Dear Editor,
I have looked at the various photos in the newspapers of the ramp and drawbridge for the Supenaam stelling and in my opinion as a chartered civil and structural engineer the beam supporting the back wheel load of the truck at the junction of the ramp and the drawbridge would have failed regardless of whether the drawbridge came off the ferry or not, since the main supporting beam appears to be both poorly sized and of poor construction.
The ramp should have been designed for a rolling wheel axle loading, including impact loading that can increase the loading by some 50%. When a heavily laden truck comes off the ferry, especially at low tide the driver has to accelerate to keep the momentum climbing up hill, and the back axle drops heavily on the supporting beam increasing the bending moment on the supporting beam. Placing an 18.5-ton on the wharf does not guarantee adequacy of the design or construction.
In my opinion this is also not the way to design the ramp. T&HD has drawings of a typical ramp and stelling and I am surprised the drawings were not given to the designer as a guide.
I am not prepared to comment further on other aspects of the design, construction and supervision of the work, except to state that the quality of engineering work has sunk to a new low in Guyana.
I also feel that the consultants should compensate the government to effect repairs and the government should ensure that all consultants carry liability insurance guaranteeing their engineering work against failure.
Yours faithfully,
M Alli
