Aquatic Technology Pool & Spa, "Creating Water as Art."™

Aquatic Technology Pool & Spa, "Creating Water as Art."™
Pools as an art form - the way it should be!

Monday, April 27, 2009

The Structural Engineer rules!

Aquatic Technology Pool & Spa
Paolo Benedetti

Since a high-end luxury custom infinity edge swimming pool (structure) in built into the ground, it is logical and required by the building codes to obtain a geotechnical report (soils report). A soils report is always done when structures are built upon the soil (e.g.: a building foundation). So why would you be so foolish as to build a structure entirely within the soil without a soils report?

HELLOOOOO..... The pool structure is even more dependent on the soil conditions, than one built on the soil!

The structural engineer will utilize the characteristics of the soils, as defined by the soils engineer, to design the structure. I proffer that the soils engineers actually overstep their bounds, when they venture into the realm of structural engineering, by even daring to specify minimum design criteria. Instead, the soils engineer should focus on the site's soil conditions & characteristics, and how they may influence the proposed structure.

The soils engineer should define the characteristics of the soils [e.g.: load bearing capacity, surcharges, expansive indexes, liquifaction potential, vertical sheer planes, earth quake fissures, poor coefficient of friction, insufficient load bearing capabilities, consolidation issues, weak sheer strengths, slope instability, expansiveness issues, saturation indexes, lithostatic pressures, seismic stability, tensiometer pressures, or potential for ground water subsidence (sink hole)]. If special construction methods must be employed to overcome any of these issues, then recommendations should be made. Care should be exercised to actually avoid specifying a size or extent of the remediation required.

By avoiding any actual specifications, the claim that the structural engineer "over designed" the engineering, will be avoided. Since the soils engineer is never (almost never) a structural engineer and rarely has performed any load or surcharge calculations, they are "speaking out of school" when they venture to define any specifications.

For instance, if caissons will be required in order to support a structure, the soils engineer can define the foundation design as "in order to overcome the expansive soil conditions & to obtain the required set-back clearances, drilled caissons or deepened foundation design(s) may be employed." This type of verbiage avoids the potential "over-designed" conflict between a neophyte soils engineer, ignorant general contractor, or arrogant architect (I'm not saying that all are... I'm a GC too!). The soils engineer has no business specifying "a minimum of 10' deep X 12" diameter drilled caissons with (4) #4 rebars 10' O.C.," when they have not performed any calculations and are not qualified to do so!

It is the structural engineer who is responsible for specifying the type of structure, defining the foundation type & design, and quantifying the elements of the structural design... all based upon the soil conditions that are outlined in the geo-technical report.

When the structural engineer later specifies "40' deep X 24" drilled caissons with (8) #8 gr-60 bars, #4 gr-40 spiral ties 12" O.C., 12' O.C. ....." there is always a collective gasp from the peanut gallery. However, those same individuals who claim "this is way over-designed" have not performed any load calculations, or calculated surcharges from adjacent slopes, soil conditions, or seismic events. They are merely "shooting from the hip" and "shooting off their mouths."

...maybe because they are only used to being around sloppy & shoddy work, built with less??

Are they really looking out for the owner's best interest??

Paolo Benedetti - Aquatic Artist
"Creating water as art."™
Aquatic Technology Pool & Spa