Transforming Foundations: A Value-Engineered Solution for IL Rt 390 Ramp Q5-PPT Presentation

PPT Presentation

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The presentation describes a value-engineered ground-improvement solution for the Q5 ramp embankment on Illinois Route 390 in Bensenville, Illinois. The original January 2022 design used 687 timber piles, averaging 39 feet long, to support areas with up to 15 feet of new fill.<br /><br />Menard proposed replacing the timber piles with controlled modulus columns (CMCs) and wick drains. The design aimed to manage settlement in soft, organic soils while reducing installation time and avoiding timber pile caps. Approval required ISTHA to accept a settlement limit of one inch after paving, supported by wick drains and settlement monitoring.<br /><br />Finite-element modeling helped identify areas where CMCs could be omitted, including near the culvert, which Wang Engineering determined did not require support. The final installation comprised 458 CMCs, 12.5 inches in diameter and averaging 37 feet long, plus 49,875 linear feet of wick drains. This was fewer columns than the 628 originally bid. One static load test and 47 pile integrity tests were completed.<br /><br />Wick drain installation began in March 2024 and proceeded largely as planned, although pre-drilling was needed through existing fill. CMC installation included both reinforced and unreinforced columns; rebar placement slowed production. A storm also caused one lost workday due to standing water and an unstable work pad. The load test reached 193 kips, compared with a design load of 77 kips.<br /><br />The presentation contrasts the systems’ construction and environmental considerations: CMCs required more concrete per unit but no pile caps, fewer elements overall, and less time for installation. Timber piles require trees and may have a shorter service life.

Keywords

ground improvement

controlled modulus columns

CMCs

wick drains

Q5 ramp embankment

Illinois Route 390

settlement monitoring

timber piles

soft organic soils

value engineering