Mark Pitman

UB Users WorkshopUB Users WorkshopSeptember 18September 18--19, 200619, 2006

University at Buffalo's University at Buffalo's NEES Equipment Site NEES Equipment Site

Shake Table TestingShake Table Testing

Mark PitmanMark PitmanTechnical Services ManagerTechnical Services Manager

Structural Engineering and Earthquake Simulation Laboratory,Structural Engineering and Earthquake Simulation Laboratory,Department of Civil, Structural and Environmental EngineeringDepartment of Civil, Structural and Environmental Engineering


• Test Execution• Test Checklist• System Identification

• Specimen natural frequencies• System Transfer Function for

compensation• Table Motions

• Historical Earthquake records• Artificial Table motions

• From test protocols• Custom motions

• Iterative process for compensating Table motions to improve fidelity

• Scaling of table motions• Time scaling• Amplitude scaling

• Project Scheduling• After the grant has been awarded• Definition of a Timeline

http://nees.buffalo.edu/docs/labmanual/SEESLLabManual.pdfhttp://nees.buffalo.edu

• Description of Equipment• Tables• Extensions• Connection Details

• Test Definition, Preparation and Assembly

• Required Resources• Personnel• Specimen Mounting details• Table motion specification• Data Acquisition• Rigging Equipment

• Test Protocols• Industry Standard Protocols

• IEEE693• AC156

• “Classic” Table Motions• System Identification

• White Noise• Sweeps• Pulses

Table of ContentsTable of Contents



Description of Description of EquipmentEquipment


Description of EquipmentDescription of Equipment


Shaking Tables Shaking Tables and Associated Hardwareand Associated Hardware




Shaking Tables• Key elements of the SEESL are the two movable, six degrees-of-freedom, shaking tables,

which can be rapidly repositioned from directly adjacent to one another to positions up to 100 feet apart. It takes approximately 2 – 3 workdays with a staff of 5 to reposition one table.

• Together, these tables can host specimens of up to 100 metric tons and as long as 120 feet, and subject them to fully in-phase or totally uncorrelated dynamic excitations.

• This positioning flexibility and both tables’ dynamic capabilities allow for test payloads of many different configurations. Some examples:

• A single-table payload with up to six degrees-of-freedom excitation.

• Two tables positioned adjacently (a mega-table) with a rigidly connected payload using the same table motions on each table (effectively doubles the payload footprint capability). This configuration provides four possible degrees of freedom.

• Two tables positioned separately at any location along the foundation trench (up to 100 ft apart) with a specimen (i.e. bridge span on piers) subjected to either:

• synchronized table motions (six degrees of freedom)• asynchronous table motions (12 degrees of freedom)




The “early days” of the lab


(1 of 2) Six Degree-of-Freedom

Shaking Table

(1 of 2)Six Degree-of-Freedom

Shaking Tablewith Table Extension





View of both shaking tables with extensions




Description of EquipmentDescription of EquipmentShaking table specifications

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. For dual-table payloads, mass capacities are doubled.

• Maximum distance between tables: 31m (100’)• Table platform size w/o table extension: 3. 6m x 3.6m (12’ x 12’)• Table size w/ extension platform in place: 7m x 7m (23’ x 23’)• Maximum specimen mass: 50 ton maximum / 20 ton nominal• Maximum specimen mass with extension: 40 ton maximum• Maximum Overturning Moment: 46 ton meter• Maximum Off Center Loading moment: 15 ton meter• Operating Frequency range: .5 - 50 Hertz nominal (to 100 Hertz maximum)• Oil Column Frequencies: (X, Y, Z): 16 Hz, 16 Hz, 25 Hz (depending on payload)• Nominal Performance (X, Y, Z):

– Displacement (m, in): (±.150, ±.150, ±.075) (±6, ±6, ±3)– Velocity (mm/sec, in/sec): (1250, 1250, 500) (50, 50, 20)– Acceleration (g): (±1.15, ±1.15, ±1.15) w/20 ton payload


Shaking Table ExtensionsThe two shake table extensions are designed to accommodate larger – footprint specimens, as well as to provide additional safety for personnel and equipment by covering the gap between the table surface and foundation walls.

