Specifications for Incremental Consolidation Soil Testing System

SPECIFICATIONS FOR FULLY AUTOMATED DIRECT SHEAR AND RESIDUAL SHEAR SOIL TESTING SYSTEM

Equipment shall consist of the following units:

1)One direct and residual shear unit, complete with all appropriate sensor mounting fixtures, two (2) shear boxes [one standard circular 2.5 in (63.5mm) diameter and one standard square 4.00 in (101.6 mm) diameter], and related test components.

2)Direct and Residual Shear control and data acquisition software and related computer interface hardware.

3)Direct and Residual Shear editing and reporting software.

4)Sensors (horizontal displacement, vertical displacement, horizontal force, vertical force).

5)Related data acquisition equipment and computer interfaces, and connection cabling.

*Note: The Direct Shear system described above shall be configured in both hardware and software such that it is capable of providing appropriate vertical and horizontal stress applications.

Training, installation, and warranties are to be included as part of this package. Refer to these sections in this document for further description.

The computer (and related equipment such as the monitor, power cords, mouse, keyboard, and etc.) will be supplied by the successful bidder.

SCOPE

The basic direct shear and residual shear system shall consist of the following:

1. Load frame and two shear boxes.
2. Appropriate sensors for the accurate and precise measure of load, and displacement.
3. Electronic control and data acquisition system
4. Appropriate electronic systems, peripheral devices and connections for the administration of the test procedure and data collection, reduction, recording and transmission.

The system shall be complete and include relevant software and hardware to present collected information in engineering units (U. S. Customary and SI) in graphical and tabular form for purposes of engineering analysis. The testing device shall be the latest production model and be new and complete, ready for immediate operation.

The device shall come equipped with all standard equipment pertinent to the test (i.e. shear box [made from materials not subject to corrosion by moisture], porous stones, appropriate equipment for application of normal loads, and sensor mounting assemblies).

FUNCTION

The Direct Shear and Residual Shear apparatus is a device for measuring the consolidated drained strength properties of soils. Several tests may be run on the same material to determine an approximation for the Mohr-Columb failure envelope of the soil in question at a range of normal loads. The test may be performed on a variety of soil types, the principal limitation being maximum particle size. This test is typically run on granular materials, though it can be used on mixed soils, and clayey soils. The results from this test are used to estimate an appropriate angle of internal friction or to predict an appropriate failure criteria. The direct shear test will also yield information about the soil density by comparing peak stresses with residual stresses (obtained from the residual shear tests)

The fully automated direct and residual shear system, is a computer controlled, automated, version of the manual test. Additions to the standard consolidation test include assessment of the completion of primary consolidation for cohesive specimens, computer control of test initiation and termination, real time monitoring of test status, and electronic automated data acquisition and reporting. With appropriate user input, calculations are made by the system to convert retrieved data into meaningful engineering units and derived results.

Under this equipment specification, PennDot shall acquire one (1) direct and residual shear test unit that shall be able to control and acquire data from this test as well as perform data reduction and reporting operations. Data shall be stored in a format that is user editable in the event of run-time test 'glitches' that result in invalid data.

For purposes of this specification, data acquisition systems connected to manual testing devices or load frames are not considered automated systems.

REQUIREMENTS

Note that the computer processor, monitor, appropriate data acquisition (D/A cards/devices, and software). and computer peripherals (i.e. pointing devices, keyboard, display, uninterruptable power supplies will be supplied by the successful bidder)

Any necessary I/O cards to accept or transmit information from/to data acquisition systems, signal processors, control devices, etc. shall be included as all relevant sensors, controls, load frames, and related attachments and fittings, wiring, and related computer software to control test function, acquire data, perform test calculations (with the exception of those requiring significant engineering judgment), and output data and graphical displays both to the screen and printed output.

The computer processor must be provided by the successful bidder, and must run under Windows 7 Enterprise (64 Bit) and Windows 10 Enterprise (64 bit) operating systems. Hardware and software must be compatible with this environment.

A. General Requirements

1)Physical Testing apparatus (for soil specimens) shall be consistent with standard sizes and methodologies used in performing standard ASTM & AASHTO tests, including:

a)"Test Method for Direct Shear Test of Soils under Consolidated Drained Conditions" ASTM D 3080/D3080M-11

b)“Method of Test for Direct Shear Test of Soils under Consolidated Drained Conditions”AASHTO T 236-08 (2013)

c)US Army Corps of Engineers EM 1110-2-1906 Laboratory Soils Testing (Residual Shear).

