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Forty Year Inspection Requirements – 7
So here’s a continuation of our topic: Forty Year Inspection Requirements:
Steel Framing System
Corrosion, obviously enough, will be the determining factor in the deterioration of structural steel. Most likely suspect areas will be fasteners, welds, and the interface area where bearings are embedded in masonry. Column bases may often be suspect in areas where flooding has been experienced, especially if salt water has been involved.
Thin cracks usually indicate only minor corrosion, requiring minor patching. Extensive spalling may indicate a much more serious condition requiring further investigation.
Of most probable importance will be the vertical and horizontal cracks where masonry units abut tie columns, or other frame elements such as floor slabs. Of interest here is the observation that although the raw materials of which these masonry materials are made may have much the same mechanical properties as the reinforced concrete framing, their actual behavior in the structure, however, is likely to differ with respect to volume change resulting from moisture content, and variations in ambient thermal conditions.
Moisture vapor penetration, sometimes abetted by salt laden aggregate and corroding rebars, will usually be the most common cause of deterioration. Tie columns are rarely structurally sensitive, and a fair amount of deterioration may be tolerated before structural impairment becomes important. Usually, if rebar loss is such that the remaining steel area is still about 0.0075 of the concrete area, structural repair will not be necessary. Cosmetic type repair involving cleaning, and patching to effectively seal the member, may often suffice. A similar approach may not be unreasonable for tie beams, provided they are not also serving as lintels. In that event, a rudimentary analysis of load capability using the remaining actual rebar area, may be required.
Alex Zylberglait provides commercial real estate investment advisory as well as research, estate planning, asset allocation, valuation, financing, special assets services, transaction advisory and commercial property acquisition and disposition services.
40-Year Inspection Requirements, Commercial Office Buildings, Commercial Real Estate, Miami, Property Management, South Florida
40 Year Inspection, Commercial Buildings, Commercial Office Building, Commercial Real Estate Investment Advisory, Measuring Office Space, Miami, Miami-Dade, South Florida
This is just great. A commercial real estate advisor blog giving tips on engineering matters.
Well, 40-year inspection is part of property management. A well-managed property reaps more value – and value is what investors are looking for.