An assessment was conducted on behalf of the main contractor by Sika Engineers, a specialist in sealing and reinforcing, which determined that "there were no issues regarding the stability of the cofferdam
On October 17, Remotely Operated Vehicle (ROV) video inspection observed small, intermittent drops of oil coming from an opening at the top and another on one side of the cofferdam
A fish biologist with CH2M Hill will be on the site while work is done within the river, and during drawdown of the water within the cofferdam
to salvage any fish that become trapped.
A pipelay barge, operated by Petroleum Marine Services was anchored about a half mile offshore and a steel cable was passed along the axis of the cofferdam
to the winch.
Temporary watertight structures called cofferdams
are being built to allow foundations to be laid for the three pylons that will support the main bridge.
The firm has already taken delivery of steel piles to be used to build a cofferdam
at its Graythorp site, near Hartlepool.
He covers groundwater control, side slopes and soil retention in open excavation, vertical soil support, cofferdam
construction, basement construction and design, cut-and-cover construction, shafts and caissons, and soil movement due to deep excavations.
A third cofferdam
was constructed perpendicular to the first two.
Workers inside a cofferdam
gently hitched a pair of cloth straps under the first cannon, then lifted it with a crane.
In addition, Case will excavate a 104-foot diameter cofferdam
78-feet deep to create a dry work environment.
award of a single contract including in particular the following quantities: - cofferdam
in the isre, - demolition of an oa with 5 spans for 120 ml, - riprap: 15 000 m 3 , - embankment: 4 000 m 3 , - piles diameter 1100: 212 ml, - concrete c30 / 37: 620 m 3 , - steel frame: 318 t, - steel ha: 150 t, - concrete c35 / 45: 320 m 3 , - gb + bb: 600 t.
The north and south pylon foundations were completed in early August 2015 and the concrete pour for the central cofferdam
foundations will take place in autumn 2015.