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Soils Reports

K

Keystone

SAWHORSE
Joined
Feb 23, 2010
Messages
1,274
Location
Lehigh Valley, Pennsylvania
For those requiring and receiving soils reports, what’s your procedure?

At what point are they required in the bldg process, will you continue to schedule and perform inspections without a soils report to keep bldg moving forward. Who reviews the soils report, the inspector in the field or the plan reviewer, if it’s a plan reviewer are they full time staff plan reviewer and ipthe report goes in the plan review pile and reviewed in the order it’s received?
 
The appropriate term and the term used in the IBC is the geotechnical report. Soils report is an old term

Geotechnical reports identify geotechnical issues that need to be considered, such as slope stability and expansive soils, and establish the technical criteria used by an engineer to design the foundation. The geotechnical report also defines the soil classification which may be needed by other code provisions.

Where does the IRC refer to the soils/geotechnical report? The IBC addresses the geotechnical report (Chapter 18).

On what basis do you require a geotechnical report? In California there are several state statutes addressing the need for soils/geotechnical reports. What does your state say. On what basis would the building department "review" a geotechnical report other than verifying that the report addressed an item that is not otherwise addressed.

I doubt that the building department staff would have the technical knowledge necessary to "review" the geotechnical repot as to its technical validity.

The inspectors use the geotechnical report, but they are typically not qualified to review the content of the report.

If a geotechnical report is required, it should be submitted with the application for the permit since you cannot review the foundation design without it.
 
Keystone said:
For those requiring and receiving soils reports, what’s your procedure?

At what point are they required in the bldg process, will you continue to schedule and perform inspections without a soils report to keep bldg moving forward. Who reviews the soils report, the inspector in the field or the plan reviewer, if it’s a plan reviewer are they full time staff plan reviewer and ipthe report goes in the plan review pile and reviewed in the order it’s received?
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The geotechnical report for the site and location of the foundation is received during the plan review stage. An engineer cannot properly design a foundation without this report. Additional reports should be submitted as unexpected conditions are uncovered during the construction process and RFIs are sent to the engineer in charge. The geotechnical reports are primarily submitted to the building department not just because they are required but for record-keeping and to ensure that the engineer is basing their design on factual information and they are not just rubber stamping it as some engineers do for quick cash. With the geotechnical report as part of the permanent records, the engineer would have a difficult time justifying their design if it conflicts with the report.
 
We require it for the plan review before issuing the permit. Sometimes the BCO (also my boss) tells me to issue the permit without it and review it later.
 
Required as a submittal document. Review consists of verifying the structural engineer has provided a design based on the report.
 
In our department a geotech report is supposed to be submitted at the site plan stage for larger projects. For smaller residential reviews I check the USDA soil survey https://websoilsurvey.sc.egov.usda....l_Survey_application_psl51svmfltygcxo12zs4wgv for the address. The USDA soils map identifies problem soils areas on the property. Depending on the type of soil found a geotech report may or may not be required. The geotech report will have recommendations the contractor must follow and may include inspections by a geotech engineer for footings and foundations. It will also dictate footing design bearing pressure and drainage requirements. The USDA Soil survey requires a bit of a learning curve to navigate but it has a wealth of information about the composition and drainage characteristics of a given property.
 
I am still not hearing what is the legal basis for requiring a geotechnical report nor am I hearing what criteria will be used when "reviewing" geotechnical reports.

I have this quaint belief that building departments can only require that which they have the legal authority to require.
 
My answer is different than most: it depends...

This is in the residential codes section, so my assumption is we are talking about low density housing as a worst case.

Soils here are usually fine to build on, so normally there is no geotechnical review of the soils. When questionable soils are encountered, a geotechnical engineer is contracted. Normally this occurs before we even see the site. I just show up and see an improved pad and they tell me the report is being emailed to the office. We don't have many situations where we have advance notice of poor soils, so we don't receive the notice at plan review.

To directly answer your question: we will do a pre-backfill inspection, but will not perform a framing inspection until the report is received.

If we are talking about larger scale construction, our code would require a sub-surface investigation for all buildings. This drives the design process and some soil improvements may be necessary. Normally we would not receive a specific report in this case, but a general letter from the geotechnical engineer indicating they completed their duties.
 
Mark K said:
I am still not hearing what is the legal basis for requiring a geotechnical report nor am I hearing what criteria will be used when "reviewing" geotechnical reports.

I have this quaint belief that building departments can only require that which they have the legal authority to require.
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Justification for Canada would be 4.2.2.1. we confirm all requirements contained in 4.2.2.3. and 4.2.2.4. have been met (as applicable).

For Part 9 buildings, 9.4.4.1. would functionally refer code users to to the section above.

The building code in Canada specifies when RDPs must be engaged.
 
Mark K said:
I am still not hearing what is the legal basis for requiring a geotechnical report nor am I hearing what criteria will be used when "reviewing" geotechnical reports.

