BSI Newsletter - Issue #9, Spring 2007

Inside this Issue

Technical Corner

New Features
Modeling Tips

Discussions with..

Henry Bollmann P. E.
Research Engineer, Bridge Software Institute

What's New at BSI

New Release v4.11
New Features Tutorial's on BSI website.

Program Status

Make sure you have the most current version
FB-MultiPier v4.11
FB-Deep v1.21

Contact BSI

Bridge Software Institute
University of Florida
PO Box 116580
Gainesville, FL 32611

Online: bsi.ce.ufl.edu
Email: bsi@ce.ufl.edu
Fax: (352) 392-3697

Welcome to the spring issue of the BSI Newsletter!

In this issue's Technical Corner we will discuss some of the new features available with the release of FB-MultiPier v4.11.

The articles 'Technical Corner' and 'Discussions' are open for input from all readers. If you have a topic that you think should be discussed, let us know. Did you create a great model with features that you want to share? Everyone is welcome to submit articles for possible inclusion in subsequent issues. Please contact BSI at BSI@ce.ufl.edu with your ideas.

We would like to announce the release of the new FB-MultiPier v4.11. The program is available for download from the BSI website.. The new version contains fixes to the latest reported bugs and also includes a number of new features. The new features include:

-In 3D Edit Window and 3D Bridge Window, added options to hide various node types, i.e. column nodes, pile cap nodes, pier cap nodes, cantilever nodes and pile node using the right click mouse option.
-Added Element Data Dialog in the 3D Edit Window
-Added Pier Cross Section Table for input of all pier cross section data from a single table. This can speed up the data entry process.
-Added file viewing feature/search option for viewing .out file. This allows for quick access to the different portions of the text output file.
-Global Axes in all 3D Windows
-Bearing Rotation option
-New Soil Type: Limestone (McVay): No 2-3 Rotation
-Standalone version of Soil Table, which can be downloaded and used free of charge.

We also have a number of short tutorials that are available on our website. These self-guided tutorials demonstrate the use of different features of the program. The aim of these tutorials is to introduce the users of all levels to new and existing features of the program. We will add new tutorials regularly to better communicate and explain the use of our program.

New Features Modeling Tips

Bearing Angle Rotation and Pier Rotation (Fig. 1) can be set at any angle on the Bridge Page. In Fig. 1, the Pier is skewed 45 deg. and the Bearings are set at 0 deg. aligned with the superstucture.

Mat foundation piles (Fig. 2) can be quickly changed to drilled shafts Fig. 3 by using the Add/Remove Cap and Add/Remove Pile feature in the Pile Edit Window. The pile cap elements in Fig. 3 serve only to connect the columns to the shaft and must be stiff in order to transfer the forces as a rigid link. The unit weight of the pile cap element would typically be given a value of zero. The column is attached to the Pile Cap via four rigid links as described in Help>General Modeling> Column Connection to the Pile Cap.

A new soil model "Limestone (McVay): No 2-3 axis Rot" (Fig. 4) allows the user to either exclude or include the effect of side shear in soil-pile interaction using the P-Y curve of Florida limestone during the analysis . This option is activated by choosing the Edit button; it is defaulted off (Fig. 5) and can be activated by checking "Soil Resistance due to Pile Rotation about 2 and 3 axes" from the Additonal Soil Properties dialog (Fig. 6). When the option is turned on to include the side shear effect in the soil response, the program adds two additional degrees of freedom with respect to rotation about 2- and 3-axis at soil springs and computes stiffness terms based on force equilibrium. However, the user should use this option with the necessary caution and only where the use is justified.

Results Viewer (Fig. 7) is a new feature, which allows the user to browse the .out file by Headers. This feature is available from the Control menu > View Analysis Data > Results Viewer. By selecting a Header in the Header List the Output Results is scrolled to the location in the output file. For complete instructions on using the results viewer check the Help Manual.

Standalone version of Soil Table. Soil Table Tutorial

Discussions with...

