Shell Cracker Plant - Wall E
Location: Monaca, PA
Owner: Shell Chemical Appalachia, LLC
General Contractor: Trumbull Energy Services
Date Complete: October 2016
An accelerated schedule, limited access, extreme site congestion, an active landslide, and partial geotechnical information were just a few challenges Brayman overcame during the construction of Retaining Wall E as part of the Franklin Early Works Project for the Royal Dutch Shell Ethylene Cracker Plant in Monaca, PA.
Paralleling the Ohio River on the eastern end of the site, Wall E is a fill wall utilizing “bottom up” construction techniques to create additional real estate, accommodating a rail yard that connects to the existing CSX line.
As a subcontractor to Trumbull Energy Services, Brayman’s scope of work included installation of soldier beams, wedge plates, walers, and tiebacks anchors while working closely with other contractors on precast panel installation and backfilling activities.
Wall E encompassed 25,000-sf, measured 1,500-ft long, consisted of 226 soldier beams, 3,000-lf of wale, and was tied back with 350 anchors. Work started in early 2016 and had to be completed by the fall to allow for grading/track ballasting completion by the end of the year.
Soldier Beam Installation
Wall E consisted of two separate walls, where Zones 100-500 required HP16x141 beams on 5-ft centers in pre-drilled 36” diameter shafts, toed 3-ft in to rock, and backfilled with 4,000 PSI concrete. Zones 1-9 needed HP14x89 beams on 8-ft centers, driven to refusal.
In order to meet the schedule demands of the project, two drill rigs operating two shifts, were incorporated into the work plan. To expedite Zones 1-8, Brayman used an ABI TM-22 Mobilram to vibrate the soldier beams to rock.
Zones 100-500 consisted of 4 rows of 12-strand anchors and Zones 1-8 consisted of single row of 9-strand anchors. Brayman’s specially built MC-E 80 drill rig was utilized on the upper rows, allowing the rig to be situated behind the wall while reaching over to drill the anchors. Duplex drilling was used to advance 7” and 9.625” permanent casing through stiff clays into shale and sandstone bedrock.
Overall anchor lengths ranged from 90 to 130 feet, with a minimum 25 foot bond length in the rock. The anchors were single stage grouted, stressed, and locked off against the permanent casing.
Working multiple shifts and weekends, 350 tiebacks were installed through double MC-18 channel, in 150 calendar days.