The Job
This MSE wall lightweight backfill project is located near Richmond, Virginia. The geotechnical investigation for a double bridge replacement in Amelia County, Virginia found a layer of compressible soils below four proposed abutments.
Anticipated settlement exceeded allowable settlement, so the abutments were designed to be backfilled with expanded shale lightweight aggregate.
The two parallel bridges have an AAWDT of 14,000. They carry a rural divided highway (US-360) over Norfolk Southern Railway & Business 360 in Amelia Courthouse, Virginia.
The Challenge
Lightweight fill placement had to be unaffected by frequent rail traffic, have a limited footprint, and be economical. The anticipated settlement at design was 2.5 inches. A challenge arose during construction mobilization due to Covid-related issues. There was nowhere to stockpile the lightweight aggregate onsite. But the trucking market was so unreliable, that the material needed to be staged onsite. This was to ensure continuous MSE wall construction.
The Solution
CJGeo provided a value engineering proposal to utilize 30lb/cuft CJFill-Ultra Lightweight cellular concrete in place of the expanded shale lightweight aggregate. This significantly reduced the unit weight of the lightweight fill. Given the 70lb/cuft density used in the design, further reducing the anticipated settlement.
CJGeo mobilized a 200CY/hour low density controlled low strength material (LD-CLSM) plant to the site and placed lifts ranging in size from 35 to 300CY. Wall erection crews were able to walk on the in-place cellular concrete without leaving footprints as quickly as 4 hours after each placement.
The total project volume was approximately 7200CY.
Speak With An Expert
Facing a similar challenge to this MSE wall lightweight backfill project? Give us a shout or shoot us a text. Click the state marker for the location of your project for contact info for the appropriate rep.
