Design of Tension Members To avoid yielding: A g P u / 0.9 F y To avoid fracture: A e P u / 0.75 F...
13
Design of Tension Members • To avoid yielding: A g P u / 0.9 F y • To avoid fracture: A e P u / 0.75 F u Or : A n P u / 0.75 F u U • where P u is the sum of the factored loads.
-
Upload
austin-owen -
Category
Documents
-
view
215 -
download
3
Transcript of Design of Tension Members To avoid yielding: A g P u / 0.9 F y To avoid fracture: A e P u / 0.75 F...
Design of Tension Members
• To avoid yielding: Ag Pu / 0.9 Fy
• To avoid fracture: Ae Pu / 0.75 Fu Or :
An Pu / 0.75 Fu U
• where Pu is the sum of the factored loads.
Design of Tension Members
• If the axial load in a slender tension member is removed and small transverse loads are applied, undesirable vibrations or deflections may occur. Thus AISC recommends:
• r L/300 ( not for cables or rods)• where r is the minimum radius of gyration of the
cross section and L is the length of the member.
Threaded Rods and Cables
• When slenderness is not a consideration, circular rods and cables are often used (hangers, suspended bridges).
• Rods are solid and cables are made from individual strands wound together.
• Threading the end of a rod reduces the cross sectional area (upset end prevents such reduction, but is expensive).
Threaded Rods and Cables
t Pn = 0.75 (0.75 Ab Fu)
• Ab = nominal (unthreaded) area
• It is common to use a min diameter of 5/8 in. for rods.
Threaded Rods and Cables
• A strand consists of individual wires wound helically around a centrl core.
• A wire rope is made of several strands laid helically around a core.
Tension Members in Roof Truss
• Trusses are used where the cost and weight of a beam could be prohibitive (long spans).
• A truss may be thought of as a deep beam with much of the web removed.
• Tension members in roof trusses include some truss members and sag rods.
Sag Rods
• Sag rods are used to provide lateral support for the purlins (to prevent sag in direction parallel to a sloping roof due to vertical applied loads).
• They are designed to support the component of roof loads parallel to the roof.
Sag Rods
• Each segment between purlins is assumed to support everything below it; thus the top rod is designed for the load on the roof area tributary to the rod, from the heel of the truss to the peak.
Sag Rods
• The tie rod between ridge purlins must resist the load from all of the sag rods on either side.
![^t Z u l ] o Ç u Z } u M · 2020. 10. 5. · o ] l o o •/ v ( o u u } Ç l P } µ v •> P v ( } u ] u u µ v } o •, } P l ] v lZ r^ v P r o ] l o o •/ v ( o u u } Ç l P }](https://static.fdocuments.in/doc/165x107/604904b8a6838d1c251385cf/t-z-u-l-o-u-z-u-m-2020-10-5-o-l-o-o-a-v-o-u-u-l-p-.jpg)
![o < o À P o } P o P ] v µ v · 2019-12-18 · µ v P µ X h v P v l o µ u ] P u u v U u v ] P µ U Z À ] ( ( t v u µ v P](https://static.fdocuments.in/doc/165x107/5fb98d91d1680979b16ecea5/o-o-p-o-p-o-p-v-v-2019-12-18-v-p-x-h-v-p-v-l-o-u-p-u.jpg)
![u } ] } v o } } } ( ] P Z r Á ] v P } o ] ] o } µ o ] u D ... · u } ] } v o } } } ( ] P Z r Á ] v P } o ] ] o } µ o ] u ... u } ] } v o } } } ( ] P Z r Á ] v P } o ] ] o } µ](https://static.fdocuments.in/doc/165x107/5e0ee75edea8723fe9108e76/u-v-o-p-z-r-v-p-o-o-o-u-d-u-v-o-.jpg)
![LGS Presentation Ne · KDD Z / > lZ d /> µ ] v U µ ] u v o ] v P } u v ] U o ] À } l v ] v P U u ] v v v Wh >/ tKZ](https://static.fdocuments.in/doc/165x107/5f919b0cc4185e1eb62a9a52/lgs-presentation-kdd-z-lz-d-v-u-u-v-o-v-p-u-v-u-o-.jpg)
![v ] u ' µ ] v ( } Z ] o W } P u v ^ µ u u Ç u · 2020-05-27 · v } À v } ( Ks/ r í õ v Ç ò ( U Á ( } À ] v P U v ] P } } Z Ç P ] v v } ( v ] u ] o ( } Ç } µ v P Z](https://static.fdocuments.in/doc/165x107/5f1e25cb8184d04d2a690a8e/v-u-v-z-o-w-p-u-v-u-u-u-2020-05-27-v-v-ks-r.jpg)
![} u u ] } z } µ } u u µ v ] Ç U ^ ^ } µ ] , o ( µ o ^ } µ v P Ks/ r í õ W o P W · 2020. 8. 7. · Ç ] P v ] v P Z ] o P U / } u u ] u Ç o ( } Z } À U } µ U v µ o X ...](https://static.fdocuments.in/doc/165x107/601a0f2661b06b7b320772b9/-u-u-z-u-u-v-u-o-o-v-p-ks-r-.jpg)
![v î ì í î U Á P v u v P ] v P } o o ] } v } ( } µ ] u ...](https://static.fdocuments.in/doc/165x107/62ad9341825bd62d1e1a4f1c/v-u-p-v-u-v-p-v-p-o-o-v-.jpg)
