and 5.4 would differ significantly among coastal cities considered as 
possible construction sites. However, prices quoted are for metropolitan 
and adjacent areas. For remote sites the costs could vary enough to 
warrant special consideration. 
ASSEMBLY TECHNIQUES 
The techniques described in these sections are in accordance with 
the philosophy expressed earlier in the text (section on Construction 
Procedure Summary). Some of the more prominient assembly methods for 
these platforms are discussed below. 
Elevated Platforms 
The assembling of large elevated platform will be a difficult task 
because of the tremendous mass and size of most of the components. The 
primary problem is that of moving and accurately positioning the support- 
ing columns: their long length and varying buoyancy are seldom encountered 
in present-day construction at sea. The proposed assembly techniques are 
based on the availability of a floating deck, which is essentially a 
large pontoon designed to accept the columns that project downward. The 
proposed techniques have not been studied in depth. 
Cable Guided Technique. Figure 5.6 schematically illustrates the 
essential steps for this technique. In step (a) the cylinder and deck 
are brought to the construction site. The cylinder is then flooded until it 
is resting vertically and fairly low in the water. A cable is attached 
to the cylinder and the other end is passed through the floating deck, 
as shown in step (b), to a winch of moderate size. The cylinder is then 
flooded further (minimum negative buoyancy) until it is low enough to 
pass under the deck and be pulled via the cable into position, and sub- 
sequently attached. The connected column would then be deballasted to 
neutral buoyancy. Step (c) illustrates how the flooded columns and deck 
would be resting in the water after all columns were attached. Finally, 
the columns would be dewatered in the appropriate sequence until the 
entire unit rises the required distance out of the water, as shown in 
step (d). 
It may be possible to install only some of the columns and then 
dewater so that the platform would be partially elevated (the deck would 
have to be designed accordingly). If this were possible it would be 
unnecessary to flood the remaining columns to the point where they are 
completely submerged, thereby simplifying attachment of remaining columns. 
Segmented Column Technique. Another suggested assembly technique 
is illustrated in Figure 5.7. In this technique easy-to-handle, water- 
tight sections are lowered through openings in the floating deck. The 
techniques requires a water-tight seal between sections and connecting 
