The document discusses the design and construction of sections 3 and 4 of the Croatian motorway programme by Bechtel International. It describes some of the key challenges in construction including working in limestone terrain prone to sinkholes and dealing with unexploded land mines leftover from the civil war. Details are provided on the bridges, tunnels, and other infrastructure built for the 148km and 68km sections, including the 5.78km Mala Kapela tunnel, the longest in Croatia constructed using the NATM method.

1. CROATIAN MOTORWAY PROGRAMME
INFORMATION ON ENGINEERING AND CONSTRUCTION OF
SECTIONS
3 & 4
BECHTEL INTERNATIONAL

2. MAP OF CROATIAN MOTORWAY PROGRAMME

3. CROATIAN MOTORWAY PROJECT
MAP OF FINAL MOTORWAY ALIGNMENT BOSILJEVO – SV. ROK AND
RIJEKA – ZUTA LOKVA ( 148km AND 68km)

4. CROATIAN MOTORWAY PROGRAMME
ENVIRONMENTAL CRITERIA

5. CROATIAN MOTORWAY PROGRAMME
WILDLIFE CROSSINGS

6. CROATIAN MOTORWAY PROGRAMME
WILDLIFE CROSSINGS

7. DESIGN AND CONSTRUCTION CHALLENGES
• LIMESTONE AND LAND MINES
• THE LAND ON WHICH BECHTEL DESIGNED AND BUILT CROATIA’S FIRST MODERN
HIGHWAY IS COMPOSED LARGELY OF DISSOLVING LIMESTONE. THE CONDITION,
CALLED KARST (AFTER THE REGION OF SLOVENIA WHERE IT WAS DISCOVERED),
CREATES SINKHOLES, CAVES, AND EVEN UNDERGROUND RIVERS. SOMETIMES A
SINKHOLE ANNOUNCES ITSELF WITH A CRACK IN THE GROUND. BUT NOT ALWAYS.
“WHILE WE WERE CUTTING EARTHWORKS, WE COULDN’T ALWAYS PREDICT WHEN
WE’D HIT AN UNDERGROUND CAVERN OR SINKHOLE,” SAYS BECHTEL FIELD
ENGINEERING MANAGER MIKE MCGARVEY. IT’S TOO COSTLY AND TIME-CONSUMING
TO DIVERT A ROAD AROUND A SINKHOLE. INSTEAD, REINFORCED CONCRETE BEAMS
ARE USED TO SHORE UP THE GROUND AND BRIDGE OVER THE SINKHOLE.
THIS PHENOMENA HAS BEEN ENCOUNTERED IN TUNNEL CONSTRUCTION ALSO,
MAJOR CAVERNS HAVE BEEN BRIDGED OVER IN MALA KAPELA AND SV. ROK
TUNNELS.
•
CREWS ON THE CROATIAN MOTORWAY ALSO FACED A FAR MORE SINISTER DANGER
IN THE FORM OF UNEXPLODED MINES LEFT OVER FROM YEARS OF CIVIL WAR IN THE
REGION. TO ANSWER THAT THREAT, DOGS WERE USED TO SNIFF OUT ORDNANCE,
BULLDOZERS WERE ARMOURED, AND DRIVERS WORE KEVLAR-EQUIPPED CLOTHING.
UNFORTUNATELY, UNEXPLODED ORDNANCE HAS BEEN A REAL THREAT ON MORE
THAN ONE PROJECT IN THE RECENT YEARS.

