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DART Rescue
Shore Construction & Testing Exercise
March 6, 2003

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On March 6th DART Rescue conducted an eight-hour shore construction and testing practice. The practice was conducted at the NASA Ames DART Shore Test Facility. Three double-FEMA Three-Post-Vertical shores were constructed and one was tested. The shore tested had a design load capacity of sixty tons. The test was terminated at approximately 70 tons. The test was terminated prior to shore system failure do to an uneven load being imposed on the shore. Twenty-six members of DART Rescue participated in the exercise. Four other personnel supported the exercise. The team was broken up into three squads.

A new technique was employed to test the shore. A dead load was supported above the shore and a smaller dead load that was supported by the shore. High-pressure airbags were placed between the upper dead load and the lower dead load and shore. The airbags were inflated between the upper load and the lower load that was supported by the shore thus imposing a greater load on the shore system. This was done to provide greater control of the load being imposed on the system than can be done by using just the crane.

For the sake of time, the shore that was tested was partially pre-constructed. The shore did not follow strict FEMA construction standards as stainless steel screws were used in lieu of nails. In addition, two vertical-three-post shores were tied together to form a "Class III" shore. Diagram "A" below shows the setup of the test stand and diagram "B" shows the layout of the shore.

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Diagram Two pre-assembled three-post-vertical shore systems being moved to shore test stand. (38,266 bytes) Pre-assembled three-post-vertical shore systems being placed under shore test stand. (40,948 bytes) Chief Dolci is conducting pretest safety talk with team members that are not performing last minute shore test preparation. (34,629 bytes) Vertical shore test stand with double 3-post vertical shore. Nine-ton load (lower block) is being transferred to shore with high-pressure air bags. (44,901 bytes)
Preparing to lift ~ 44-ton dead load and transfer to shore test stand. (23,016 bytes) Transferring ~ 44-ton dead load to shore test stand. (36,209 bytes) Centering and lowering dead load to upper slab. (42,613 bytes) Setting Concrete dead load on upper slab. Cribbing and the two lower support blocks support the upper slab. Load blocks weigh 5.5 to 6 tons each. (37,027 bytes) South side of shore. Shore currently supporting just lower ~ 9-ton slab.  High-pressure air bags will be used to impose additional load on shore. (30,820 bytes)
North side of shore. Note slight compression of header at posts and compression of wedges. (34,760 bytes) North side of shore. Note curling of wedges. Approximate load is 20-tons. (39,953 bytes) North side of shore looking south. Shore loaded to approximately 20-tons. Chief Dolci is South side of shore. ~65-ton load on shore. Note cracks and compression in header. Also, note compression of wedges and lack of compression in grade beam. Does this imply that stress on header would be reduced if 2 South side of shore. Approximate load on shore is 70-tons. Note cracks in header and in posts. Also, note compression of header. Of the six posts, post SE sustained the greatest damage. (33,979 bytes)
North side looking south at posts SE, and SC. Load has been reduced to approximately 9-tons. Note the compression of the 2 Note point of conversion between post and header at post NE. NE was the least damaged post. (28,461 bytes) Note compression and cracks in header. Left post (SE) sunk into header by ~3/4    

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