A chase is an intentional opening in a floor truss created by omitting specific diagonal webs to provide space for HVAC ducts, plumbing lines, or electrical runs. For structural efficiency, chases should be located within the middle third of the truss span, where shear forces are lowest....

Girder trusses are trusses specially designed to carry extra load from tie-in trusses and equipment. If a single ply is insufficient to carry the entire load, the truss designer specifies a multiply girder, that is made of identical trusses and fastened together to act as one unit to support the...

Bearing: A structural support, usually a beam or wall, which is designed by the building designer to carry the truss reactions to the foundation. [For all images, See PDF or View in Full Issue.] MiTek’s engineering software uses two common types of bearings, roller and pinned. There is...

In the truss industry, camber refers to the gradual curvature of a chord member either naturally occurring or created to alleviate the natural deflection of a truss structure. That sounds simple enough, but there are key elements about camber that should be considered. Camber in Action All...

In our October article, Because Good Ingredients Matter, we focus on the word quality and the many ways that MSR lumber has become synonymous with high quality structural building components. Having laid the groundwork for why MSR has become so important for optimizing truss designs and an...

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...

Since the 1960s, fabricators have used machine stress rated (MSR) lumber of all species to improve the performance and reliability of their engineered components and structures. Nowadays, you don’t have to look far to find a successful component manufacturer who relies heavily on MSR...

This August marked the 30th anniversary of the Florida landfall of Hurricane Andrew, one of the most damaging, and influential, hurricanes ever to hit the United States. Hurricane Andrew hit South Florida with Category 5 winds early on the morning of August 24, 1992. Andrew caused damages of $25...

Every truss design is evaluated for numerous criteria to determine if it is structurally sound. One of those checks is the capacity of the truss to resist buckling at a bearing location. This article focuses on checking out-of-plane buckling when a truss member is loaded in compression...

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...