Influenza and Other Respiratory Virus Weekly Activity Report, November 1, 2008, Week 44

Weekly report of the Iowa Influenza Surveillance Network produced by the Iowa Department of Public Health.

Friday Facts, December 18, 2009, Vol. 44

Bureau of Nutrition and Health Promotion part of the Iowa Department of Public Health produces of weekly newsletter about the Iowa WIC Program for the State of Iowa citizen.

Preventing Cracking at Diaphragm/Plate Girder Connections in Steel Bridges, HR-393, 1998

Some of the Iowa Department of Transportation (Iowa DOT) continuous, steel, welded plate girder bridges have developed web cracking in the negative moment regions at the diaphragm connection plates. The cracks are due to out-of-plane bending of the web near the top flange of the girder. The out-of-plane bending occurs in the "web-gap", which is the portion of the girder web between (1) the top of the fillet welds attaching the diaphragm connection plate to the web and (2) the fillet welds attaching the flange to the web. A literature search indicated that four retrofit techniques have been suggested by other researchers to prevent or control this type of cracking. To eliminate the problem in new bridges, AASHTO specifications require a positive attachment between the connection plate and the top (tension) flange. Applying this requirement to existing bridges is expensive and difficult. The Iowa DOT has relied primarily on the hole-drilling technique to prevent crack extension once cracking has occurred; however, the literature indicates that hole-drilling alone may not be entirely effective in preventing crack extension. The objective of this research was to investigate experimentally a method proposed by the Iowa DOT to prevent cracking at the diaphragm/plate girder connection in steel bridges with X-type or K-type diaphragms. The method consists of loosening the bolts at some connections between the diaphragm diagonals and the connection plates. The investigation included selecting and testing five bridges: three with X-type diaphragms and two with K-type diaphragms. During 1996 and 1997, these bridges were instrumented using strain gages and displacement transducers to obtain the response at various locations before and after implementing the method. Bridges were subjected to loaded test trucks traveling in different lanes with speeds varying from crawl speed to 65 mph (104 km/h) to determine the effectiveness of the proposed method. The results of the study show that the effect of out-of-plane loading was confined to widths of approximately 4 in. (100 mm) on either side of the connection plates. Further, they demonstrate that the stresses in gaps with drilled holes were higher than those in gaps without cracks, implying that the drilling hole technique is not sufficient to prevent crack extension. The behavior of the web gaps in X-type diaphragm bridges was greatly enhanced by the proposed method as the stress range and out-of-plane distortion were reduced by at least 42% at the exterior girders. For bridges with K-type diaphragms, a similar trend was obtained. However, the stress range increased in one of the web gaps after implementing the proposed method. Other design aspects (wind, stability of compression flange, and lateral distribution of loads) must be considered when deciding whether to adopt the proposed method. Considering the results of this investigation, the proposed method can be implemented for X-type diaphragm bridges. Further research is recommended for K-type diaphragm bridges.

Water Summary Update, October 10, 2014, No. 44

A snapshot of water resource trends prepared by the Iowa DNR in collaboration with the Iowa Department of Agriculture and Land Stewardship, the U.S. Geological Survey, and The Iowa Homeland Security and Emergency Management Department.

CIRAS News, Summer/Fall 2008, Vol. 44, no. 1

CIRAS is to enhance the performance of Iowa industry, and associated entities, through education and technology-based services. This newsletter holds information regarding these services.

CIRAS News, Winter/Spring 2009, Vol. 44, no. 2

CIRAS is to enhance the performance of Iowa industry, and associated entities, through education and technology-based services. This newsletter holds information regarding these services.

Iowa Influenza Surveillance Network: Weekly Activity Report Week 44, November 7, 2015

The Iowa Influenza Surveillance Network (IISN) was established in 2004, though surveillance has been conducted at the Iowa Department of Public Health. Schools and long-term care facilities report data weekly into a Web-based reporting system. Schools report the number of students absent due to illness and the total enrolled. Long-term care facilities report cases of influenza and vaccination status of each case. Both passively report outbreaks of illness, including influenza, to IDPH.