I have this quaint belief that building departments can only require that which they have the legal authority to require.
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I can only speak to California.
I provided the link in post #8 for City of Los Angeles, and I believe that link shows where they have adopted into their Municipal code.
In California, for other than one- and two-family dwellings:
1663354882038.png

For one-and two family dwellings, in places other than Los Angeles, the language of the residential code allows for subjective determination on the part of the building official:

1663355343311.png


After, that California Residential code R401 gets much more specific about geotechnical reports:

R401.4 Soil Tests

Where quantifiable data created by accepted soil science methodologies indicate expansive soils, compressible soils, shifting soils or other questionable soil characteristics are likely to be present, the building official shall determine whether to require a soil test to determine the soil's characteristics at a particular location. This test shall be done by an approved agency using an approved method.

R401.4.1 Geotechnical Evaluation

In lieu of a complete geotechnical evaluation, the load-bearing values in Table R401.4.1 shall be assumed.

TABLE R401.4.1

PRESUMPTIVE LOAD-BEARING VALUES OF FOUNDATION MATERIALSa
CLASS OF MATERIALLOAD-BEARING PRESSURE
(pounds per square foot)
Crystalline bedrock12,000
Sedimentary and foliated rock4,000
Sandy gravel and/or gravel (GW and GP)3,000
Sand, silty sand, clayey sand, silty gravel and clayey gravel (SW, SP, SM, SC, GM and GC)2,000
Clay, sandy, silty clay, clayey silt, silt and sandy siltclay (CL, ML, MH and CH)1,500b

For SI: 1 pound per square foot = 0.0479 kPa.
  1. Where soil tests are required by Section R401.4, the allowable bearing capacities of the soil shall be part of the recommendations.
  2. Where the building official determines that in-place soils with an allowable bearing capacity of less than 1,500 psf are likely to be present at the site, the allowable bearing capacity shall be determined by a soils investigation.



R401.4.1.1 General and Where Required for Applications Listed in Section 1.8.2.1.1 Regulated by the Department of Housing and Community Development

Foundations and soils investigations shall be conducted in conformance with Health and Safety Code Sections 17953 through 17957 as summarized below.

R401.4.1.1.1 Preliminary Soil Report


Each city, county, or city and county shall enact an ordinance which requires a preliminary soil report, prepared by a civil engineer who is registered by the state. The report shall be based upon adequate test borings or excavations, of every subdivision, where a tentative and final map is required pursuant to Section 66426 of the Government Code.

The preliminary soil report may be waived if the building department of the city, county or city and county, or other enforcement agency charged with the administration and enforcement of the provisions of Section R401.4.1.1, shall determine that, due to the knowledge such department has as to the soil qualities of the soil of the subdivision or lot, no preliminary analysis is necessary.


R401.4.1.1.2 Soil Investigation by Lot, Necessity, Preparation and Recommendations


If the preliminary soil report indicates the presence of critically expansive soils or other soil problems which, if not corrected, would lead to structural defects, such ordinance shall require a soil investigation of each lot in the subdivision.

The soil investigation shall be prepared by a civil engineer who is registered in this state. It shall recommend corrective action which is likely to prevent structural damage to each dwelling proposed to be constructed on the expansive soil.


R401.4.1.1.3 Approval, Building Permit Conditions, Appeal

The building department of each city, county or city and county, or other enforcement agency charged with the administration and enforcement of the provisions of this code, shall approve the soil investigation if it determines that the recommended action is likely to prevent structural damage to each dwelling to be constructed. As a condition to the building permit, the ordinance shall require that the approved recommended action be incorporated in the construction of each dwelling. Appeal from such determination shall be to the local appeals board.

R401.4.1.1.4 Liability

A city, county, or city and county or other enforcement agency charged with the administration and enforcement of the provisions of Section R401.4.1.1, is not liable for any injury which arises out of any act or omission of the city, county or city and county, or other enforcement agency, or a public employee or any other person under Section R401.4.1.1.1, R401.4.1.1.2 or R401.4.1.1.3.

R401.4.1.1.5 Alternate Procedures

The governing body of any city, county, or city and county may enact an ordinance prescribing an alternate procedure which is equal to or more restrictive than the procedures specified in Sections R401.4.1.1.1, R401.4.1.1.2 and R401.1.1.3.

R401.4.2 Compressible or Shifting Soil

Instead of a complete geotechnical evaluation, where top or subsoils are compressible or shifting, they shall be removed to a depth and width sufficient to ensure stable moisture content in each active zone and shall not be used as fill or stabilized within each active zone by chemical, dewatering or presaturation.
 

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ICE said:
Your delusions are not shared by the population at large.
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I take this to mean that the ICC is delusional.

