BRAE433 Lecture Ch 4

# BRAE433 Lecture Ch 4 - RC Design Ch 4 Shear in Beams BRAE...

This preview shows pages 1–7. Sign up to view the full content.

1 RC Design BRAE Cal Poly Ch 4 – Shear in Beams Introduction - Shear Shear (like bending moments) create tensile stresses Concrete is not good in tension BRAE Cal Poly

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
2 Introduction - Shear Bending stress and Shear stress BRAE Cal Poly BRAE Cal Poly
3 Bending Stresses • Flexure Formula (from Ch 1) –f b = Mc/I or M/S x where S x = I/c b = calculated bending stress, psi – M = applied moment – c = distance from the neutral axis to the outside BRAE Cal Poly tension or compression fibre of the beam – I = moment of inertia of the cross section about the neutral axis (Rect Beam I = bh 3 /12) unit vertical shear ν Shear Stresses unit vertical shear - ν = V x Q / (I x b) = Vh 2 / (8 I) where, V = external shear Q = static moment of area about NA I = moment of inertia of the cross section about the NA BRAE Cal Poly I = moment of inertia of the cross section about the NA b = width of the cross section ν = V x Q / (I x b) = Vh 2 / (8 I) rectangular beam

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
4 Isolation of a small element f b = 0 BRAE Cal Poly Horizontal shear stresses (v) are equal in magnitude to the vertical shear stresses BRAE Cal Poly Courtesy: Mr. Hopkins
5 Shear stresses on inclined plane 0.707 ν 0.707 ν 1.414 ν ν BRAE Cal Poly Plane at 45 Deg angle subject to tension and if the “diagonal tension” is large enough, must be reinforced Shear reinforcement Shear Span Cracks… vertical stirrups Stirrups - protect ½ way to neighbor BRAE Cal Poly inclined stirrups main reinforcement bent up at ends

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
6 Concrete only - Shear V c V c = 2 x (f' c ) 0.5 x b w x d (concrete shear strength) Vu ( from factored loads ) must be less than or equal ½ x φ V c (
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 01/13/2011 for the course BRAE 433 taught by Professor Styles during the Fall '10 term at Cal Poly.

### Page1 / 17

BRAE433 Lecture Ch 4 - RC Design Ch 4 Shear in Beams BRAE...

This preview shows document pages 1 - 7. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online