Is a 3-lane bridge with a movable section the best technical solution for the Demerara River Bridge?
Dear Editor, Given that the feasibility study for the new Demerara River Bridge is not readily available to the Guyanese public or the engineering community, even before we attempt to solve the complex financial questions of tolls and subsidies and financing arrangements for the construction of the bridge, it would be useful if the Ministry of Public Infrastructure could address the following technical questions, so that we perhaps can all be assured that a “3-lane bridge (3LB) with a movable section” is indeed the best technical solution.
Bridge design 1 - What is the vehicular capacity per hour of a 3-lane bridge assuming free-flowing conditions?
2 - What are the vehicular traffic forecasts for peak hour flows 5, 10, 15, 20 years hence?
3 - How does the vehicular capacity compare with these traffic forecasts at peak hours?
Economic feasibility 4 - What is the estimated life-cycle cost of a 4-lane high-level bridge which would cause no disruption to either vehicular or marine traffic?...Cost 1
5 - What are the estimated construction, maintenance and operational costs of the proposed 3-lane bridge with a movable section over its design life (3LB)?...Cost 2
6 - What is the estimated cost of lost time due to disrupted vehicular traffic whenever there is a retraction/lift over the design life of the 3LB?...Cost 3
7 - Has Cost 3 been added to the life-cycle cost of the 3-lane bridge? 8 - How does (Cost 2 + Cost 3) compare with Cost 1? 9 - Has the possibility of a modular oil refinery at Linden and the consequential increased marine traffic on the Demerara River been factored into the projected marine traffic forecast for larger vessels, hence need for retractions/lifts per year for the 3LB?
10 - Has the possibility of further development of the bauxite industry at Linden and the consequential increase in maritime traffic, ie the resuscitation of the alumina plant or an aluminium smelter which may become viable as a result of lower energy costs from a gas-fired power plant, been factored into the projected marine traffic forecast for larger vessels, hence need for retractions/lifts per year for the 3LB?
The answers to the above questions may go a far way in reassuring the engineering community that the selected bridge type is indeed the optimal solution available to Guyana at the present time. Yours faithfully, (Name and address provided)