The ICC publication "Legal Aspects of Code Administration" recognizes the need of the building department to operate in accordance with the laws. This book contains the statement "if the applicant meets all the requirements of the building code and other pertinent laws and ordinances, then the building official has no justification to refuse to issue the permit."

Thus if there is no applicable law the building official cannot require something.
 
Section 107 is in the California Building Code which is based on the IBC but the question had to do with the residential building code. While local jurisdictions may "adopt" the building code it is mostly symbolic in California since the CBC applies whether or not the jurisdiction takes any action.

It should be recognized that the California provisions are unique to California and are based on state statutes.

The question remains on what basis can the building department "review" the geotechnical report/investigation. Does the building department have on staff or on contract a geotechnical engineer? The point is that once a geotechnical report has been prepared the building department has little option but to accept the report as valid.
 
Mark K said:
The point is that once a geotechnical report has been prepared the building department has little option but to accept the report as valid.
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Are you a geotechnical engineer? Do you have a geotechnical engineer explain the report to you before you do your structural design? Do you do your structural design and have the geotechnical engineer review your drawings? How qualified are you to design based on a geotechnical report if you are not a geotechnical engineer? Does your state have different licenses for P.E.'s? How do you qualify as a geotechnical engineer or a structural engineer? Is this by claim based on your experience? Do engineers get board certified like physician's do?
 
R-401.1 exists in the International Residential Code, not just California's version of it:
1663361983842.png

In the same way that I don't believe there is any requirement for a building official to be a licensed architect or engineer in order to review plans prepared by a DPOR, I don't think the building official is required by law to have special training to review geotechnical reports.
The extent of the building department review is up to them. If may be a perfunctory check-off on a list; it may be a quick review of allowable bearing values; or, as some jurisdictions around here do, the BO may require the foundation plan to be the submittal review stamp and signature of the engineer who prepared the geotechnical report.
 
jar546 said:
Are you a geotechnical engineer? Do you have a geotechnical engineer explain the report to you before you do your structural design? Do you do your structural design and have the geotechnical engineer review your drawings? How qualified are you to design based on a geotechnical report if you are not a geotechnical engineer? Does your state have different licenses for P.E.'s? How do you qualify as a geotechnical engineer or a structural engineer? Is this by claim based on your experience? Do engineers get board certified like physician's do?
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Not answering for Mark but yes, geotechs review the structural design. The geotech report provides in fairly plain language what the allowable bearing pressure is for structural to use in their footing design and equivalent fluid pressure for foundation wall design. Most states would have all structural and geotechnical under the civil license. It is up to the engineer to determine if they are competent in particular areas. The west coast is a little different with structural and seismic though. Structural requires an SE, instead of a PE in CA, OR, WA.
 
Mark K said:
Thus if there is no applicable law the building official cannot require something.
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There's a few thousand building officials in California. When you get to the last one you'll have to start over.
 
jar546 said:
Are you a geotechnical engineer? Do you have a geotechnical engineer explain the report to you before you do your structural design? Do you do your structural design and have the geotechnical engineer review your drawings? How qualified are you to design based on a geotechnical report if you are not a geotechnical engineer? Does your state have different licenses for P.E.'s? How do you qualify as a geotechnical engineer or a structural engineer? Is this by claim based on your experience? Do engineers get board certified like physician's do?
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I am a registered Structural Engineer. I do not review the technical adequacy of the geotechnical report. If I have a question regarding the geotechnical report, I will contact the geotechnical engineer. It is common practice to recommend the geotechnical engineer review my design to verify that I have interpreted his recommendations properly.

Geotechnical engineers prepare their reports with the assumption that the recommendations will be used by Civil Engineers who are not experts in geotechnical engineering.

Engineers in California are licensed not board certified. In California a Civil Engineer is licensed to practice geotechnical engineering for most buildings that are not hospitals or public schools. In California all Structural Engineers are also licensed Civil Engineers. In California a licensed Geotechnical Engineer is required on public school and hospital projects.

I have had a basic course in geotechnical engineering but appreciate my limitations and except for very minor project will use a geotechnical report prepared by a Geotechnical Engineer. I have over 40 years experience with both small and large projects. I believe my practices are similar to most Structural Engineers in California

But the question is not what practices the engineer designing a building should follow but rather what can the building department require. I have also asked what ability does the typical building department have to review the technical adequacy of a geotechnical report. What criteria would the building department use if they attempted to review the technical adequacy of a geotechnical report?
 
Mark K said:
It is common practice to recommend the geotechnical engineer review my design to verify that I have interpreted his recommendations properly.
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If the geotechnical engineer can review the structural engineer’s design…why would anyone need the structural engineer? If you’re into value engineering…build in some value.
 
Mark K said:
What criteria would the building department use if they attempted to review the technical adequacy of a geotechnical report?
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Most soils reports are not making mountains out of mole hills. The only soils reports that had me wondering were rife with poor grammar.
 
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