Engineering

2018 North Carolina Residential Code Prescriptive Tables for Selection of Support Elements for Beams, Girders, and Headers: Example Problems

The tables are intended as a practical tool to assist contractors in the selection of footing widths and the determination of the quantity of wood studs required for supporting the end reactions of beams, girders, and/or headers. 

Put Out the Design Fire Before it Starts

Getting information up front on sprinkler systems can ease the design process.

Rock the Block

CM increases profit with pre-designed shear blocking panels.

Thinking Through a Curve

A complex roof with multiple arcing panels provided design challenges both before and during construction.

The Best Way Forward is a Solid Path Downward

A best practice for building designers: find a friend to check your load paths.

Lumber Design Values

No matter the species, component manufacturers (CMs) purchase and rely on the accuracy and reliability of many different lumber design properties, including: bending (Fb); shear parallel to grain (Fv), compression perpendicular to grain (Fc^), compression parallel to grain (Fc), tension parallel to grain (Ft), and modulus of elasticity (E and Emin).

Fire Rating For Truss Assemblies Built With 2x3 Lumber

Question: 

Are there any published studies or guidelines on the fire rating of floor trusses built with 2x3 lumber?

Notched Top Chords On Gable Ends

Question: 

The industry suggests notching the gable end truss to support the overhang. Is this wise? What about a structural gable, or a gable designed with drag loads, or one with only partial bearing? How safe is it for a framer working with a truss that has the top chord cut repeatedly?

Uplift Values On Truss Design Drawings

Question: 

I am a building inspector and I have a question on information provided on truss design drawings. What does the uplift reaction number represent? Some manufacturers are very specific and state “to provide for mechanical connection of the truss to the top plate with a connector capable of withstanding a specific load.” Others simply list the uplift reaction with no further information. These are the ones that have caused a debate as to what the number actually represents.

Truss Blow Down

Question: 

If trusses blew down from insufficient temporary bracing and the contractor put them back up without the knowledge of the truss manufacturer and gave the truss manufacturer a letter stating that the trusses were okay, is that sufficient? Do you know of any truss manufacturer who would accept this?