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REHABILITATION OF THE OLD BRIGE MOSTAR |
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NEWSLETTER 1 JULY 29,2002 MOSTAR, BOSNIA AND HERZEGOVINA
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The
Mostar story
The oldest
written testament of the existence of medieval Mostar date back to the 15th
century, prior to the invasion of the Ottoman Turks. The testament was the
work of Herceg Stjepan Radivoj (the Duke of Herzegovina). Mostar developed
at a rapid pace, eventually taking the primacy of Blagaj. Mostar developed
into a strategic and commercial hub becoming the meeting point of roads from
the sea connecting the south to the north and northern regions to the western
regions. The first
medieval bridge in Mostar was a wooden suspension bridge which was very
unstable and of fragile construction. When The Turks invaded and conquered
Mostar, they used the old wooden bridge for crossing from the east bank of
the Neretva river to the west bank. (It is rumoured that the bridge swayed so
much, that to cross it, one would be taking his life in his own hands). There
are some notes pertaining to the construction of the wooden bridge but as to
their whereabouts is another matter, we know that the bridge was made from
wood without any pilasters and was suspended from chains. Remains of this
bridge are still visible on the left bank (east) and south of the Old Bridge
just below the museum (“Zavicajni Muzej”) Today we can find ruins from that
era (that is, prior to the Turkish invasion). The foundation walls used for
carrying the chains are still visible on the left (east) bank of the river,
on the right (west) bank there are no traces of buttress walls. In conclusion
we know: In the 16th
century Sultan Sulejman the Magnificent ordered the construction of a new
bridge in Mostar. From the reports of Hadzi Kalfa, the bridge was completed
in 1566 which coincidentally was the last year of Sulejman's reign. Evlija Celebija
the famous Ottoman traveler and writer produced more information on the Old
Bridge, claiming it was built by Kodza Mimar Sinan, son of Aga Abdulmenan
under the orders of Sulejman the Magnificent. Evlija also mentions that there
was plumbing within the bridge which was installed by a master craftsman;
truly remarkable. However, Evlija erred as to the architect of the bridge. A
Turkish historian uncovered a document in which it clearly states that the
bridge was built by Hajrudin, Sinan's student. |
The arch vault
is built of voussoirs with radial links that are equal to the height of the
front arch. The voussoirs were placed out in horizontal rows, with three or
four in one line [from two to five per row even if frequently is three-four],
some of these stones exceeded 2m in length. The builder knowing that the
structure, being of elegance, was very fragile, that he made absolutely
certain that no unnecessary stones were used. He made the front walls on both
sides 80cm thick [variable measure]
and refused to fill the cavities or core of the bridge with heavy
stones and soil which was the usual procedure on other bridges, (Zepa bridge
being a prime example), instead of this he introduces one middle rib and
where possible he incorporated cavities to reduce the weight of the bridge.
This method of construction was used on the "Kriva Cuprija" bridge
which straddles the Radobolja brook, a tributary of the Neretva river.
However, circumstances were different for the Old Bridge, which required a
more sophisticated sense for weight and balance of the construction
[structurally speaking this statement is not proved]. Viewing the bridge in
cross-section we can appreciate the method of construction: a cavity on the
upstream (north) side of the bridge measures 20cm wider than the one on the
downstream (south) side [today it is not possible to verify the above measure
and peculiarity, which anyhow might have been presumably variable along the
structure]. Two other cavities were discovered during maintenance work being
done after World War II [even about this peculiarity no verify and location
is currently possible]. The transition
from the arch to the front walls is highlighted with a decorative profile
[lower cornice] 15cm in height; the profile extends 15cm from the face of the
bridge [see following paragraphs for detailed notes about measures and
technical data]. The front faces of the bridge are on the same layer as the
extended profile and are composed of tenelija ashlars in horizontal rows.
