Detailed plan view of shake table platform (pdf)

Shake table actuator specifications (pdf drawing)

Actuator servo valve specifications (pdf drawing)

The Laboratory has three 110,250 lb (50 ton, 450 kN) biaxial shake tables in operation. Manufactured by MTS, each table measures 14 x 14.6 ft (4.3 x 4.5 m), has a stroke of +/- 12 in (+/- 300 mm), and can reach a peak velocity of 40 in/sec (1000 mm/sec) and an acceleration of 1g under the full 50 ton payload (450 kN). All there tables are relocatable. To achieve these maxima, two banks of blow-down accumulators are used. The maximum cumulative stroke is 330 in. (8.4 m). With the actuator under the table, the tables are designed to handle simultaneously a maximum pitch moment of 1000 kip-ft (1356 kN-m) along with a maximum roll and yaw moment of 400 kip-ft (542 kN-m). If a single table were to be operated by the continuous oil supply, the maximum velocity reduces to 25 in./sec (635 mm/sec). All three tables can be constrained to act together as a single large table, or they can be operated individually with independent motions.

System Specifications (Three identical shake tables):

	Table Size	14.0 ft x 14.6 ft  (4.3 m x 4.5 m)
	Maximum Specimen Mass	100,000 lbm  (45,352 kg)
	Maximum Pitch Moment	1,000,000 ft-lb  (1,356 kN-m)
	Maximum Yaw Moment	400,000 ft-lb  (542 kN-m)
	Maximum Roll Moment	400,000 ft-lb  (542 kN-m)
	Force Rating	165,000 lb  (734 kN)
	Vertical Live Load	+/-150,000 lb  (+/-667 kN)
	Maximum Dynamic Displacement	+/-12 inches  (+/-300 mm)
	Maximum Static Displacement	+/-14 inches  (+/-350 mm)
	Maximum Velocity	+/-50 in/sec  (+/-1270 mm/sec)
	Maximum Acceleration	1 g at 100,000 lbm specimen
	Operating Frequency	0-50 Hz

System Components:

Specimen Table Assembly	The table supports the specimen that is to be tested and provides threaded mss with minimounting holes for securing the specimen to the table. The table is constructed to provide high stiffneum possible weight. Reinforced sections of the table accommodate attachment of the hydraulic actuators. Two table assemblies are provided. Each table assembly consists of the table, four base plate-bearing assemblies, bumper boxes, and preloader assemblies. The biaxial table assembly also has a crossbrace assembly.
Hydraulic System
Hydraulic Power Unit (HPU)	Three hydraulic power units (MTS 506.82, MTS 506.62, and MTS 506.41) provide the pressurized hydraulic fluid to the hydraulic distribution system in direct response to control signals received from the Remote Pump Control Panel.
Hydraulic Service Manifold (HSM)	The hydraulic service manifolds use check valves, pressure relief valves, accumulators, and solenoid controlled valves to adjust the hydraulic pressure to the MTS multi-stage servovalves and blowdown system.
Blowdown System	The blowdown accumulators are used to maintain system performance during short-term, high-demand test conditions. There is one blowdown system for each actuator.
Flow Averaging Accumulators	Flow averaging accumulators mounted on each leg of the main pressure piping and the main return piping reduce the pressure fluctuations in the hydraulic system.
Sump Pump	A sump pump returns hydraulic fluid that has accumulated in the sump reservoir to the hydraulic fluid reservoir through the main return pipe.
Series 244.50S Actuators	The actuators provided for the seismic test system are specially designed for high performance. Externally mounted actuators are attached to the seismic table and external buttresses with swivel mounting fixtures. An internally mounted actuator is located under the table and is attached to the table and internal buttress. A linear variable differential transformer (LVDT) is mounted inside the actuator to provide an electrical feedback signal that indicates the actuator position. The Series 244.50S actuator has a dynamic stroke of 12 inches (300 mm).
Servovalves	The actuators are equipped with multistage servovalves which control the direction and amount of fluid flow to the actuators. The actuators have two Series 256.25 servovalves which provide a total rated flow of 500 gpm (1890 lpm).
469D Digital Controller	The 469D digital real-time controller provides closed-loop control of table motion and the operator interface to the system. The controller provides programming and feedback summing to ensure faithful reproduction of the desired waveform on the shaking table surface so that accurate tests on the specimen can be conducted and evaluated.
Digital Computer Subsystem	The Digital Computer Subsystem is used for table programming, control and compensation, and data acquisition and analysis. It consists ofcomputer systems, data acquisition system, and software packages.

