Software

Can you explain drag loads and how to calculate a drag load pertaining to roof trusses?

I am a structural engineer designing pool cage structures that are typically attached to the house at the fascia board. Sometimes, the structure is attached where trusses are behind the fascia board and other times there is a framed gable end overhang. Do you know of any information concerning this additional load on the trusses or overhang under design wind loads? Is there a limiting distance on the amount of overhang? I know trusses are designed for certain uplift and the pool cage will add to this uplift at design load, but what about the gable end overhangs?

What are the qualifications (if any) required to be considered a truss technician?

We have been using Turb-O-Webs for about four months. We are very happy with their performance, although there have been a few ripples along the way. The main thing that concerns me at present is the need for performance documentation and testing data. Do you have anything that will help, or know of people or organizations that could offer assistance?

I'm looking for a book that will provide formulas and design criteria for trusses. Can you give me any suggestions of where to find a book or fairly inexpensive software?

The lumber used in most metal plate connected wood trusses is either visually- or mechanically-graded solid sawn dimensional lumber. However, the Truss Plate Institute's ANSI/TPI 1 allows the use of structural composite lumber (SCL) products such as laminated veneer lumber (LVL), laminated strand lumber (LSL) and parallel strand lumber (PSL). These engineered wood products can conceivably compete with sawn lumber and complement it in truss designs.

If the truss design drawing specifies using 2x4 1650F SPF, can 2x4 No. 2 southern pine be used instead? What are some things that need to be checked?

This presentation provides information on and requirements for truss repairs.

Knowledge is power when it comes to making decisions, so the more knowledge the better. SBCRI unequivocally gives us access to knowledge no one else has.
  • Understanding how the computer software automatically loads a truss can help designers avoid unintended consequences when optimizing trusses.
  • When fascia loads are missing from a project, there is incorrect loading on the jack trusses, sub girders and the corner girder/hip jack.
  • Missing loads can lead to extensive repairs and may even require that the trusses be revised.