These ashlars continue partly down the side walls of the bridge. The bridge was
partly annexed on the front rows of stone on the right side (west bank) in
order to lower the slope. This wedge shape form has three rows of stones in
its final spot, and its joints are perpendicular to the primary steep. It is
difficult to tell whether this correction was made after or during the construction
of the bridge, but we can assume that it was the second option, because there
are no visible marks of different procedure in the following construction.
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The steep of the bridge is transparent on the façades, by the profile
[upper cornice] similar but thicker from the one above the arch
(approximately 20-24cm thick) [variable
measure]. This profile is also going over the front walls for 14cm. From the
top of the bridge level is steeply falling to the left and right side. The
highest spot is on 60.39m above the see level, that means 20.34m above the
summer river level [variable
measure]. On the right side it goes down to 57.24m, and on the left 57.05m [see following paragraphs for detailed
notes about measures and technical data]. The path over the bridge is from the both sides framed by stone plates
parapet 23-25cm thick [variable
measure], and 94.50cm height [variable
measure]. The parapet is tighten to a profile in same layer as the front
walls, so the profile [upper cornice] stays plastically accented from the top
and from the bottom. It is
interesting to note that the stone parapets were chamfered on one side and
placed on top of the side walls [spandrels] with the chamfered end of the
stone facing away from the bridge. Why this was done, we do not know, we may presume that was the fine
sense for optical effects, as in ancient pilasters or similar. The path is paved by regular (big and small) stone plates, from the
firm white limestone [not limestone but krecnjak stone], with cross threshold, which keeps
from slipping of the people or horses. The stones are densely compressed and
anchored with mortar, so that only few drops of water were allowed into the
construction. The threshold end before the parapets, so that the rain would
drain quickly and avoid making puddles. Underneath this pavement there is the
layer of cm15 of gravel stone with mortar made of red earth and lime. This
lowest level is leaned on the big stones with which the cavities were vaulted
with [for technical details concerning different layers below pavement refer
to following paragraphs]. In following years, we can’t tell exactly when, most possible during
the further reconstruction [maybe Austro-Hungarian period], the iron fence was added to the existing
stone parapets. . This was
more than likely done for safety reasons while crossing the bridge. The side walls
which are attached to the supports from down and upstream side, and from some
angle are protecting the parts of the shore, to which the bridge is spanning,
from the water strokes, are mostly made to the same height as the front walls
of the bridge. The technique of building these walls isn’t all alike and not
similar to the masonry of the bridge, so we can presume that it must have
been rebuilt or repaired sometimes during the centuries. This is mostly
visible on the side walls on the left shore. Just on that place the two signs
about the reconstruction were found. A community
formed around the Old Bridge and developed into a strategic and commercial
hub. The surrounding mountains, the deep rocky river bed of the blue-green
Neretva, houses composed of various geometrical shapes, the two towers, the
bridge itself, all made from the same grey-white type stone, slate type covered
roofs of the same stone only lighter in shade, leaves a deep impression on
the observer. The towers of
the bridge were considered to be construction parts that were necessary for
the support of the Old Bridge. However, this was over exaggerated and not the
case, the towers provided an artistic flare to the bridge and they did not
serve as supports. There are
disagreements as to the dates of construction of the towers. The facts based
on the two signs (mentioned earlier in this text) the bridge being 974 (1566)
and the towers 1087 |
(1676). Some
historians claim that the left tower on the east bank was built prior to the
tower on the west bank. The masonry also reveals different periods of
building. The bridge was made of precisely cut stone (as most other public
buildings) whereas the towers were constructed of gravel stone and other half
worked materials. From historical
evidence it became obvious the two towers existed in 1452 (some writers
describe them even 84 years before the bridge). The assumption
that the towers are from the pre Turkish era were confirmed by researches
completed on the site. Research was first carried out on the tower situated
on the right bank of the Neretva. After the mortar was removed from the tower
it was found to contain gear grindings, similar traces were found on the left
tower which proves an older dating of the construction of the towers. This
fact indicates that the towers where from the medieval Bosnian State era and
later modified for the needs of the Ottoman Turks. The first renovations of
the towers were made during the reign of Mehmed the II el-Fatih also he
carried out renovations on the then existing old wooden bridge. During that
time the whole town of Mostar was converted into a fortification. The towers on
either side of the bridge had a specific shape. half cylinders with the flat
side facing the bridge. The left tower (east bank) known as the Tara or
Hercegusa, was transformed into a storage area for ammunition and powder,
during the occupation in 1878. The right tower (west bank) was called the
Halebinovka or Celovina tower. The lower portion of the Halebinovka tower
served as a prison while the upper floors were used as observation posts.
