Correctly Defining Truss Members MiTek Staff When designing trusses for special loads or special conditions, it is important to define the individual truss members correctly. Without proper member definitions, trusses could be inadvertently under-designed and/or have incorrect analog. The most common member types are webs and chords. Top... Read More May 2023 Issue #15286 Page 92
Bracing on Truss Design Drawings MiTek Staff Trusses are designed as individual components to resist the in-plane stresses resulting from the loads applied in the same in-plane direction. To resist out of plane forces, adequate bracing/restraint is required. In absence of designed temporary and permanent bracing plans, BCSI (Building... Read More April 2023 Issue #15285 Page 104
Minimum Uniformly Distributed Live Load For Habitable Attics MiTek Staff Attic truss with 7 feet room height – should it be designed for 20 psf (pounds per square foot), 30 psf or 40 psf room live load? IRC (International Residential Code) defines Habitable Space as a space in a building for living, sleeping, eating, or cooking. Per IRC 2018 Table... Read More March 2023 Issue #15284 Page 93
Effects of Ripping Structural Truss Lumber MiTek Staff How does ripping lumber, cutting a board along its length, affect its grade or strength values? Structural lumber is graded or inspected which provides designers, through the National Design Specification® (NDS®) for Wood Construction, the strength/design values for the lumber members.... Read More February 2023 Issue #15283 Page 112
Construction Loading MiTek Staff Per BCSI-B4 (Building Component Safety Information): The term “construction loading” is typically used to describe Loads from workers and Building materials on unfinished structure, as, for example, when builders temporarily stack bundles of panel sheathing or gypsum board on... Read More November 2022 Issue #14280 Page 112
Understanding Bearing Size at a Wall or Beam MiTek Staff The first thing to consider with bearing sizes is the minimum required by the building codes. Per 2018 IRC, International Residential Code for One- and Two-Family Dwellings, Sec. R802.6 – When a ceiling joist is supported directly on wood or metal, the minimum bearing size required is... Read More April 2022 Issue #14273 Page 112
Recommendations and Limitations for Depth and Deflection of Parallel Chord Trusses MiTek Staff In addition to allowable lumber stress limitations, parallel chord truss designs are also regulated by maximum permissible deflection-to-span and depth-to-span limitations. All of the following recommended limitations should be achieved to provide a quality roof / floor system and assure... Read More February 2022 Issue #14271 Page 105
ASCE 7-16 Changes That Impact Truss Designs MiTek Staff 2018 International Building Code (IBC-2018) is the latest version of the I-Code which is starting to be used or adopted in the United States and in other nations. While both the 2012 and 2015 IBC referenced the 2010 edition of ASCE 7, the 2018 IBC refers to the 2016 edition of ASCE 7,... Read More November 2019 Issue #11244 Page 112