‘Safe for our staff ... community:’ PLYMC gives update on floor safety at Poland branch
In July of this year, the Public Library of Youngstown and Mahoning County notified the community that there was floor heaving in parts of the Poland library and that an engineering firm would be hired to determine the cause.
Experts with engineering firm Geotechnical Consultants found portions of the concrete floor slab along the southeast side of the library are experiencing slab uplift, also known as heaving.
GCI drilled holes through the floor slab to determine the composition of the soils below the slab.
Holes drilled in areas of significant slab heaving encountered slag-based fill materials. A hole, drilled in a floor area not experiencing any slab uplift, found stable, natural soils below the floor.
“We are assured by our architects and GCI that the Poland library is safe for both our staff and the members of the community who use our services while the architectural review continues,” said PLYMC spokesperson Michael Stepp.
What is heaving caused by?
Here’s a statement from GCI issued to PLYMC:
“In the Mahoning Valley, slag (steel or ferrous slag) was historically produced during steel production. Over the years engineers and design professionals have learned that the chemical properties of slag give it the potential to expand, which can sometimes lead to detrimental impacts on structures. Slag expansion has been attributed to pavement failures, tilting of walls, and heaving of floor slabs, sidewalks, and building foundations. Unfortunately, risks associated with slag are often unpredictable, and the properties that make some slag expansive can last for decades following its production.
“Slag samples obtained during the drilling process at the Library were tested for expansive properties and found to be readily expansive. Based on this, it is GCI’s opinion that the floor slab heaving occurring at the Library is the result of expansive slag below the floor. Extensive research has been done to develop techniques to eliminate the expansive properties of slag encountered on building projects; however, these studies have not been able to produce reliable, long-term acceptable results to prevent its expansion. The only proven method to remediate slag expansiveness is to remove it from problem construction areas.”
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