Laserfiche WebLink
Pedestrian Underpass Feasibility Study June 17, 1997 <br /> East Marietta Street and East Condit Street <br /> underpass and pedestrian crossings marked directing pedestrians to the south side of <br /> Condit Street. <br /> Lighting requirements, fencing of the railroad right of way and sealing of water seepage as <br /> noted in Alternate SA would apply to Alternate SC. <br /> omnari�on of lternates <br /> Alternate 2- Advantages: The top elevation of a concrete box culvert can be <br /> constructed as close to the bottom of the temporary brid�e <br /> as possibie, thus keeping the floor elevation as high as <br /> possible. <br /> Once the temporary structures are in place and the railroad <br /> is back in operation the construction process can proceed <br /> with little interference to the railroad. <br /> Lighting and drainage can be incorporated in the concrete <br /> walls and floor to provide more security for those features. <br /> Soil conditions will not be a major coi�cern since the entire <br /> area will be excavaxed and then replaced with suitable <br /> bacl�ill. <br /> Alternate 2 - Disadvanta es: The floor elevation will be about three feet above a 30 inch � <br /> g <br /> by 40 inch city combined sewer system located about 200 <br /> feet west of the structure. To prevent surcharge flow back I <br /> � into the subway, either a bacld�low valve or a pumping I <br /> system would need to be installed. A pumping system will <br /> � add additional costs to the project and the pumps, or <br /> backflow valve, will add maintenance costs_ Maintenance <br /> will also be required to keep the floor of the structure and <br /> ramps clean to prevent debris from entering the pumping <br /> system. <br /> Installation of the temporary bridge structures will require <br /> the railroad to remove and replace track during the sta�in� <br /> process. The construction of the bridges, and removal and <br /> replacement of the trac� will be performed by the railroad <br /> company, not the contractar. The railroad company is <br /> �P COI�OTQtZOtZ Pabe - 8 <br />