Severud Associates Consulting Engineers PC Museum of the American Indian Washington, D.C. Yale University Ingalls Hockey Rink New Haven, CT Eventi Hotel th Avenue, New York, NY US Airways Terminal, Philadelphia International Airport The US Mission to the UN New York, NY

Severud Associates Consulting Engineers PC Bank of America Tower New York, NY Jefferson National Expansion Memorial Saint Louis, MO The Times Square Edition th Avenue, New York, NY

Typical Concrete Strength and Stiffness Specs for High Rise (Over 500 feet) in NYC Spec concrete strength6 ksi to 12 ksi Actual concrete strength6 ksi to 19 ksi Specified E value4.7Mpsi to 6.6Mpsi Actual E value8Mpsi max No. concrete mixes w/c ratio0.29 to 0.35 (verified by microwave test)

Concrete Placement Rules 95% max water content added at the plant. Max 5% water available for addition at the site. 5% held water added on site only to raise the slump of the concrete. Superplasticizer to be made available on site during all concrete placing operations, for re-dosage as required. All trucks delivering to the site shall be supplied with a re-dosage chart. All concrete trucks arriving to the jobsite will have a computerized batch ticket to be given to the inspector for review prior to pouring concrete. The batch ticket must indicate truck number, total batch size, strength in psi, time of discharge, amounts of materials added at the plant, percentage of moisture in the aggregate. Trucks arriving on site without the computerized batch ticket shall be rejected.

Concrete Placement Rules (cont.) Pre-approved design mixes and admixtures only. A pre-approved mix is defined as one having the exact same constituent proportions and constituent sources. Any truck arriving on site with a mix or admixture that is different than the approved design mixes shall be rejected. Pour time limit = 90 minutes after leaving plant, with a possible extension to 120 minutes (pending the temperature of the concrete). However, if the mix is provided with a hydration control admixture that has been pre-approved, this time limit may exceed 120 minutes. Lab shall measure concrete temperature after 90 minutes F < Temperature < 90 0 F : Inspector’s or Engineer’s call Temperature > 95 0 F : concrete is rejected regardless of mix time Temperature < 50 0 F : concrete is rejected regardless of mix time

Concrete Placement Rules Time > 120 minutes : concrete is rejected (unless the mix is provided with a pre-approved hydration control admixture) Slump exceeds max value shown on design mix (with tolerances): concrete is rejected No concrete placement without both Severud and the testing lab present An insulated coring box with sufficient room to place all the required samples shall be provided on site. A microwave oven will be provided at the site to verify the moisture content in the concrete in accordance with the specifications. Slump tests for every 50 yards of concrete placed, and at any time upon a request from Severud, at the point of discharge (at the truck). The contractor will be responsible for delivering the required samples from the point of placement to the concrete inspector on request every 150 cubic yards if concrete is placed using a pump.

Typical 8,000psi Mix – Vertical Elements

Typical 10,000psi Mix – Vertical Elements

Typical 12,000psi Mix – Vertical Elements

Modulus E Chart for Test Cylinders Modulus of Elasticity and Poisson’s Ratio: ASTM C469 / C469M–14

Microwave Oven Testing Used to test water content and water cementitious ratio of discharged concrete at the site AASHTO T318 for Guidelines One test per every five trucks (or fifty yards), typically Used for verification of water content, not for rejection* * if it is a frequent issue, rejection and remediation will be required Microwave Test Equipment (Courtesy of National Concrete Pavement Technology Center)

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