Welcome Everyone My name is Christopher Paolini. I am a Licensed Professional Engineer. I am Member and a Principal Geotechnical Engineer of CME Engineering Group, PLLC. (CME). CME is a a Geotechnical and Civil Engineering firm, established in 2002. CME and its sister company, CME Associates, Inc. have five offices strategically located across New York State. Locations include Albany, Buffalo, Rochester, Syracuse and Elmira. Today, we are going to discuss Chapter 18 (with some references to Chapter 16) of the 2007 Version of the Building Code of New York State.
Building Code of New York State Chapter 18 - Soils and Foundations Chapter 18 provisions shall apply to building and foundation systems in those areas not subject to scour or water pressure by wind and wave action.
Section 1802 Foundation and Soils Investigation Foundation and soils investigations shall be conducted in conformance with said code and shall be made by a registered design professional. Basically, you want an experienced Licensed Geotechnical Engineer in responsible charge of this operation. *Note: The Code Enforcement Officer (CEO) may not require a foundation or soils investigation where soil data is available from adjacent areas that demonstrate that an investigation is not necessary.
What is required of the Foundation and Soils Investigation? Soil and Bedrock classification; i.e., What type of Soils and Bedrock are present at the site in question, and can they support the planned improvements? Determine if Expansive Soils are present at the site. Determine where the Groundwater Table is at the site. Question: How do we provide these requirements? Answer: Through an investigation program designed by your experienced Licensed Geotechnical Engineer.
Additional studies shall also be made as necessary, for items such as Slope Stability The effect on moisture variation on soil bearing capacity Compressibility Liquefaction And other items deemed applicable by the Licensed Geotechnical Engineer
How does one know what type of investigation is required? Answer: Rely on your Geotechnical Engineer to prepare the Investigation Program. Why? Engineering starts with the preparation of the subsurface investigation program. Let the investigation program be designed by your Geotechnical Consultant, who has the applicable expertise.
What type of investigation may be required? Answer: Test Borings Test Pits Laboratory testing In-situ testing Shear wave velocity testing Or a combination thereof Your Geotechnical Consultant shall prepare the exploration program such that there is a specific number of exploration locations outlined on a location plan, with estimated depths, along with the required laboratory testing.
The 2002, and subsequently 2007, version of the Building Code of New York State requires some specific items that were not required prior. During boring and sampling procedures, the Registered Design Professional shall have a fully qualified representative on the site to supervise the program. A determination of the seismic site class, pursuant of the Building Code of New York State, must be made (Chapter 16).
The product of the investigation program and analysis by your Geotechnical Engineering Consultant is a. Geotechnical Report
The written report of the investigation shall be submitted and shall include but not be limited to the following: A plot showing the location of test borings and/or excavations. A complete record of the soil samples. A record of the soil profile. Elevation of the water table, if encountered. Recommendations for foundation type and design criteria, including but not limited to: bearing capacity of natural or compacted soil; provisions to mitigate the effects of expansive soils; mitigation of the effects of liquefaction, differential settlement, and varying soil strength; and the effects of adjacent loads. Expected total and differential settlement. Pile and pier foundation information in accordance with section 1807.2.1, if requested. Special design and construction provisions for footings or foundations founded on expansive soils, as necessary. Compacted fill material properties and testing in accordance with Section 1803.4. Additionally, site specific concerns shall be addressed by the Geotechnical Engineer.
Presumptive Load-Bearing Values of Soils In lieu of a geotechnical evaluation, the load bearing values in Table 1804.2 may be used. However, these values are conservative and do not take settlement into account. Therefore, it is always good to have a geotechnical investigation conducted at your site. You do not want to encounter surprises which could have been identified during an investigation program.
Chapter 18 then goes through the design requirements that the Structural Engineer/Architect will utilize (based on the geotechnical investigation results) and then in their design, i.e Design of actual foundations Uplift Design of reinforcing, etc. We are not going to go through these items in detail, but know that these elements do exist in Chapter 18.
Let s switch gears to the next topic Seismic Site Class (In Chapter 16) Pursuant to Section 1615.1.1 of The 2007 Version of the Building Code of New York State. The site shall be classified as one of the site classes defined in Table 1615.1.1. These include the best site class, A ; and the worst site class, F, and are determined based on the average soil shear wave velocity in the top 100 feet. When shear wave velocity, V s, of the soil is not known, the Geotechnical Engineer shall determine the site class through a computational analysis of the average standard penetration resistance or un-drained shear strength of the soil in the top 100 feet. This methodology is conservative. To determine actual soil shear wave velocity, direct shear wave velocity testing is required.
How is direct shear wave velocity testing accomplished? Answer: by installing a grouted borehole to 100 feet depth, or at least 10 feet into sound bedrock, whichever is less, and directly measuring shear wave velocity through each distinct soil strata.
This service may be beneficial on projects where a conservative Site Class results in a conservative Seismic Design Category, or when the computational analysis from the boring data results in a poor Site Class. CME has recently provided direct shear wave velocity testing, where the Site Class improved, resulting in a more liberal Seismic Design Category, thus saving the client money.
A site is automatically given a Seismic Site Class F if the soil profile has one or more of the following characteristics Soils vulnerable to failure or collapse under seismic loading, i.e. liquefiable soils. Peats or highly organic clays greater than 10 feet in thickness. Very high plasticity clays (H>25 feet). Soft/medium stiff clays (H>120 feet).
Liquefaction What is it? What type of analysis should be conducted? Do we have liquefiable sites in this area?
Any Questions?
Quiz 1. Who Shall conduct the classification and investigation of subsurface soil and bedrock at the site? A Registered Design Professional (RDP) 2. Does the RDP need to determine if expansive soils are present? Yes 3. Who must be present during the geotechnical field investigation? A Representative of the RDP 4. Does Chapter 18 provide presumptive soil load bearing values? Yes 5. What Types of Investigation may the RDP conduct? Soil Borings, Test Pits, In-Situ Testing, etc.