Vulcan 06 Hammer: Specifications and Information

The 06 hammer is basically a #1 hammer with a 6,500 lb. ram.  It uses the same leaders and driving accessories.  An 06 at the Chattanooga facility is above, general arrangements of the hammer are below.     Specifications for the Vulcan 06 are below.     In the late 1970's Vulcan made an important … Continue reading Vulcan 06 Hammer: Specifications and Information

What We Need is a Light Trailer

In 1967 Vulcan opened a fabricating facility in West Palm Beach, Florida. Across the street from our new plant was “U and Me Transfer and Storage,” (see photo above) which we hired to move a lot of our machinery. We sent one of our supervisors to Florida to help set the shop up. The shop … Continue reading What We Need is a Light Trailer

Inverse Method for Pile Dynamics Using a Polytope Method: IFCEE 2018

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This paper–which is part of the STADYN project–was presented at the IFCEE 2018 conference in Orlando, FL, 7 March 2018. The slide presentation for the paper is below.

The preprint for this paper can be found at ResearchGate.

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New Version of TAMWAVE Online Wave Equation Program Now Available

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The completely revised TAMWAVE program is now available.  The goal of this project is to produce a free, online set of routines which analyse driven piles for axial and lateral load-deflection characteristics and drivability by the wave equation. The program is not intended for commercial use but for educational purposes, to introduce students to both the wave equation and methods for estimating load-deflection characteristics of piles in both axial and lateral loading.

We have a series of posts which detail the theory behind and workings of the program:

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TAMWAVE 7: Analysis for a Cohesive Soil

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With the analysis of the concrete pile in cohesionless soils complete, we turn to an example in cohesive soils.

The analysis procedure is exactly the same.  We will first discuss the differences between the two, then consider an example.

Differences with Piles in Cohesive Soils

  • The unit weight is in put as a saturated unit weight, and the specific gravity of the soil particles is different (but not by much.)
  • Once the simulated CPT data was abandoned, the “traditional” Tomlinson formula for the unit toe resistance, namely $latex q_t = N_c c $, where $latex N_c = 9 $, was chosen.
  • The ultimate resistance along the shaft is done using the formula of Kolk and van der Velde (1996).  This was used as a beta method, for compatibility with the method used for cohesionless soils.  Unless the ratio of the cohesion to the effective stress is constant, the…

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TAMWAVE 6: Results of Wave Equation Analysis

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With the data entered for the wave equation analysis, we can now see the results.  There’s a lot of tabular data here but you need to read the notes between it to understand what the program is putting out.  If you are not familiar at all with the wave equation for piles, you need to review this as well.

General Output for Wave Equation Analysis
2018-01-06T10:13:03-05:00
Time Step, msec0.04024
Pile Weight, lbs.15,000
Pile Stiffness, lb/ft600,000
Pile Impedance, lb-sec/ft57,937.5
L/c, msec8.04688
Pile Toe Element Number102
Length of Pile Segments, ft.1
Hammer Manufacturer and SizeVULCAN O16
Hammer Rated Striking Energy, ft-lbs48750
Hammer Efficiency, percent67
Length of Hammer Cushion Stack, in.16.5
Soil Resistance to Driving (SRD) for detailed results only, kips572.7
Percent at Toe35.39
Toe Quake, in.0.220
Toe Damping, sec/ft0.07

For those familiar with the…

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TAMWAVE 5: Wave Equation Analysis, Overview and Initial Entry

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With the static analysis complete, we turn to the wave equation analysis.  TAMWAVE (as with the previous version) was based indirectly on the TTI wave equation program.  Although the numerical method was not changed, many other aspects of the program were, and so we need to consider these.

Shaft and Toe Resistance

Most wave equation programs in commercial use still use the Smith model for shaft and toe resistance during impact.  Referencing specifically their use in inverse methods, Randolph (2003) makes the following comment:

Dynamic pile tests are arguably the most cost-effective of all pile-testing methods, although they rely on relatively sophisticated numerical modelling for back-analysis. Theoretical advances in modelling the dynamic pile-soil interaction have been available since the mid-1980s, but have been slow to be implemented by commercial codes, most of which still use the empirical parameters of the Smith (1960) model. In order to allow an appropriate…

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TAMWAVE 4: Shaft Resistance Profile, ALP and CLM2

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With the basic parameters established, we can turn to the static analysis of the pile, both axial and lateral.

Shaft Resistance Profile

Shaft Segment Properties
Depth at Centre of Layer, feetSoil Shear Modulus, ksfBetaQuake,inchesMaximum Load Transfer, ksfSpring Constant for Wall Shear, ksf/inSmith-Type Damping Constant, sec/ftMaximum Load Transfer During Driving (SRD), ksf
0.5048.40.1630.00220.0094.0345.3940.009
1.5083.90.1630.00380.0276.9919.9110.027
2.50108.30.1630.00500.0459.0213.5720.045
3.50128.10.1630.00590.06310.6810.5430.063
4.50145.30.1630.00670.08112.118.7300.081
5.50160.60.1640.00740.09813.387.5090.098
6.50174.60.1640.00800.11614.556.6230.116
7.50187.60.1640.00860.13415.635.9480.134
8.50199.70.1640.00910.15216.645.4140.152
9.50211.10.1640.00970.17017.594.9800.170
10.50222.00.1640.01020.18818.504.6180.188
11.50232.30.164

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TAMWAVE 3: Basic Results of Pile Capacity Analysis

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With the soil properties and lateral loads finalised, we can proceed to look at the program’s static results.  These are shown below.  We will concentrate on cohesionless soils in this post; a sample case with cohesive results will come later.

Pile Data
Pile Designation12 In. Square
Pile MaterialConcrete
Penetration of Pile into the Soil, ft.100
Basic “diameter” or size of the pile, ft.1
Cross-sectional Area of the Pile, ft21.000
Pile Toe Area, ft21.000
Perimeter of the Pile, ft.4.000
Soil Data
Type of SoilSW
Specific Gravity of Solids2.65
Void Ratio0.51
Dry Unit Weight, pcf109.5
Saturated Unit Weight, pcf130.5
Soil Internal Friction Angle phi, degrees32
Cohesion c, psf
SPT N60, blows/foot20
CPT qc, psf211,600
Distance of Water Table from Soil Surface, ft.50
Penetration of Pile into Water Table, ft.50

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TAMWAVE 2: Modifying the Soil Properties

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With the first step out of the way, we can proceed to the second: allowing the user to modify the properties of the soil.  This option must be used with care since it is easily possible to put together a set of soil properties that is physically unrealistic if not impossible.

Also, if you have chosen a sand or clay, you have chosen the methodology you will use.  Adding cohesion to a sand or gravel, for example, will have no effect on the subsequent performance of the model.

Finally, depending upon the choice of a free or fixed head, you are given the option of entering lateral loads and/or moments for the pile head.  In this case we have opted to add a lateral load of 10 kips to the pile and no moment.  The default is zero for both load and moment; this will produce some coefficients but…

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