• Table extension size: 7m x 7m (23’ x 23’)• Tie-down hole diameter: 1.5” (accommodates 1.25” bolts or threaded rod)• Maximum payload mass: 40 ton• Operating Frequency range: .5~50 hertz nominal/100 hertz maximum

• Frequency response of table/extension/payload combination will vary with specimen mass, height, mounting details and natural frequency.

• Best performance of table/extension payload is achieved for nondestructive tests when several tuning/iteration runs can be used to refine the system performance.





Plan View of Table Extension

Description of EquipmentDescription of EquipmentShaking Table Extensions



Table extension detail

Description of EquipmentDescription of EquipmentShaking Table Extensions




Interface Plates• Several steel interface plates of various sizes and thicknesses are available to

facilitate connection of specimens to the tables or table extensions.

• The interface plates are predrilled to connect directly to the hole patterns on the tables, extensions and lab strong floor.

• Most of the interface plates are drilled to accommodate one of more of the lab’s “standard” test fixtures (towers, frames, etc.)

• The plates have also been drilled for nonstandard specimens, and in most cases can be re-drilled to accommodate future proposed payloads.




Controller SoftwareController Software



Description of EquipmentDescription of EquipmentMTS 469D – The User Interface to the Table Controller



Description of EquipmentDescription of EquipmentMTS STEX – The Table Motion Database and Compensation Engine



Test Preparation Test Preparation and Assemblyand Assembly



Test Preparation and AssemblyTest Preparation and AssemblyTypical Test Personnel

• A typical NEES project conducted at this facility is a collaborative effort requiring the dedicated participation of the local staff (all of whom have different background and skill sets), sometimes with contributions from staff and students from the project PI’s institution.

• Access to the project PI (both onsite and offsite) is critical during all phases of planning and execution.

• Personnel requirements for a given experimental program vary with the complexity and duration of the program, but the breakdown of assignments and responsibilities remains roughly the same.

• The following pages list the personnel requirements and workload distribution for a typical testing program conducted at this facility, regardless of funding source.



• Principal Investigators (1 or 2)• Project PI – defines requirements for test

• UB Faculty• NEES Equipment Site Faculty• Non-NEES Site Faculty

• Site PI – evaluates requirements from Project PI• SEESL Lab director• Other local faculty

• Technical Services Manager - Test Operator (1)• Provides PI with laboratory specifications as needed• Assigns other staff to project-specific functions• Evaluates requirements of the proposed testing program

• System limits & Safety concerns• Acquires and/or defines table motions per requirements

• Scaling (time and amplitude)• Filtering (low frequency elimination to limit excessive displacement)

• Evaluates system readiness and corrects deficiencies• Pre-qualifies table motions

• Actual test runs without specimen (dead load in place of specimen mass)• Conducts tests and directs other test personnel during tests

Test Preparation and AssemblyTest Preparation and Assembly



• Graduate Student or Post-Doctoral Research Assistants (1 or 2)• Assists PI with design of experiment• Assists Lab Personnel with all phases of test as needed• Reduces data and reports results

• Fabricators/Installers (2 or 3)• Fabricate components• Prepare interfaces• Install test specimen• Remove and dispose of tested specimen at project’s completion

• Lead Mechanical Technician• Evaluates installation requirements supplied by PI• Procures materials and supplies as needed• Supervises installation effort

• Staff Technicians• Permanent staff• Undergraduate assistants• Visiting technical staff (from PI’s university)




• Information Technology Services Manager (1)• Provides and supports the infrastructure needed for telepresence, data acquisition

and archival.• Develops custom software applications to address unique requirements.

• Instrumentation/data acquisition specialists (2 or 3)• Sensors and DAQ Specialists

• Evaluates requirements from PI and procures items as needed• Calibrates, installs and cables sensors• Configures DAQ hardware and Software

• Telepresence Cameras and Video specialist• Evaluates requirements from PI and procures items as needed• Installs cameras and cabling• Configures Video DAQ hardware and Software




Specimen Fabrication Issues

• Specimen design and fabrication are the responsibility of the Project PI and his or her team. The UB-SEESL/NEES mechanical technician staff is available to assist with rigging, unloading, specimen mounting and dismounting, and, WHERE NEEDED, minor fabrication details (drilling, in-field repairs, etc.).

• Offsite researchers have the option of fabricating their test specimens either near the home institution OR in the Buffalo area. We have a list of quality steel fabrication shops which can be made available to interested parties.

