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Test Floor:

The main test floor of the Structures Laboratory is a heavily reinforced concrete slab providing 8400 sq ft (780 sq m) of useable test area.   This area is serviced by two 25 ton (222 kN) overhead cranes with a clear height of 36 ft (11 m). Figure 1 shows a plan view of the floor which measures 101 x 56 x 3 feet,  length x width x thickness (31 x 17 x 0.91 m), and has about 2000 tie down holes on a 2 x 2 foot (0.61 x 0.61 m) grid.

The floor was designed as a one-way slab supported by two north-south basement walls, three intermediate bearing walls and a footing slab at grade.  Principal reinforcement includes top and bottom mats of #14, grade 60 bars at 12 in (305 mm) centers in both directions.  All slab-wall and wall-footing joints are monolithic.  As a result, the test floor, basement walls, and footing slab form a box girder that is 15 ft (4.5 m) deep, 56 ft (17 m) wide and 101 ft (31 m) long.  Specified concrete strengths were 4000 psi (28 MPa).  Test cylinder strengths at 28 days reached 5000 psi (34 MPa).

At the center of the east wall is a post-tensioned strong wall that is 20 ft wide, 19 ft high and 2 ft thick (6.1 x 5.8 x 0.61 m) (Figure 2).  The wall is perforated with tie-down holes on the same 2 ft by 2 ft (0.61 x 0.61 m) grid as the test floor.  The wall may be used in conjunction with modular reaction blocks to permit a variety of reaction and anchorage loading configurations including L-shaped systems.

Twenty-four, 20 K (89 kN) reaction blocks are currently available in the Laboratory.  They may be stacked together to form temporary reaction walls and buttresses of various shapes and capacities. They are each 4 x 4 x 8 ft  (1.2 x 1.2 x 2.4 m) in size and perforated in three directions with anchor holes that match the 2 ft by 2 ft (0.61 x 0.61 m) grid in the test floor.  Each has been cast to meet tight dimensional and flatness tolerances.  Blocks are assembled together and anchored to the floor and/or the strong wall using hydrostone and Dywidag bars.  Steel molds are  available to cast additional blocks should they be necessary.

Bridge Cranes:

Two overhead cranes service the Laboratory (Figures 2 and 3). Each has a 25 ton (222 kN) main hook and a 5 ton (44.5 kN) auxiliary hook with clear heights of 29 ft (8.8 m). All four hooks can be raised at either 6 or 20 ft/min (1.8 or 6.1 m/min).The bridges of both cranes can travel at either 25 or 80 ft/min (7.6 or 24.4 m/min) along the length of the Laboratory. Hook trolleys can traverse their respective bridges at either 20 or 63 ft/min (6.1 or 19.2 m/min). The cranes are remotely controlled and can operate in unison or independently of each other.

Basement:

The foundation slab of the four-cell box girder provides a basement area for locating the blow-down and other accumulators for the shake tables and servo-hydraulic actuators, access to the underside of the tie-down floor for the anchoring of text fixtures, and general storage.  It is also used to run electric power and hydraulic lines to, and from, experimental equipment on the floor above. Headroom is about 8 ft (2.4 m).

Hydraulic hardlines feed the Laboratory from an external pump house located just outside the south-east corner of the building.  Each of the two supply lines can provide 250 gpm (945 l/min) at 3000 psi (21 MPa). Seven ports along the centerline of the Laboratory floor  provide access to feed, return and drain lines (Figure 1).  The current distribution system is running at the maximum pump capacity. 

Access

Direct access to the test floor for heavy vehicles is available through roll-up doors at the northern and southern ends of the building.  A ramp also provides vehicle access to the basement from the northern end of the storage yard.  A removable grate and staircase permits crane access to the basement at the south-east corner of the floor. (Figure 1)

Fabrication and Staging Area:

A 8000 sq ft (745 sq m) fabrication, staging and storage area is available adjacent to the building.  Two XX sq ft (XX sq m) concrete beds are used for specimen fabrication. Lifting and maneuvering of specimens in this area is assisted by a 16.5 ton (145 kN) forklift truck. Equipment parts and other tools are transported by a 2.1 ton (18.5 kN) forklift.

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Additional Features:

Natural lighting is provided by skylights in the roof and a bank of windows in the north wall.  Electric power (110 and 220 volt), compressed air, and water outlets are provided around the perimeter wall and in the basement (except for 220 volt lines).  A control room is available on the west side of the test floor.

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Design Criteria and Load Ratings:

The test floor was designed as a continuous one-way slab spanning the narrow direction of the Laboratory from one exterior wall to the other, and supported on three intermediate load-bearing walls.  Two-way plate action was considered at boundaries, discontinuities and for the distribution of large point loads applied to the slab.

The capacity of the floor for loads distributed over large areas, is determined by the flexural reinforcement.  Based on ACI, and using appropriate strength reduction factors, the flexural capacity per unit length of slab is estimated to be 300 K-ft/ft (1335 kN-m/m).  For concentrated loads, the capacity is controlled by shear and this is estimated to be 40 K/ft (584 kN/m),again based on ACI.

Using load factors of 1.4 for dead loads and 1.7 for live loads, the rated load of the test floor is estimated as follows:

Uniform loads and patch loads of any size,  in balanced or unbalanced configurations,  in any direction up or down:	3.4 K/sq ft  (163 kN/sq m)
North-south line loads, in any single slab, in any direction up or down:	varies linearly from 35 K/ft (511 kN/m) at mid span to 23 K/ft (336 kN/m) at 3 ft (0.93 m) from the supports
Single point loads, with no other load applied within 12 ft (3.7 m) of the load, and not adjacent to the basement stair openings:	300 K (1335 kN) upward, 240 K (1068 kN) downward

A lower live load factor of 1.4 may be used for experimental live loads that are controlled and monitored.  In this case the above load ratings may be increased by 20%.

The strong wall on the east side of the Laboratory is intended for small-scale experiments.  It is a vertical cantilever projecting from the exterior wall of the basement.  Reinforced with mild steel, the wall has been  post-tensioned to a uniform compression of 950 psi (6.5 MPa).  Load rating is limited by the allowable tensile and compressive stresses in the precompressed zone at the base of the wall.

The box girder test floor weighs about 5000 K (22,250 kN).  Desirable mass ratios of between 50 and 100 imply that specimen weights for dynamic tests should be in the range of 50 to 100 K (222 to 445 kN).

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