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File #: 2024-0441    Version: 0 Name: 143rd Street at John Humphrey Drive, Phase II Engineering, Supplement #1, Additional Geotechnical Investigations
Type: MOTION Status: PASSED
File created: 5/30/2024 In control: Board of Trustees
On agenda: 6/3/2024 Final action: 6/3/2024
Title: 143rd Street at John Humphrey Drive, Phase II Engineering, Supplement #1, Additional Geotechnical Investigations
Attachments: 1. Orland JHD Geotech Supplement Request, 2. Patrick Engineering - CO#2 to John Humphrey Drive @ 143rd Street

Title
143rd Street at John Humphrey Drive, Phase II Engineering, Supplement #1, Additional Geotechnical Investigations

History
Patrick Engineering (Patrick) is currently under contract with the Village of Orland Park (Village) to assist in preparing the contract and construction plans for the 143rd Street and John Humphrey Drive intersection which includes addressing differential settlement issues at the dry land bridge along 143rd Street just east of John Humphrey Drive. Based upon geotechnical studies conducted for the project, peat has been found in and adjacent to the project site. Peat is a partially decomposed organic layer of soil that accumulates in wetland conditions, such as peatlands, bogs, mires, moors, or muskegs. Peat is not a suitable material for foundations and requires additional geotechnical studies to establish its limits.

Therefore, additional geotechnical information within the project area is necessary to properly design the structural and subsurface remediation measures to provide a sound and stable roadway facility for the travel demand. Patrick proposes to obtain additional geotechnical borings, to supplement borings taken during earlier phases of the project, to develop a more accurate picture of the subsurface conditions in the area of the dry land bridge and the intersection. The previous geotechnical boring program performed by Patrick during Phase I was targeted at the areas at the immediate ends of the existing dry land bridge to determine the cause of the differential settlement that was resulting in safety issues along this heavily traveled roadway corridor. This effort identified the presence of seams of peat in these areas.

Based on these findings, a supplemental boring program was undertaken during Phase II, which was targeted at locating an area beyond the bridge limits where no peat was present, which would yield a suitable location where to end the bridge expansion and locate the approach slabs. This effort found some ...

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