Payment for additional testing is often a point of contention on many jobsites, even though the ASCC-NRMCA "Checklist for the Concrete Pre-Construction Conference" includes the following questions that would help to resolve questions about payment responsibility:
- How do the project specifications handle additional testing? If additional testing is required how will the parties be notified?
- What investigative procedures will be used?
- Who will be employed to conduct additional testing and who employs them?
- How will the test results be evaluated?
- Who pays the costs of additional testing: If specifications are confirmed? If specifications are not confirmed?
To illustrate the need for getting early answers to these questions, imagine the following two situations:
- You finish a cast-in-place concrete project and several months later a mechanical subcontractor drills a hole in a slab on deck. He uncovers a void about one inch deep and less than one foot square under a cluster of congested reinforcing steel.
- On the same project, an opening for a machine foundation is cut in a slab on ground. The slab, with a design thickness of 6 inches, is found to be only 5 inches thick on one side of the opening.
You patch the void in the slab on deck. You also cut out concrete around the floor opening for the machine foundation until all sides are at least 6 inches thick, then replaced the concrete to a depth of at least 6 inches. Now, however, the engineer, owner, or general contractor wants you to pay for testing the entire slab on deck to detect other possible voids. They also want you to test the entire slab on ground for other possible thin spots. This despite the fact that "Specification for Tolerances for Concrete Construction and Materials (ACI 117-10) and Commentary" states the following regarding localized occurrences of reduced thickness for slabs-on-ground: "22.214.171.124 When corrective action is required, additional samples shall be taken in the vicinity of unacceptable results to establish the extent of corrective action."
They say the additional testing is needed because the two examples of nonconformance led them to believe that more of your work may be deficient.
There were quality assurance and quality control inspectors making observations and measurements during all placements, and your argument is that the voids or thin sections are isolated instances. You are willing to pay for repair of any further defects that are uncovered but don't believe you should have to pay for any further testing, especially on sections where no such defects are subsequently found. What is the best way to handle this problem?
The fishing trip mentality
Unfortunately these "fishing trips" happen all too often when a defect is discovered during or after construction. They may be triggered by core tests resulting from low strength tests or situations similar to the ones described.
Most specifications describe repair materials and methods to be used. For instance, Section 3.16 of the 2008 AlA MASTERSPEC contains the following requirements:
- Perform structural repair of concrete, subject to Architect's approval, using epoxy adhesive and patching mortar.
- Repair materials and installation not specified above may be used, subject to Architect's approval.
That and sections in other commonly used construction specifications imply that some repair will be needed and that the contractor is expected to make the repairs at no additional cost. The specifications, however, should not require contractors to search for defects or pay to search for defects.
The following sections in ACI 301-05, Specifications for Structural Concrete, explain this as well.