24.02.2017 Views

Structural Concrete - Hassoun

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

888 Chapter 22 Prestressed <strong>Concrete</strong> Bridge Design<br />

22.2 TYPICAL CROSS SECTIONS<br />

Typical cross sections of precast prestressed girders commonly used for short- and medium-span<br />

bridges have been developed and standardized by AASHTO and PCI for highway bridges. The<br />

dimensions, sectional properties, and span range of these standard AASHTO-PCI girders are introduced<br />

in this section.<br />

22.2.1 AASHTO Solid and Voided Slab Beams<br />

Solid and voided slab beams (Fig. 22.1) are typically used for short-span bridges ranging up to<br />

55 ft based on simple span, HS-25 (highway semitrailer with the first two axles weighing 25 tons)<br />

loading and f ′ c = 7000 psi. Dimensions and properties of AASHTO solid and voided slab beams<br />

are given in Tables 22.1 and 22.2, respectively.<br />

L<br />

L1 L2 L2 L1<br />

H<br />

LC<br />

Figure 22.1<br />

Cross section of AASHTO solid and voided slab beams.<br />

Table 22.1<br />

Dimensions (inches) of AASHTO Solid and Voided Slab<br />

Type L H L1 L2 No. of Voids D1 D2<br />

SI-36 36 12 — — 0 — —<br />

SII-36 36 15 10.5 7.5 2 8 —<br />

SIII-36 36 18 10.5 7.5 2 10 —<br />

SIV-36 36 21 10.0 8.0 2 12 —<br />

SI-48 48 12 — — 0 — —<br />

SII-48 48 15 10.0 14.0 3 8 8<br />

SIII-48 48 18 9.5 14.5 3 10 10<br />

SIV-48 48 21 10.0 14.0 3 12 10<br />

Table 22.2<br />

Properties of AASHTO Solid and Voided Slab<br />

Type Area (in. 2 ) Y bottom<br />

(in.) Inertia (in. 4 ) Weight (kip/ft) Max. Span (ft)<br />

SI-36 432 6.0 5,184 0.450 40<br />

SII-36 439 7.5 9,725 0.457 47<br />

SIII-36 491 9.0 16,514 0.511 52<br />

SIV-36 530 10.5 25,747 0.552 57<br />

SI-48 576 6.0 6,912 0.600 42<br />

SII-48 569 7.5 12,897 0.593 49<br />

SIII-48 628 9.0 21,855 0.654 53<br />

SIV-48 703 10.5 34,517 0.732 57

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!