Skip to main content

Possible online services disruption due to Internet related outage

A worldwide technology outage is causing disruption to some State of Illinois online systems.  We are aware of this issue and are diligently working on restoration.

Agency Alert

Welcome to the new IDOT home page.  Our location has changed, please update any bookmarks.

Specific Scope of Services

Compliance materials are organized by specific scope of service, please click to expand the necessary portion.



Technical Manuals


Bridge Manual Design Guides and Examples

Design Guides Reference Revised

Design Guides Reference Revised

Bridge Information
The following site is a tool to offer bridge inspection and inventory information to the public.


Foundations and Geotechnical

Department Wide Geotechnical Engineers Organizational Chart and Staff Phone Numbers

Technical Manuals and Policy Memorandums

Design Guides and Spreadsheets

The Geotechnical Design Guides have been developed by the Bureau of Bridges and Structures' Foundations and Geotechnical Unit in an effort to document the calculations and proper use of the Geotechnical Spreadsheets.


Design Guides Spreadsheets Description Revised
Liquefaction Analysis LIQUEFACTION Calculates the Factor of Safety Against Liquefaction November 2018
Axial Capacity of Drilled Shafts in Soft Shale DRILLED SHAFT AXIAL CAPACITY - SHALE Provides Drilled Shaft Factored Resistances in Soft Shale <100ksf for various diameters and depths as well as the top of shaft deformation under service loading. May 2017
Axial Capacity of Drilled Shafts in Rock DRILLED SHAFT AXIAL CAPACITY IN ROCK Provides Drilled Shaft Factored Resistances in hard rock for various diameters and depths as well as the top of shaft deformation under loading. October 2016
Existing Foundation Load Carrying Capacity EXISTING PILE CAPACITY Provides maximum pile capacity that can be assumed when checking to see if a substructure can be re-used. August 2016
Temporary Sheet Piling Design Charts TEMPORARY SHEET PILE DESIGN ANALYSIS Provides a Simple but Conservative Procedure to Provide a Temporary Sheet Pile Design May 2015
Cohesive Soil Settlement Estimate COHESIVE SOIL SETTLEMENT ESTIMATE Estimates Primary Settlement of Cohesive Layers using Moisture Content and Qu December 2014
Integral Abutment Pile Selection INTEGRAL ABUTMENT FEASIBILITY ANALYSIS Determines the Feasibility of using an Integral Abutment Given Bridge Length, Skew and Soil Borings October 2017
Permanent Sheet Pile Design Policy SSP DIMENSIONS ALL-ILDOT (8) Provides Sheet Pile Properties to determine (b/tmin)ε used to determine if local buckling will control the sheeting section modulus design. November 2011
Brom's Overturning & Torsion Capacity of Short Single Shaft BROM’S OVERTURNING & TORSIONAL SHAFT ANALYSIS Provides the Shaft Foundation Depth Necessary to Resist the Overturning and Torsional Load from Traffic Signals, Sign Structures and Light Poles/Towers August 2011
  WSDOT PILE BEARING VERIFICATION Provides Pile Inspectors Charts/Graphs to Determine the Nominal Driven Bearing Indicated by the WSDOT Dynamic Formula February 2010
Axial Geotechnical Resistance of Driven Piles PILE CAPACITY AND LENGTH ESTIMATES IDOT Static Method of Estimating Pile Length vs. Resistance January 2010
LRFD Soil Site Class Definition SEISMIC SITE CLASS Provides a Bridges Seismic Site Class January 2010
Cofferdam Seal Coat Design COFFERDAM SEAL COAT DESIGN Determines a Cofferdams Factor of Safety Against Hydrostatic Uplift November 2006
Temporary Geotextile Wall Design TEMPORARY GEOTEXTILE WALL ANALYSIS Analyzes the Pullout Resistance and Stress in Geotextile Walls November 2006


Bridge Management and Inspections

Click here to go to Bridge Management and Inspections

Load Ratings

Click here for Bridge Load Ratings


Type Size and Location Drawings (TSL)

Please navigate to the Type Size and Location Drawings webpage to view a list of approved drawings.

Technical Manuals

Bridge Manual Design Guides & Detail Examples


Technical Manuals

Bridge Information
The following site is a tool to offer bridge inspection and inventory information to the public.