Print this page Engineered Wood Connections For Snow Loads
Dennis Keierleber, P.E.
Course Outline
Engineered wood products are changing light frame wood construction. Prefabricated wood I-joists have been used for decades and structural insulated panels (SIPs) have been around for approximately 20 years. Despite the increasing use of these products, the issues and special requirements of connection details continue to be poorly understood in the construction industry. Prescriptive designs and details are not what they seem and most connections may require substantiation with submitted calculations. This course offers a review of engineering mechanics as they relate to bending members installed on a rake, shows how to calculate the components of reactions on sloped bearing surfaces, and present recommended connection details with suggested calculations. This course will enable the designer to avoid potentially hazardous situations with I-joist and SIP connections and design and detail safe connections.
This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of the course materials.
Learning Objective
At the conclusion of this course, the student will:
- Have an introduction to prefabricated wood I-joists and structural insulated panels;
- Understand the difference between prescriptive and performance based design;
- Understand how to calculate roof snow load from specified ground snow load using the snow load chapter of ASCE7;
- Understand the mechanics involved in a rake beam member;
- Understand the forces involved with bearing on a sloped surface and the implications for connection design;
- Be introduced to the National Design Specification for Wood Construction with emphasis on published nail values;
- Be introduced to the concept of perpendicular to grain tension and how to reinforce beams to resist those stresses; and
- Be able to design and detail safe connections for wood I-joists and structural insulated panels used as roof framing members.
Intended Audience
This course is intended for engineers, architects, contractors and structural plan reviewers with some basic knowledge of engineering mechanics.
Benefit for Attendee
Attendee of this course will be able to determine roof snow load from specified ground snow load, design safe connections for wood I-joists and structural insulated panels, and avoid potentially hazardous situations with connections of roof framing members.
Course Introduction
Manufacturers’ details for roof connections with wood I-joists are limited to 70-psf ground snow load. Even within that limitation, some details shown are not adequate for the forces involved and/or are not completely described in the manufacturers’ literature. The manufacturers of structural insulated panels (SIP) show typical details but all SIPs, used as roof framing members, require calculations consistent with standard engineering practice be submitted for all connection details. This course will show how the designer can produce safe details and calculations for these products.
Course Content
The course content is contained in the following PDF file:
Engineered Wood Connections For Snow Loads
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Course Summary
The course begins with the method of calculating roof snow load from specified ground snow load. Basic engineering mechanics are reviewed to obtain the reactions of the framing member. Calculations to resolve the reactions on sloped bearing surfaces are discussed and how those relate to the internal member forces. Typical details for wood I-joists at ridge beams, exterior walls and intermediate bearing points are shown with calculations on how the forces are resolved. Typical manufacturers’ details are shown for structural insulated panels (SIPs) at ridge and eave locations and issues with those details are discussed. Suggested details for SIPs at those locations, similar to the I-joist details, are presented.
Quiz
Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.
DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.
