Reinforced concrete bridges - Computational Analysis and Design of Bridge Structures - page 119

Bridge response plot
−800.

BOBJ1—entire bridge section (Case DEAD) moment about horizontal axis (M3)

0

800.

Min value = −665.413

Max value = 335.9718

(a)

Bridge response plot
−150.

BOBJ1—interior girder 1 (Case hl_93_two lane loaded inmpact) moment about horizontal axis (M3)

0

150.

Max value = 132.0396 Min value = −125.0185

(b)

Figure 4.13 CSiBridge results. (a) Dead load moment diagram. (b) Live load moment
envelop.

in the analysis of a skewed bridge. Another benefit of using 3D finite element
model is that nonuniform moment distribution of the entire bridge due
to skewness can be obtained, not by assuming the uniform distribution
cross section-wise but by the line strip model. Other moment comparisons
are shown in Table 4.1. It is concluded that for this three-span continu-
ous concrete slab bridge, finite element model assuming two lanes loaded
with HL-93 vehicle on each lane provides more accurate results, whereas

Table 4.1 Comparison of moments based on line strip and FEM methods
Dead/live
moment

Line strip moment in
kip-ft/ft (kN-m/m)

FEM moment in k-ft/ft
(kN-m/m) Location in ft (m)

Dead positive 12.3 (54.7) 9.24 (2.8)

286/26.8 = 10.7 (47.6)

Dead negative −15.3 (−68.1) −665/32 = −20.8 a (−92.4) 22.6 (6.9)

Live positive 22.3 (99.2) 333/32 = 10.4 (46.3) 11.3 (3.4)

Live negative −16.9 (−75.2) −647/32 = −20.2 a (−89.9) 22.6 (6.9)

If the width along the skewed line 43 ′ is used, dead negative moments are 15.5 and 15.0 kip-ft/ft,
respectively.

a