These numbers are for three locations included in the slope stabilization project on I-90 near mileposts 66. Crews began work in June 2006 and substantially finished by Nov. 6, 2006.
Dump truck loads removed during this work: 44,000 cubic yards, that is 3,000 dump truck loads or 75,000 tons
The size and weight of the biggest rock: Slab type rock 15 feet by 20 feet
Large rocks removed in this work: In the east cut we removed about a dozen car-sized loose rocks with the initial controlled blasting. In the middle cut we removed a large area of column rock. In the west cut we removed pieces of a large wedge and a large rock overhanging the roadway, these came down in smaller sized rocks.
Holes drilled in the rock: 138
Dowel bars inserted in the rock: 138 rock anchors (bolts and dowels). The lengths range from 20 feet to 30 feet deep.
The cost: $5.3 million total cost, $4.9 contract including construction engineering, $400,000 in design (including geo-technical consulting).
Number of working days on this contract: Contract set for 120 working days. Contractor worked day and night at times. The work was completed three weeks ahead of schedule. Time savings are attributed to the use of the large mechanical scaler from Rhine which brought rocks down quicker and safer.
How much protective netting was used? The entire slope is covered with 125,000 sq. ft. of protection netting.
Injuries: No work related injuries.
The average daily traffic during the week on I-90: 30,000 +
The average daily traffic on the weekends of I-90: 48,000
The average daily traffic on I-90 over a holiday weekend: 58,000
The number of unstable slopes on the unstable slope list put together by WDOT in January 2006: 2700
The cost to stabilize these three slopes: $5.3 million for all work
Number of page views to the I-90 rockslide blog between Nov. 6 and Dec. 13:
Nov. 7 had the most page views with more than 48,700 in one day.
Nov. 23 had the second most page views with more than 40,000 in one day.