Custom Search
|
|
|
||
 From Equation (127), ultimate shear stress is
vu
= Vu
An
= 99.4/3.0
= 33.1 psi
(13) Required area of shear reinforcing from Equation (128)
assuming s = 4 inches
Av
= vubs
[phi]yf
= 33.1 x 8 x 4
.85 x 70000
= .0178 in2 No. 9 gauge
Use 3 legs of No. 9 gauge wire at 4 inches on
center.
(14) Using T/TN of 2.8 and Xm/XE of 16.5, rebound from
Figure 6-8 of NAVFAC P-397 is
r -/r
= .58
r -
= .58 x 1.42
= .82 psi
Rebound shear at support,
Vr = r - x L
2
= .82 x 150
2
= 61.5 lb/in
Required area of anchor reinforcing.
Use 3/16-inch diameter triangular ties.
b.
Design of Precast Prestressed Roof.
Problem:
Design a precast prestressed roof (double tee section) for the
blast loads shown.
Given:
(1)
Pressure-time loading.
(2)
Material strength.
(3)
Dynamic increase factors.
2.08-253
|
 
|
|
|
||
