An open web steel joist features top chord 14, bottom chord 16 and a web that measures approximately 18. The web comprises pre-formed bar sections arranged in a “W” formation with their ends situated adjacently on either end of the top chord, save for their outer ends.
I-joists are an engineered wood product that offers an environmentally-friendly alternative to conventional lumber floor and roof framing, thanks to their lightweight, uniform shape and inert nature. Their cross-sectional shape enables easy placement of pre-punched or drilled holes for electrical, plumbing and mechanical services; as well as no needing sheathing or cladding like traditional lumber construction requires. Unfortunately they don’t fare so well when handled with carelessness and may not respond as readily to job-site changes orders than other options do.
Short-term failure behaviour of latticed LVL web I-joists was investigated via experimental tests conducted on 241 mm and 305 mm deep joists. Bending test results demonstrated that both depths could sustain high moment carrying capacities; with 241 mm series being slightly less capable due to using UF adhesive, which was susceptible to tension failure perpendicular to grain in their webs – as evidenced by early failure modes observed in Joist 241-1-B and 305-1-B in Figure 7.
305mm joists manufactured using PRF adhesive performed much better in bending tests, with comparable moments to solid OSB webbed joists. This could be attributed to their superior structural adhesive performance – it resists tension failures in the web and helps prevent premature failures.
Modern wood I-joists are produced in factories through an intricate manufacturing process using specialized equipment and assembly methods. Fabricated from prefabricated panels of finger-joined solid sawn lumber or laminated veneer lumber (LVL) flanges joined together by finger joints are attached by various techniques to a web of plywood or OSB using glue made of exterior-rated waterproof adhesives, the web may also feature tongue-and-groove or toothed joints with square panel ends; holes for electrical, plumbing or mechanical services may also be drilled through according to manufacturer recommendations.
Technology is a result of applying conceptual knowledge creatively and innovatively to organised tasks involving people and machines to meet human needs and reach sustainable goals. It encompasses scientific, engineering, mathematical, historical, linguistic and social sciences knowledge used to produce tools or systems which harness natural phenomena for practical human use.
Implementation of new technologies can have profound effects on society and the environment, from decreasing manual labor requirements to increasing prosperity and providing comfort and convenience. Unfortunately, some technologies can also have negative repercussions such as polluting natural resources and depleting existing social hierarchies; furthermore they may challenge traditional values or create ethical dilemmas that threaten society itself.
Joists are typically pre-punched or drilled to enable electrical, plumbing and mechanical services to attach easily, although it’s essential that holes comply with manufacturer recommendations. Furthermore, urea-formaldehyde or phenolic adhesives may be used to adhere the joists together.
Design of a fabricated wood I-joist must meet specific performance specifications of any given building project, including load bearing capacity and allowable deflection. Once designed, its size must then be determined so as to accommodate for as many panels as possible.
A typical joist will contain an odd number of panels running its length. Each panel is then secured into place within its respective W or V pattern with adjacent welding on their respective Ws (or Vs).
Apex welding creates an end compression leg of a joist which is almost vertical, thus eliminating the need to turn it on its side during fabrication and thus requiring lower welding voltage/current settings and lessening worker fatigue.
Once taken from the inverter, they are then banded into bundles for further processing – such as pickling as necessary and paint tank dipping before draining and tagging before being loaded onto trailers to be delivered directly to job sites. All this happens within a standard steel fabricating shop environment for maximum efficiency compared to traditional wood framing operations.
Steel joists that support your floors and roof may not require rocket science, but proper training is required for their assembly. Weyerhaeuser provides on-demand software solutions that allow users to create framing specifications, cut lists, manage inventories and design structural frames.
Open web joists make plumbing and electrical installation much simpler, saving both labor costs and effort. I-joists feature prefabricated knockout holes which make running HVAC and electrical systems effortless without cutting or drilling into the joist itself.
Note that I-joist manufacturers can be particular about where openings appear in I-joists; typically, they prefer that these openings be located far from bearing points that support floors, ceilings or roofs and away from cantilevers; too many small holes near cantilevers could amount to one large one in time! In addition, having holes near supports could reduce load-bearing capacity of floors and roof structures significantly, thus impacting load-carrying capacity negatively and necessitating costly repair bills later down the line! It is therefore imperative that manufacturers adhere strictly to rules in terms of placement of openings in order to meet their specifications – otherwise work delays could occur and repair bills could ensue later down the line!