quivalent-linear Earthquake site Response Analysis
Version 2000
This page was last updated on February 10, 2020

EERA is a modern implementation of the equivalent-linear concept of earthquake site response analysis, previously implemented in the original and later versions of SHAKE.

System requirements, downloading files and user's manual

Windows 95/98/NT/2000/XP and EXCEL 97 or later.
EERA does not work for other operating systems and spreadsheet programs.
All the files required for EERA can be downloaded from the table below:

File Size Description
EERA.xla                  389 kB   Microsoft Excel Add-in
EERAM.xls 4.6 MB Example file (metric units)
EERA.xls 3.9 MB Example file (British units)
EERA.dll 97kB EERA Dynamic Link Library
Forrt.dll 411kB Additional Dynamic Link Library
Diam.acc 21kB Example earthquake input acceleration file 1.9 MB All the files above but zipped
EERAManual.pdf   Example for multiple analyses
EERAManual.pdf 3.8 MB User's manual and technical manual

The user's manual and technical manual are also available online.

Note: Use the right mouse button to download a file.

Installing EERA

Install EERA on your computer as follows:

  • If you have downladed instead of individual files, unzip the contents of
  • Move file EERA.dll and Forrt.dll in the directory Windows/System of your hard drive.
  • Copy the other distribution files in a directory on your hard drive. Do not move EERA.xla after having performed the next step.
  • From within EXCEL, install the Add-in EERA.xla using Tools and Add-ins... As shown in the figure below, use Browse to locate EERA.xla. Do not move EERA.xla after installing it.

  • When EERA is installed properly, the EERA menu appears to the right of the EXCEL pull-down menus as shown in the figure below.

Removing EERA

EERA can be de-installed by using Remove EERA in the EERA pull-down menu. 

Reporting problems and asking questions

EERA is a free software distributed without a technical support. Please check the FAQ sectio. If you problem is not reported there, please report it in detail by sending an email message to J. P. Bardet at Problems with EERA will be fixed and new frequenly asked questions will be compiled.

Frequenly Asked Questions (FAQ)

  1. Question: I encounter some error messages about eera.dll after running EERA for the first time.
    Solution: Please check that the files eera.dll and dforrt.dll are in the directory Windows/system32.

For problems or questions regarding this web contact [].
Last updated: August 08, 2014.

For problems or questions regarding this web contact [].
Last updated: August 08, 2014.