A tight programme and difficult ground conditions contribute to the challenges of building Croatia's first postwar motorway.
Judith Cruickshank reports.
Imagine a European road project so eagerly wished for by local people that when central government announces that there is no money for its construction, they dig into their own pockets to fund it. Such was the case with the Zagreb-Split motorway in 1971 when Yugoslavia still existed as a country.
The scheme was never built and Croatians murmur darkly that the US$30M raised went to fund a transport project in Belgrade. But today a newly independent Croatia is anticipating that the resurrected BreganaZagreb-Split motorway will be open by 2005, and a joint venture of the US's largest contractor Bechtel and Turkey's Enka Insaat ve Sanayi is currently forging ahead on the 145km section between Bosiljevo and Sveti Rok.
Bechtel Enka's involvement in Croatia's roads programme dates from a 1996 trade mission to the state following the end of the Balkans conflict. The Zagreb-Split connection was perceived to be an important step in the process of rebuilding the country. Current journey journey time between the two centres is three hours. It will also allow easier access for tourists visiting the interior of the country.
The road will also eventually form part of the Adriatic Ionian route linking Croatia, Greece and the other Balkan states with Italy and southern Europe.
Design work on the dual two carriageway road is being carried out by a team from three local Croatian bodies; Institut Gradjvinarska Hrvatske, Industrijshi Projehtui Zavod and Pijelia Projeht. The client is Hrvatske Autoceste, a company set up by the Croatian government for the construction, maintenance and management of the country's motorways.
The design of the many structures has been kept simple.
Piers are cast insitu and decks are either precast, pre-tensioned U-beams or precast post-tensioned I beams. And while there is no eye-catching concrete, the natural beauty of the heavily forested landscape should ensure that this stretch of the route will be genuinely spectacular. Particular care has been taken with drainage, and project director Jack Hume describes as the overall design as 'very environmentally aware'.
Bechtel was instrumental in raising the finance for the project, in particular a US$1bn loan from US Exim Bank. This will be repaid through tolls and a tax on fuel. The joint venture signed a contract in 1998 and has already completed the 14km section one, the northernmost stretch of the route running between Bregana near the Slovenian border and Zagreb. This was opened to traffic six months ahead of schedule in December 2000.
Work on the current stretch, section three, began in October 2001 and the first 27km sub-section is on schedule for completion just 12 months later in October 2002. Completion of a further 14.5km is expected by the end of the year. Work on subsections B1 and B2 is well under way, directed from a new compound at Gospic, and the joint venture is awaiting final design before commencing the 45km which will link the two sections.
However, even then motorists will have to wait for the 5.7km tunnel at Mala Kapela, the contract for which has just been let to an Italian consortium with work due to start this year. And local politics are playing a part in decisions regarding the final, southern stretch of the road.
Talk is that the project may be split into a number of small contracts, which would allow local Croatian companies to bid. The downside of this is that should there be a delay on any one contract, opening date for the entire route is jeopardised.
Bechtel Enka's contract involves a 21M. m 3muckshift.
The mountainous route means deep cuttings, high embankments and a plethora of bridges and underpasses.
Added to the equation is the Karst - a landscape shaped by the action of water on the dolomitic limestone bedrock into a complex of sinkholes, vertical shafts and disappearing springs with inclusions of a loose reddish material known as terra rossa. It is ideal for caving enthusiasts and rock climbers, less so for engineers who have to deal with unmapped sinkholes which can be up to 15m deep and 40m wide, large enough to swallow an excavator.
Gospic, at the southern end of the contract, lay right on the front line of the recent war. The walls of houses on the outskirts of the little town are still pocked with bullet marks and final mine clearing is under way in advance of the main muckshift. Altogether some 7km of the alignment passes through major minefields.
Although the Croatian Mine Action Centre cleared mines to the 99.6% standard defined by United Nations guidelines, unexploded ordnance is still a real and present danger. Bechtel Enka employs a team of mine clearance experts, provides mine avoidance training for the entire workforce and is using armour plated Caterpillar D9 and D10 dozers for initial site stripping.
The terms of the US Exim loan specified that US-built equipment should be used for the project, so the entire US$83M worth of kit was brought in from the US to Croatia by ship. Caterpillar has supplied all the equipment for the joint venture's vast earthmoving fleet, together with compactors and asphalt pavers.
Much of the other equipment - generators, drill rigs and a fleet of 90 on-highway trucks - is Cat powered.
Local dealer Contek prepared the machinery and provides service support, though its involvement with the project dates from before the start of work. Working with Caterpillar specialists, Contek provided advice on the make-up of the fleet to Bechtel Enka, drawing on its knowledge of local conditions.
Five service engineers are dedicated to the project. A parts requirement analysis carried out prior to the start of work has resulted in a three-pronged support strategy. The joint venture maintains stocks of all consumable items such as filters and lubricants. Contek holds an emergency stock for all models in the fleet and all major components are stocked at the Cat facility at Grimbergen in Belgium.
Caterpillar also supplied one of its specialists to advise on the detail of the muckshift early on in the contract. Having looked at all the parameters - site layout, material, access, the rate of production required, the level of skills available - he reported back to Bechtel Enka with a list of recommendations for achieving greater efficiency. Since then he has been involved with the project on a regular basis, in particular advising the on-site supervisors.
Hume says he is 'very happy with the support' he has received from Contek.
Earthmoving is far from straightforward. The dolomitic limestone is hard and secondary breaking or blasting is frequently required. Blasted rock is loaded 3rock buckets. The trucks then haul the material to the fill area where it is spread by dozers.
Bechtel Enka is making every effort to avoid double handling the material, but given the tight time frame and the number of structures, some stockpiling is inevitable. Near Gospic, towards the southern end of the route, crushed stone for the embankments is being brought in from a local quarry, much to the delight of the owner and the local economy generally.
Some 200 tippers, all owned and operated by local Croatian drivers, are delivering the material to site. And in another happy arrangement, soil not required for the motorway is being dumped in sinkholes which local landowners are keen to fill.
At the northern end of the route, work is virtually complete and a fleet of pavers is busy laying the polymer modified bitumen surface. It is here in the completed cuttings that the difficult nature of the material is most clearly demonstrated. Even despite the fact that slope angles were altered to make them less steep, every type of slope stabilisation technique is on view; mesh, shotcrete, mesh and shotcrete, rock anchors and masonry. In some areas, the skills of local climbers were called on to help with access.
One of the major achievements of the project has been the welding together of the mixed workforce - US, Turkish and Croatian, numbering around 1,500 in total. This has involved training in construction skills, including machine operation, languages and safety awareness.
The final stage of the entire project will be the upgrading of the coastal road which runs from Split to Dubrovnik. Once this is complete this route will play a major part in uniting and bringing prosperity to a nation which has finally won independence after nearly eight centuries of occupation.