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RECONSTRUCTION OF THE MOSTAR |
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NEWSLETTER 9 MARCH 31, 2003 |
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CENTERING
Six wooden
half-circled planks were placed on the steel construction of the centering, of
which we wrote about in more details before. They allow the curve of The Old
Bridge arch to be completely executed as it was before its demolition. Because of
their dimensions, half-circled planks were transported in parts to the site
and placed on the platform. They were lifted one by one from the platform
onto centering by crane, then placed on foreseen location and put
together.
First two wooden half-circled planks were placed Wooden
covering was placed onto half-circled planks from the upper side, and it
consists of planks placed by their length vertically onto extending direction
of half-circled planks. This covering will be the final layer of the
centering and all stone blocks will be placed directly on it. At the moment
its surface looks exactly as the
Wooden covering on the half-circled planks Although technical acceptance of the
centering has already been conducted, half-circled planks on the left bank
are not completely installed. This will allow undisturbed injection of the
abutment wall on that side. Immediately after the injection process, the
remaining few parts of the half-circled planks will be installed on the left
bank. Covering with planks will be continued after that, on both sides of the
bridge at the same time. PORTAL
CRANE
Portal
crane which will be used at reconstruction works is out serial. It was made
according to special order, only for reconstruction of the
Erected
portal crane Crane is
capable of caring a cargo in all three directions: forward-backward on steel
trails along the centering, then left-right, with the help of the “cat” and
naturally up-and-down by lifting the pulley on steel chain. Manipulation
of the crane is manual. This way of handling allows maximum of preciseness.
Moreover, with manual handling we avoid swinging of cargo, namely heavy stone
blocks.
Portal
crane Lifting
power of portal crane is 3 tons, which is more then double then the weight of
the heaviest block in the arch. After this,
mechanism must be found which allows that every block is put on its place
without any damage and as precisely as possible. It is very
important to make the mechanism in the best and most effective way because
the safety of the stone blocks and the workers will depend on it. The value
of each stone block is enormous, not only when it is measured in money, but
also because there is not much more blocks with
these characteristics in the Mukoša quarry, from
which tenelija was extracted. Because of that,
great attention is given to the fact that every stone is faultlessly placed
on its location. PAVEMENT
Pavement is
the part that will be mostly reused in the “new Pavement
that remained on the bridge entrances was numbered and marked before dismantling.
After that it was dislocated and stored in cemetery Semovac,
onto specially prepared bedding and piled in the shape as they were on the
bridge.
Pavement on
the left bridge entrance Momentarily,
it is determined how many of original pavement stones will be returned onto
bridge surface, meaning that for each stone it will be separately decided
whether it will be returned to the bridge surface and its entrances. On the
basis of above mentioned, evaluations and orders are made for the new stones.
It is important that the new stones for the pavement, those that will replace
separate original stones, satisfy the same criteria as the old stones. That
means the new stones need to have the same quality and texture, and that
other important characteristics match the characteristics of the old stones.
Bridge entrance on right bank before dismantling All of this
is very important because the pavement, as the surface layer of the arch and
bridge entrance, will be exposed to the most numbered “supervision”, that is
the citizens of Mostar who lived with that
bridge. Pavement
will be made according to precise calculations and projects; which means
according to precise dimensions and location of each separate pavement stone
on bridge entrances and the arch. Stone will be extracted from the quarry in
Opine, although several other locations were considered. Effort was made that
all other materials that will be used on reconstruction of the Chiseling
of different stone surfaces (inner, outer, etc.) is also tested in Komos storage. At the same
time, stove for lead is being manufactured according to the special order.
