Padma Multipurpose Bridge Project

equirementsConstructabilityConstruction programConcrete Extradosed Bridge Steel Truss Bridgepermanent loads and 598mm under permanent and liveloads. Therefore the live load deflection is 283mm, withinthe limit of 300mm (span/500)6 yearsTotal construction period of the Bridge will be about 6years. The foundation construction will take longer(about 30 months) due to the additional piles, but themain delays will be due to the construction of the deck.loading it is 77mm, giving a combined figure of 165mm which issignificantly less than the span/500 requirement.3 yearsThe total construction can be completed in 3 years by carefullyplanning and implementing the logistics and activities. Theconstruction of the foundations takes about 28 months. The steeltrusses are fabricated and assembled off-site and therefore manyactivities can run in parallel, benefiting the constructionprogrammeEase of construction Laborious construction Easy constructionEase of construction of composite steel truss bridge is one of themain advantages over the extradosed concrete bridge. The steeltrusses can be fabricated by welding members in the controlledenvironment of a yard thus ensuring quality while permittingsimultaneous construction of a number of trusses at the sametime. The trusses can be fabricated at a single location or atmultiple locations.MaintenanceInspection and maintenanceaccess provisionsOperational IssuesComplexA travelling maintenance trolley system is required toprovide access to the external faces of the concrete oxgirder and cable anchorages. This trolley system wouldbe a complex and sizeable piece of equipment.Have several disadvantages.In order to carry out maintenance of the railway, accesswill be required from the fast lanes of the highway.Consequently any maintenance will require lane closureson the highway disrupting traffic flows.For a long bridge there will likely be accidents andmaintenance required to the carriageways. It isEasyA travelling maintenance trolley system will be relatively simplebecause of the ease of mounting off the steel truss.No disadvantage.With the railway running on the lower deck there is adequatespace within the truss to provide walkways both for emergencyand maintenance use. If a train is evacuated the passengers willwalk along the emergency walkways to either of the bridge ends.Emergency accesses to the top deck and the piers can also beprovided although under normal conditions these accesses would6-14