Shake Tables

The University at Buffalo’s Structural Engineering and Earthquake Simulation Laboratory (SEESL) equipment includes:

  • A set of two high-performance, six degrees-of-freedom shake tables, (Shake Tables A & B) which can be rapidly repositioned from directly adjacent to one another to positions up to 100 feet apart (center-to-center). Loacted in Test Area 2.
  • Together, the tables can support specimens of up to 100 metric tons and as long as 120 feet. Table motions can be fully in-phase or uncorrelated dynamic excitations.
  • Adjacent to the shake tables, a large reaction wall equipped with external dynamic actuators allows the application of computer-simulated forces on shake table-mounted substructures, thus simulating the reaction of the entire structure (Real-Time Dynamic Hybrid Testing, or RTDHT).
  • Equipment required to operate the shake tables, including a high-capacity, high-performance hydraulic supply and distribution system (up to 1600 gpm), and numerous digital control systems.
  • Networked tele-experimentation capabilities using modular and expandable teleobservation and teleoperation equipment, tied to the testing systems using discrete and global sensors, including high-resolution digital video and imaging capabilities.
  • Located in Test Area 1, the 3.66 by 3.66 m shake table (Shake Table O) has six controlled degrees of freedom (excluding the transverse translational movement). The longitudinal (horizontal), vertical and roll degrees of freedom are programmable with feedback control to simultaneously control displacement, velocity, and acceleration. This shake table has been in use at the University at Buffalo for nearly 20 years. In 2004, it has been refurbished with a new controller and re-built actuators.

Detailed Views of the lab with dimensions

   
   
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Detailed Planview of the lab
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Detailed Cross section of the lab
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Shake table A& B specifications:

  • The two shake tables located in Test Area 2 (Shake Tables A and B) are designed for the following theoretical performance
      Note: Nominal performance specifications are for continuous uniaxial sinusoidal motion with 20-ton rigid specimen and without table extension. System performance levels will be reduced with payloads larger than nominal and/or with table extension in place.

    Table platform size w/o table extension:

    3. 6 meter x 3.6 meter

    Table size w/ extension platform in place:

    7 meter x 7 meter

    Maximum specimen mass:

    50 ton maximum / 20 ton nominal

    Maximum specimen mass with table extension platform in place:

    40 ton maximum

    Maximum Overturning Moment:

    46 ton meter

    Maximum Off Center Loading moment:

    15 ton meter

    Frequency of operation:

    .1~50 hertz nominal/100 hertz maximum

    Nominal Performance:

    X axis Y axis Z axis

    Stroke:

    ±.150 m ±.150 m ±.075 m

    Velocity:

    1250 mm/sec 1250 mm/sec 500 mm/sec

    Acceleration:

    ±1.15 g ±1.15 g ±1.15 g (w/20ton specimen)



  • Table Design and Manufacture (quantity = 2)
    • A 3.6 x 3.6 meter table platform of welded steel construction with a weight of approximately 8 tons. The table has a painted top surface.
    • A 7 x 7 meter shake table extension platform of welded steel construction with a weight of approximately 9.8 tons. The extension has painted top surface.
  • Parking Frame System
      A Parking Frame System consisting of a welded steel frame with electric actuators raises the table for repositioning within the length of the trench. The carrier capable of raising the table with the (4) horizontal actuators, (2) actuator buttresses, and (4) vertical actuators is attached. A beam for securing the horizontal actuator buttresses to the table during movement. The carrier rides on polyurethane wheels for ease of positioning and tracks along a center rail embedded in the trench floor being moved with a winch system.
  • Hydraulic Actuator Assemblies

      1. Longitudinal (X and Y-axis) hydraulic actuator (quantity = 2 each axis)
        MTS Model 244.4 Hydraulic Actuator with a dynamic force rating of 21 metric ton and a dynamic stroke of 300 mm (±150 mm). The actuator assembly includes the following:
          a. Hollow single piece rod
          b. Model 256.25S servovalve rated at 1000 lpm
          c. LVDT type stroke transducers
          d. Swivel heads and bases
          e. Close-coupled pressure and return accumulators
          f. Differential pressure cells

      2. Vertical (Z-axis) hydraulic actuator (quantity =4)
        MTS Model 206.S Hydraulic Actuator with a dynamic force rating of 25 metric ton and a dynamic stroke of 150 mm (±75 mm). The actuator assembly includes the following:
          a. Hollow single piece rod
          b. Model 256.18s servovalve rated at 650 lpm
          c. LVDT type stroke transducers
          d. Swivel heads and bases
          e. Close-coupled pressure and return accumulators
          f. Differential pressure cells
          g. Integral static support with 20 ton capacity (total static support capacity is 20 ton x 4 = 80 ton) will all necessary nitrogen supply and control system
  • Hydraulic Power Supply Subsystem
      MTS Model 506.92 HPS (quantity =4)
      Rated at 185 gpm (700 lpm) at 3,000 psi (207 bar) each.

Shake table O specifications:

  • Physical data:
  • The five degree-of-freedom shake table has payload capacity of 50 tons and a useful frequency range of 0 to 50 Hz. The table is normally furnished with a reinforced concrete testing platform of 6.1 m by 3.66 m plan dimensions that extends the useful testing area beyond the table's dimensions but limits the payload to 42.5 tons. The testing platform has holes on a one foot square grid for attaching test specimens.
  • Capacity data:
  • The five degrees-of-freedom shake table is designed for the nominal performance shown in Table 2. These performance data are based continuous uniaxial sinusoidal motion with 20-ton rigid specimen. System performance levels will be reduced with payloads larger than nominal.
  • Table size

    3. 66 meter x 3.66 meter

    Maximum specimen mass:

    50 ton maximum / 20 ton nominal

    Maximum Overturning Moment:

    46 ton meter

    Maximum Off Center Loading moment:

    15 ton meter

    Frequency of operation:

    0.1~50 Hz

    Nominal Performance:

    X axis Z axis

    Stroke:

    ±0.150 m ±0.075 m

    Velocity:

    762 mm/sec 500 mm/sec

    Acceleration:

    ±1.15 g ±2.30 g (w/20ton specimen)

    Shake Table Drawings

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    Overall Floor Plan
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    Top view of the table extension platform
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    Plan view of the table extension platform, Detail 1.
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    Top view of the table
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    Bottom view of the table
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    Side view of the table
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    Mounting Bolt detail
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SEESL - Structural Engineering and Earthquake Simulation Laboratory
212 Ketter Hall, Buffalo, NY 14260, USA
phone. +1(716)645-3019       fax. +1(716)645-3733