2)The testing device shall be able to:

a)Apply a predetermined normal stress.

b)Provide for drainage or wetting of the test specimen.

c)Consolidate the specimen under the normal stress quickly without exceeding it. And capable of maintaining it with an accuracy of ±1 percent for the duration of the test.

d)Unlock the frames that hold the test specimen and

e)Apply a shearing force to shear the specimen either under displacement or load control

f)Automatically reverse travel during residual shear

3)The system shall operate on110V/60Hz power.

4)The unit shall consist of a computer control and data acquisition system, appropriate sensors (and sensor interface,signalconditioners, A-D converters, and etc.), the load frame and other related components.

5)The device (and software) shall be capable of running tests with circular specimen areas for testing extracted undisturbed 'thin-walled' samples as well as laboratory prepared and compacted samples on remolded clays and granular materials. The circular shear box’s shall be able to accommodate the standard 2.5 in (63 mm) test specimen type. The square shear box shall be able to accommodate the standard 4.0 in (101.6 mm) test specimen type. Automatic computations for area correction for both boxes shall be able to be performed by the software.

6)The unit shall be appropriately rugged to withstand a standard laboratory testing environment with a projected service life of 10-15 years.

7)The unit shall be designed to operate at a standard room temperature environment 50-90oF (operating). The equipment should be able to withstand temperatures of 10 - 120 oF for shipping and storage.

8)The unit shall use shielded electrical cables to reduce signal noise and interference that may otherwise result in undesirable effects.

9)The unit shall come equipped with all standard equipment pertinent to the test including, but not limited to, the shear box, connecting pins and adjustment screws, porous inserts, top block, load application devices, and sensor mounting assemblies.

10) The load frame system shall not require external connections to hydraulic (or other) supplies, except standard AC power as indicated in A2, above.

B.Test Control Requirements

1)The test apparatus shall be both computer controlled and stand alone unit with manual controls on the front panels of the load frame with keypads and LCD’s. The load frame shall be able to have loads applied and removed (controlled) by the computer control system. Loading rate shall be controlled by the computer as well as the number of residual tests. The computer interface shall also be able to allow the user to adjust calibration factors and the rate of data acquisition.

The apparatus shall also have appropriate control functions to allow the operator to manipulate the location of displacement components for functions such as resetting the apparatus for a new test.

2)Horizontal forces/displacements shall be applied either hydraulically, servo-mechanically, or through the use of micro-stepper motors at appropriate rates and within specified tolerances (consistent with those indicated in the relevant ASTM and AASHTO specifications). Horizontal displacements shall be able to be applied at rates up to 2.54 mm per minute (0.1 inch per minute).

3)Vertical loadings shall be applied either hydraulically, servo-mechanically, or through the use of micro-stepper motors at appropriate rates and within specified tolerances (consistent with those indicated in the relevant ASTM and AASHTO specifications) pneumatic loading systems for the application of vertical loads may not be used.

4)Vertical and horizontal loads and displacements shall be monitored by appropriate sensors that transmit the information to the data acquisition system for use in engineering calculations and real time display and recording of load, displacement, and applied stresses/strains.

5)Test control parameters (applied loads and/or displacement rates and end of test criteria) shall be adjustable during the testing sequence. The test control software shall allow the test to be aborted at any time without the loss of existing data. The test should terminate if sensors detect an overload or 'out of range' condition.

6)Readings, in engineering units, from test sensors shall be available for monitoring in real time on the computer control system.

7)Sensor readings shall be able to be electronically "zeroed" in the test control program.

8) The residual test shall run automatically and not require user intervention to initiate reversals of shear displacement direction.

C. Tolerance Requirements

1)Horizontal and vertical displacements must be able to be determined to a precision of 0.0025 mm (0.0001 in) or greater. The measuring devices shall have an accurate range of a minimum of 12.7 mm (0.5 in).

2)Vertical loading must be maintained for the duration of appropriate testing periods (at each increment) with an accuracy of 1 N (0.22 lbf) over the range of the applied load. The mechanism for load application shall be capable of applying a 1,000 lbf load.

3)Sensors for reading and data acquisition of applied loads shall have an accuracy and precision of 0.025% of the sensor range.

4)The vertical and horizontal load sensors shall have a range of applied load of 0 lbf to 1,000 lbf load.

5)Time shall be recorded to the nearest second (minimum).

D. Data Acquisition Sensors

1)Loads (applied vertical force) shall be measured with self contained load cells which read loads directly. Calibrated proving rings or mechanical spring systems coupled with digital dial gages or LVDTs or similar systems are not acceptable.

2)Displacements shall be measured with linear variable displacement transducers (LVDTs). These devices shall have sufficient travel and resolution for the proper and reasonable operation of the direct shear test.

E. Calibration

1)Applicable calibration information shall be provided with all sensors including instructions for use, and calibration factors as well as any additional instructions relating to their inclusion in the data acquisition system.

