Integral Bridge Abutment-to-Approach Slab Connection Final Report, June 2008

The Iowa Department of Transportation has long recognized that approach slab pavements of integral abutment bridges are prone to settlement and cracking, which manifests as the “bump at the end of the bridge”. A commonly recommended solution is to integrally attach the approach slab to the bridge abutment. Two different approach slabs, one being precast concrete and the other being cast-inplace concrete, were integrally connected to side-by-side bridges and investigated. The primary objective of this investigation was to evaluate the approach slab performance and the impacts the approach slabs have on the bridge. To satisfy the research needs, the project scope involved a literature review, survey of Midwest Department of Transportation current practices, implementing a health monitoring system on the bridge and approach slab, interpreting the data obtained during the evaluation, and conducting periodic visual inspections. Based on the information obtained from the testing the following general conclusions were made: The integral connection between the approach slabs and the bridges appear to function well with no observed distress at this location and no relative longitudinal movement measured between the two components; Tying the approach slab to the bridge appears to impact the bridge; The two different approach slabs, the longer precast slab and the shorter cast-in-place slab, appear to impact the bridge differently; The measured strains in the approach slabs indicate a force exists at the expansion joint and should be taken into consideration when designing both the approach slab and the bridge; The observed responses generally followed an annual cyclic and/or short term cyclic pattern over time.

Heat Dissipation and Crack Control in Massive Concrete at the Burlington Bridge, MLR-94-1, 1995

The large concrete placements at the Burlington Bridge were expected to cause great temperature differentials within the individual placements. In an attempt to reduce cracking due to the large temperature differentials, the Iowa Department of Transportation required that contractors continuously monitor the temperatures and temperature differentials in the concrete placement to assure that the temperature differentials did not exceed 35 deg F. It was felt that if temperature differentials remained below 35 deg F, cracking would be minimized. The following is a summary of the background of the project, and what occurred during individual concrete placements. The following conclusions were drawn: 1) Side temperatures are cooler and more greatly affected by ambient air temperatures; 2) When the 35 deg F limit was exceeded, it was almost exclusively the center to side differential; 3) The top temperature increases substantially when a new pour is placed; 4) The use of ice and different cement types did seem to affect the overall temperature gain and the amount of time taken for any one placement to reach a peak, but did not necessarily prevent the differentials from exceeding the 35 deg F limit, nor prevent cracking in any placement; and 5) Larger placements have a greater tendency to exceed the differential limit.

Iowa Insurance Division Report to the Governor for Year End 2001

Iowa Insurance Division Report to the Governor for Year End 2001

Iowa Insurance Division Report to the Governor for Year End 2002

Iowa Insurance Division Report to the Governor for Year End 2003

Iowa Insurance Division Report to the Governor for Year End 2003

Iowa Insurance Division Report to the Governor for Year End 2003

Iowa Insurance Division Report to the Governor for Year End 2004

Iowa Insurance Division Report to the Governor for Year End 2004

Iowa Insurance Division Report to the Governor for Year End 2005

Iowa Insurance Division Report to the Governor for Year End 2005

Iowa Insurance Division Report to the Governor for Year End 2006

Iowa Insurance Division Report to the Governor for Year End 2006

Iowa Insurance Division Report to the Governor for Year End 2007

Iowa Insurance Division Report to the Governor for Year End 2007

Iowa Insurance Division Report to the Governor for Year End 2008

Iowa Insurance Division Report to the Governor for Year End 2008

End of Project Report to the Iowa Power Fund, October 31, 2008

The 2008 Biobased Industry Outlook Conference was held September 7-10 on the Iowa State University campus. Over 750 people attended the plenary sessions on the morning of September 8th; 580 people registered for the full conference. Sponsorships: $92,500 in sponsorships in addition to the IPF was secured for the conference (considered “match” to the IPF grant). Including the $11,250 IPF sponsorship ($12,500 minus overhead charges of $1,250), the total amount contributed for conference sponsorships was $103,750. A list of sponsors and the amount of sponsorship is listed in Appendix A. Sponsorship funds received from the Iowa Power Fund were used for supplies and materials. Please see Appendix B which documents the transfer of IPF grant funds internally at ISU and their use.