Connections

Multi Ply Girders

Question: 

Girders are trusses specially designed to carry extra loads that are a result of the structural framing members they support. Sometimes a single ply girder truss is insufficient to carry the entire load, so the truss designer designs a multiple-ply girder. This is where identical trusses are built and fastened together to act as one unit to support the load. ANSI/TPI 1 states that girder trusses up to three plies thick can be fastened together with nails. Girders over three plies must be pre-drilled and bolted rather than nailed.

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.

Partition Wall Attachment To Bottom Chords

Question: 

I am remodeling a 16-year-old ranch style home. The roof consists of 4/12 26 ft. span trusses, 24 in. O.C., over 2x4 stud walls. What is the recommended means of affixing the top plate of new interior partitions to provide the lateral support needed for the partition? Also, I want to hang a soffit above and overhanging the new kitchen cabinets (recessed lighting placed within). What is the recommended means of attaching the soffit to the underside of the trusses so as not to interfere with the designed movement of the trusses under the variable live load experienced (snow load)?

Alternate Nailing Patterns

Question: 

Some truss lumber repair nailing patterns call for 16d common nails. Most nail guns do not support 16d nails, but have an equivalent to a 12/10d nail. Is there a substitution guide or ESR report that could help us?

Deck Ledger Attachment to Residential Wood Truss Floor Systems

This Research Report provides construction details for residential deck ledger attachment to metal plate connected wood truss floor systems. Proper attachment of the deck ledger to the house is critical for ensuring that an “attached” deck is safely and securely supported at this location. 

Exterior Brick Masonry Veneer Supported by Wood Trusses

Code compliant use of Metal Plate Connected Wood Trusses (MPCWT) to support brick veneer can be accomplished by both individual designs and by adhering to the recommendations that follow within this report. This discussion focuses on a common use of MPCWT’s; the gable end at the transition from a wider section of a building to a narrower section.

Overdriven Nails in Structural Sheathings - Educational Program

This presentation provides information on overdriven nails in structural sheathing.

Heel Blocking Requirements and Capacity Analysis - Educational Program

This presentation provides information on heel blocking requirements and related analysis.

Conventionally Framed Roofs & Roof Trusses: Code-Compliant Construction

This Research Report reviews pertinent sections of the 2006, 2009 and 2012 International Residential Code (IRC), the 2012 IRC Commentary, and additional sources in an effort to compile the related data and identify discrepancies or omissions. The focus is catered toward meeting and better understanding the requirements for conventionally framed roofs and roof truss construction per IRC Section R802. 

Heel Blocking Requirements and Capacity Analysis

Both the International Residential Code (IRC) and the International Building Code (IBC) require that the top plates of exterior braced wall panels be attached to the rafters or roof trusses above. This report will discuss the code requirements and provide alternate engineered designs and capacities, including heel/bird blocking, partial height blocking and blocking panels.