• All specimen connections must be designed to sustain the combined shear, axial (pull out) and moments using the maximum expected dynamic loads applied statically, unless a complete dynamic analysis is done and submitted to the Site PI and/or testing staff. Details must be reviewed and approved by Site PI and Lead Mechanical Technician.




Specimen Mounting Issues

• The design of payload mounting details are the responsibility of the Project PI or his designate (research assistant or other). Information regarding mounting details is available in the SEESL lab manual (see hyperlinks below). Additional information can be obtained by directly contacting the lab.

• Again, all connections must be designed to sustain the combined shear, axial (pull out) and moments using the maximum expected dynamic loads applied statically, unless a complete dynamic analysis is done and submitted to the operators.

• Details must be reviewed and approved by Site PI and Lead Mechanical Technician

• Potentially unsafe mounting conditions will not be permitted. The Site PI and LMT will propose and implement changes where needed.




Table Motion Specification and Validation

• The PI will specify the table motions (test protocols) required. Careful attention must be paid to the table motion limits in order to ensure both the safety of lab personnel and the integrity of the test equipment.

• The Lab director and Test Operator will review the requirements analytically and (where possible) experimentally.

• When specified table motions exceed the rated capacity of the shaking table for a given specimen, those motions will be subject to elimination from the test protocol.

• Problematic table motions may be either filtered to eliminate problematic frequency content (e.g. those resulting in large low frequency displacements) or executed at a reduced amplitude.

• Compensation see next slide



Motion CompensationMotion Compensation



Data Acquisition

• The Project PI (or his/her designate) will provide a detailed instrumentation plan to the lab Sensors Specialist for review.

• The Sensors Specialist will evaluate the instrumentation plan in conjunction with the Project PI to ensure completeness and availability of required instrumentation.

• Any modifications to the original instrumentation plan will be submitted to the Project PI for approval.

• SEESL has an extensive inventory of instrumentation available to the NEES and other research communities. See the Lab Manual for details. Instrumentation requirements beyond the scope of SEESL inventory are to be covered by the project budget.




Payload Delivery, Rigging and Moving Issues

• The main test floor in UB-SEESL (NEES facility) has a 40 ton overhead crane available for lifting and moving test specimens (either whole or components) from the delivery area to the shaking tables (or anywhere within the lab).

• The original SEESL (non-NEES) lab has a 15 ton crane for moving payloads to any locationwithin that lab.

• The 2 low bay (fabrication and receiving areas) each have a 7.5 ton crane for moving payloads and unloading trucks.

• The lab maintains a full complement of lifting straps, hooks, chains, lifting eyes and shackles. Specific information can be obtained by contacting the Lead Mechanical Technician or the Site PI/Lab Director).

• All PIs proposing projects for execution within SEESL must consider the lifting limits imposed by the crane capacities listed above. In addition, payload materials that can be delivered to the lab are constrained by the size of the 2 overhead doors:

• Direct access to lab test floor (adjacent to west table): 15’h x 15’w. Note: this entry can accommodate a full-length flatbed semi trailer for direct unloading with the 40t overhead crane

• Access to receiving low bay (adjacent to main lab entry): 15’h x 15’ w




Overhead crane (40T) located in the main SEESL/NEES lab




Test Protocols Test Protocols andand

Table MotionsTable Motions


Test Protocols and Table MotionsTest Protocols and Table MotionsStandard Seismic Qualification Protocols

• IEEE 693 (2005 Draft)• ICCB AC156 (2004)• GR-63-CORE (2002) – Formerly BELLCORE

Note:Other protocols are available through professional organizations and online from various sources. UB-

SEESL/NEES will review protocols proposed by potential users to determine the feasibility of their implementation at our facility.

Generic Seismic Testing Protocols:• Historic recorded table motions (El Centro, Northridge, Kobe, Mexico City, etc.). SEESL maintains a

database of many commonly used motions. In addition, many recorded table motions are in the public domain and can be obtained from several web-based services.

• Filtered versions of the above; for eliminating large displacements at low frequencies or for simulating upper story motions on multistory structures.

• Artificially generated table motions – based on custom shock response spectra designed for specific test programs.

• Random (banded white noise) signals used specifically for structural system identification, table-structure interaction measurement, and instrumentation checkout prior to seismic testing.

