Structural Engineering and Materials Laboratory

The structural testing capabilities at Georgia Tech were significantly enhanced by the addition of a new Structural Engineering and Materials Laboratory (SEML), with a total area of just under 1672m2 (18,000 ft.2).  The facility opened in early 1999 and is shown in Figure 1.  It includes a strong floor 55 m (180 ft.) long by as much as 18.3 m (60 ft.) wide, for a total strong floor area of about 743m2 (8,000 ft.2).  The floor has 900 kN (200 kip) anchor points on a 1.2m (4 ft.) grid.  The anchor points consist of an embedded grid of DYWIDAG bars that permit prestressing forces of over 8000 kN (400 kip) per load point in addition to the external loads.  The floor is 1.8 m (6 ft.) thick near the wall and 1.2 m thick in the area away from the wall. 

The facility includes an L-shaped reaction wall, with anchor points on a 1.2 m (4 ft.) grid and capacities ranging up from 450 kN (100 kip) along the wall sections to 1350 kN (300 kips) on the buttresses.  The EW wall is 17 m (56 ft.) long and 10.4 m (34 ft.) high.  The NS wall is 18.3 m (60 ft.) long; the first 11 m (36 ft.) of the wall is 7.9 m (26 ft.) high, and the   remaining  7.3 m is 10.4 m (34 ft.) high.  The system is designed to carry over 90,000 kN-m (50,000 kip-ft) of overturning moment on the NS wall and 49,000 kN-m (36,000 kip-ft) on the EW wall.  This bi-directional wall system permits the full-scale testing of full-sized three-story buildings, and has comparable characteristics to the ATLASS facility at Lehigh University. 

Hydraulic distribution and data acquisition systems modular ports are distributed throughout the testing bay to facilitate testing setup.  Near the walls, a hardline hydraulic system capable of peak flows of 1300 lpm (350 gpm) to five substations.  Along the long NS axis of the testing bay, a similar system with half the flow capacity is available.  Currently, the hydraulic power comes from a 570 lpm (150 gpm) unit running at 3000 psi (20.7 MPa) pressure.  Two 400 kN (30 ton) cranes service the main testing bay.  The cranes have access to a width of about 16.5 m (54 ft.), and a clear height of 10.9 m (36 ft.) to the lifting hook.

In addition, the lab houses a 1400 ft2 concrete mixing and preparation facility with full ASTM test apparatus. An environment test room 19-ft. long, 13-ft. wide, and 12-ft. high with cyclic temperature range from 160oF to -40o F, from 20% to 95% relative humidity, fresh and saltwater spray, and UV lighting can be used for all types of exposure and durability testing. There are also constant temperature and humidity rooms for long-term materials evaluation and concrete curing. The lab also houses a 800 ft2 chemistry laboratory equipped with a fume hood, sinks, and chemistry benchtops.

Modern structural testing equipment includes:

  • Two single-ended, servo-hydraulic MTS actuators with 365 kN (82 kip) compression and 240 kN (54 kip) tension capacity; one with 760 mm (30 in.) stroke and one with 300 mm (12 in.) stroke.  Both have 57 lpm (15  gpm) servovalves.
  • Two single-ended, servo-hydraulic MTS actuators with 650 kN (146 kip) compression and 450 kN (100 kip) tension capacity; both have 760 mm (30 in.) stroke, and 57 lpm (15 gpm) servovalves.  Recently a 350 lpm (90 gpm) servovalve has been fitted to one of these actuators.
  • One single-ended,  servo-hydraulic MTS actuator with 1460 kN (328 kip) compression and 960 kN (216 kip) tension capacity; with 510 mm (20 in.) stroke and a 57 lpm (15 gpm) servovalve.
  • One double-ended, servo-hydraulic MTS actuator with 960 kN (216 kip) tension and compression capacity;  with 150 mm (20 in.) stroke and a 57 lpm (15 gpm) servovalve.
  • One four-channel TestStar digital controller, and associated hardware and software, including pseudo-dynamic testing capabilities.
  • One two-channel TestStar digital controller, and associated hardware and software, including pseudo-dynamic testing capabilities.
  • In addition to the computer-controlled MTS actuators, the laboratory has numerous manually-controlled ones, including several new Power Team and older ENERPAC ones.  The new Power Team equipment includes two 270 kN ( 60 kip), 250 mm (10 in.) actuators and two 450 kN (100 kip), 250 mm (10 in.) ones that can be used in combination with the MTS system to provide constant loading or displacement to test specimens.