Mass Shaker System:

 

The MK-12.8A-4600 Eccentric Mass Shaker System by ANCO Engineers, Inc. consists of an eccentric mass shaker, a drive motor, a frequency inverter with a remote operator's station, interconnecting cabling, and flexible shafting. The system is portable and can be disassembled into individual elements and transported. The eccentric mass shaker consists of two match sets of weights, a 4,600 lb-in (520 kN-mm) eccentricity set and a 980 LB-in (110 kN-mm) eccentricity set. The force output is limited to 10,000 lb (44 kN) continuously and 20,000 LB (89 kN) intermittently at frequencies less than 10 Hz with the large weight set installed. The small weight set must be used if the system is operated in the 10-20 Hz range. Eccentricity of the shaker is continuously adjustable over the ranges of 0-980 LB-in (0-110 kN-mm) and 0-4,600 LB-in (0-520 kN-mm). The shaker is powered by a 10-hp (7.4 kW), 6-pole (1200 rpm) induction motor. The inverter rectifies 230-volt, 3-phase, 60-Hz line current to a direct current and constructs a pulse width modulated motor drive current whose frequency and voltage can be varied and controlled. The maximum output current frequency can be selected to be either 60 Hz or 120 Hz permitting either 10 Hz or 20 Hz full-speed shaker operation. Running speed of the shaker is controlled either by rotation of a 10-turn potentiometer or by application of an external 0-9.0 volt dc signal. The shaker can either be operated from the inverter or from a remote operator's station. Cabling permitting, a 100 ft (30 m) separation between the inverter and the remote operator's station is provided.

Hydraulic Actuators:

 

Six servo-controlled actuators are available for dynamic and cyclic load testing

 

MTS Actuator (Model 243.31):

 

This actuator has a load capacity of +/-55 kips (+/-250 kN), a stroke of +/-3 in. (+/-75 mm), and a composite servovalve system (Models 252.21C and 256.09) with flow rate of 91 gpm (345 lpm).  The actuator has a load cell for measuring the forces and internal LVDT for measuring the displacements.

 

MTS Actuator (Model 244.41):

 

This actuator has a load capacity of +/-110 kips (+/-500 kN), a stroke of +/-11 in. (+/-275 mm), and a servovalve system (Model 252.25C) with flow rate of 15 gpm (55 lpm). The actuator has a load cell for measuring the forces and internal LVDT for measuring the displacements.

 

MTS Actuator (Model 244.41):

 

This actuator has a load capacity of +/-110 kips (+/-500 kN), a stroke of +/-11 in. (+/-275 mm), and a dual servovalve system (Model 252.33A) with a total flow rate of 120 gpm (450 lpm).  The actuator has a load cell for measuring the forces and internal LVDT for measuring the displacements.

 

MTS Actuator (Model 244.51S):

 

This actuator has a load capacity of +/-220 kips (+/-1000 kN), a stroke of +/-15 in. (+/-375 mm), and a composite servovalve system (Models 252.21C and 256.09) with a total flow rate of 91 gpm (340 lpm).  The actuator has a load cell for measuring the forces and internal LVDT for measuring the displacements.

 

MTS Actuator (Model 243.80):

 

This actuator has a load capacity of 460 kips (2050 kN) in compression and 300 kips (1335 kN) in tension, a stroke of +/-20 in. (+/-500 mm), and a servovalve system (Model 252.25C) with a total flow rate of 15gpm (55 lpm).

 

MTS Actuator (Model 243.90):

 

This actuator has a load capacity of +/-500 kips (+/-2225 kN), a stroke of +/-10 in. (+/-250 mm), and a servovalve system (Model 252.25C) with flow rate of 15 gpm (55 lpm).

 

MTS Actuator (Model 243.100T):

 

This actuator has a load capacity of 700 kips (3115 kN) in tension and 945 kips (4200 kN) in compression with a stroke of +/-48 in. (+/-1220 mm), and a dual servovalve system (Model 252.256) with flow rate of 15 gpm (55 lpm) each.

 

List of actuators available at the facility:

Hollow Core Jacks:

 

The following table shows the available hydraulic, hollow core jacks available at the facility:

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MTS Test Systems and Controllers:

MTS Digital Control System (FlexTest IIm):

 

MTS's FlexTest Iim is a direct digital test control system and is designed for structural testing applications. FlexTest IIm is a multi-channel, multi-station controller that uses an industry standard VME architecture and a windows-based graphical user interface to provide a versatile test controller.

Major Features and Capabilities:

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Hydraulic Power Supplies and Manifolds:

 

The following table shows the available hydraulic power supplies (HPS) and hydraulic system manifolds (HSM) by MTS:

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Information can also be accessed on NEEScentral Facilities .