REHABILITATION OF THE OLD BRIDGE

IN MOSTAR

NEWSLETTER  13                       July 31,  2003             MOSTAR, BOSNIA AND HERZEGOVINA  

 

ARCH ASSEMBLING

 

foto by adis dziho

Assembling of the stone block of the arch

 

Assembling of arch blocks has been continued as planed and according to the previously established dynamic. Assembling of arch is progressing without any difficulty or stopping, which is pleasing everybody involved in the building of bridge. In the period from 01.07. to 31.07. rows from 24th  to 45th have been assembled on the left side, and rows from 89th to 67th have been assembled on the right side of the arch. Within this month, in total 44 rows of stone blocks were assembled in the arch. Since the assembling of the first stone until the end of this month, in total 89 rows of stone blocks have been assembled (including 5 existing original rows on the right side of the arch) Out of 111 rows in total, 22 rows remain to be assembled. Procedure and technique of assembling have been explained in previous newsletters. As far as the dynamic of building is concerned, we will repeat that two rows of the arch are assembled daily, one row from the left side and one row from the right side of the arch. Assembling of the arch is planned to be completed by the end of August, although it is the most probably that arch will be finished in the first half of August.

 

Top side view of the arch

 

REHABILITATION OF WING WALLS

 

The making of drawings for damaged parts has started upon testing and determining of damage degree of upstream and downstream wing wall at the left bank. The photo documentation has been prepared for these damaged parts. These were first preparations for rehabilitation of wing walls. With this it was determined that approximately 100m² of

 

Preparations for rehabilitation are performed by cleaning the walls first, which means removing of the surface layer of concrete that was layered over the wing walls. On this concrete layer “fake” joints were pointed to achieve a look of wall made of stone blocks. However, the original look of the wall appeared just after removing this layer, and the real stone blocks and joints between them were completely visible only after this. Upon this, we started with taking out of a certain number of damaged stones from the wall. Each stone that had to be replaced was precisely measured before extracting from the wall. Based on these measurements, drawings were made for each stone separately. Using these drawings, the new stones for replacement of the old ones will be chiseled. The stone and its previous place are numerically marked, so that a new stone with identical dimensions could fit in this place later. Treatment and chiseling of these stones will be performed in Komos in accordance with already mentioned precise drawings. Rehabilitation of wing walls and replacement of damaged stones will start immediately after finalizing of the works on the arch of the bridge.

 

 

Part of the wall with removed concrete layer

 

FILLING OF THE BACK SIDE OF THE ARCH

 

Filling of the back side of the arch has to be done due to the statically reasons, in order to achieve fixing and disable moving of arch bearing. Arch, as the main pontoon, will take over the load from all the other parts of the bridge (including its own load) and therefore has to be supported with this filling up to 1/3 of its height.

 

    

Details of filling of the back side of the arch

 

Preparation works and filling of the back side of the arch have started in the second half of the month of July. Before filling of the back side of the arch, all unnecessary material between the abutment wall and back side of the arch had to be removed, the cavity was further excavated and it was also leveled surface of abutment wall.

The crushed conglomerate stone is used for filling as well as limestone and tenelija stone. A mortar used for filling is M-22 and it is a different type of mortar compared to one that is used for the arch of the bridge. Filling will be made in layers as follows: the first layer is 50 cm thick and PVC injection pipes are placed in it. The new layer, 30 cm thick, is made over the first one. This layer is made of the same material   and it fits into the wall like a cover over the first layer.

 

 

wall surface should be repaired. Rehabilitation of walls has to be done primarily as a prevention, which means to prevent their further damaging caused by stream-bed erosion and weather conditions. The other factor closely related to erosion is the stability of these walls, which could be severely endangered due to the further damages. Perturbation of stability of these walls may cause perturbation of stability of the whole bridge construction, because the load of the bridge itself is transferred over these walls onto surrounding rocks. Esthetical reason is also immanent, since the old, uncleaned, dark and damaged wing walls would make a huge visual contrast compared to a new and bright construction of the Old bridge.

 

 

 

Detail of wing wall before cleaning and rehabilitation

 

 

Removing of surface layer

 

 Repointing of joints on wing wall

 

 

These layers are made one after the other to approximately ⅓ of arch’s height. Injection pipes stay even after finalization of works on filling and injection. Filling of the back side of the arch is performed parallel to its reconstruction.

 

Layer of filling

 

 

 

INJECTION OF GROUND FOUNDATIONS

BEHIND ABUTMENT WALL ON THE RIGHT BANK

 

 

After finalization of injection works of ground foundations behind abutment wall on the left bank, injection work of ground foundations behind abutment wall started on the right bank.

A purpose of injection is to connect the old and the new parts within construction, and in this particular case, this serves to fill the cavities in foundations of abutment walls. 

 

foto by adis dziho

Injection works on ground foundations

 

 

VISITS TO THE SITE

 

General Major of Turkish Army, Mr. Salih Zeki Čolak, visited the Site on 17.07.2003, in the afternoon hours. Respectful guest had a tour on the site accompanied with representatives of Contractor, and was fully informed about process and progress of the works performed in reconstruction of the Old bridge. 

 

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