General Analysis Details

  • Solvers that have been tried and tested by the industry for over 35 years.
  • Advanced SAPFire Analysis Engine
  • Multiple 64-Bit Solvers for analysis optimization
  • Eigen Analysis
    • Autoshifting for ill-conditioned problems
  • Ritz Analysis

Response Spectrum Analysis

  • Response-spectrum analysis is a statistical type of analysis for the determination of the likely response of a structure to seismic loading.
     
  • Response-spectrum analysis seeks the likely maximum response to these equations rather than the full time history.
     
  • The earthquake ground acceleration in each direction is given as a digitized response- spectrum curve of pseudo-spectral acceleration response versus period of the structure.

Power Spectral Density

  • Power-spectral-density analysis is available to determine the probabilistic response of a structure due to cyclic (harmonic, sinusoidal) loading over a range of frequencies. This is useful for fatigue studies, random response due to earthquakes, and other applications. 
  • Multiple loads may be applied at different phase angles, and may be correlated or uncorrelated. 
  • The structure may be damped or undamped.
  • Frequency-dependent stiffness and damping (complex impedance) properties may be included for modeling foundations and far-field effects, including radiation damping.
  • Power-spectral-density curves may be plotted for any response quantity, and the integrated expected value is automatically computed.

Steady State Analysis with Damping

  • Steady-state analysis is available to determine the response of the structure due to cyclic (harmonic, sinusoidal) loading over a range of frequencies.
  • Multiple loads may be applied at different phase angles.
  • The structure may be damped or undamped.
  • Frequency-dependent stiffness and damping (complex impedance) properties may be included for modeling foundations and far-field effects, including radiation damping.
  • The response may be viewed at any phase angle. The effects of multiple machines operating at different frequencies can be considered by combining the results of several analyses in the same model.

Buckling Analysis

  • Linear buckling (bifurcation) modes of a structure can be found under any set of loads.
  • Multiple buckling modes can be found, each giving the mode shape and the buckling factor of safety.
  • Multiple sets of loads can be considered. Buckling modes can be found for the structure at the end of any staged construction case or any nonlinear static or dynamic analysis.
  • Nonlinear buckling analysis is also available considering P-delta or large-deflections effects. Snap-through buckling behavior can be captured using static analysis with displacement control.
  • Dynamic analysis can also be used for modeling buckling, including follower-load problems.
  • Linear and nonlinear buckling analysis can be combined for the greatest flexibility in understanding structural instabilities.

Time History Analysis

  • Two methods of Time History Analysis:
    • Modal Time History
      • Uses the method of mode superposition
      • Nonlinear
    • Direct Integration Time History
      • Solves equations for the entire structure at each time step
      • Linear
      • Nonlinear
  • Time History Functions Functions
    • Sine
    • Cosine
    • Ramp
    • Sawtooth
    • Triangular
    • User defined
  • Nonlinear direct-integration time-history analysis cases can be chained together with other nonlinear time-history or static cases (including staged construction), to address a wide range of applications.
     

Tension and Compression only Springs

  • Frame elements may be assigned compression limits for modeling braces and stay cables, or tension limits for modeling masonry or special physical devices.
     
  • In the example, the base plate is modeled with both tension and compression springs.
    • An elastic analysis allows springs to take both tension and compression.
    • A nonlinear analysis allows springs to take tension only or compression only.

P-Delta Analysis (large and small)

  • The P-Delta effect refers specifically to the nonlinear geometric effect of a large tensile or compressive direct stress upon transverse bending and shear behavior. A compressive stress tends to make a structural member more flexible intransverse bending and shear, whereas a tensile stress tends to stiffen the member against transverse deformation.

 

Pushover Analysis

  • FEMA 273/ATC-40 hinge and fiber hinge option based on stress-strain
  • Nonlinear layered shell element enables users to consider plastic behavior of concrete shear walls, slabs, steel plates and other area finite elements in the pushover analysis.
  • Force-Deformation relations for steel and concrete hinges
  • Modal, uniform, or user defined lateral load patterns
  • Capacity spectrum conversions
  • Effective damping calculation
  • Demand spectrum comparisons
  • Performance point calculation
  • Summary reports including plastic hinge deformations

Concrete Shrinkage and Time Dependent Creep Analysis

 

  • Long term deflections due to creep and shrinkage can be computed along with staged sequential construction analysis.
  • Time dependent material properties based upon the 1990 edition CEB-FIP code and user defined curves are used to compute creep strains.

 

Target Force Analysis

  • During nonlinear static analysis, cable and frame elements can be automatically strained to achieve specified target axial force values. This is most commonly used to tighten cables to pre-specified tensions, but it can also be used to jack structures to a specified force using frame elements, as well as other applications.
  • Multiple, simultaneous targets can be considered in a single load case.
  • During staged construction, different target forces can be specified in different stages.

Model Alive

  • For small to medium sized structures, analysis can be performed on-the fly as you build and modify the model.
  • For each change you make to the geometry, properties, or loading, the structure instantly responds with the new deformed shape, moment diagram, or any other plot of results. It’s like working with a live model, and it is a very powerful tool for conceptual design and for testing "what-if" scenarios.