CSI Perform-3D Version 5.0.1

New crack, license available until July 2017!

CSi Perform-3D - Nonlinear Analysis and Performance Assessment of 3D Structures Software

Traditionally, earthquake-resistant design has been strength-based, using linear elastic analysis. Since inelastic behavior is usually allowed for strong earthquakes, this is not entirely rational. Strength-based design considers inelastic behavior only implicitly. Displacement-based (or deformation-based) design considers inelastic behavior explicitly, using nonlinear inelastic analysis. Displacement-based design recognizes that in a strong earthquake, inelastic deformation (or ductility) can be more important than strength. PERFORM-3D allows you to use displacement-based design.

Procedures for displacement-based design using inelastic analysis are specified in ASCE 41, “Seismic Rehabilitation of Existing Buildings”. ASCE 41 applies to the retrofit of existing buildings, but the procedures can be applied to the design of new buildings. PERFORM-3D implements the procedures in ASCE 41. However, PERFORM-3D is a general tool for implementing displacement-based design. It is not limited to ASCE 41.

The response of a structure to earthquake ground motion, whether elastic or inelastic, is highly uncertain. Capacity design is a rational way to improve the response of a structure in a strong earthquake, by deliberately controlling its behavior. Capacity design controls the inelastic behavior of a structure, by allowing inelastic behavior only in locations chosen by the designer. In these locations the structural components are designed to be ductile. The rest of the structure remains essentially elastic, and can be less ductile. Controlling the behavior in this way improves reliability, reduces the amount of damage, and can reduce construction costs. PERFORM-3D allows you to apply capacity design principles.

PERFORM-3D has powerful capabilities for inelastic analysis, but it is not intended for general purpose nonlinear analysis. If you have no idea how your structure will behave when it becomes inelastic in a strong earthquake, PERFORM-3D can probably help you to identify the weak points, and hence can guide you in improving the design. However, PERFORM-3D is not intended for “design by analysis”, where the engineer expects the analysis to determine exactly how a structure will behave. PERFORM-3D is a powerful tool for implementing displacement-based design and capacity design. It will help you to produce better designs, but it will not do the engineering for you.

CSi PERFORM-3D 5.0.1 Enhancements



* A 64-bit version of the analysis engine is now utilized when Peform-3D is installed on a 64 bit computer. The 32-bit analysis engine is still used on 32-bit computers. The 64-bit engine allows larger problems to be solved, and tends to run faster than the 32-bit engine.

* A large-capacity eigenvalue routine has been added. In earlier versions, the eigenvalue routine could not accommodate structures with very large numbers of mass points. The new eigenvalue routine (the same as in SAP2000) allows a larger number of mass points than was previously possible.

* Warnings are now provided when an unstable or ill-conditioned stiffness matrix is detected. When an analysis model is set up for a complex structure, a common problem is that the model may be poorly conditioned numerically, or may be unstable. For an explanation of the causes of poor conditioning and instability, see the book Modeling for Structural Analysis: Behavior and Basics, by Powell, Chapter 3, especially Section 3.5, available from CSi.

* Formal documentation is now provided describing the format of the binary results files. For each analysis, Perform-3D writes the analysis results in a number (often a large number) of short binary files. Many users access these binary files directly, to add post-processing operations that are not included in the graphical user interface.

* The number of modes shapes printed in the text file M000.txt can now be specified. In earlier versions, all mode shapes were printed in this file, and for a large structure the file could be very large. Usually the number now specified will be zero, so that detailed mode shapes are not printed, and the M000.txt file will be quite short.

* The analysis logs for each Analysis Series are now written to separate files, making them more manageable. In earlier versions, a “log” of each analysis in the series is also included in ECHO.txt, showing details of the analysis, the computation time for each analysis step, and an energy balance. For a large structure, this made the ECHO.txt file very long