Venetian warriors attacked Mostar in 1652, 1693 and 1694. After the first
attack it was evident that it would be necessary to take measures to ensure
the protection of the city as well as the bridge crossing. We know very
little about the repairs made on the bridge outside of the fact that
Hajrudin's work was so solid that it resisted wear and tear through the
centuries. We can assume that the only fragile spot on the bridge was on the
left (east) support and side walls which indicated traces of building repair.
Despite the fact
the “sign” (mentioned earlier in this text) and dated 1676 mentions no repair
work on the bridge the facts prove that indeed that repair work was carried
out at that time. The second sign mentions that repairs on the bridge were
completed in 1150 (1736-1737). During the
Austro-Hungarian occupation of Mostar area many renovations were made. The
sloping ground on either side of the bridge was raised by 80 cm. in order to
accommodate the current traffic problems. The path on the bridge was also
increased and re-surfaced. To adapt to the current situation, main streets
leading to the bridge were increased in elevation, also the elevation of the
entrance doors of the bridge were increased. After World War II,
reconstruction around the bridge area continued and the remains of
Austro-Hungarian intervention were removed. During the Austro-Hungarian
period damaged stones on the bridge were repaired using cement mortar, this
was a poor solution as the mortar left stained dark spots on the bridge. During World War
II plans were made to destroy the Old Bridge, luckily these plans were
discarded. However, some damages, due to mine slots, were done and even after
mortar repairs, water could penetrate the construction leading to further
damages. The situation was considered very serious therefore, restoration began
in 1955. Supports were restored on either side of the bridge and damaged
walls and empty |
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cavities fully
repaired, the restoration was completed by the end of 1965. The second stage
of restoration involved the arch of the Old Bridge using the injection
method, with a special mixture of 82.50% cement, 15% mixture of stone flour
composed of limestone tenelija, 2.50% bentonit. The required volume of this
mixture for the repairs came to 7 cubic metres which gives us a good
indication that the arch (vault) was severely damaged also cracks were
appearing in the stone and mortar joints. At this time damaged stones on the
vault as well as on the façade were replaced, cavities of cement mortar were
removed and replaced with a special mixture that blended in with the colour
of the tenelija stone. The Old Bridge
of Mostar was destroyed in November 1993 by shelling during recent war
events; the moments in which shelling were ongoing have been filmed and from
that documentation it has been possible to gather some technical data and
observations. From analysis of
the remaining portions of the bridge located by the east abutment, it is
possible to observe an higher surface deterioration on the north side than in
the south one, but, as far as it was possible to see from the movie, shelling
were coming from south side and hit mostly the south east portion of the
bridge over the arch reins: nowadays the widest remaining portions of the
bridge are located on that side. This seems quite strange but it is most likely
that shootings were directed also to the north elevation during other war
attacks, and this is the reason why the bridge had been protected by tyres,
(temporary structures over the footpath were instead aimed at the protection
of the people from shootings). Moreover shelling was performed with accuracy
almost on the same spot in order to cause the collapse using the minimum
numbers of shells and the structure was divided in two main parts: a small
one below the arch reins by the east bank, (still built-in and on-site), and
a big one which ruined wholly in the river. From
observations of the movie it is possible to note how shells have gradually
brought to the bridge collapse: §
the load
bearing arch was the main target element of the shelling: a wide portion of
it was destroyed before final collapse, (from the reins to the key stone for
a thickness of about a meter); §
other
shelling which were higher than the target perforated the spandrel wall with
escaping of fill; §
the attack
has been performed by people that knew the basic functioning of a bridge
structure; §
shelling was
performed with the aim of causing the collapse of the bridge and not of
