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INSTRUCT Version 1.1 Software


Read the installation instructions and system requirements before downloading the software.

The Windows-based computer program, INSTRUCT (INelastic STRUCTural Analysis of Reinforced-Concrete and Steel Structures) is capable of performing 1) moment-curvature analysis of reinforced-concrete circular and rectangular sections; 2) pushover analysis of typical concrete column intermediate bents; and 3) pushover analysis of typical steel pile cap bents. For concrete column bents, all possible column failure modes are checked by INSTRUCT. In addition, column axial load-moment interaction and axial load-plastic rotation capacity are incorporated into INSTRUCT. For steel pile cap bent, the post buckling behavior of bracing members is considered in the pushover analysis.  INSTRUCT is a useful tool for bridge engineers to assist in implementing the latest seismic design and retrofitting methodology. 

Note: The pushover analysis, or nonlinear static monotonic analysis, has become a common practice for performance-based bridge seismic design. The 2009 AASHTO Guide Specifications for LRFD Seismic Bridge Design explicitly requires pushover analysis for Seismic Design Category D bridges. The 2006 FHWA Seismic Retrofitting Manual for Highway Structures (Part I-Bridges) adopted the pushover analysis for bridges in Seismic Retrofit Categories C and D, to assess bridge seismic capacity. The popularity of pushover analysis is mainly due to its ability to identify the failure modes of bridge piers and provide the progressive collapse sequence of damaged bridges when subjected to major earthquakes.


The Windows-based computer program, INSTRUCT (INelastic STRUCTural Analysis of Reinforced-Concrete and Steel Structures) software product is disseminated under the sponsorship of the U.S. Department of Transportation in the interest of information exchange. The United States Government assumes no liability for its content or use thereof. This software product does not constitute a standard, specification, or regulation.

The United States Government does not endorse products or manufacturers. Trade and manufacturers' names may appear in this software product only because they are considered essential to the objective of the software product.

Limited Warranty and Limitations of Remedies

This software product is provided “as-is,” without warranty of any kind-either expressed or implied (but not limited to the implied warranties of merchantability and fitness for a particular purpose). The Federal Highway Administration (FHWA) and distributor do not warrant that the functions contained in the software will meet the end-user's requirements or that the operation of the software will be uninterrupted and error-free. Under no circumstances will the FHWA or the distributor be liable to the end-user for any damages or claimed lost profits, lost savings, or other incidental or consequential damages rising out of the use or inability to use the software (even if these organizations have been advised of the possibility of such damages), or for any claim by any other party.


The use and testing of the INSTRUCT software is being done strictly on a voluntary basis. In exchange for the provision of INSTRUCT software, the user agrees that the Federal Highway Administration, U.S. Department of Transportation, any other agency of the Federal Government or distributor shall not be responsible for any errors, damage or other liability that may result from any and all use of the software, including installation and testing of the software. The user further agrees to hold the FHWA, the Federal Government, and distributor harmless from any resulting liability. The user agrees that this hold harmless provision shall flow to any person to whom or any entity to which the user provides the INSTRUCT software. It is the user's full responsibility to inform any person to whom or any entity to which it provides the INSTRUCT software of this hold harmless provision.

The origin of this INSTRUCT software must not be misrepresented; there shall be no claim that this software is the product of or written by any individual, company or organization other than the Federal Government. An acknowledgement would be appreciated in any product in which this INSTRUCT software is included or referenced. Altered versions of this SSAM software shall be plainly marked as ‘altered’ and must not be misrepresented as being the original INSTRUCT software. This notice may not be removed or altered from any distribution, recording, copy or use of this INSTRUCT Software.

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United States Department of Transportation - Federal Highway Administration