e-mosty September 2018 Vessels and Equipment Used for Bridge Construction | Page 57

Figure 9 : Illustrated view of driving the inclusion piles in underwater
Gravel bedding
The tower foundations ( caissons and steel shafts ) are supported on a gravel bed at 40m below sea level . The gravel bedding was placed using a tremie pipe and continuously fed by hopper and conveyor combination , mounted on “ Alparslan-2 ” floating crane .
The surface of the gravel bedding was levelled by specially designed and built hydromechanical underwater levelling equipment ( ULE ) carried by “ Kaptan Aydemir ” Catamaran Barge which was also specially designed and constructed for operation by ULE only .
“ Alparslan-2 ” crane barge was used for dredging operations and for placing the gravel bedding .
Figure 12 : An underwater photograph of driving the inclusion piles in underwater
For transporting and handling of the ULE “ Kaptan Aydemir ”, a catamaran barge was specially designed . The ULE was carried on four sling wires fixed to an assembly beam .
Before starting levelling operations an interim bathymetric survey was carried by a survey boat to obtain accurate data and provide levels and coordinates .
Figure 13 : “ Kaptan Aydemir ” Catamaran Type ULE Carrier Barge
Figure 10 : “ Alparslan-2 ”
Figure 11 : Visualisation of gravel bedding operation
3 / 2018
Figure 14 : ULE in stand-by position