Padma Multipurpose Bridge Project

Fisheries and other aquatic lifeMaterial Quantity of SuperStructureDredgingAestheticsConcrete Extradosed Bridge Steel Truss Bridgebe anticipated on the River ecology and aquaticecosystem.Cast-in-place construction may increase the silt load dueto disposal of debris and possibility of pump or unloadconcrete into the River. However, Pre-cast segmentalconstruction will reduce impacts on the River.More impact due to construction of more number (572) ofpiles and more construction period.Concrete quantity 181,641 m 3 Concrete quantity 72,000 m 3Dredging is required for bringing of heavy constructionequipment to bridge sites.The extradosed girder scheme would provide a strikingappearance with cables extending above the deck level.The concrete box girder would be similar in appearanceto other large bridges in Bangladesh.construction period.Extensive site welding will be required which will generate toxicfumes, gas, noise and radiations. Welding will also pose safetythreat to the workers if proper safety procedure is not followed.Less impact due to construction of lesser number (334) of piles.Hilsa migrates from the estuary to upstream through an average of10m deep channel. In addition, other aquatic habitats (dolphin) inPadma use the river for migration and breeding purpose. Basedon the 2008 and 2009 bathymetric survey at the bridge site, thereare two juvenile Hilsa migration routes in Padma River. At bridgesite, juvenile Hilsa migration takes place between March and Mayand breeding period of Gangetic dolphin is April-July. Both Hilsaand dolphin are very sensitive to noise and vibration. Therefore,construction activities generating huge noise and vibration shouldbe restricted in channels with certain depth specific time of theyear.Steel quantity 84,400 tMore dredging may be required for bringing constructionequipment (barge) as well as transporting steel by large ship tothe bridge site.The appearance of the composite steel truss would appearslender and elegant with an open view through the truss. Thestructural form of the composite steel truss would be quite differentto other large bridges in Bangladesh.Noise Generate less noise during operation Generate more noise during operationProven Previous UseThere are many examples of extradosed concretegirders for highway bridges. There are few examples ofextradosed concrete bridges for railway applications andthese are for lighter passenger rail (JapaneseShinkansen rail). No experience and knowledge of anMost long span combined road and rail bridges have beenconstructed using two level composite steel truss superstructures.This is primarily because of the benefit achieved from the flexuralstiffness associated with the depth of structure. There are manyexamples around the world of bridges comprising combined road6-16