ruining the bridge; the bridge collapsed when a shell broke definitely the
continuity of the load bearing arch. The above
mentioned movie has helped the work for the repositioning of the recovered
stones since it has been possible to determine the voussoirs that were most
likely definitely lost and reduced to powder due to direct hit. The renovation
program on the Old Bridge was in the works for ten years and many reports
were written by D. Krsmanovic, H. Dolarovic and Z. Langof, these reports and
all technical data are available today. The Old Bridge
in Mostar was the inspiration for many poets final
rehabilitation and restoring of the Monumental Complex of the Stari Most (Old
Bridge) of Mostar. Main design assumptions: §
The Bridge
of Mostar has been totally destroyed and doesn’t exist anymore as a whole
structure, its ruins are the only left portions that should be considered the
real and the only original Old Bridge of Mostar. §
The
recovered stones are, at the moment, the only valuable elements of a great
ancient monument, they have historical value, and they represent an
interesting example of the ancient technique of assembling voussoirs and a
constructive method which should be studied and investigated. §
Some bridge
stones and arch voussoirs have been recovered from the river and stored on a
platform. Recovered stones, which are apparently not broken and which
original position has been determined, are 9% of the global amount. §
Some bridge
stones and arch voussoirs are still built-in next to the former bridge
springers. Those built-in stones, which are apparently not broken, are 13% of
the global amount. §
Abutment
walls are, by now, damaged either by structural fractures, either by heavy
and light shootings, and by small surface degradations due to time. §
Something,
with the war, has been definitely lost and may not be recovered or restored. Main design interventions: §
Recovered
bridge stones and arch voussoirs, being what is left of the Old Bridge of
Mostar should not reused, but should be preserved exactly as they are and
kept in good condition to ensure their long lasting. This due either to
restoration, either to structural requirements (since the reuse would have
caused a new stone cut and a disassembling of the voussoirs). §
Recovered
bridge stones and arch voussoirs may be settled in a purpose built museum and
they may be organised for exhibition purposes. The original Old Bridge would
be therefore represented by those ruined portions, and this intervention
would totally match the International Principles of Restoration: it
guarantees complete safeguarding and preservation of the ruins and moreover
it would be reversible and absolutely not invasive. §
Recovered
huge blocks of assembled voussoirs, that could not be settled on the platform
due to their weight, should be moved in a museum as well as all the other
recovered stones, to avoid their quick deterioration due to the river waters.
(This despite ICE wanted these blocks to be left as a monument by the shore).
§
On the spot
where the bridge was, following the willing of the citizen of Mostar and for
social, political and symbolical reasons a “new old bridge” may be rebuilt as
a declared copy of the previous one. This copy should be built not
approximately or just close to the original one, since the value and the
meaning of the new structure should be in the "philological" and
historical research of the ancient monument as if this were an integration or
a preliminary introduction to the
visit of the real Old Bridge settled in the museum. §
Remaining built-in bridge stones and arch voussoirs, |
and writers it
also created many legends. Evlija Celebija talks of the bridge as well as the
“cardak”. The cardak was on the west bank of the Neretva, being the meeting
place of well educated people of that time. Today a coffee bar stands where
the cardak use to be. From ancient
times until today the Old Bridge has remained a symbol of Mostar, it remains
as an attraction for its inhabitants as well as for the many travellers and
tourists. The tradition of jumping from the top of the arch down to the river
will remain a symbol, carried by the generations to come, forever, as long as
the Neretva river and the “Stari Most” (Old Bridge) exist. […]” The
Reconstruction
PCU is a specialized agency whose responsibilities are performing
professional and other jobs for coordination of the project of the building
of the Old Bridge and other structures within
Pilot Cultural Heritage Projects of Bosnia and
Herzegovina.