Lead must be of certain temperature when it is poured into holes for dowels
and cramps, so it would not break later or close the channel for filling the
cavities, or other possible difficulties. This will be discussed in the
following newsletter, with a description of a vessel in which the lead will
be melted. QUALITY CONTROL
The
laboratory This is one
of the most important pre-phases of every process. Characteristics of material
that wants to be used in reconstruction must be tested and determined
precisely; visual (which are also important in this case, because it is the
matter of reconstruction), as well as physical, chemical, statical
and other important characteristics of material. All
material that will be used in reconstruction of Old Bridge must go through
these tests. By that we mean everyday tests by the team of people with
adequately equipped hand-laboratory. They take samples and perform
momentarily analysis, and what can not be tested on the spot, is sent to
their laboratories outside the site.
Testing of
solidity In the
purpose of better and faster testing of material, Contractor provided
mentioned hand-laboratory on the platform. To date,
characteristics of all kinds of stones that will be used were tested (tenelija, limestone, breča),
metal for cramps, dowels, and bridge fence, lead for connection of metal
parts, sand and naturally distinguished lime for the mortar and re-pointing
of walls, etc. |
Workers are putting half-circled planks on the left
side Technical
acceptance of the centering was conducted on 14.03.2003, in the presence of
the Contractor, Subcontractor and the Supervision. “As built” design of the
centering was checked by comparing with the condition foreseen by the
project. The centering on 14.03.2003 Naturally,
all phases of the construction and installation of the half-circled planks
are followed by geodetic measuring. Teams of the Contractor and Supervision
are always present on the site. Phase of installing the half-circled planks
and wooden covering is withal the most important, because correct
installation of the Detail of the centering INJECTION
WORKS
Equipment
for injection Most of the
injection work is finalized to date. Almost all abutments above and beneath
the cornice are injected. Abutments above the cornice are injected
reciprocally. Microinjection is done from the outer side of the wall; drills
are made through the joints between the blocks, in order to minimize the damage
on the stone itself. Injection above cornice on the left bank From the
inner side of the wall, which we approached only after the archaeological
excavations were finished, drilling of holes with wider diameter was done to
allow easier injection of grouting mixture. The arch spring on the left bank
above cornice was additionally injected.
The
importance of this phase in the whole project was already emphasized, because
without strong and healthy walls it was not possible to approach the construction
of the arch itself. Drilling
machine for injection Pavement on cemetery Šemovac the
builders could not have had the adequate means of transportation to allocate
larger cargos on longer distances. Therefore that radius was very small. For
all those reasons and for satisfying all other characteristics, stones from
this location will be used. KOMOS
Stone blocks prepared for chiseling Selection
and chiseling of stones for the first couple of test rows of the arch is done
in Komos storage. First couple of arch rows will be
placed in “dry”. They will be placed with “masculine” dowel which is already
poured with lead, in order to mutually match. These few rows will be mounted
to test how technique of placement functions, how portal crane functions, and
in what way measurement will be taken. So, this is the last test before
finally approaching the procedure of masonry.
Treated
surface of the stone block NEW GROUP OF STONE-CUTTERS Because the
works on the site are reaching their peak, and also stone chiseling is at
full power, new groups of Contractor’s stone-cutters are arriving on the site
every few days. Stone-cutters
are put in categories according to their experience, practice and shown
knowledge, and also the manner of chiseling and they are assigned to
different tasks. We assume
that working hours will be doubled during summer period, while the day is
worm and long, which means that two shifts will be arranged. For that reason,
large number of stone-cutters is necessary. Long summer day, low water-flow
and warm weather must be used for the works on the bridge. It is
foreseen that one arch row is finished every day – that is two to five
blocks. This would be the optimal dynamic of work that would satisfy safety
and time-schedule demands.
Stone-cutters
in Komos WEB SITE
Web
site of the Contractor is in the procedure of construction. The information
of its exact address will be given in the next newsletter. This web site will
allow approach to the information about all current activities on the site,
contact addresses, links, photo-gallery etc. A few video cameras will be
placed soon, which will allow continuous 24-hour follow of the activities on
the site itself and the flow of reconstruction of the
View on the front page of the Contractor’s web site |
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This NEWSLETTER was made in accordance with prevailing articles of the Contract
No 002/2002 about the
Rehabilitation of the