8. CROATIAN MOTORWAY PROGRAMME

9. CROATIAN MOTORWAY PROGRAMME
DESIGN DETAILS
6,6Maximum cross fall to carriageway (%)
20000convex
13000concave
Min. Radius vertical curves (m)
140Min. Length of transit curve (m)
800Min. Horizontal Radius (m)
130Design Speed (km/h)

10. CROATIAN MOTORWAY PROGRAMME
• TYPICAL MOTORWAY CROSS-SECTION ABOVE
EARTHWORKS :
– CAPPING LAYER 600mm
– SUB BASE 250mm
– CEMENT STABILISED BASE 3% 250mm
– ASPHALT BASE 120mm
– ASPHALT WEARING COURSE 50mm
– NOTE: Design frost penetration depth 600mm

11. CROATIAN MOTORWAY PROGRAMME
FACILITIES
• All facilities in which services are provided to drivers and
passengers (petrol stations, shops, restaurants, motels, car repair
shops, etc.) are considered roadside service facilities. Thereby, a
safe and comfortable ride is ensured for them, as well as meeting of
their needs for fuel, rest, food, beverages, various technical and
repair services. Besides, they also get acquainted with tourist and
natural sights of the surroundings and are given a possibility of using
available information, Internet, banking services, of meeting specific
needs of disabled persons and children, etc.
• The use of road land for construction of roadside service facilities
and performing service activities is awarded by the public
competition procedure to the most favourable bidder for the period
of 25 years, for which he is obliged to pay the legally prescribed fee
for the road land use and the fee for performing services.

12. CROATIAN MOTORWAY PROGRAMME
TOLL STATIONS

13. CROATIAN MOTORWAY PROGRAMME
BRIDGES AND VIADUCTS

14. CROATIAN MOTORWAY PROGRAMME
BRIDGES AND VIADUCTS
• SECTIONS 3 & 4 INCORPORATED 126 BRIDGES OF 28.6km TOTAL LENGTH
• DESIGN DETAILS - GENERAL
– FOUNDATIONS BORED PILE CONSTRUCTION
– PIERS HOLLOW RECTANGULAR CROSS SECTION
– BEAM SUPPORT IN SITU RC STRUCTURE
– BEAM BEARINGS NEOPRENE PAD
– BRIDGE BEAMS UP TO 36m SINGLE SPAN, U-SECTION PRECAST
PRE-STRESSED CONCRETE BEAMS
• BRIDGE MASLENICA – PC ARCH – 262m SPAN (PHOTO ABOVE)
• BRIDGE BISTRA - STEEL STRUCTURE ON CONCRETE SUPPORTS MAIN SPAN 82m

15. CROATIAN MOTORWAY PROGRAMME
BRIDGES AND VIADUCTS

16. CROATIAN MOTORWAY PROGRAMME
TUNNELLS
SECTIONS 3 & 4 INCORPORATED 11 TUNNELS
FROM 280 TO 5780m IN LENGTH

17. CROATIAN MOTORWAY PROGRAMME
TUNNELLS
MOTORWAY “BREGANA – ZAGREB – DUBROVNIK”, SPECIFICALLY ITS SECTION III
“BOSILJEVO – SV. ROK”, IS A PART OF AN INTERNATIONAL ROAD ROUTE “AUSTRIA –
MARIBOR – ZAGREB – BOSILJEVO – SPLIT”.
THE HIGHWAY IS CLASSIFIED AS E-59 IN THE EUROPEAN ROAD ROUTES, LINKING
NORTHERN AND CENTRAL PARTS OF EUROPE WITH ITS SOUTH-EASTERN PART AND THE
MEDITERRANEAN.
THE “MALA KAPELA” TUNNEL IS LOCATED AT THE END OF UBSECTION IIIA2, AND THE
“GRIČ” TUNNEL IS LOCATED ON SUBSECTION IIIB1 OF THE SAME SECTION. EXCAVATION
(DRILLING) OF BOTH TUNNELS IS DONE BY USING NATM (NEW AUSTRIAN TUNNELLING
METHOD), WHILE DRILLING AND BLASTING IS DONE IN SIMILAR GEOLOGICAL
SURROUNDINGS – KARST.
BOTH TUNNELS ARE BEING CONSTRUCTED IN TWO PARALLEL TUBES DESIGN, WITH 25M
AXIS DISTANCE BETWEEN THE PARALLEL TUBES.
BOTH TUNNELS ARE PASSING THROUGH MOUNTAIN RANGES WITH RESPECTIVE
IDENTICAL NAMES.
THE LEFT TUNNEL TUBE OF THE “GRIČ” TUNNEL, (DIRECTION NORTH- SOUTH), IS 1210
METERS LONG, WHILE THE RIGHT TUBE IS 1235 METERS LONG. THE LEFT TUNNEL TUBE
OF THE “MALA KAPELA” TUNNEL, (DIRECTION NORTH-SOUTH), IS 5821 METERS LONG,
WHILE THE RIGHT TUBE IS 5780 METERS LONG. THE SURFACE OF THE CROSS SECTION
OF BOTH TUNNELS DURING EXCAVATION IS IDENTICAL AND IT AMOUNTS TO APP. 75 -
78 M2.

