1920 concrete beam restoration help!!

[ashhafPE]

This is the situation,
Pier & beam residence built in 1920. Concrete perimeter beam with drilled shaft piers (installed in 1995). The structure is a 1-story brick veneer with comp. shingles. We removed all interior beams, joists and piers. Now that it is all nice and open, the concrete perimeter beam is cracked, deflected and in some areas you can actually break some of the concrete by hand. Is there anything out there that will fix this beam or do we need to replace it? Keep in mind that the brick is supported by the concrete beam. Some of the brick veneer is bowed and cracked. I have no idea why my client bought this house. Any hints, sites for restoration or help will be appreciated.

 

[JAE]

You might offer some more detail. For instance, describing how interior beams, joists and piers are removed while the perimeter is not - I assume this house is in Texas (correct?). If so, the house might have experienced some major soil heaving due to expansive clays if the house is in that kind of region.

The cracks and distress in the perimeter beams may be due to cyclic heaving and shrinking over time, causing flexural and/or shear cracks in the beam. The fact that you describe the piers as being more recent tells me that the previous owner had the heaving problems, and hired someone to attempt to underpin the foundation - possibly leveling it as well.

There are many contractors in TX that do this sort of thing and it never made sense to me in that the short piers were still usually founded on expansive clays as well and the "fix" would only last a short while, or simply minimize the movement but not get rid of it.

As far as fixing the beams - that depends on the severity of the damage - and that would be up to you as the structural engineer. Some minor cracks can be infilled with epoxy. Added steel strapping or wrapping could also be a possibility.

If the concrete itself is bad (you said it comes off by hand - could be due to flex/shear distress or material deterioration) then replacement may be your only option. The brick walls and roof could be temporarily shored in short segments to allow this.

 

[ashhafPE]

Jae,
Thanks for the reply. The interior wood beams and joists are rotted and had to be replaced. The interior piers are shallow piers (blocks). The exterior is a concrete perimeter beam that was supported with footings. In 1995 new drilled shaft piers approx. 10' deep were installed inbetween the existing footings. We removed all the beams and joists from the interior. We temporarly supported the interior piers. We installed new drilled shaft piers in the interior and added new beams and floor joists. I still have a problem with the concrete beam. You are correct, we are in south texas with very expansive clay soils. The natural ground in the interior of the residence is approximately 12" lower than the exterior natural ground. (Drainage issue). I am considering either epoxy or replacing the concrete beam.