under continuous surfacing the main causes of
defects aremostly relatedwith a deficient design and especially
with prescription errors; deterioration of the pavement,
characteristic of this type of defect, is very often associatedwith
joint movements higher than those allowed by joints such as
these;
for asphaltic plug joints, prescription errors (joints movements
higher than predicted) and manufacturing errors (inherent to
joints manufactured in situ) assume important roles;
as for nosing joints with poured sealant, lack of maintenance
seems to be themain reason for defects; as amatter of fact, since
they aremostly old joints (the average age of the bridgeswhere
they are installed is 27 years), there is nowa need to replace the
existing elastic sealant way past the end of its service life;
as a concluding remark, older joints tend to present a greater
proportion of causes associated with manufacturing errors,
i.e. quality control has improved.3.5. Inspection and diagnosis methods
The total number of potentially useful inspection and diagnosis
methods registered was 582, averaging 1.6 methods/defect.
Discounting direct visual observation that was used in almost
every defect identified (99.2%), the average decreases to 0.6
methods/defect.
As expected, the distribution in percentage of the inspection
and diagnosis methods identified in the sample by category (DA
observation (67), DB acoustic techniques/noise measurement
(4), DC geometric measurement/verification techniques (23),
DD mechanical techniques (3), and DE (2)) reveals that visual
observation, either direct or using amplifying equipment, is the
watertightness and drainage verification techniques method most
used in inspecting joints. It is also concluded that the next most
adequate inspection and diagnosis methods for joints fall within
category DC Geometric measurement/verification techniques.
In Fig. 8 the distribution of the inspection and diagnosis
methods by category and type of joints (excluding types 9, 11 and
12) is presented, leading to a few conclusions:
the type of joints does not have a substantial influence in
the distribution by category of the inspection and diagnosis
methods identified; the main exception occurs in nosing joints
with poured sealant (JSME);
these joints are usually inspected using observation techniques
only due essentially to the nature of thematerials applied; if the