Bridge Software Experience - VBridge, VBent, CTBridge, SEISAB, PAPIER, and more

Why Us?

At Viathor, we continue to play a leadership role in bridge
software development. Our practical hands-on experience
gives us first-hand knowledge of what the bridge designer
needs. We constantly strive to add new features including
enhancement requests by our users. Because our software
is written with the latest available programming tools, we
can quickly and accurately respond to user requests as well
as changes in the AASHTO design specifications.

In addition to the features found in many pier programs,
Viathor was the first company, and in many cases still
the only company, to offer the following features:

· VBridge to VBent data transfer

· Read a CTBridge file

· The industry’s first LRFD/LFD integral (monolithic) pier program

· Locality/Custom design approaches

· True 3-D modeling

· Program intelligence

· Real-time graphics

· Extensive output control of desired results

· Automatic generation of load combinations

· Column bottom pins

· Hyperlinked Table of Contents

· Unlimited undo

· Import PAPIER input file

VBridge to VBent data transfer: Viathor's new VBridge program now generates VBent input files. The VBent input file is exported from within VBridge to quickly and accurately design the bent cap, columns, and footings. The VBent geometric model is created, and dead load, live load, and prestress forces generated from the VBridge analysis are placed into VBent for use in the the 28 load combinations. By automatically transferring model and load data, potential errors are eliminated and the design process is expedited. Back to Top

Read a CTBridge file: VBent input files are easily created from CTBridge output information. In addition to creating the VBent geometric model, dead load, live load, and prestress forces generated from the CTBridge analysis are brought into VBent for use in the the load combinations. By using these two programs together, caps, columns, and footings are quickly designed without the need for cumbersome manual transfer of data from one program to another. Back to Top

The industry’s first LRFD/LFD integral (monolithic) pier program: This popular pier support type had largely been ignored by the bridge software community prior to Viathor introducing VBent. Our first-hand knowledge of integral bridges, such as the box girder bridge, provides us with valuable insights into the unique complexities required to properly model this structure type. For example, VBent includes the superstructure stiffness in the finite element model. Without it, the total structure resistance to longitudinally applied loads will not be properly represented, and the bent will behave as a cantilever in the longitudinal direction. By including the superstructure, the moment at the column top will help resist loads such as wind, temperature, live load braking, etc. Back to Top

Locality/Custom design approaches: Most states customize their bridge design requirements to local practices. This may consist of modifying the Standard AASHTO design specifications, preferences on how live load vehicles are applied to the pier, or default member sizes and support types. Viathor has built Locality settings into our programs in order to set program defaults to local practices. Current program Locality settings include standard AASHTO methodologies, California, and Pennsylvania. Viathor can easily add additional Locality settings as requested. However, even when a desired Locality setting is not currently available, many of these settings can be individually specified by the user. Back to Top

True 3-D finite element modeling: The finite element (FE) model generated by our programs accurately represents the structure described by the user. Unlike programs that describe the model in 3D, but only create a 2D model, our programs create a full three-dimensional model. The user can view the generated FE node and element locations in the model view. Using a true 3-D model allows VBridge to model horizontal curves, skews, and the location of each column in a multiple column bent. In VBent, 3D modeling allows the capture of column offset behavior and the superstructure stiffness for integral bents. Back to Top

Program intelligence: When describing a pier, only those options that are applicable are available to the user. This reduces potential confusion and assists the user by presenting only that information which is pertinent to the model. For example, if a spread footing foundation is selected, then pile layout and capacity information is not made available. Back to Top

Real-time graphics: As geometric data is specified, a graphic window displays the data as it is entered. For example, when defining girder bearings on the pier cap, a plan view graphic depicts each bearing location as the data is entered. The user does not need to complete all data in the dialog and return to a model view in order to visually inspect the input. Real-time graphic windows are available for span, cap, column, and footing cross-section dimensions, pile layouts, column locations and offsets, reinforcement description, etc. Each of these is shown in scaled views as the data is entered. Back to Top

Extensive output control: Our programs allow the user to determine the level of output desired. By default, summary level reports are produced, including geometric data and controlling capacity to demand ratios. Additional reports that detail the “numbers behind the numbers” can be requested. These additional reports simplify the process of checking results and provide reassurance to the designer that the program is producing accurate results. Some of the additional reports that can be requested include: individual forces within a load combination, live load control such as truck placement on the deck and influence line results, unfactored forces for each load type applied to the structure, individual values within specification equations, etc.
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Automatic generation of load combinations: VBent’s powerful load combination algorithm automatically determines applicable AASHTO combinations based on applied loads. The user does not have to manually determine load combinations or decide which loads to include within each load combination. This eliminates the possibility of omitting a potential controlling load combination, or contributing loads within a load combination. However, if desired, the user may manually eliminate load combinations, modify load factors, or create their own user load combinations.

In addition to automatically determining which load combinations to consider, VBent analyzes 7 load cases for the cap, 28 load cases for the column, and 24 load cases for the footing within each combination. Many loads, such as wind, temperature, and braking forces can be applied in more than one direction. The load cases are needed to ensure that the maximum force effect within each component is considered. For example, one load case considers maximum longitudinal moment with concurrent transverse moment and axial force. This load case may control column design when considering temperature rise. But when temperature fall is considered, a similar load case with minimum longitudinal moment may control. VBent envelopes all of these load cases for all AASHTO load combinations and presents the controlling case to the user. Back to Top

Column bottom pins: Not only is VBent the first GUI based integral pier program, VBent is the only pier program capable of analyzing integral (monolithic) bents with a longitudinally pinned column bottom support condition. This support condition is commonly used in post-tensioned box girder bridges with multiple column bents in order to reduce footing sizes. This support condition is possible because VBent includes the superstructure stiffness in the integral bent finite element model to provide stability and stiffness to the model. Back to Top

Hyperlinked Table of Contents: From the Table of Contents simply click on the name of the desired output report and our programs jump to the top of the selected report table. Back to Top

Unlimited undo: All changes made to a bridge model can be undone one dialog change at a time back to the beginning of the session. This behavior is unaffected by saving the input file. Back to Top

Import a PAPIER input file: PennDOT PAPIER files can be imported into VBent, allowing the model to be viewed in 3D and input changes to be easily made from the VBent dialogs. Back to Top