3 resultados para Attachment Patterns

em Iowa Publications Online (IPO) - State Library, State of Iowa (Iowa), United States


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A century ago, the majority of workers were employed near their homes—on farms or in cities and towns. As industrialization increased and suburbs surrounded central cities, commuting meant going from homes in suburbs to jobs in cities. Today, there is a growing trend of workers commuting between suburbs. On any given day, 61,775 workers commute to jobs in Iowa counties other than the one in which they live. The most important reason for increased commuting has been employment growth. Rising incomes and the growth of suburbs have also been factors. In the past, the increased employment of women added to the number of commuters. Commuting patterns are a key consideration in transportation planning. In more urban states than Iowa, there is concern that the use of mass transit continues to decline. In Iowa, where so much of our commuting is between counties, private vehicles are often the only practical means of getting to and from work. On any given day, 1,155,008 single-occupancy vehicles are driven to and from jobs somewhere in Iowa. At the same time, an additional158,699 workers share rides by participating in carpools.

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A report produced by the Department of Natural Resources on the historical pattern the rivers take.

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The Iowa Department of Transportation (IaDOT) was interested in investigating the use of epoxy adhesive anchorages for the attachment of posts used in the BR27C combination bridge rail system. Alternative anchorage concepts were developed using a modified version of the ACI 318-11 procedures for embedded anchor design. Four design concepts were developed for review by IaDOT, including: (1) a four-bolt square anchorage, (2) a four-bolt spread anchorage, (3) a twobolt centered anchorage, and (4) a two-bolt offset anchorage. IaDOT representatives selected the four-bolt spread anchorage and the two-bolt offset anchorage as the preferred designs for evaluation. In addition to these two proposed configurations, IaDOT also requested that the researchers evaluate a third option that had been previously installed on the US-20 bridge near Hardin, IA. The proposed alternative anchorages and the original cast-in-place anchorage for the BR27C combination bridge rail were evaluated through dynamic component testing. The test of the original cast-in-place anchorage was used a baseline for comparison with the alternative designs. Test no. IBP-1 of the original cast-in-place anchorage developed a peak load of 22.9 kips (101.9 kN) at a deflection of 1.5 in. (38 mm). All three of the tested alternative anchorages provided greater load capacity than the original cast-in-place design and were deemed acceptable surrogates. Of the three alternative designs, the two-bolt offset design was deemed the best option.