Medical Research Expands with Concrete

The University of Nebraska Medical Center (UNMC) desired to expand their medical research facilities and consolidate their high-end researchers into one building. Anchoring the new research mall, the Durham Research Center in Omaha, Nebraska, fulfilled the wishes of UNMC. The Durham Research Center enables UNMC to enhance its numerous areas of research, including cancer, cardiovascular diseases, neurosciences, transplantation biology, genetics and eye research.

“Concrete is the superior framing material for buildings of this use,” said Michael Kuhse, structural engineer of record. Cast-in-place concrete has natural characteristics and stiffness advantages to reduce vibration, a concern for research facilities. Preliminarily, the concrete design was more expensive than steel. After the steel design sizes were increased to account for vibration control, concrete became more competitive in pricing.

Concrete also has the strength to support the heavy laboratory loads with an economical floor depth, while accommodating the complex floor layout to allow for a more “flowable” design. The intricate stairwell in the northwest corner, dictated by the architect, lent itself to using concrete. This prominent architectural feature called for cast-in-place exposed colored concrete to make its statement. More.

For more examples of concrete in healthcare, click here.

Some of the greatest concrete innovations today are focused on creating new mixes. Supplementary cementitious materials (SCMs) are part of the picture, redirecting industrial byproducts from landfills and supplying concrete with greater durability, strength, and finishability. Name a design challenge, and there’s a concrete mix with SCMs that can solve it.

There are four main kinds of SCMs: fly ash, ground granulated blast furnace slag (also known as slag cement), silica fume, and natural pozzolans. Of the four types, fly ash and slag cement are the most widely used: in 2002, the cement industry used 11.4 million metric tons of fly ash; shipments of slag cement in 2003 topped three million metric tons. More.

Favorable Fire Tests Spark Code Revisions for High-Strength Concrete

Data from PCA and CAC sponsored research completed at the National Research Center of Canada on the fire endurance of high-strength concrete columns has resulted in proposed revisions to ACI Standard 216.1 "Standard Method for Determining Fire Resistance of Concrete and Masonry Construction Assemblies." Proposed changes in the standard, currently being balloted, address concrete columns when the specified compressive strength is in excess of 12,000 psi. Variables in the ten 16-inch-square columns tested included compressive strength, loading, tie geometry, type of aggregate, and the addition of silica fume. More.

For more information or a copy of the complete report, Fire Endurance Experiments on High Strength Columns, click here.

Q: Can I use fibers instead of wire mesh for a concrete slab?

A: Fibers are primarily used to control shrinkage cracking and seem to do a very good job in that capacity. They do not, however, provide any structural strength should cracking start due to load and design characteristics.

Steel mesh does provide shear strength, which will assist in reducing the width of cracks, and control the elevation of the slab from one side of the crack to the other. This reduces the possibility of the development of a tripping ledge.

For a high quality slab with a minimum investment, PCA suggests the use of fiber and a mat of steel, perhaps #3 bar on 18” centers or #4 bar on 24” centers. As a percentage of the overall job, the costs of this method are small, and the long-term service of the slab is assured.

For more FAQs, click here.

Documentation Adds On-Line Support

pcaStructurePoint website is offering more and more on-line support to help you find out what PCA software can do and how to install and run it effectively. Whether you have our software or are looking for new concrete design software, this information is readily available for you.

Please visit the documentation page which now includes Brochures, Quick Start Guides, and Manuals for each of the pcaStructurePoint software products.