representative of the more than 1500 bridges within the network,
the distribution in terms of type, age and geographical location of
the 71 bridges inspected was established in order to replicate the
one of the global universe of bridges.
The distribution of the bridges inspected by type is shown in
Fig. 2 and compared with the global universe. Generally a good
approximationwas obtained, particularly in the case of overpasses.sample. Since the number of these joints in the sample is high
(33), it can be safely stated that in Portugal in recent times, the
installment of elastomeric flexible strips betweenmetallic profiles
is uncommon.
3.2. Joints manufacturers
The sample also allowed evaluating some of the specific
characteristics of the expansion joints market in Portugal, namely
in terms of the main manufacturers/franchisers of joints for Brisa:
Fernando Lemos (24%), VSL (29%), Alga (18%), FIP Industriale (7%),
Freyssinet (3%), and unknown (20%).
It must be pointed out that this statistical study comprised
only joints installed within the traffic lanes of the bridges. Joints
installed in the sidewalks that often have no relation with those
in the lanes were not considered. This discrepancy is the more
conspicuous the older the bridge (Fig. 5, left). In the oldest bridges
of the sample, where joints were made to order, sidewalks joints
were normally identical to those at the lanes. Sincemost lane joints
have already been replaced, it is very easy to detect the differences
between the present and the past solutions. In the younger bridges
within the sample, the current solution for sidewalks is steel
sliding plates. Situationswhere the sidewalks joints are continuous
with the lanes joints may be considered rare (Fig. 5, right).
This study shows a significant ratio of 20% for joints whose
manufacturer is unknown. That is so because older joints within
the sample were made specifically for each bridge instead of
mass pre-fabricated and do not present the manufacturer's brand.
Furthermore, asphaltic plug joints cannot be identified unless at
the moment of in situ manufacture/molding. This may explain a
lesser percentage of Freyssinet joints, one of the main providers of
joints of this type (under the commercial brand name Viajoint). The
high percentage of joints by Fernando Lemos is explained by their
being a national firm and should not be extrapolated abroad.
3.3. Defects
The list of potential defects (presented in [1]) comprises 28
different types grouped in 7 categories. In the campaign performed
22 of the 28 types were found and the analysis of these data
resulted in some changes to the initial list, namely in some of the
designations in order to broaden its scope. A distribution of the
defects detected according to the different categories is as follows:
AA transition to the pavement/pavement (35%), AB geometry
(7%), AC movement (7%), AD anchorage to the structure (21%),
AE joint/joint material (20%), AF watertightness/drainage (9%),
and AG users comfort (0%).
Defects in category AA are the most frequent, especially AA1
Deterioration of the transition strip and AA3 Detachment in the
transition. Both happen in about 2=3 of the joints. Categories
AD and AE also have an important role in the deterioration of
joints, with overall ratios over 20%. In category AD, defect AD1
Deterioration/loss of sealant of anchorage cavities stands out since
it was found in 45% of the joints detected. Therefore, one of the
conclusions of this survey was that the transition strip and the
anchorage cavities must be subjected of current maintenance.
Fig. 6 is enlightening in terms of distribution of defects by
category and type of joint. It is noticed that asphaltic plug joints (JBM) are particularly affected by the material used and therefore 公路桥梁伸缩缝检查英文文献和中文翻译(2):http://www.youerw.com/fanyi/lunwen_16504.html