The following specification is for work on 2 crossings Sweden and Hebron Rd. CATS is looking to stabilize and level crossing tub panels that are pumping. This will involve 5 outbound panels at Sweden and 4 inbound panels at Hebron. CATS will require the contractor to pump a polyurethane stabilization foam that is specifically designed to fill under the crossing structures without causing lift by filling the void that was created from these tubs pumping.
Each crossing on the Blue Line has a soil consist of solid particles and the spaces (voids) between these particles. However, void spaces in soil has caused big problems for these road crossings. Under concentrated loads, crossing tubs can literally squeeze air and water from soil as traffic transverse over it. When this happens, the soil sinks and crossing tubs follow closely behind and begin to pump creating defects and damaging the tubs.
The contractor will simply drill strategically placed holes into each panel. Using a portable pump and flexible hoses, they will fill these holes with the mixture (polyurethane foam) Lifting the panel crossing using this method. The contractor will perform this work during a weekend or beginning at non-revenue hours. CATS requires the contractor to provide a work schedule that will show a timetable of beginning work to completion for both Sweden and Hebron Rd. Crossings.