Lect.11

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CE -515: Design of Steel Structures CE -515: Design of Steel Structures

CE-515: Design of Steel Structures

M. Engg. (Civil), Fall 2013

Lecture 11


Beam Design Charts

• There are many design charts, tables and graphs available in the manual.

• The curves of moment strength versus unbraced length given in Part 3 of the manual.

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CE -515: Design of Steel Structures CE -515: Design of Steel Structures Example 1:

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CE -515: Design of Steel Structures CE -515: Design of Steel Structures LRFD

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CE -515: Design of Steel Structures CE -515: Design of Steel Structures ASD

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LRFD

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Floor and Roof Framing Systems

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Floor and Roof Framing Systems…


Floor and Roof Framing Systems…

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CE -515: Design of Steel Structures CE -515: Design of Steel Structures Solution:

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Holes in Beams • If beam connections are made with bolts, holes will be punched or

drilled in the beam web or flanges.

• In addition, relatively large holes are sometimes cut in beam webs to provide space for utilities such as electrical conduits and ventilation ducts.

• Ideally, holes should be placed in the web only at sections of low shear, and holes should be made in flanges at points of low bending moment.

• For relatively small holes such as those for bolts, the effect will be small, particularly for flexure.

• Holes in beam flange are of concern for the tension flange only, since bolts in the compression flange will transmit the load through the bolts.


Holes in Beams… • Bolt holes in beam flanges are to be accounted for when

the nominal tensile rupture strength (fracture strength) of the flange is less than the nominal tensile yield strength.

• If Fy /Fu > 0.8, the nominal tensile yield strength is to be increased by 10%.

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Holes in Beams…

• The nominal flexural strength is to be limited by the condition of flexural rupture. This limit state corresponds to a flexural stress of

Where can be considered to be a “net” elastic section modulus. The nominal flexural strength is


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Lect.11