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• Tension members are found in:– Bridge trusses,– Roof trusses,– Towers,– Bracing systems– As tie rods

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Types of Tension Members

• Circular Rods– One of the simplest of tension members– Difficult to connect to many structures

• Single Angles ( used in roof trusses)• Double angles• Tees (used in welded trusses)• Channels (Bridges and large roof trusses)• W sections (Bridges and large roof trusses)• Built up from plates and rolled shapes ( to have

sufficient cross-sectional area and rigidity)

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• Steel cables are tension members– in suspension bridges– as roof supports– Strength of about 200,00 to 250,000 psi

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• Members consisting of more than one section need to be tied together.

• Tie plates or tie bars are used to tie them

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• Pn Nominal Strength

• Ag Gross area• An Net area

• Ae effective net area

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• Bolt holes = D + 1/8• An = Ag – n ( D + 1/8) t +

Structural Steel Design, Fifth Edition, McCormac and Csernak, 2012 (International 8

• Empirical equation, AISCS (B4.3b)• S is the pitch (distance c-t-c parallel to Tension)• g is the gage (distanc c-t-c perpendicular to

Tension)

Net Area Calculations

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Effective Net Area Ae

• U is a factor to account for non uniform stress distribution• Value of U is affected by:

– cross section of the member– Length of connection

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27

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3-35 Determine the allowable strength of the section WT6x26.5, A992 steel, attached through the flange with six – 1 inch diameter bolts as shown in Fig. P3-35

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