Engineering consultancy services for echo metric tests, underwater inspection and assessment of pilings of the Third Mainland Bridge in Lagos - Nigeria
The Third Mainland Bridge is
a 3 lanes independent dual carriageway structure with a median separator. The
overall width of the superstructure is 33.10 m. The typical spans are 45.0m in length
and, in the navigable channel, 60.0m in length. Each pier consists of two
slender concrete septa. The typical foundation consists of four 1.5m large
diameter bored piles, with average depth of 42.0 m.
The object of the consultancy
services has been the assessment of the substructure condition with particular
attention to the state of preservation of the submerged parts.
To this purpose, an echo metric test
campaign has been undertaken with the collaboration of Mr. Brignola of MOST
Srl, an Italian expert having the CICPND Level 3 certification, according to EN
Furthermore, an underwater visual inspection has
been carried out with the collaboration of Messr. HydroDive Nigeria Ltd, a
Company Member of the International Marine Contractors Association (IMCA).
In the first phase, the investigation has
been carried out on selected foundation pilings.
A report of findings, including the results
of the technical inspection on piers and pile caps, and the proposal for
different types of intervention according to the severity of the damage have
Report of findings and intervention proposal
(2012) for Borini Prono & Co (Nig) Ltd – Federal Ministry of Works (F.M.W.)
In the second phase, comprehensive
investigations and design of intervention have been carried out according to
the following scopes of works:
survey of the lagoon bed along Third Mainland Bridge from Lagos to Ebute Metta,
for a width of 50m upstream and 50m downstream the bridge, with a particular
attention to the evaluation of erosion;
of sonic echo tests on all the piles in water of section I and II and 25% of
the piles on land;
of coring on selected piles, where anomalies of sonic echo tests are
registered; collection of samples from each core and execution of compressive
- Report of findings and conclusions of the pile
inspection of pile caps including sample Non Destructive Testing of materials,
sample coring of concrete and execution of compressive tests;
- Report of findings and conclusions of pile caps
inspection and collection of pictures and videos of all the piles of the
section I (from Lagos to Ebute Metta) and of the 50% of the piles of the
section II (from Ebute Metta to Oworonshoki) of Third Mainland Bridge;
of findings and conclusions, including the results of the underwater inspection
as well as the comparison with the results of echo metric tests and tests on
and description of the most appropriate rehabilitation intervention for every
type of damage detected on piles and recommendations for the rehabilitation;
- Preparation of BEME;
of tender documents.
Assignment for the Federal Ministry of Works
(F.M.W.) in 2013.