Standard Interpretations - Table of Contents|
| Standard Number:||1926.752(a); 1926.752(a)(2); 1926.752(b); 1926.755(b); 1926.755(b)(2)|
December 23, 2005
Re: Notification requirements for concrete compressive strength and anchor bolt modifications.
Dear Mr. Skinner,
This is in response to the e-mail correspondence you sent to this office on November 17, 2005. Your questions have been paraphrased as follows:
Question (1): On some jobs the steel erector is provided concrete inspection reports that list the compressive strength that concrete foundations have attained (without narrative conclusions). If the listed test results exceed 75 percent of the intended compressive design strength, is the report sufficient to meet the notification requirements of §1926.752(a)?
Answer: Section 1926.752(a) states in part:
Before authorizing the commencement of steel erection, the controlling contractor shall ensure that the steel erector is provided with the following written notification:In addition, §1926.752(b) provides:
Commencement of steel erection. A steel erection contractor shall not erect steel unless it has received written notification that the concrete in the footings, piers and walls or the mortar in the masonry piers and walls has attained, on the basis of an appropriate ASTM standard test method of field-cured samples, either 75 percent of the intended minimum compressive design strength or sufficient strength to support the loads imposed during steel erection.In this case, the inspection report is sufficient. As you can see, there are two ways to establish concrete strength. ASTM standard tests can be done to show that the concrete has attained 75 percent of the intended minimum compressive design strength. Steel erection can also proceed if you are notified that the tests show that the concrete has enough strength to support the loads that will be imposed on it during erection.
In our conversation, you stated that you had been provided with the "daily concrete report," which stated that the design strength for the concrete samples had reached 146 percent. Your inspection report provides sufficient notification of the strength of the concrete, which in your case, is well above the 75-percent minimum. There is no need for the written notification to come in the form of a letter. Therefore, the inspection report meets the requirements of these provisions.
Note that the report you describe is sufficient because it lists the concrete test results in terms of compressive design strength (and the results equal or exceed 75 percent). In contrast, if a report listed test results instead in terms of load strength, such a report would not be sufficient. Load strength data alone is insufficient because additional calculations would have to be done to determine whether it is strong enough to support the load in question.
Question (2): Scenario: Anchor bolts for a column have been modified. The general contractor provides the steel erector with a copy of a "Request For Information" (RFI). The RFI indicates that, in certain locations, anchor bolts need to be relocated. Does providing that RFI to the erector meet the notification requirements of §1926.755(b)(2)?
Answer: Section 1926.752(a)(2) states:
(a) Before authorizing the commencement of steel erection, the controlling contractor shall ensure that the steel erector is provided with the following written notification:Section 1926.755(b) requires the following:
(1) Anchor rods (anchor bolts) shall not be repaired, replaced or field-modified without the approval of the project structural engineer of record.According to §1926.752(a)(2), where anchor bolts have been modified, the controlling contractor must inform the erector that the modification has been done in accordance with the requirements under §1926.755(b). Section 1926.755(b) has two requirements: (1) no repair, replacement or modification shall take place without the approval of the project structural engineer of record, and (2) the erector must be informed in writing that there has been a repair, replacement or modification. Therefore, in combination, §§1926.752(a)(2) and 1926.755(b) mandate that the controlling contractor provide you with written notice that a modification/repair "has been" done, and that the work was done with the approval of the project structural engineer of record. This is to ensure that the erector is informed that changes to the initial anchor bolts were made and performed in a manner consistent with original specifications.
The RFI described above, which simply indicates that certain anchor bolts need to be relocated, is not sufficient notification under "1926.755 of a modification. First, the RFI in this case, which was written prior to the changes, may not identify all the bolts that were actually changed. For example, in the course of carrying out the RFI instructions, if different bolts were modified than the ones identified in the RFI instructions, that would not be reflected in this RFI. In addition, the notification does not indicate that the changes were done with the approval of the project structural engineer of record.
If you need additional information, please contact us by fax at: U.S. Department of Labor, OSHA, Directorate of Construction, Office of Construction Standards and Guidance, fax #202-693-1689. You can also contact us by mail at the above office, Room N3468, 200 Constitution Avenue, N.W., Washington, D.C. 20210, although there will be a delay in our receiving correspondence by mail.
Russell B. Swanson, Director
Directorate of Construction
Standard Interpretations - Table of Contents|