soils investigation and seismic testing in Memphis TN

[structengineer]

Has anyone done work in the Memphis, TN area? We are currently designing a two story structure in the area and have had some issues with the owner and the soils investigation. My initial investigation into the lateral design shows that I am designing this structurure for seismic design category D which kicks you into 1802.2.7 of the IBC 2003 code which requires the assesment of potential consequences of any liquefaction and soil strength loss, etc.

The owner recieved a soils engineer estimate and told them they were way to high and decided to shop the bid to some local firms. At this point, another soils firm has been hired and has stated that the additional seismic testing, etc is not required. Based on my interpertation of the code, the soils firm is violating what the code requires and where does this leave me as the EOR? Should my firm back out of the project or write a letter sharing our concerns making it known that the soils engineer is going against the code? We are a subconsultant to another firm so we have no say in the scope of the soils engineer.

As far as working in the Memphis TN area, has anyone else ran into the contridiction between the code and the soils engineers?

 

[eric1037]

If you look at IBC 1615.1.1 Site Class definitions, it says "Where specific data are not available to a depth of 100 fee, appropriate soil properties are permitted to be estimated by the registered design professional preparing the soils report based on known geologic conditions."

In a nutshell, this means that if the local geotechnical engineer has sufficient knowledge of local soil conditions, it is not necessary to perform a soil boring to a depth of 100 feet. They may have information from nearby projects that enables them to determine the Seismic Site class.

I hope I answered your question.

 

[Loui1]

Are you sure the geotech firm knows that this is a design category D building? Typically they're not going to assume that unless they're told or they know the soil is really bad.

If they know the soil class will result in a design category D, then they're required to give a liquefaction assessment.