Civil Engineering Reference
In-Depth Information
9144
Roadway slab
TXDOT Type-A
Beams
2642
2642
2642
2642
(a) Layout of designed Girder and Slab
Wu = 131 kN/m
12200
(b) Elevation of Designed Girder
1040
304
152
406
(c) Typical Cross Section of Designed Girder
Figure 8.24
Design example 1 using TxDOT type A beams (units are in mm unless otherwise men-
tioned) (Note: 1 mm
=
0.039 inches, 1 kN/m
=
0.069 kips/ft)
scatter, ranging from 0.872 to 4.77. This scatter is much larger than for the UH method (Figure
8.21) and the ACI method (Figure 8.22).
8.3.7 Shear Design Example
8.3.7.1 Problem Statement
TxDOT Type A girders, 12.2 m (40 ft) long, are designed to support a deck slab 9.14 m
(30 ft) wide and 203 mm (8 in.) thick, as shown in Figure 8.24(a-c). A uniform load of
49.6 kN per square meter (1.04 kips per square foot) requires four girders spaced at 2.64 m
(8.67 ft) c/c. Each girder is reinforced with 18 seven-wire, low-lax strands of 12.7 mm (1/2-in.)
diameter and a strength of 1862 MPa (270 ksi). The moment capacity of a composite girder is
2617 kN m (1929 kip ft). The reduction factors
φ
are based on ACI-ASCE Joint Committee
343 Report (1995, R2004).