The following contracts within the bridge components
by means of international and limited international competition have
been signed so far: ·
GEOLOGICAL
INVESTIGATIONS ·
DESIGN, PHOTOGRAMMETRY
AND CALCULATIONS FOR THE OLD BRIDGE ·
LABORATORY TESTS ·
REHABILITATION OF
“TARA AND HALEBIJA” TOWERS – ARCHITECT AND ARCHEOLOGICAL ASSIGNMENT ·
TECHNICAL CONSULTANT
FOR PCU ·
CUTTING "TENELIJA" STONE STORED IN
"KOMOS" ·
SUPERVISOR FOR
CUTTING "TENELIJA" STONE
STORED IN "KOMOS" ·
GEOLOGICAL INVESTIGATION (
INSTITITE FOR GEOLOGY SARAJEVO – BiH ) ·
FONDATIONS OF THE OLD BRIDGE IN MOSTAR ·
RECONSTRUCTION OF THE OLD BRIDGE
(ER-BU - Turkey) ·
SUPERVISION OF THE RECONSTRUCTION OF THE OLD BRIDGE ·
( Omega Engineering - Croatia) Design objectives This Pilot
Project has been named, in agreement with PCU as "Rehabilitation of the
Old Bridge of Mostar" since it is partially composed by different
practical approaches: conservation
and preservation, remedial and repair interventions, dismantling and remounting operations and reconstruction works. All the above should be aimed at the next to the springers and to the
abutments, should be
partially
dismantled, during the remedial works, and remounted in the original locations, during
the reconstruction works trough an
anastilosis technique. This dismantling is required only to
match structural and safety
requirements. §
Strengthening
of the abutment walls next to the bridge springers should be performed before
and while dismantling operation
are ongoing. §
Declaration
between former bridge elements and new intervention should be performed
trough refined and light marking devices, (as defined by design specifications
and drawings). §
Ancient
abutments should be repaired only for what concern structural fractures and
heavy shootings: only for those damages that, due to the river floods, may
lead to further degradation if not repaired. §
In the
adjacent areas, concrete blocks should be totally demolished and remedial
works should be performed over the ancient flooring. §
Repair works
should be performed leaving all the signs of time and small traces of the
war, avoiding any intervention that may lead to a polished and renewed
masonry layout. rehabilitation of the old bridge is therefore designed as: §
conservation
and preservation of the ancient stones recovered from the river; §
remedial and
repair of built-in stones, bridge remnants, abutment walls and flooring; §
dismantling
and remounting in the original locations of some portions of the bridge
remnants; §
reconstruction
of a "new old bridge" marked and declared as a recent intervention; §
demolishing
of the concrete provisional blocks built during the war and post-war period;
News ·
On
25.06.2002, the Project Manager of the PCU announced the official beginning
of the Works for the Contractor: the ER-BU
Company. The works on the Project Documentation, Methodology Procedures and
other documents are in preparations. Works on the Site started: the soil was
firmed, drainage pipes for Radobolja River were repaired and reinstalled,
condition of the roads was improved, fencing of the area started. Also the
first scaffolding for the repair of the walls was erected. ·
On 05.07.2002. Onega Engineering, signed the
Contract for the Supervision of the Reconstruction of The Old Bridge. They
situated in new office, provided and equipped by the Contractor – ER-BU. |
This NEWSLETTER was made in accordance with prevailing articles of the
Contract No 002/2002 about the Rehabilitation of the Old Bridge, by ER-BU CONSTRUCTION / TURKEY