Non-Residential Codes (IBC)

Two Hour Assembly Ul Number

Question: 

We have a local builder wishing to use floor trusses with a 2-hour assembly. I have shown him the 2-hour design on pages 17-27 of the second edition of SBCA’s Metal Plate Connected Wood Truss Handbook. Is this assembly UL approved? If so, what is the design number?

Main Wind Force Resisting Systems Vs Components Cladding

Question: 

As an engineer, I have noticed truss designers in some high wind states routinely using “Main Wind-Force Resisting Systems” wind pressure coefficients as opposed to “Components and Cladding” coefficients to design for wind uplift. A roof truss is not a main wind-force resisting system and would have to have a tributary area of more than 1000 sq. ft. before qualifying for the lower Primary Frame coefficients. In my experience this practice is routine.

Deflection Of Long Span Scissors Trusses

Question: 

I was wondering if you have any information or anecdotes relating to the deflection performance of long span scissors trusses? We recently sold a job with 70 ft. long scissors trusses. The customer is in the process of installing the trusses and doesn't like the deflections he is seeing. To make matters worse, the scissors trusses are framing into a valley set (which we provided) that is erected on 35 ft. Howe trusses. The Howe trusses are exhibiting very little deflection. Any ideas?

Design Loads Vs Typical Loading Conditions

Question: 

The Corps' guide spec for wood construction requires the drawings to indicate the design forces on each truss member for the worst loading condition. Loading conditions, of course, can include wind, snow build up, and unbalanced loading, to name a few. Many A/E firms submit drawings lacking these member forces, but instead show typical loading conditions. What does the wood truss fabricator want to see – truss diagrams with maximum loads on each member? Or would he prefer to design the truss from many required loading diagrams?

Liability Issues With Lvl Beams

Question: 

We have been specifying laminated veneer lumber (LVL) beams for some time now. The plans usually state, “Beam to be engineered and supplied by truss manufacturer.” What kind of liability issues do I need to watch out for?

Wood Framing

Question: 

I am conducting an investigation on the costs associated with building a 15,000 sq. ft. addition to an existing school building. I need to determine if wood trusses, steel bar joists or light gauge steel trusses would be the most economical material for the building system. The truss spans range from 42 ft. to 56 ft.

Long Span Truss Installation

Long span trusses can pose significant risk to installers. The dimensions and weight of a long span truss can create instability, buckling and collapse of one or many trusses, if not handled, installed, restrained and braced properly. As such, they require more detailed safety and handling measures than shorter span trusses. This research report provides guidelines for proper handling and installation of long span trusses for both wood and cold-formed steel.

Impact of C&C loads due to ASCE/SEI 7-16

ASCE/SEI 7-16 Minimum Design Loads for Buildings and Other Structures has revised Chapter 30 regarding Components & Cladding (C&C) wind loads on roofs. This report clarifies the type and scope of changes being made that will also change in the 2018 edition of the model building codes. 

Deflection Limits for Floor Trusses

There are circumstances when the deflection requirements for a specific structure that utilizes floor trusses as structural members are questioned. The current residential and commercial building codes provide minimum design requirements for loads and for deflection of structural floor members, which also apply to floor trusses. The building designer may specify more stringent requirements. This research report will focus on manufacturer or trade association deflection requirements for a number of floor topping/covering related products

Fire Retardants and Truss Design - Educational Program

This presentation provides information and analysis of fire retardant-treated wood and metal plate connected wood truss designs.