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Composite Buildings
Published in Bungale S. Taranath, Tall Building Design, 2016
Use of tapered composite girders with a maximum depth at center span is limited, as the main mechanical duct loop normally runs through the center of the beam span rather than at each end. On the other hand, a castellated beam has a constant depth. It is formed from a single rolled wide-flange steel beam cut and reassembled by welding. The resulting beam has increased depth and provides for hexagonal openings over the entire span. However, its use in the United States is somewhat limited because of increased fabrication costs, and standard castellated openings may not be large enough to accommodate the required mechanical ductwork.
Steel elements
Published in Trevor Draycott, Structural Elements Design Manual, 2012
To form a castellated beam, the basic rolled section is first flame cut along its web to a prescribed profile as shown in Figure 5.28 a. Then the resulting two halves are rejoined by welding to form the castellated beam shown in Figure 5.28b. The finished section is stronger in bending than the original but the shear strength is less. However, this usually only affects heavily loaded short span beams, and may be overcome where necessary by welding fitted plates into the end castellations as shown in Figure 5.28c.
Structural steelwork and pipework
Published in Roger Timings, Fabrication and Welding Engineering, 2008
Structural steelworkDescribe the basic differences between a British Standard Beam (BSB) and a rolled steel joist (RSJ).Figure 8.33 show a section through a steel-framed building. Copy out and complete the table naming the various features of the structure. List the more commonly used connections in structural steelwork and discuss the relative advantages and limitations of each of the systems you have listed.Sketch and describe two types of stanchion base, explain why such bases are required and state where each would be used.Sketch and describe:a stanchion splicea beam-to-stanchion connectiona beam-to-beam connection.Describe under what circumstances web stiffeners are required and sketch a typical example.With the aid of sketches show the difference between N-type fabricated beams and Warren-type fabricated beams. List the advantages and limitations of such beams and describe the method of construction.Explain what is meant by a ‘castellated’ beam. What are the advantages and limitations of such a beam, and how can it be fabricated with minimum waste of metal?Because of the size of structural steelwork it cannot be marked out on a surface table in the usual workshop manner; therefore, describe how roof trusses can be marked out and pre-assembled.
Strengthening of thin-webbed castellated beam using CFRP
Published in International Journal for Computational Methods in Engineering Science and Mechanics, 2018
In general, the beams with web openings along its length with regular intervals are termed as castellated beams. These web openings are commonly used for providing the service lines like air ducts, water lines, sewage lines, and so forth. The fabrication of castellated beam is the process of cutting the web portion of I section in a zig-zag pattern along its centre line (Fig. 1). The separated parts are turned and re-joined by welding, which in turn will increase the depth of an I section without adding or changing any weight in that beam. Meanwhile, this process will lead to increase beam’s section modulus and moment of inertia which results in greater strength and rigidity. Commonly, the web openings of castellated beam usually take the shape of hexagon, circular and octagon. However, the structural behaviour of the castellated beam entirely differs from plain webbed beam as the presence of openings in the web portion may cause various failure modes. The major failure modes of castellated beam are pointed below [1] Web-post bucklingFlexure mechanismVierendeel mechanismRupture of welded jointLocal failures under point loadOverall lateral torsional buckling in case of laterally unsupported beams