18. TUNNEL MALA KAPELA

19. TUNNEL MALA KAPELA 5780 lm
IN OPERATION

20. TUNNELS
MOTORWAY A-1 CROATIA, TUNNEL DESIGN AND
CONSTRUCTION
• MALA KAPELA TUNNEL - THE LONGEST TUNNEL IN CROATIA
• WITH ITS LENGTH OF 5780 M, THE MALA KAPELA TUNNEL IS BE THE LONGEST TUNNEL
IN CROATIA. IT IS SITUATED ON THE BOSILJEVO - SV. ROK SECTION OF THE ZAGREB -
SPLIT MOTORWAY. THE CONSTRUCTION STARTED IN MAY 2002. BOTH TUNNEL TUBES
ARE REALIZED SIMULTANEOUSLY BUT, IN THE INITIAL PHASE, THE TRAFFIC WILL BE
OPERATED VIA THE RIGHT TUBE ONLY, WHILE THE COMPLETION AND OPENING OF THE
LEFT-SIDE TUBE WILL DEPEND ON THE INCREASE IN TRAFFIC VOLUME.
• THE OMMENCEMENT OF WORK WAS SOMEWHAT DELAYED BY THE SELECTION OF
SOLUTION FOR CROSSING THE WATER-RICH GACKA VALLEY WITH ITS INTACT NATURE.
FOR THAT REASON THE TUNNEL WAS SOMEWHAT EXTENDED.
• TUNNEL CONSTRUCTION METHOD APPLIED WAS A NATM METHOD.
• THE NATM INTEGRATES THE PRINCIPLES OF THE BEHAVIOUR OF ROCK MASSES UNDER
LOAD AND MONITORING THE PERFORMANCE OF UNDERGROUND CONSTRUCTION
DURING CONSTRUCTION. THE NATM IS NOT A SET OF SPECIFIC EXCAVATION AND
SUPPORT TECHNIQUES.

21. TUNNELS
• THERE ARE SEVEN FEATURES ON WHICH NATM IS BASED:
• MOBILIZATION OF THE STRENGTH OF ROCK MASS - THE METHOD RELIES ON THE
INHERENT STRENGTH OF THE SURROUNDING ROCK MASS BEING CONSERVED AS THE
MAIN COMPONENT OF TUNNEL SUPPORT.
• PRIMARY SUPPORT IS DIRECTED TO ENABLE THE ROCK TO SUPPORT ITSELF.
• SHOTCRETE PROTECTION - LOOSENING AND EXCESSIVE ROCK DEFORMATION MUST BE
MINIMISED.
THIS IS ACHIEVED BY APPLYING A THIN LAYER OF SHOTCRETE IMMEDIATELY AFTER
FACE ADVANCE.
• MEASUREMENTS - EVERY DEFORMATION OF THE EXCAVATION MUST BE MEASURED.
NATM REQUIRES
INSTALLATION OF SOPHISTICATED MEASUREMENT INSTRUMENTATION. IT IS
EMBEDDED IN LINING,
GROUND, AND BOREHOLES.
• FLEXIBLE SUPPORT - THE PRIMARY LINING IS THIN AND REFLECTS RECENT STRATA
CONDITIONS. ACTIVE
RATHER THAN PASSIVE SUPPORT IS USED AND THE TUNNEL IS STRENGTHENED NOT BY
A THICKER
CONCRETE LINING BUT BY A FLEXIBLE COMBINATION OF ROCK BOLTS, WIRE MESH AND
STEEL RIBS.

