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Computers and Structures, Inc. is proud to release CSiBridge, a new comprehensive state-of-the-art software product for the structural & seismic analysis, design and rating of simple and complex bridges. All operations are integrated across a single user interface that provides an easy-to-use and intuitive workflow environment. Bridge models are created parametrically resulting in enhanced productivity, saving engineering time while redefining the standards of accuracy and versatility.

pdf Introduction to CSiBridge

Please contact or (+88) 01714-054 837 for more information.

The following is an outline of the capabilities of the new CSiBridge product.


A powerful tool that guides users along the model creation path.

• Step-by-step creation of complete bridge model
• Detailed guidance for each step
• Tree view of bridge model updated with each change
• Automatically update model by changing parameters

A comprehensive assemblage of all components that make up the bridge model.
• Switch between spine, shell, and solid models with single click
• Parametric modeling of steel and concrete deck sections
• Concrete and steel diaphragms
• Restrainers and bearings
• Linear/nonlinear foundation springs
• Non-prismatic superstructure variation
• Skewed abutments, bents, and hinges
• Single-bearing & double-bearing bents
• Prestress tendon layout
• Superelevation
• Curved beams and girders
• Diaphragms and staggered cross-frames

Sophisticated options for capturing accurate bridge behavior.

• Abutments may be modeled as bents
• Bearing properties and location may be user defined
• Kinematic effects due to abutment and bearing geometries are included
• Bridges may be analyzed as full 3D-shell or spine models


Flexible and powerful control over bridge geometry.

• Quick definition of highway layout
• Bearings and stations notation
• Horizontal and vertical curves
• Spiral transitions

Allows for quick creation of arbitrary section shapes.

• Arbitrary steel, concrete, or composite sections
• Caltrans sections
• Calculation of section properties
• Automated fiber layout for fiber hinges
• PMM interaction surfaces
• Moment-curvature relationships

Vary geometric parameters to easily modify deck and girder arrangements.

• Concrete box girders
• Full parametric definition of cross sections
• Concrete tee beam sections
• Precast I and U girder sections
• Steel girders with composite deck
• Variable section definition parameters

Rapidly specify lanes and the associated vehicles.

• Lanes based on layout lines or frames
• Width effects for lanes and vehicles
• Auto transfer of vehicle loads to bridge structure
• Extensive vehicle library including AASHTO and other codes
• Custom vehicles

Refined options for laying out tendons and forces.

• Quick tendon layout
• Tendons in frames, shells, and solids
• External tendons
• Secondary force calculation
• Creep, shrinkage, relaxation, anchorage slip,
elastic shortening losses
• Explicit time-dependent effects in tendons
• Automatic location of tendons in girders


Advanced modeling capabilities allow foundations to be included with the superstructure.

• Pile or spread footings
• P-Y multi-liner force deformation assignments
• Compression only soil springs
• Grade beams as line springs
• Soil springs properties may be linear on nonlinear


Support for an exceptionally wide range of moving, static and dynamic load and analysis types.

• Moving loads with 3-D influence surfaces
• AASHTO, Chinese, or user-defined nonlinear temperature gradients
• Multi-step static and dynamic moving load analysis
• Response spectrum and time-history analysis
• Geometric and material nonlinearity
• Pushover analysis
• Buckling analysis
• Multi-support base excitation
• Response spectrum and time-history analysis
• Parametric loading of superstructure
• Live load distribution by code or analysis
• True dynamic effects of moving live loads
• High frequency blast dynamics using Wilson FNA


Powerful techniques for state-of-the-art bridge analyses.

• Speed and power of the SAPFire engine
• Large Capacity Eigen and Ritz model analysis
• 3D Pushover Analysis
• Multi Support Excitation Dynamics
• Energy Dissipation Designs
• Buckling Analysis
• Staged Construction
• Linear and Nonlinear Dynamic Analysis

Provides users with intuitive control over time effects.

• Segmental, composite, and other bridge types
• Gantt chart construction scheduler
• Creep, shrinkage, and strength change
• Camber calculation and shape finding
• Automatic cable tensioning
• Add/remove elements and loads, change section properties, change supports, modify frame end releases


Offers modeling tools for the rapid determination of cable shapes.

• Automatic cable shape finder
• P-Delta plus large displacement geometric nonlinearity
• Cable target force determination
• Full 3D gravity, wind and seismic analysis capabilities
• Multiple point excitation for time-history analysis
• Large deformation catenary cable analysis
• Automatic jacking and cable-tensioning control
• Shape-finding for camber calculation

Effective visualization options for interpreting bridge response.

