Before the concrete is placed for the pier foundations, the site is dewatered with temporary cofferdams. Figure 2.2 shows the steel framework about to be placed inside the cofferdam to brace the sheet pile walls against the tremendous hydrostatic forces. Once the cofferdam is complete, the inside is pumped dry and equipment is moved along side or barges and piles are driven. The protruding piles shown in Figure 2.4 are being prepared for the reinforcing steel of the pier foundation. The pier construction is continued until eventually the cofferdam is flooded and removed. See the Pier and Foundation images for more images on the construction of the substructure.

fig 2.2

fig 2.4

No figures for this section.