• Sine sweeps of fixed or varying amplitude – an alternative to white noise, but sometimes more dangerous to the test specimen.



Test Protocols and Table MotionsTest Protocols and Table MotionsIEEE 693 - Recommended Practices for Seismic Design of Substations

• The recommended practice contains recommendations for the seismic design of substation buildings, structures, and equipment. Response spectra are presented, from which appropriate time histories are generated for qualifying various types of electrical substation equipment.

• The UB-SEESL/NEES facility has tested switchgears, transformers, bushings and arrestors to this specification, using 3 simultaneous degrees of freedom.

• When necessary, the lab can provide electrical power requirements to the client for testing equipment while under operation

• This is a rigorous test protocol with many possible variations in qualification requirements. Clients desiring to use this protocol are advised to seek the services of a professional engineer with expertise in qualification testing for consult during the design and execution of the proposed tests.





Response Spectra – IEEE 693 High Performance Level




Table Performance – IEEE 693 High RRS (Potential Transformer Tests)


Test Protocols and Table MotionsTest Protocols and Table Motions(ICCB) AC156 (2004) - Acceptance Criteria For Seismic Qualificationby Shake-table Testing of Nonstructural Components And Systems

• This criteria establishes minimum requirements for the issuance of ICC Evaluation Service, Inc., evaluation reports on seismic qualification shake-table testing of nonstructural components and systems (hereinafter referred to as “equipment”). Such reports relate to the seismic design requirements for architectural, mechanical, electrical and other nonstructural systems, components, and elements permanently attached to structures, as specified in Section 1632 of the 1997 Uniform Building Code™ (UBC) and Section 1621 of the 2003 International Building Code® (IBC).

• This acceptance criteria is applicable for shake-table testing of nonstructural components and systems that have fundamental frequencies greater than or equal to 1.3 Hz.

• The UB-SEESL/NEES facility has extensive experience using this protocol for the seismic qualification of nonstructural components, including:

• Warehouse racks• Rotating machinery (chillers, generators)• Suspended ceiling systems



Test Protocols and Table MotionsTest Protocols and Table Motions


(ICCB) AC156 (2004) - Acceptance Criteria For Seismic Qualificationby Shake-table Testing of Nonstructural Components And Systems


SUSPENDED CEILING TESTSUSPENDED CEILING TEST




(ICCB) AC156 (2004) - Acceptance Criteria For Seismic Qualificationby Shake-table Testing of Nonstructural Components And Systems




Some available historic ground motions:• Northridge (1994) All recording stations• El Centro (Imperial Valley 1940)• Mexico City (1985)• Taiwan (Chi Chi) 1999• San Fernando Valley (Pacoima Dam) 1971

Many others…..just ask!




Key Points to Remember When Specifying Table Motions

• All proposed motions are subject to evaluation prior to implementation in order to minimize safety concerns and to keep within system limits.

• If a specific motion is not in our possession, most likely it is available in the public domain or from other research groups. Please contact SEESL directly for information on available motions.

• When supplying table motions to SEESL for evaluation, please provide data in ASCII column (Excel) format, with a time step column in the leftmost position and with a header identifying engineering units, time scaling factor and table motion Identification.

• It is permissible to include all degrees of freedom (i.e. X,Y,Z) in the same file, as long as the columns are clearly identified.

• All system limits (displacement, velocity, acceleration, overturning moment) need to be evaluated prior to approval of a specific table motion.



Test Test ExecutionExecution



Test ExecutionTest ExecutionTest Readiness

• Test checklist has been modified for the specific testing program.• Specimen payload assembled, mounted and secured to table platform• Table Motions identified, scaled, and (where possible) pre-tested• Safety equipment in place and tested for proper operation where necessary

(barricades, warning lights, rigging for possible collapse containment)• Table systems functional and ready for operation

• Hydraulic systems• Controllers and Software• Table motions (pre-qualified and scaled)• Mechanical components

• Data Acquisition, Instrumentation and Telepresence systems configured, mounted, connected and signal paths verified

• Test personnel assigned tasks and in place• Test checklist distributed to all test personnel• Test floor cleared of all nonessential personnel



Test ExecutionTest ExecutionThe Test Checklist

• A checklist has been developed (and is customized on a per-project basis) in order to improve quality control and minimize the chances of operator error.

