Engineering Information Program - December 1997 - Reinforced Concrete Columns - Page 1

CONCRETE REINFORCING STEEL INSTITUTE

INFORMATION FOR DESIGNERS OF ENGINEERED STRUCTURES

Comprehensive computer program is now available for designing reinforced concrete buildings.
    After extensive testing and some reworking, PCA-Build is now available as a major engineering tool for the analysis and design of reinforced concrete building structures. This comprehensive computer program is a logical next step after the architect/engineer evaluates different systems in the early conceptual design phase of a building project. CRSI’s conceptual design package of the Guide to Structural System Selection and the Workbook for Evaluating Concrete Building Designs gives the tools needed for preliminary design, then Portland Cement Association’s program PCA-Build can do the comprehensive design. Written for the Microsoft Windows environment, PCA-Build offers a state-of-the-art user interface that displays a three-dimensional representation of the structure, and allows the user to input the building plan and gravity loads on a floor-by-floor basis (with generation and copying capabilities). The columns, shear walls, beams, slabs, drop panels, and footings are designed in accordance with the ACI 318 Building Code, and a materials estimate module gives the required quantities of concrete and reinforcing steel. Also available is the PCA-Tools module that allows the user to quickly determine member capacities.
    Contact CRSI for more information on conceptual design materials, and contact Portland Cement Association at (847) 966-6200 for more information on PCA-Build.

Reinforcing steel again shows its strength in concrete pavements.
   A study by the University of Illinois and the Illinois Department of Transportation shows that continuously reinforced concrete pavements (CRCP) are far superior to jointed reinforced concrete pavements (JRCP). Conducted in cooperation with the FHWA, the study included about 2,000 miles of heavily traveled interstate concrete pavements constructed between 1957 and 1994. In an interesting comparison between CRCP and JRCP the report states "A loin. CRCP carries far more ESALs (2.1 times) than a lo-in. JRCP on average. The performance of JRCP and CRCP are clearly different, which is not in agreement with the AASHTO design guide. The guide is clearly over designing CRCP?" The report, Performance of Original and Resurfaced Pavements on the Illinois Freeway System, Research Report 540-l) is dated February 1997.

A small amount of additional reinforcing steel can make a huge difference.
    Architects/engineers need to be aware of the fact that just a small amount of additional reinforcing steel, for a small increase in project cost, can lead to a large increase in load-carrying capacity. This can be a big benefit to owners who may need to have load increases in their buildings because of changes in the structure’s use. A detailed example in CRSI’s Workbook for Evaluating Concrete Building Designs shows that with a 2% increase in reinforcing steel, a typical floor framing system can increase its load capacity by 67%. And in another example illustrating this same point, at a presentation on the Oklahoma City Federal Building bombing during the annual ASCE meeting in Minneapolis during the week of October 5, two panelists stated that a small amount of additional reinforcing steel in lateral bracing likely would have prevented much of the building’s progressive collapse. See Engineering News-Record, October 20, 1997, pg. 10 "Design Lessons Lie in Disasters."

ENGINEERING INFORMATION PROGRAM-DECEMBER 1997

"...a small amount of additional reinforcing steel, for a small increase in project cost, can lead to a large increase in load-carrying capacity. This can be a big benefit to owners... "

"...continuously reinforced concrete pavements (CRCP) are far superior to jointed reinforced concrete pavements (JRCP)."