Quality, Service & Commitment


  • 08 May 2018

    IRTBA Announces INTERRA President To Serve On Green Council Board Of Directors

  • 28 Apr 2018


  • 08 Dec 2017

    INTERRA Honored With 2017 IRTBA Green Industry Achievement Award For Green Initiatives

More News


Laboratory Certifications

  • IL & WI State DOTs
  • ASTM


Firm Certifications

  • DBE with IDOT
  • MBE with City of Chicago

Read More


Chicago O’Hare Airport, Terminal 6 Project: “We would like to extend our appreciation to you and all of your employees who worked on the Terminal 6 Project.  All work was performed professionally, accurately and thoroughly. Your commitment to quality and …

Read More

Precast Plant Inspections – IDOT, Illinois Tollway, CDOT, U.S. Navy

INTERRA Services

 Precast concrete plant inspections

Project Summary

With its certified PCI inspectors, INTERRA has provided precast plant inspection services as per the Manual of Precast Pre-stressed Concrete Products; section 1.3 Quality Assurance specifications. INTERRA has provided these services on numerous Illinois Tollway Authority, Chicago DOT, Illinois DOT, and Navy projects. Specific responsibilities have included observation of strand tensioning and fabrication details, concrete pour, tolerance measurements, observation of compressive strength tests for strand release, and final shipping strength (28 days). Final inspections for crack measurements were performed for every beam and daily inspection forms were completed and submitted to state personnel, as required.  At the time of shipping, each beam was inspected and stamped.

 INTERRA has provided inspection services at the following plants: Mid-States Concrete (South Beloit, IL); PEC (Blackstone, IL); ADL (Michigan and Wisconsin); Welch Brothers (Elgin, IL); ATMI (Aurora, IL); Utility Products (Romeoville, IL); Hoosiers (Salem, IN); Egyptian Concrete (Salem, IL); and Sanders (Indianapolis, IN). Typical structures that were inspected included: Deck Beams (Box Beams), Noise Walls, MSE Wall Panels, Drainage Structures, Retaining Walls, and Architectural Panels.