In a statement released in Dubai, United Arab Emirate and signed by Karen Gallacher-Smythe on behalf of BASF Construction Chemicals, it was disclosed that the main contractor of the landmark project, Julius Berger Nigeria PLC is making use of advanced construction techniques and products to overcome environmental and logistical challenges and meet stringent design specifications. BASF Construction Chemicals' high performance admixtures and building system products are vital ingredients.
Initiated in 2009, it has taken considerable engineering and construction knowhow to bring the bridge close to completion.
The 1.357 meter long Lekki-Ikoyi Link Bridge comprises a 722-meter full-span approach bridge and the main cable stayed segmental bridge of 635 meters in length at the center of which is a 90-meter high pylon. Walkways on both sides of the bridge are two meters wide and the width of the two main carriageways -- east- and westbound respectively -- will be 2 x 4 meters each.
The challenges faced included building the 90m-high pylon and bridge above water in segments, handling heavy weights up to 250 tons. The contractor also had to overcome access and traffic challenges throughout the construction of the bridge, and had to ensure the batching plant was producing concrete of a sufficient type and quality.
All works were done above water and Julius Berger Nigeria's Health, Safety and Environmental skills were essential throughout to account for the unique hazards of this particular environment.
The German subsidiary Julius Berger International GmbH (formerly Bilfinger Berger Nigeria GmbH) handled the planning, design and support of Julius Berger Nigeria, including logistics and supply of materials and equipment that were difficult or impossible to procure inside the country.
Says John Gilbertson, Business Development Manager, West Africa for BASF Construction Chemicals: "This was the first cable bridge to be built in Nigeria and to be considered successful it needed to meet high functional, engineering and aesthetic standards. The BASF solutions, used successfully internationally and elsewhere on the African continent, assisted to smooth construction processes and meet engineering standards."
Key to servicing this site was the logistics to ensure supplies were available when they were needed and technical skills from BASF were available onsite to test and monitor the quality of the concrete put out by the batching plant.
While the segments for the bridge superstructure - the approach bridge as well as the main bridge - were cast in the precast yard, the concrete for the foundation piles and the pylon had to be transported to site.
Challenges with regard to this casting process include getting the concrete mix just right so that it remained workable for an appropriate length of time in the hot and humid climate. It also needed to be of the right consistency - i.e., pourable - to enable suitable filling of formwork.
The early, high and final strength of the concrete also needed to be just right to enable a suitably rapid pace of work to be maintained. And last, but hardly least, aesthetics were important. Julius Berger had to achieve a fine and smooth finish on all concrete segments.
Says Gilbertson: "The finish of the concrete is superb and comfortably similar to that found in Europe. In addition, our levels of service and pricing met their unique needs in this difficult working environment."