22. TUNNELS
NATM - CONTINUED
• CLOSING OF INVERT - QUICKLY CLOSING THE INVERT AND CREATING A LOAD-BEARING
RING IS IMPORTANT. IT IS CRUCIAL IN SOFT GROUND TUNNELS WHERE NO SECTION OF
THE TUNNEL SHOULD BE LEFT OPEN EVEN TEMPORARILY.
• CONTRACTUAL ARRANGEMENTS - SINCE THE NATM IS BASED ON MONITORING
MEASUREMENTS, CHANGES IN SUPPORT AND CONSTRUCTION METHOD ARE POSSIBLE. THIS
IS POSSIBLE ONLY IF THE CONTRACTUAL ARRANGEMENTS ENABLE THOSE CHANGES.
• ROCK MASS CLASSIFICATION DETERMINES SUPPORT MEASURES - THERE ARE SEVERAL
MAIN ROCK CLASSES FOR TUNNELS AND CORRESPONDING SUPPORT SYSTEMS FOR EACH.
THESE SERVE AS THEGUIDELINES FOR TUNNEL REINFORCEMENT.
BASED ON THE COMPUTATION OF THE OPTIMAL CROSS SECTION, JUST A THIN SHOTCRET
PROTECTION IS NECESSARY. IT IS APPLIED IMMEDIATELY BEHIND THE TUNNEL BORING
MACHINE, TO CREATE A NATURAL LOADBEARINGRING AND THEREFORE TO MINIMIZE THE
ROCK'S DEFORMATION.
ADDITIONALLY, GEOTECHNICAL INSTRUMENTS ARE INSTALLED TO MEASURE THE LATER
DEFORMATION OF EXCAVATION. THEREFORE A MONITORING OF THE STRESS
DISTRIBUTION WITHIN THE ROCK IS POSSIBLE.

23. TUNNELS
THIS MONITORING MAKES THE METHOD VERY FLEXIBLE, EVEN AT SURPRISING
CHANGES OF THE GEOMECHANICAL ROCK CONSISTENCY DURING THE TUNNELING
WORK, E.G. BY CREVICES OR PIT WATER. SUCH (USUAL) PROBLEMS ARE NOT SOLVED BY
THICKER SHOTCRETE, BUT THE REINFORCEMENT IS DONE BY WIRED CONCRETE WHICH
CAN BE COMBINED WITH STEEL RIBS OR LUG BOLTS.
THE MEASURED ROCK PROPERTIES LEAD TO THE APPROPRIATE TOOLS FOR TUNNEL
STRENGTHENING. THEREFORE IN THE LAST DECADE NATM WAS ALSO APPLIED TO SOFT
GROUND EXCAVATIONS AND TO TUNNELS IN POROUS SEDIMENTS.
THE FLEXIBLE NATM TECHNIQUE ENABLES IMMEDIATE ADJUSTMENTS IN THE
CONSTRUCTION DETAILS, BUT THIS REQUIRES A FLEXIBLE CONTRACTUAL SYSTEM, TOO.
CAVERN DISCOVERED ON THE ALIGNMENT OF THE LEFT TUNNEL TUBE.
THE TERRAIN WHERE EXCAVATIONS FOR BOTH TUNNELS ARE BEING DONE IS
PREDOMINANTLY OF LOWER CRETACEOUS SEDIMENTS. PRIMARY ROCK MASS IS
LIMESTONE INTERCHANGING WITH POST-SEDIMENT LIMESTONE BRECCIA.
IN THE ROCK MASS OF THE “GRIČ” TUNNEL, THERE ARE JELAR SEDIMENTS, CONSISTING
OF BRECCIA AND BRECCIACONGLOMERATES, ABOVE CRETACEOUS SEDIMENTS. WHILE
THE “MALA KAPELA” TUNNEL PREDOMINANTLY CONSISTS OF LIMESTONE AS WELL AS
DOLOMITE AND DOLOMITE BRECCIA. REGARDING OTHER SEDIMENTS, THERE IS
PRESENCE OF CLAY, MOST COMMONLY OF RED AND RED-BROWN COLOR, HIGH-
PLASTICAL AND COMPRISED (“TERRA ROSSA”) – FILLING CARSTIFICATION WIDENED
DISCONTINUITIES.

