To start with, the program is user-friendly. Designers can input design data in a coherent, step-by-step way that makes it difficult for them to overlook any design fundamentals. But, crucially, this simple structure has been achieved without sacrificing any flexibility.
FBEAM does not require a particularly powerful machine. To create beam designs, the software can be downloaded from a CD-ROM on to an ordinary PC running Windows.
All data is input using drop-down menus familiar to most PC users. And there is a graphics window that can be used to check that data has been input correctly. It is possible to return to a previous screen to review or alter the input as necessary.
When fabricating long-span beams, it is essential that the designs are flexible enough to be tailored to the specific buildings. FBEAM meets this requirement by allowing a wide range of input – beams may span from 1 to 35 m, and within this, there are an immense range of additional possibilities.
The first step of the program shows a menu offering the range of Fabsec beam profiles, including a wide selection of flat or curved plate beams. If none of these suits the design requirements, it is possible to opt for a customised profile.
The menu then asks whether the beam is destined for a roof or a floor, and whether it is an internal or an edge beam. This initial classification sets up all the relevant prompts for options, which means designers will not be inundated with choices for a roof beam, for example, when they are working on a floor beam.
For floor-beam design there is a comprehensive choice of standard deck profiles – the deck sits on top of the beam. But, again, should the design step outside this range, it is possible to establish a user-defined deck.
Up to 50 secondary beams can be accounted for, but, cleverly, FBEAM allows for independent definition of lateral restraints during the construction stage. Lateral restraints are used to stop the beam buckling. Be warned, though:
if the information for the specified number of secondary beams is not correctly filled in, you will have to deal with a full complement of error messages.
Loading options default to typical roof and floor loading where appropriate, but it is easy to include additional points and uniformly distributed loads. Loads are classified as dead – the weight of the floor it is supporting – or imposed – the weight of the people moving around.
FBEAM also examines natural frequency. Although the vibration limit defaults to 4 Hz, the usual frequency for a rigid floor, the user may alter that if appropriate.
Another important aspect of fabricated long-span beams is the ability to place tailor-made holes for the building services. Using FBEAM, the designer can use the drop-down menu to place holes wherever they are needed. Holes can be readily incorporated in the beam, irrespective of whether the hole is elongated, rectangular or round.
To complete the input requirements, web stiffeners can be incorporated in the vicinity of holes in the same straightforward fashion used elsewhere.
Once all the information has been provided, there is an opportunity to review it. The data is neatly classified under simple headings and as with all the programme’s design steps, the analysis option considers all avenues – it is possible to design for composite or non-composite, propped or unpropped scenarios.
The results are presented clearly. First, a summary sheet provides a complete beam specification. This is supported by a breakdown of the input data and the design calculations.
The program can even e-mail the results to Fabsec to obtain a costing for the design.
Of course, FBEAM is not perfect. The most obvious flaw is that the user cannot access the Help menu while inputting data.
Admittedly, the input process has been made so simple that it may never be necessary to refer to Help, but it is always preferable to have the option.
Having said that, the Help option is very good. It is easy to find the answer to a query and the information is in no way clouded in jargon.
Another weakness of the program is that it is not possible to print the graphics. Although it is easy to view a cross-section, a floor plan, bending moment and shear force diagrams, and deflection profiles for the construction and built stages, a hard copy of all this useful information cannot be obtained.
Finally, an irritating peculiarity of the program is that its platform momentarily disappears from the screen when you are passing from one design step to the next.
However, these minor teething problems aside, FBEAM does achieve its objective of offering a simple program for the design of long, fabricated beams. Because of this, the program may well be incorporated in the software suites of engineering companies up and down the country. Buro Happold, for one, is already considering using it on a scheme.
