Settlement Management:
A Comparative Study of Geotechnical Polyurethanes for Settlement Correction versus Designing Out Differential Settlement using Low Density Cellular Concrete
October 16, 2024 @ 5:30 pm
Schedule:
5:30PM: Networking & Cash Bar
6:30PM-8:30PM: Dinner & Presentation
Topic:
It can be a tough call when designing a project to determine how much anticipated settlement is considered tolerable when the predicted total and differential settlements exceed 1 inch. Additionally, the designer cannot always account for the proper execution of construction quality assurance and control (QA/QC) measuresPE, Ph.D to significantly reduce the potential impact of poor construction practices that can increase anticipated settlements.
CJGeo looks at two projects in Pennsylvania and Virginia. The first project is a private project in Pittsburgh, Pennsylvania where improper placement and compaction of 35 vertical feet of 57 stone & onsite soil backfill, during building construction, resulted in up to 6 inches of settlement of an industrial kitchen. This significantly impacted operations, and cost much more to repair than it would have cost to use a self-consolidating backfill during construction. CJGeo reviews the costs and feasibility of self-consolidating lightweight backfill, and also the costs of the compaction grouting used to correct the settlement.
The other project was two sets of bridges in Richmond, Virginia. One set of bridges encountered up to 6 inches of settlement in the bridge approach & departure slabs, which resulted in 520 crashes over a period of 5 years. It cost VDOT approximately $1.2 million to fix using compaction grouting and paving. This is compared to another bridge replacement project where 57 stone backfill of four MSE abutments (with anticipated settlements of up to 5 inches) was replaced with a LDCC lightweight backfill to significantly reduce the new embankment load on compressible soil layers. The LDCC cost an $225,000 additional upfront construction spending on a $7.8 million project, but reduced the anticipated total settlements to tolerable limits of 1 inch or less.
Speakers:
Kirk Roberts: VP of Preconstruction
Kirk Roberts is Vice President of Preconstruction at CJGeo, a lightweight and chemical specialty grouting contractor. Mr. Roberts focuses on special projects, most of which involve addressing unanticipated challenges in the underground & civil markets with chemical and cellular grouts. From solving a 25MGD mine infiltration problem to stabilizing shafts that are sinking, not being sunk, the more unique, the better.
Brian Bucek; Geotechnical Engineer
Brian Bucek is a Professional Engineer in the Commonwealth of Virginia and CJGeo's in-house Geotechnical Engineer for Preconstruction. Brian worked as a geotechnical engineer consultant for over 15 years prior to joining CJGeo in May 2022. His current duties include performing engineering calculations for bearing, buoyancy, settlement, and lateral pressure considerations; and review and oversight of third-party laboratories performing unconfined compression testing on CJFill cellular concrete.