24. TUNNELS
TECTONICALLY, THE SITE IS VERY COMPLEX AREA, WITH NUMEROUS FAULTES. THE ENTIRE
AREA IS INTENSELY CARSTIFICATED,AND THERE IS PRESENCE OF NUMEROUS KARST
SINKHOLE FORMATIONS FILLED WITH CLAY MATERIAL ON SURFACE. IN THE INTERIOR
SUCH FORMATIONS ARE MANIFESTED AS CAVERNOUS ZONES WITH TECTONICALLY
INTENSELY CRUSHED ROCK MATERIAL. CATEGORIZATION, BASED ON RMR
CLASSIFICATION, PREDICTED CATEGORIES II, III, IV AND V OF THE ROCK MASS, WITH
PREDOMINANT CATEGORY III IN THE “GRIČ” TUNNEL AND CATEGORY II IN THE “MALA
KAPELA” TUNNEL.

25. TUNNELS
BRINJE TUNNEL
THE BRINJE TUNNEL IS A FOUR-LANE HIGHWAY TUNNEL IN CROATIA, WHICH FORMS PART
OF THE A1 HIGHWAY FROM ZAGREB TO ŠESTANOVAC (PLANNED TO DUBROVNIK).
THE TUNNEL IS 1,570 M (1,720 YD) LONG AND WAS OPENED IN 2004.
IN THE SCOPE OF ZAGREB – SPLIT HIGHWAY, SECTION IIIC THERE WOULD BE CONSTRUCTED
THREE TUNNELS (BRINJE, BREZIK AND PLASINA). THE COMMON CHARACTERISTIC OF ALL
THREE TUNNELS IS THAT THE WORKS ARE EXECUTED APPLYING NEW AUSTRIAN METHOD
(NATM) UNDER DIFFICULT CONDITIONS OF WELL-FORMED KARST, I.E. IN VERY POROUS
LIMESTONE ROCK MATERIALS, WITH NUMEROUS FISSURE, CLAY AND CAVE ZONES.
ACCORDING TO THE GEOMECHANICAL CATEGORIZATION OF ROCK MASSES, TUNNELS ARE
EXCAVATED IN CATEGORIES II, III, IV AND V OF EXCAVATION, WITH CONSTRUCTED IN ALL
TYPES OF PRIMARY SHORING UP STRUCTURES.
SPECIFIC FEATURE OF TUNNEL BRINJE CONSTRUCTION IS ACTUALLY THE FIRST TIME IN
CROATIA APPLIED TECHNICAL –TECHNOLOGICAL APPLICATION OF MICRO-REINFORCED JET
CONCRETE FOR THE PRIMARY SHORING UP EXCAVATION, INSURANCE (INSTEAD OF
REINFORCEMENT MESH, SMALL STEEL NEEDLES WERE USED AND SHOT WITH THE CONCRETE)

26. TUNNELS
TUNNEL BRINJE IN OPERATION

27. TUNNELS – KARST CAVERNS

28. TUNNELS
CONSTRUCTION

29. TUNNELS
CONSTRUCTION