Issue No. 45 Addresses Bridge Deck Cracking

The current issue of HPC Bridge Views is devoted to bridge deck cracking—one of the main causes of bridge deterioration. The first article provides guidance on selection of materials, design details, and construction practices to minimize deck cracking.

The next article highlights South Carolina’s research and development efforts to control deck cracking since the implementation of HPC in 1993. The state has been able to construct crack-free HPC bridge decks with improved strategies such as emphasis of on-site quality control/quality assurance, careful placement sequence, accounting for effects of vibration associated with more flexible bridge superstructures, reduced cement content, and 7 days of wet cure.

The third article reports how Pennsylvania used the lessons learned from the construction of the westbound lanes of the Kernville Viaduct in Johnstown, combined with additional research, to construct the eastbound lanes with a dramatic reduction in the frequency and width of deck cracks. A Q&A on how to measure the cracking tendency of concrete rounds out the newsletter.

Download the issue.
Past issues of HPC Bridge Views.

Rapid Bridge Construction—How to Get There

The benefits of accelerated bridge construction are well known. They include minimized traffic disruption and congestion, improved work zone safety, and minimized environmental impact. Additionally, prefabrication can improve constructability, increase quality, and lower life-cycle costs. A full-day workshop was conducted during the 2006 Concrete Bridge Conference to develop guidance on what is needed to further implement rapid bridge construction nationwide. Four topic areas were addressed:

• Decision-making process
• Contracting strategies
• Costs
• Specifications

Click here for a PDF of the summary report.
Click here for the key presentations.

2006 Concrete Bridge Awards Presented at ACI Convention

The ten winners of PCA’s Tenth Biennial Bridge Awards Competition were selected based on creativity, functionality, and economy by a jury of three prominent bridge professionals: Daniel Dorgan, State Bridge Engineer, Minnesota Department of Transportation; Mary Lou Ralls, Ralls Newman, LLC, Austin, Texas; and Louis Triandafilou, High Performance Structural Materials Specialist, FHWA Resource Center, Baltimore, Md. The winners of the Bridge Awards were recognized at the American Concrete Institute Awards Program held in November 2006 in Denver, Colo.

Click here for a video of the presentation ceremony.
Click here for more on the award-winning bridges.

Does HPC need to be air entrained for frost resistance?

The primary purpose of air entrainment in concrete is to improve concrete’s resistance to cycles of freezing and thawing when exposed to water or deicing chemicals. Consequently, the need for air entrainment depends on whether the structure, made either of conventional concrete or HPC, is subjected to freeze-thaw cycles. More.

Read more Q&As on HPC.

Optimized Sections for High-Strength Concrete Bridge Girders–Effect of Deck Concrete Strength

A recent report by FHWA contains an evaluation of the effect of high-performance concrete on the cost and structural performance of bridges constructed with high-performance concrete bridge decks and high-strength concrete girders. More.

New LRFD Seminar Scheduled

Starting October 1, 2007, all bridges receiving federal funding will have to be designed by the LRFD specifications. PCA will conduct a one-day seminar on the design of concrete bridges by the LRFD specifications on Friday, May 25, 2007 at PCA headquarters in Skokie, Ill. The seminar emphasizes the new state-of-the-art design methods in the LRFD specifications that are significantly different than the current ones in the Standard specifications. Seminar attendees will be awarded 6.5 PDHs. More.

The National Ready Mixed Concrete Association’s 2007 Concrete Technology Forum: Focus on High Performance Concrete will be held May 22-24, 2007 in Dallas. The forum will bring researchers and practitioners together to discuss the latest advances, technical knowledge, continuing research, tools and solutions for high performance concrete. PCA is an organizational partner of the 2007 CTF.

The First International Conference on Recent Advances in Concrete Technology (rac07) will be held September 19-21, 2007, at the Sheraton in Crystal City, Va. The conference is being organized by the University of Maryland, Howard University, and CI-Premier PTE Ltd of Singapore, and co-sponsored by PCA.