• During the conduct of an experiment, the Test Operator works through the checklist, marking each task when completed by the pertinent test personnel.

• Copies of the checklist are distributed to all test personnel prior to beginning daily test program.

• The checklist becomes a part of the permanent documentation for the experimental program.



Test ExecutionTest ExecutionThe Test Checklist


System IdentificationSystem Identification


Test ExecutionTest Execution


System Identification via White Noise

• Verify functionality of all instrumentation at a low excitation level

• Identify specimen natural frequencies

• Obtain system Transfer Function (Model) for later table motion Compensation

• banded white noise (0.5-50 Hz; pga .05g –0.1g)

• Duration can vary; typically not less than 80 seconds per degree of freedom (longer produces better transfer functions)

• For measurement of a System Model, discrete excitation of the active DOFs is required

• For specimen identification, either simultaneous or discrete excitation of the active DOFs is acceptable (typically up to the discretion of the PI)

http://nees.buffalo.edu/docs/labmanual/SEESLLabManual.pdf



Test ExecutionTest ExecutionOther System ID Methods

• Sine sweep• Typically a constant amplitude sine

function with a frequency that varies from F(min) to F(max) at a rate specified in (n) Oct/min.

• Specimen will resonate as the sweep passes through the structure’s natural frequencies.

• Can be dangerous for specimen if the Sweep Rate is too slow.

• Each Degree of Freedom is excited discretely in order to minimize cross-coupling effects.

• Sine Pulse (Half or Full Cycle)• Sometimes used when long-duration

identification tests are potentially damaging to the specimen

• Each Degree of Freedom is excited discretely in order to minimize cross-coupling effects

Typical Sine Sweep

Typical Sine Pulse




Uncompensated Uncompensated Seismic TestingSeismic Testing


Test ExecutionTest ExecutionSeismic Testing - Uncompensated• No System Model is necessary

• Used typically in “one-shot” destructive testing when it is determined that repeated low level runs (white noise or compensation iterations) would cause premature damage to the specimen

• Seismic records are scaled to appropriate amplitude and test is executed in one step

• If required by the test program, table motions are scaled up and repeated until the desired effects are observed on the specimen

• Depending on table-specimen interaction (and the skill of the operator), table motions will be reproduced with varying degrees of accuracy.


http://nees.buffalo.edu

Response Spectra – Uncompensated Testing

Time Histories – Uncompensated Testing




Compensated Compensated Seismic TestingSeismic Testing


Test ExecutionTest ExecutionSeismic Testing – Compensated

• A System Model is created from the System Transfer Function (computed from a discrete-axis white noise test).

• Used most often when repeated low-level runs will not cause premature specimen damage.

• Initial drive signals consist of the desired table motions modified by the System Model to account for inaccuracies in the table performance due to table-specimen interaction.

• Drive signals are scaled to 60 – 80% of the desired level for the initial run, and following the run an Error signal is computed for each degree of freedom. A percentage of the Error signal is applied to the drive signals for the next run.

• With each subsequent run (iteration) of a given test, achieved table motion data from the previous test is compared to the desired motions, and the drive signals are again modified using the error in an attempt to converge on the desired motion.

• When convergence is satisfactory (users’judgment), the motion is saved and used for all subsequent runs at the current amplitude.

• For higher amplitude tests, the drive motions can be directly scaled with a multiplier, and subsequent iterations can be performed at the higher levels to further refine the drive motions.

Response Spectra – Compensated Testing

Time Histories – Uncompensated Testing

Time Histories – Compensated Testing




Compensated Compensated Testing, Testing,

Step by StepStep by Step



Test ExecutionTest Execution1.1. Discrete white noise Discrete white noise excitation of each active Degree of Freedomexcitation of each active Degree of Freedom

2.2. Determination of Determination of System Transfer FunctionSystem Transfer Function

3.3. Creation of Creation of System Model System Model (modified Inverse Transfer Function)(modified Inverse Transfer Function)

4.4. Determination of Determination of Initial Drive SignalsInitial Drive Signals1.1. Apply System Model to Desired MotionsApply System Model to Desired Motions2.2. Scale initial Drive SignalsScale initial Drive Signals

