ATLSS Facility

The ATLSS Multidirectional Experimental Laboratory was constructed, beginning in 1987, to be a major new facility for large-scale structural testing. The lab was opened and dedicated in the second quarter of 1989. It is located in the Imbt Laboratories Building on Lehigh University’s Mountaintop Campus. A summary of the major equipment housed in the facility is given in the table below. The lab is the largest of its kind in North America, with a 30.5m by 12.2m strong test floor, bordered on two adjacent sides by an extended L-shaped monolithic, rigid reaction wall that is 15.2m tall at one side and steps down incrementally on the other side from 12.2m to 9.1m to 6.1m tall. The L-shaped reaction wall runs continuously from one corner of the strong test floor to the diagonally opposite corner of the test floor, and has monolithic 6.1m tall continuations that extend around the corners at the ends of the wall. The reaction wall and test floor have a 1520mm square grid of high capacity anchor points which allow large-scale two-and three-dimensional test structures and test frames to be fastened to the wall and floor to facilitate multidirectional (multi axis) loading.

The lab is equipped to generate multidirectional static and time-varying loads. The primary component of the loading system is the hydraulic power system, which operates at 20.7 MPa (3000 psi) and 2270 (600 gpm) liters/min. The hydraulic power system serves numerous, computer-driven servo-controlled hydraulic actuators simultaneously and independently using a system of 6-150 liters/min (40 gpm) independent hydraulic service manifolds. The hydraulic piping encircles the laboratory, while the hydraulic pumps, motors, reservoir, and cooling systems are in an adjacent pump house area. The equipment in the lab includes 27 hydraulic actuators. Five separate Vickers computer-driven control systems and two MTS controllers are available for controlling the loads generated by the hydraulic actuators. Most of this equipment is in good working condition, however, none of this equipment is capable of generating the real-time loading rates required for the real-time multi-directional (RTMD) earthquake simulation system described earlier (the largest servo-valve is 150 liters/min).

The ATLSS Center has three main data acquisition systems (1 with 256 channels and 2 with 192 channels) for conditioning and acquiring data from experimental research. More than 200 channels of signal conditioners are available for use with these systems. Data acquisition systems for remote data logging are available for field tests; these systems are also used in the lab. The laboratory floor has been equipped with a switched gigabit network, providing network connections every 4.57m along the reaction walls. Network connections in the laboratory currently connect to the main campus backbone by way of a switched fiber optic network.

Teleobservation, or video data acquisition equipment is not frequently used in the lab therefore, when it is necessary, the equipment is leased. All of the experimental facilities are connected to the switched 100-megabit infrastructure, although some research offices and computing laboratories are equipped with the gigabit copper infrastructure.

Adjacent to the reaction wall and strong test floor is a large area where additional tests can be setup, as well as sizeable service areas for specimen fabrication, preparation, instrumentation, and storage. The additional test area was developed, beginning in 1998, for a new large-scale facility for testing structural subassemblages (in particular for testing half-scale ship hull test specimens for the US Navy) under constant bending moment with or without axial force.

The ATLSS Multidirectional Experimental Lab is served by a 180kN radio-controlled overhead traveling crane for handling specimens and equipment on the test floor, and a 90kN radio-controlled overhead traveling crane for the main service area and the additional test area. Large overhead doors (6.1m tall by 7.6m wide) and large paved areas outside the lab provide easy access for tractor-trailer trucks delivering test specimens, equipment, materials, and supplies to the lab. The lab service areas contain welding equipment, a large-bed drill press, a band saw, a grinder, and an array of hand tools. Within the Imbt Laboratories Building, the ATLSS Center operates a Mechanical Testing Laboratory, a Welding and Heat Treating Laboratory, and Metallography and Microscopy Laboratories, all constructed in 1992. The Mechanical Testing Laboratory includes a 2670kN computer-controlled universal test machine, and a 245kN servo-controlled dynamic tension/compression test machine with hydraulic grips. In addition it houses a Charpy V-Notch testing machine and SEM and Light Microscopy equipment.