• 3D Influence surface plots for joints, frames shells and links
• Influence line or surface plots for joint displacement or reactions
• Plots as contours
• Plots along lane center or lane widths

Sophisticated design for a wide-range of steel and concrete bridge types.

• Bridge Superstructure Design:
    - Composite Steel Girder (AASHTO LRFD 2007 and 2008 interims)
    - Precast I and U Girder (AASHTO LRFD 2007)
    - Concrete Box Girder (AASHTO LRFD 2007)
    - Principal stress checks
• Automatic load combinations
• Design checks include:
    - Stress checks
    - Shear checks
     - Flexure checks
    - Principal stress checks

Numerous choices for displaying and reviewing analysis results.

• Animated displacement and stress plots
• Graphical results on screen
• Tabular output to Microsoft Excel
• Analysis and Design report in Microsoft Word format

PDF Superstructure Design Manual


Advanced technology automatically determines complex bridge rating factors.

• Concrete box girder bridges (AASHTO LRFR 2005)
• Precast I and U girder bridges (AASHTO LRFR 2005)


Animate vehicles and other results to help understand bridge behavior.

• Create real time movie files showing time-history and moving vehicle responses
• Include multiple vehicles
• Displays may include displacements and stresses

Video Golden Gate Bridge Animation
Video Moving Vehicles
Video Moving Vehicles and Deflections



• Minimum: Intel Pentium 4 or AMD Athlon 64.
• Recommended: Intel Core 2 Duo, AMD Athlon 64 X2, or better.
• A CPU that has SSE2 support is required.
• The SAPFire® Analytical Engine includes a multi-threaded solver that can take advantage of multi-core CPUs.

Operating System:
• Microsoft® Windows XP with Service Pack 2 or later, Microsoft® Windows Vista, or Microsoft® Windows 7, 32- and 64-bit versions.
• With a 64 bit operating system, the SAPFire® Analytical Engine can utilize more than 4 GB of RAM, making it possible to more efficiently solve larger problems.

• Minimum: 2 GB for XP O/S, 4 GB for Vista/Windows 7 O/S.
• Recommended: 4 GB for 32-bit O/S, 8 GB or more for 64-bit O/S.
• The problem size that can be solved & the solution speed increases considerably with more RAM.
• Vista/Windows 7 requires more RAM than XP for the operating system itself.

Disk Space:
• 6 GB to install the program.
• Recommended: 500GB or larger Hard Disk Drive (7200 rpm SATA)
• Additional space required for running and storing model files and analysis results, dependent upon the size of the models.

Video Card:
• Minimum: Supporting 1024 by 768 resolution and 16 bits colors for standard (GDI+) graphics mode.
• Recommended: Discrete video card with NVIDIA GPU or equivalent and dedicated graphics RAM (512 Mb or larger) for DirectX graphics mode. The card must be DirectX 9.0c compatible (DirectX SDK Aug 2009 – Build 9.27.1734.0).
• DirectX graphics mode fully utilizes the hardware acceleration provided by a GPU and dedicated graphics RAM.
•  For better graphics quality in terms of anti-aliasing and line thickness, the device raster drawing capabilities should support legacy depth bias.



Significant enhancements included in CSiBridge v15.0.1:

  • A new option has been added for the modeling of I-girders in composite steel-girder superstructure sections. In addition to the existing options to model the I-girders as frame objects or as area objects (for both web and flanges), the girders can now be modeled using area objects for the webs and frame objects for the flanges.

  • A new bridge seismic design check has been added to the Chinese version that follows the Chinese code JTG/T B02-01-2008, "Guidelines for Seismic Design of Highway Bridges".

  • Bridge design for prestressed concrete box girder superstructures using Chinese code “JTG-D62-2004” in the Chinese version has been updated as follows: (1) The effect of existing longitudinal rebar is now accounted for in flexural design. (2) A new design check has been added for tendon stress.

  • The Chinese 2002 building design codes are available for concrete and steel frame design in the Chinese version.

  • Concrete frame design has been enhanced to improve the smoothing of P-M-M interaction surfaces in those rare cases where they become non-convex due to kinks in the P-M curves.





For further information contact CAE sales department at:

Telephone: +88 0714 - 054 837
email: or visit:

Computer Aided Engineering (Pvt.) Ltd. • Dhaka, Bangladesh
Tel: (+88) 01714-054 837 •

CSI software products are proudly developed in the United States of America.