Abstract:
Continuous segmental bridge construction is relatively new to the Sri Lankan bridge
industry. Progressive cantilever method of construction is one method employed for
continuous box-girder bridges. This technique is competitive for spans between 30 - 50 m.
This construction procedure has several advantages. There is no consideration of balancing
cantilevers and provides easy access through parts already constructed. Also horizontal
curved shapes can be easily accommodated. From a structural sense progressive placement
method is advantageous in substructure design where bearings can be placed immediately.
The main disadvantage arising from cantilever action is very high bending stresses. This
can be minimized by introducing temporary cables or intermediate supports. The other
disadvantages are slow progress and that the superstructure undergoes stress reversal.
Often other construction methods may be necessary for the first span.
