TR Circular E-C058_9th LRT Conference_2003.pdf - Florida ...

466 Transportation Research Circular E-C058: 9th National Light Rail Transit Conference
2. Rainfall on the tunnel approaches;
3. Rainfall entering through open-top box section;
4. Flood events; and
5. Fire flows during emergencies
Water entering the tunnel would need to channel to a floor drain at the low point of the
tunnel. A sump would need to be built beneath the bottom of the tunnel slab. A permanent sump
pump would be required to discharge the water.
The estimated cost for this undercrossing increased more than 50% from the estimate
performed during preliminary engineering because of the new drop in vertical alignment.
Because of this drop, excavation depths increased beyond the capacity of conventional sheet-pile
shoring assumed in the original estimate. This also resulted in increased quantities of tied-back
shoring walls, excavation, and backfill. In addition, concrete and reinforcing had to increase due
to additional soil loads at the new alignment depth.
FHWA’s REJECTION ON THE AT-GRADE CROSSING AT VICTORY BOULEVARD
Upon reviewing the 60% final design submittal, FHWA rejected the at-grade crossing proposal
at Victory Boulevard based on the following reasons:
1. The crossing is within the interchange vicinity of Interstate 5 and Victory Boulevard.
The at-grade crossing is too close to major freeway and highway ramps.
2. The at-grade crossing would create intrusion to the highway access control zone.
3. Advanced warning devices could not guarantee safety because of the limited sight
distance.
4. The at-grade crossing could induce potential problem during events at PIR.
All these reasons are associated with safety issues. Additionally, FHWA and Oregon
Department of Transportation (ODOT) maintained their opposition to the Schmeer Road atgrade
crossing.
TriMet immediately conducted management and technical level workshops to review
options with ODOT and FHWA. Seven different alignment options were investigated. Options
included variations on the location of the Delta Park Station, flyovers, undercrossings, and atgrade
crossings. Factors considered for each included safety, local access to the station, and
proximity of the station to the park-and-ride facilities, security, impacts on PIR events, traffic
impacts, and cost impacts.
Although it was not critically affecting the decision whether or not at-grade crossing
should be placed at Victory Boulevard, it might be worthwhile to mention that during early final
design, Multnomah Drainage District discovered that the LRT profile north of Vanport/Delta
Station cut into the flood control levee by 13 ft. If the crossing at Victory Boulevard altered to
grade separation with an aerial structure, this flood levee issue was almost automatically solved.
An elevated LRT profile over Victory Boulevard would naturally require an aerial
structure over the Highway 99W to Victory ramp and over Highway 99W to grade separate the
ramp and the highway. Once the design of long bridges south and north of Schmeer Road were