Analysis

To

Project team

From

Daniel P. Colwell

Date

October 17, 2026

Re

Phase V, Analysis: design parameters, calculations and independent check

What is performed

Analysis turns data into results. The engineer builds the design subsurface profile and groundwater level, selects design parameters for each stratum, and runs the calculations the project needs: foundations, settlement, retaining structures, slope stability, subgrade and pavement. Each parameter is traceable to a test, a correlation or a documented engineering judgment.

How it is performed

1. Build the design profile. Combine the boring logs into representative strata and a design groundwater level for each part of the site.
2. Select design parameters. For each stratum the workflow summarizes the tested values. Where a property has no test, a conservative value from a published correlation (for example SPT N₆₀ to friction angle or undrained strength) is assigned. Every value is labelled Tested, Assumed or Selected (chosen by the engineer with a note).
3. Run the analyses. Bearing resistance and settlement, axial and lateral deep foundation capacity, retaining wall and earth pressure, slope stability under railroad loading (for example Cooper E-80), subgrade and pavement, and seismic site class per AASHTO LRFD. The Design Parameters page shows each value with its source, ready for the calculations.
4. Check sensitivity. Vary the parameters that matter most and confirm the conclusions hold.
5. Independent check. A second engineer reviews the parameters and calculations before they go into the data report.

Why it matters in the workflow

This is where the earlier phases pay off. Because each parameter is labelled tested, assumed or selected, anyone reviewing the work can see how much of the design rests on measurement and how much on judgment, and where more testing would reduce risk. Using one parameter table for every analysis keeps the numbers consistent from one analysis to the next.

What comes in and what goes on

Use and disclaimers

This phase guidance describes general practice for training and reference. It is not engineering advice for any project. Any value, calculation or report prepared with NANCY must be checked and accepted by a professional engineer licensed in the project jurisdiction, and governing codes, owner standards and the current editions of referenced standards take precedence. NANCY is provided as is, without warranty, and is independent of any employer or client. Use is subject to the full Use and Disclaimers.