2)Computer software shall be able to perform relevant corrections for system. [i.e. no post-processing shall be required]

3)Sensors and Data Acquisition equipment shall be of appropriate quality, construction, and durability to maintain their precision such that calibration of the apparatus be required no more frequently than on an annual basis [given typical and reasonable maintenance and use].

4)The system shall have an internal process for calibrating sensors and shall be able to perform a linear regression analysis and graph results to determine appropriate offset and calibration constant values.

F. Data Input

1)Data relevant to the direct and residual shear test (i.e. sensor reading intervals, test specimen dimensions, etc.) shall be entered into the computer via the standard keyboard/numeric keypad interface and be determined by the user.

2)The computer control program shall provide a method for correcting input errors (i.e. use of delete, backspace, etc...). The control program should be of such a design where an error in the input process does not require the test to be aborted and re-started from the beginning.

G. Computer Environment (Hardware)

1)Computer test control, data input, and reporting software shall be operable on a PC (personal computer), with appropriate memory, hardware cards, etc. as stated in Annex 1.

2)The successful bidder will supply a computer unit with a Windows 7 Enterprise (64 Bit) and/or a Windows 10 Enterprise (64 bit)operating system

H. Computer Program Environment (Software)

1)Computer test control, data input, and reporting software shall be applications that operate on a standard personal computer in a standard Microsoft Windows based environment.

2)The software shall be either developed for or fully compatible with the Windows 7 Enterprise (64 Bit) and Windows 10 Enterprise (64 bit)operating system.

3)The software user interface shall incorporate standard MS Windows conventions (i.e. use of mouse, use of minimize and maximize window functions, 'tab' and 'arrow' keys-to move between fields, 'enter' key- to accept information, function keys, numeric keypad, standard Windows tools-such as cut, copy, paste, etc.) where relevant.

4)The user interface shall be internally consistent (i.e. if 'function key 4 [F4]' means one thing in one part of that program it shall mean that same thing in another part of the program).

5)The computer test control, data input, and reporting software program shall be compatible with Microsoft Windows Networking.

6)The computer test control data input, and reporting software program shall be able to present reports graphically on the computer screen as well as print reports (including tables and graphs) to both local and network printers and plotters.

7)The computer test control, data input, and reporting software shall be developed by a single software developer; each part of the program shall be integrated to provide a user friendly, intuitive, operating environment. Nomenclature of input variables shall be consistent with that used in appropriate ASTM & AASHTO specifications and shall be presented clearly such that confusion is minimized (i.e. rather than "tare weight" use "weight of empty sample can [tare]".

8)The system editing and reporting software may run separately from the control and acquisition software. If the programs are separate, they shall be integrated (i.e. using the same data storage and retrieval and naming conventions) and fully compatible with one another. Other software shall not be required to manipulate data for import or export between programs (if multiple programs are used). Graphical user interfaces shall be consistent such that naming of data items in the input is consistent with naming in the output. Units of measure, significant figures, etc. shall also be consistent among all programs or program components.

9)The software program[s] shall operate in such a manner that data/results from one (or more) tests may be manipulated and reported while tests are actively controlled by the control software*. [*desired- not mandatory]

10)The computer software shall be capable of displaying real time sensor readings, in engineering units. Display of readings shall be automatically updated without user action.

11)Software shall have appropriate labeling of data, graphs, and displays. Graphs and tables shall have the test title or filename clearly associated with them such that they may be readily identified if multiple windows are open. Additionally, graphs and tables should have appropriate headings, axes labels, column labels, etc... Values shall be accompanied by appropriate engineering units (i.e. pressure values accompanied by the engineering units, in kPa [or U.S. Customary equivalent if these units are used in the given test.]). Units of measure for this test may be found in the applicable ASTM/USACOE & AASHTO specifications.

I. General Test Process Function

1)The test system shall be programmable by the user so that displacement rate or applied force can be automatically applied by the computer control system during the test. The test shall be able to be controlled either by load (applied force) control or by displacement control [standard method].

2)The control program shall record the horizontal and vertical displacements and vertical and horizontal forces [stresses] applied to the sample.

3)The user shall be able to run tests with applied normal loads ranging from a nominal 0 [zero] normal force {minimum} application to a maximum of 1,000 lbf {maximum}.

4)The system shall automatically record time, horizontal and vertical displacements, and horizontal and vertical force information at intervals determined by the user (these reading intervals will typically be consistent with ASTM & AASHTO specifications).

5)The system shall be able to monitor specimen consolidation at the beginning of the direct/residual shear test to ensure completion of primary consolidation under the applied normal load.