Technical Reference Manual

5.58 Development History of STAAD.Pro
In the late 1980's, Research Engineers, Inc. (REI) of Marlton, NJ developed a structural analysis program called STAAD-III for the MSDOS platform. This program could read a formatted text file—written in largely plain English text—as input and output requested analysis and deign results to screen, text file, or printer.

The core of STAAD's analysis and design capabilities lie in what is known as the analysis engine, which processes the text input, performs the necessary static and dynamic calculations, and generates text output. The text input read by the analysis engine uses a syntax of plain English commands (many of which can be abbreviated to only the first three letters) in order to provide structural model and load data as well as to instruct the analysis engine as to what methods of analysis and design to use. This command syntax, developed by REI, was a leap in user friendly interface for a text-based program.

The original source code for this program was written in Fortran 77 and Fortran 90, with later versions of STAAD III written in Fortran 90, Digital/Compaq Fortran, and more recently, Intel Fortran. Portions of the original analysis engine were based on the 1972 version of an open source program called SAP IV, created by K-J Bathe, E.L. Wilson, and F.E. Peterson at the University of California, Berkeley. Many of the dynamic features of STAAD—such as master/slave nodes, frequency and modal extraction, response spectrum analysis, and time history analysis—are based on the subroutines included in SAP IV.

Additional portions of the of the source code were developed by REI staff based on the text book Matrix Analysis of Framed Structures, by J. Gere and W. Weaver. The formalized stiffness matrix method described in Chapter 4 of this text is the procedure implemented by STAAD's basic (or, standard) solver. Consideration of shear deformation, support displacements, inclined supports, tapered members, member releases, and other issues are also taken essentially verbatim from the methods described in this text.

5.58.1 Graphical User Interface
In the early 1990's, a rough graphical interface for using STAAD in the MSDOS environment was developed by REI for the purpose of generating input and reviewing output from the engine. This was made possible by using a third-party graphics library by the Lahey company.

After the release of the Windows 3.1 operating system, the graphical interface was migrated to a the 16-bit windows environment by the REI staff. In later years, the same interface was adapted to the 32-bit environment for use on Windows 95, Windows NT, and Windows 2000 operating systems. During this time, some of the new analysis and design features were written in C++ in order to make use of this language's dynamic memory allocation.

In 1997, REI acquired a UK-based company named QSE, which had an excellent user interface for the STAAD program. Further refinement of this interface was released as the current program generation: STAAD.Pro. STAAD.Pro has the same core analysis engine, with new features and enhancements, but with a robust user interface capable of post-processing and design stages.

5.58.2 Analysis and Solution Techniques
Analysis techniques unique to the structural engineering community—such as P-Delta analysis, pushover analysis, and cable analysis—were developed by REI staff in more recent years, which relocated to Yorba Linda, CA in the early 1990s. Analysis in STAAD is based on small deflection theory as described in a variety of texts.

In 1995, REI acquired the source code for a program called STARDYNE, which is capable of advanced dynamic and buckling analysis and was widely used in the aerospace industry. The STARDYNE solver was available as a separate solution option. Several of the subroutines used by STARDYNE were also incorporated into the STAAD analysis engine solvers, as well. Particularly, the method for beam analysis including shear deformations performed by the STAAD analysis engine is now that developed for STARDYNE. Other engine features such as curved beams, composite damping, imposed displacements, missing mass, and steady state analysis are also based on STARDYNE subroutines. Similarly, the STAAD analysis engine has the ability to detect singular matrices and solve them via a technique developed by STARDYNE.

Recent versions of STAAD.Pro include a faster solver for matrix inversion written by and licensed from Visual Kinematics, Inc (VKI). VKI's stiffness matrix inversion solver and eigensolution solver are implemented in STAAD.Pro's advanced solver.

In 2006, Bentley Systems, Incorporated acquired Research Engineers, Inc. along with RAM International, another structural engineering software firm based in Southern California. Additional structural engineering analysis techniques—such as cable analysis and an improved geometric nonlinear analysis—were written by the Bentley staff using industry textbook techniques.