"35W Bridge Design Build"
35W Bridge Removal Causeway Removal Plan I. Determination and Mobilizaiton Anticipated high flows or other impacts may require emergency removal of the causeway. If it has been determined that the existing causeway requires emergency removal one of the following will happen: a) Excavator onsite will be relocated to the causeway from other operations for emergency use. Onsite trucks or articulated haul trucks will be re-assigned to the removal of the causeway. This can be accomplished within 1 hour of determination. This is the most likely scenario. b) If no excavation equipment is onsite, they can be hauled in and ready for work within 4 hours. This would be unlikely given the nature of the project and the schedule requiring continual work to be done on the approach spans. II. Work Schedule Depending upon the urgency of the issue requiring removal of the causeway one of the two options below can be implemented. a) If it is extremely urgent to remove the causeway, light plants and second crews can be utilized to provide for 24 hour per day and weekend operations. If the causeway is excavated continuously it is estimated complete removal can be accomplished within 24 hours. b) If time allows, the complete removal of the causeway can be accomplished within 2 working days utilizing 12 hour shift. This would be the preferred method. III. Work Activities To completely remove the causeway it is required to excavate and remove approximately 8,000 tons of Class I and Class IV riprap. Additionally, approximately 1,600 SY of geotextile fabric must be retrieved from the bottom. Prior to any work, a silt curtain will be installed in the river around the perimeter of the work. To accomplish this a 345 backhoe will be placed on the southern most tip of the causeway. Excavated material will be loaded into trucks, hauled and stockpiled on the bank in the northwest quadrant of the project. Excavation will continue as the causeway will be removed going north to the bank. The geotextile fabric will be pulled in and retrieved by the backhoe as it is uncovered. We do not anticipate much disturbance to stabilized soils, however, if any disturbance is required, it will be immediately re-stabilized upon completion of the removal.