Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 51
51
the ducts, but the cracks shown in Figure 5-7 were the primary
failure planes.
Another significant analysis versus test comparison is
shown in Figure 5-14: the lateral force versus deflection at the
mid-height of the duct bank relative to the slab. The compar-
ison shows that for both the BC and 1.0DC girder webs, the
analysis is simulating the response (initial stiffness and stiff-
ness degradation with accumulating damage) and the lateral
force capacity reasonably well.
These comparisons and experience with many similar re-
inforced concrete analyses indicate that the FE representation
Figure 5-10. Deformed shape (displacements 50) and modeling strategy are appropriate for moving on to the
at 1.0 DC deflection of 0.07 inches. prototype models.
Local Analysis of Multicell
2.00E-4. Figure 5-11 shows widespread cracking in the Box-Girders
vicinity of the ducts and much more severe cracking at the BC
configuration than at the 1.0DC. For the NCHRP 12-71 project study, there are two basic
Figure 5-12 shows similar strain contours, but in an end local model types:
view at a lower displacement. Here the crack zones are also · Multi-cell box (three-cell box with super-elevation/
fully formed, but are easier to see in cross section. Figure 5-13 vertical interior webs, and inclined exterior webs; also ran
shows the same deformed shape as Figure 5-12, but viewed in with vertical exterior webs)
conjunction with principal strains, is used to estimate the ex- · Single-cell box (prototypical pre-cast box with super-
tent of cracks. Using this information, and judgment from elevation and inclined webs)
experience with many similar analyses, actual cracks implied
by the analysis are drawn onto the figure. Comparing to Fig- The prototype geometry for the multicell box girder was
ure 5-7 shows similar trends in the location of the cracking as super-elevated since this is how curved girders often occur in
compared to the test. In making this conclusion, it is assumed practice. In the multicell studies conducted, the only effect of
that the test also showed other small cracks in the vicinity of super-elevation was a small difference in the end conditions of
Figure 5-11. Contours of max principle strains at 1.0DC deflections of 0.07 inches.
