Procurement & Construction
Lali-Masjed Soleiman, Iran
Oct., 7, 2007
Lali Bridge is the longest Cable-Stayed bridge in Iran. Regarding the construction of Gotvand dam in Khouzestan, it was inevitable to construct this new bridge on Karoun River, between Lali and Masjed Soleiman cities.
The old bridge of this route which was constructed by the British Contractors in 1950, was located in the upstream of this Cable-Stayed Bridge. Regarding the construction of Gotvand Dam which led to increase the water level as much as 126 meters, so the old bridge and the strategic oil and gas pipeline of the region would be out of service, it was required to design and build Lali Bridge in this region with a height of 256 meters. Technical Specification This bridge total length is 460 meters with 3 spans (100 meters left-260 meters middle-100 meters right). The maximum
water level of the lake is about 230 meters and it should be 10 meters below the deck. Also the maximum level on top of bridge’s deck was considered to be more than 240 meters. The concrete supports have an A-shaped transverse section which consists of a pier and a pylon. The piers have a box cross-section with a constant dimension. The piers heights are 75 meters. At the top of the piers a horizontal cross beam between the two legs was arranged.
General Works’ Quantity
Earth Works 250,000 m³
Concreting 27,000 m³
Reinforcement 4,000 tons
Formworking 26,000 m²
Sliding formwork 32,000 m²
Metal works 1,500 tons
Post tensioned cable 200 tons
The pylons heights are 68 meters.
Piers and pylons wall thickness is
Two circular caissons with a diameters of 10 meters work as a deep foundation for each pier-pylon. The thickness of the caissons are 1 meter and their depth are 20 meters which were built based on the project geotechnical investigations results. The piers and pylons were constructed using sliding formwork system. The cables have a fan-like arrangement and are attached to the super structure by some transverse girders with a distance of 12 meters. The cables are arranged in 2 plans and the dead-end anchorages system was used for the cable-web connection.
The road width is 13.5 meters which is suitable for 3 lanes (2 lanes for vehicles and one refuge lane). There is a walkway on each side of the road. The width of each walkway is 1 meter. The cable connection point to deck is on
the outer side of the walkway. In addition to the above-mentioned width in each side of the deck there were 2 meters cantilever passage for the oil and gas pipeline. Finally, the total width of the bridge is 21.5 meters to fulfill all of the above requirements. The bridge’s deck has been pulled up and installed in its service location using heavy lifting system.