Henry Bollmann P. E. Research Engineer, Bridge Software Institute

"FB-MultiPier only allows me to generate a pin or a fixed connection between pile and cap. What options do I have for modeling partial fixity?"

The program allows for multiple cross-sections along each pile of a pile set. Segment one (at the pile head) can be dimensioned and reinforced in such a manner that the assumed strength of the connection is modeled. A very common example is the assumed connectivity of a prestressed pile embedded only a foot or two into a pile bent cap. One may wish to take advantage of the partial fixity, particularly for an extreme event case. By viewing the strength interaction diagrams, generated by the software, one can quickly see if the assumed behavior will be met.

Recently we encountered an interesting model where the foundation consisted of two different pile types. A few drilled shafts carried all the horizontal forces and a multitude of small pre-cast piles carried ONLY axial compression. For this case the designer modeled the small piles using a segment located at the pile head which had the desired axial compressive characteristics but with almost no bending resistance and a separate soil set was specified which allowed for no axial soil resistance other than the one way tip compressive resistance.

"What is the best use for the MultiPier option?"

This release of FB-MultiPier allows for the independent rotation of the bearings and substructure unit, as shown above. This feature enhances the usefulness of a multiple pier model when the substructure is skewed to the superstructure. The multiple pier models can be created very rapidly by copying one substructure unit and then editing each unit. These models are useful to establish the relative stiffness of bridge units and the overall force distributions. For the case of vessel collision loading this multiple pier model is particularly powerful. If a multiple pier model is used for purposes other than establishing global force distributions to the foundations, then users should first verify that the bearing reactions calculated by the program are what is expected. Modeling assumption/approaches of Multi-Pier must be well understood. For instance, the users may have to adjust the properties of superstructure by trial and error such that the transfer beam would represent a realistic system stiffness of bridge span and girders (and diaphragm where applicable) in order to achieve a desired load distribution to the bearings, particularly when multiple bearings are specified.

BSI Program Status

FB-MultiPier V4.11 Download a FREE demo today!

Released: May 8, 2007 - Continuing Development - Technical Support Available

FB-MultiPier is the successor to FB-Pier. In addition to all the capabilities of FB-Pier the FB-MultiPier program allows for the modeling of an entire bridge that consists of multiple piers that are connected with bridge spans. In addition to the multiple load cases and the AASHTO coefficients that are available in FB-Pier, the new program is capable of performing dynamic analysis for the entire bridge. For more information about FB-MultiPier, click here.

FB-Deep V1.21 Download a FREE demo today!

Released: March 11, 2005 - Continuing Development - Technical Support Available

The FB-Deep computer program is a Windows based program used to estimate the static axial capacity of drilled shafts and driven piles. The methodology is based upon Federal Highway Administration (FHWA) reports. FB-Deep guides the user through pile and shaft materials data, shape and dimensional inputs, soil properties, and boring log info. FB-Deep presents the data analysis in both clear graphical and text form. For more information about FB-Deep, click here.

FB-Pier V3.21

Released: October 15, 2004 - Final Release - Technical Support Available

This program has been replaced by FB-MultiPier and all sales or renewals will be directed to the FB-MultiPier program. FB-Pier is still available for download by valid licensed holders.

FB-Pier was designed for the analysis of bridge pier structures composed of nonlinear pier columns and cap supported on a linear pile cap and nonlinear piles/shafts with nonlinear soil. FB-Pier couples nonlinear structural finite element analysis with nonlinear static soil models for axial, lateral and torsion soil behavior to provide a robust system of analysis for coupled bridge pier structures and foundation systems. The program performs the generation of the finite element model internally given the geometric definition of the structure and foundation system as input graphically by the designer. For more information about FB-Pier, click here.

Contact BSI

If you need to contact BSI for any reason you can use any of the methods below:

Online: bsi.ce.ufl.edu
Email: bsi@ce.ufl.edu
Fax: (352) 392-3697

Mailing Address:

Bridge Software Institute
University of Florida
PO Box 116580
Gainesville, FL 32611

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