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I 1 3.09 REMOVAL OF FORMS A. Except as otherwise specifically authorized by the Engineer, forms shall not be removed before the concrete has cured as specified above in subparagraph 3.08C 1 and the concrete has attained a strength of at least 30 percent of the ultimate strength prescribed by the design, and not before reaching the following number of day-degrees (whichever is the longer): Forms for Day-Degree* Beams and slabs 500 1 Walls and vertical surfaces (non-water retaining) 100 Walls and vertical surfaces (water retaining) 150 *Day-degree: Total number of days times average daily air temperature at surface of concrete. For example, 5 days at a daily weighted average temperature of 60 degrees F equal 300 day-degrees. Temperatures below 50 degrees F not to be included. 1 B. Shores shall not be removed until the concrete has attained at least 60% of the specified strength and also sufficient strength to support safely its own weight and the construction live loads upon it, but concrete shall be minimum age of 14 days before such removal. 3.10 FAILURE TO MEET REQUIREMENTS A. Should the strengths shown by the test specimens made and tested in accordance with the above provision fall below the values given in Table A, the Engineer shall have the right to require changes in proportions as outlined above to apply to the remainder of the work. Furthermore, the Engineer shall have the right to require additional curing on those portions of the structure represented by the test specimens which failed, the cost of such additional curing to be at the Contractor's expense. In the event that such additional curing does not give the strength required, as evidenced by core and/or load tests, the Engineer shall have the right to require strengthening or replacement of those portions of the structure which fail to develop the required strength. The cost of all such core borings and/or load tests and any strengthening or concrete replacement required because strengths of test specimens are below that specified, shall be entirely at the expense of the Contractor. In such cases of failure to meet strength requirements the Contractor t and Engineer shall confer to determine the adjustment, if any, can be made in conformity with Sections 16 and 17 of ASTM Specification C94 for Ready-Mixed Concrete. B. When the tests on control specimens of concrete fall below the required strength, the Engineer will permit check tests for structure in accordance with ASTM Methods C42 and C39. In case of failure of the latter, the Engineer, in addition to other recourses, may require, at the Contractor's expense, load tests on any one of the slabs, beams, and columns in which such concrete was used. Test need not be made until concrete has aged 60 days. 1 C. Slabs or beams, under load test, shall be loaded with their own weights plus a super-imposed load of 2 times design live load. The load shall be applied uniformly over portion being tested in approved manner, and left in position for 24 05/08 03300-11 05-4893