astellated beams have been used as struc tural members - PDF document

been used as struc-Europe and theUnited States sincethe castellated beam is to increasethe beam’s depth and strengthwelding technology, the manufac-turing process used to make castel-manually. This was labor intenseand costly. With rising labor costs,expanded production, gained effi-ciencies and advancement in man-ufacturing of rolled shapes, the useabandoned until recently. SMIa single target market in mind;SmartBeams are manufacturedtomated computer-controlledplasma torch, separating the twowith an automated submerged arcwelding process as shown in Fig. 1.This process increases the depth ofthe beam by approximately 50%,therefore increasing the strengthand stiffness by 40%. An originalbeams are welded back togetherwith camber build in, thereforeeliminating a costly offline camber-ing process. SmartBeam Designsimilar to that of Vierendeel trussdesign in that the shear componentcreates bending through the webfor in the bending stress calcula-tions. The design procedure fortail in a time tested and respectedThe Design of WeldedStructuresThere are 3 basic design checks in Billy Milligan, P.E. Billy Milligan, P.E., is Vice President of CMC Steel Group dba SMI Steel Products Vierendeel BendingVierendeel bending is a combi-nation of true bending and vieren-deel bending created by sheartransfer across the web openings asing stress is generated by momentor a flange force in the beam, eithertension or compression, and is ap-plied uniformly over the area of thetee. The secondary stress, or veiren-deel stress, is caused by the transferof shearing forces over the webopening. The resulting overallstress is the sum of the primary andsecondary stresses. The tee sectionmethods in accordance with AISC’sthrough the opening and horizon-tally through the web post. Theizontal shearing stress, more com-stress, has to bechecked at incremental intervalscause of the variability of the crossWeb Post BucklingThe web post design procedurewas developed by Drs. Dick Red-wood and A. A. Aglan of McGillUniversity in Montreal, Canada.Dr. Redwood has spent severalyears testing and developing de-sign procedures for both castel-full scale destructive as well as fi-range of opening heights, openingfull range of the previously men-tioned variables. The published ca-pacities are simply compared to therequired resistance for the geome-Although there are numerousdifferent applications for which aSmartBeam can be economicallytraditionally used spans. As a re-sult of the deeper section, theistics than other structural floorOffice Buildings/MezzaninesSmartBeams are ideally suitedfor long-span composite floor con-struction. Today owners are look-ing for more flexibility in spaceplanning which leads to more col-umn-free space. This economicallythe intrusion of interior columns.By incorporating the HVACthrough the web openings, about1’-0” of floor-to-floor height can being compared to other long-spanParking GaragesWith increasing real estate costs,developers have determined that itis more cost effective to buy lessproperty and to maximize theirspace by using multi-level parking.SmartBeam parking decks havebeen constructed for as little asapproximately $1500 per spaceover a comparable pre-cast parkingof $750,000 per garage. The long-span nature of parking garageslends these types of structures tonate gives owners a clear-span, col-umn free parking area with thedeck and the efficiencies and costcompetitiveness of a steel framedSummary and ConclusionThe castellated beam is a timeproven composite structural floor-has become a more economicalfloor framing system. With Smart-Beams excellent long-span capabil-ity, vibration characteristics andcost effectiveness it will become thelong-span composite structuralmaterial of choice for floor con-struction. May 2001 / Modern SteelConstruction figure 1