King Fahd Causeway
- Ballast Nedam
- Saudi Arabia and Bahrain
- Concrete piles in oversized drilled holes
- PBA 925
A causeway connecting Saudi Arabia and Bahrain by a series of bridges. The idea was born in 1954 and in 1968 both countries formed a joined committee assessing the financial undertaking for the task. In 1981 the agreement was signed for the start of the construction.
Building a conical bridge, both in saying as in construction
In total almost 500 holes are drilled 3,75 m diameter. First a casing is installed in unstable layers and approximately 50 cm into the bedrock. When the borehole was at the correct depth the drilling rig was removed and a concrete pile was installed. By using a drill with an under reamer pre drilling with a max. diameter of 3950 mm was carried out to allow the casing to be pushed through the cap rock.
Field tests had proven that a torque of 250 kNm was required for drilling. In December 1981 Wirth was awarded to deliver within nine month four 250 kNm pile top rigs. During the nine months the rigs, which were not standard, had to be designed and manufactured from scratch.
With four PBA 925/3800 an average production of 6,5 piles per week was achieved. As an average of 4,5 piles per week had been planned. This led to being considerably ahead of schedule. The four PBA’s did very well and exceeded expectations.