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t <br />l� <br />�I <br />1 <br />3.09 REMOVAL OF FORMS <br />A. Except as otherwise specifically authorized by the Engineer, forms shall <br />not be removed before the concrete has cured as specified above in <br />subparagraph 3.08C and the concrete has attained a strength of at least <br />30 percent of the ultimate strength prescribed by the design, and not <br />before reaching the following number of day- degrees (whichever is the <br />longer): <br />Forms for Day - Degree* <br />Beams and slabs 500 <br />Walls and vertical surfaces (non - <br />water retaining) 100 <br />Walls and vertical surfaces (water <br />retaining) 150 <br />*Day- degree: Total number of days times average daily air temperature <br />at surface of concrete. For example, 5 days at a daily weighted average <br />temperature of 60 degrees F equal 300 day- degrees. Temperatures <br />below 50 degrees F not to be included. <br />B. Shores shall not be removed until the concrete has attained at least 60% <br />of the specified strength and also sufficient strength to support safely its <br />own weight and the construction live loads upon it, but concrete shall be <br />minimum age of 14 days before such removal. <br />3.10 FAILURE TO MEET REQUIREMENTS <br />A. Should the strengths shown by the test specimens made and tested in <br />accordance with the above provision fall below the values given in Table <br />A, the Engineer shall have the right to require changes in proportions as <br />outlined above to apply to the remainder of the work. Furthermore, the <br />Engineer shall have the right to require additional curing on those portions <br />of the structure represented by the test specimens which failed, the cost <br />of such additional curing to be at the Contractor's expense. In the event <br />that such additional curing does not give the strength required, as <br />evidenced by core and /or load tests, the Engineer shall have the right to <br />require strengthening or replacement of those portions of the structure <br />which fail to develop the required strength. The cost of all such core <br />borings and /or load tests and any strengthening or concrete replacement <br />required because strengths of test specimens are below that specified, <br />shall be entirely at the expense of the Contractor. In such cases of failure <br />to meet strength requirements the Contractor and Engineer shall confer to <br />determine the adjustment, if any, can be made in conformity with Sections <br />16 and 17 of ASTM Specification C94 for Ready -Mixed Concrete. <br />December 2006 <br />03300 -14 <br />06 -5723 <br />