5.5. First Iteration First Iteration (initial test run)(initial test run)

6.6. Calculation of Error Calculation of Error (Achieved (Achieved vsvs Desired) and Drive CorrectionDesired) and Drive Correction

7.7. Convergence (Achieved vs. Desired) towards Convergence (Achieved vs. Desired) towards Final RunFinal Run

8.8. Scaling up Scaling up to a higher excitation levelto a higher excitation level


Test ExecutionTest ExecutionSeismic Testing - Compensated

•• Discrete White NoiseDiscrete White Noise excitation is applied to the system, and response of all active DOFs are measured to determine cross-axis excitation (cross-coupling)

• Longer duration excitation produces more data and results in a smoother transfer function, but this must be weighed against the possibility of damage to the specimen. Excitation level must be low enough to prevent damage to specimen but sufficient to produce a reasonable system response (operator’s judgment with input from PI or Research Assistant)

Discrete Random Excitation for Transfer Function Determination




•• System Transfer FunctionSystem Transfer Function computed from data obtained from discrete DOF white noise excitation of the table and payload (care must be taken to avoid inelastic behavior of the specimen)

• For a 3 DOF experiment, a 3 x 3 matrix is developed to quantify any cross-coupling between the tested degrees of freedom




•• System ModelSystem Model (Inverse Transfer Function) is essentially a filtered and windowed Inverse Transfer Function, and is used to compensate the desired table motion in order to improve the accuracy of the test




•• Initial Drive SignalsInitial Drive Signals are determined by multiplying the desired table motions by the System Model (inverse Transfer Function) in the Frequency Domain, then using an inverse Fourier Transform algorithm to convert the modified drives back into the Time Domain. The initial drive is then scaled (60-80% of original) to prevent overshoot during the first run.

• System inaccuracies (example: table-structure interaction at the natural frequency of the structure; cross-coupling between DOFs) are accounted for in the Initial Drive Signals.




•• First Iteration First Iteration achieved results are evaluated and compared to the desired tablemotions (in time or frequency domain).

• The Test Operator (in consult with the PI or RA) then determines if further refinements of the drive are needed in order to converge on the desired

• ….




•• Average Error Average Error (Achieved Results vs. Desired Motion) is evaluated and tabulated. If further improvements are needed, correction signals are determined from the Achieved vs. Desired data, then scaled and applied to the Drive Signals

• The run is repeated (iterated) as many times as necessary to produce the required convergence. Error should continue to decrease for every iteration.

• If error begins to increase, the system has been over-corrected and iterations should cease




•• Final Run Final Run - when the table motion Achieved vs. Desired is determined to be satisfactory, OR when no further Convergence is observed, the test is saved and the final iteration is used for all subsequent runs at this level

• If further improvements are needed (i.e. due to model degradation affecting System Transfer Function), further iterations can be performed at the discretion of the operator




•• Scaling Up Scaling Up - if the test program requires that the table motions be scaled to higher levels for subsequent runs, the operator can simply scale the Compensated Drive motions to the higher level. However, due to system nonlinearities, the drive motions may require further iterations at the higher level in order to converge on the new Desired motion. USE WITH CARE




Project Project SchedulingScheduling


Project SchedulingProject Scheduling•• When a NEES (or other) grant has been awarded:When a NEES (or other) grant has been awarded:

–– Contact UBContact UB--SEESL/NEES management:SEESL/NEES management:•• Site Operations ManagerSite Operations Manager•• Technical Services ManagerTechnical Services Manager•• Site PI (Lab Director)Site PI (Lab Director)

–– Develop a project timeline (Gantt Chart)Develop a project timeline (Gantt Chart)•• Will be integrated into Master Lab Project ScheduleWill be integrated into Master Lab Project Schedule•• Adjustments to the timeline will be made to accommodate other Adjustments to the timeline will be made to accommodate other

projects and avoid conflictsprojects and avoid conflicts–– Keep the lines of communication openKeep the lines of communication open

•• Budget issues Budget issues –– Site PISite PI•• Technical issues Technical issues –– Technical Services ManagerTechnical Services Manager



Project SchedulingProject Scheduling


April 1, 2006 December 1, 2006Project SchedulingProject Scheduling



More in Example More in Example

Project SchedulingProject Scheduling


Thank You !Thank You !

Questions ?Questions ?

Mark Pitman

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