Lecture 2 PDF

Lecture 2 Jawad Butt M.Eng. Civil (UOT), PMP [email protected] 1  Lecture Objectives To familiarize you with the project Geotechnical Investigation Report and help you understand its application during the construction process. To familiar...

Lecture 2 Jawad Butt M.Eng. Civil (UOT), PMP [email protected] 1  Lecture Objectives To familiarize you with the project Geotechnical Investigation Report and help you understand its application during the construction process. To familiarize you with Environmental Site Assessments and Chemical Analysis Report and help you understand their application during the construction process. 2 Project Geotechnical Investigation Report 3 Geotechnical Investigation Report Geotechnical (soil) investigation is one of the most critical site investigations and is a mandatory requirement, for all types of projects, prior to the design stage of the project. The information obtained from the geotechnical investigation is used in project design by the consultants. The geotechnical (soil) investigation is carried out by a licensed Geotechnical Engineer. 4  Requirement Of Geotechnical Investigation Report A Geotechnical investigation provides information about: – the various types of soil present on the site, the strength (bearing capacity) to carry the load of the structure, moisture content of soil as well as other soil characteristics. – design recommendation for design and construction of elements that are to be supported by the soil such as footings, slab on grade, pavement, pipe beddings. etc. 5  Various Methods To Carry Out Geotechnical Investigation Geotechnical investigation may be carried out in three ways: 1) Test Pits 2) Borehole Drilling 3) Cone Penetration Testing (CPT) 6  1) Test Pits Involves excavating test pits typically excavated with hydraulic excavators. ‘Grab’ samples can be obtained from the side walls of the test pit (if shallow enough to allow safe entry) or from the excavated soil. The soil samples are taken to the laboratory for testing and ascertaining the properties of soil. Traditionally used where soil investigation is required for shallow depths only. 7  2) Borehole Drilling Requires drilling a hole into the ground Drilling Rig using a drilling rig and soil samples are obtained through the borehole at discrete depths. The depth of investigation typically extends to the bed rock. These soil samples are then taken to the laboratory for testing. 8  2) Borehole Drilling Borehole logs are prepared to display the depth- wise results of borehole drilling and are a detailed record of: – the type and depth of various soil types encountered during drilling. – Standard Penetration Resistance ‘N’ values of various soil types encountered (used to measure bearing capacity of soil) – Moisture content of various soil types encountered during drilling.. – Etc. 9 Page 15 of Geotechnical Report 10  Standard Penetration Resistance (N Value) The Standard Penetration Resistance Test is performed during the bore hole drilling and is used to estimate the strength (bearing capacity) of soils. The test uses a split-barrel sampler which is driven from the bottom of a pre-bored hole (of diameter normally between 60 and 200 mm) into the soil by means of a 63.5 kg hammer, dropped freely from a height of 0.76 m (30 inches). 11  Standard Penetration Resistance (N Value) The sampler is first driven to a depth of 6” below the bottom of the pre-bored hole to seat it firmly on the soil; “N” is the number of blows required to drive the sampler another 12” into the soil. N value is known as the Penetration Resistance of the soil and is incorporated in a formula to ascertain the bearing capacity of soil. The higher the value of “N”, the greater its bearing capacity. 12 13  2) Borehole Drilling Number of Boreholes & Borehole Spacing – The spacing depends on the scope of the project and should be such that all areas of main construction activity are adequately covered also keeping in account expected variation in the conditions. – It should be remembered that each additional borehole/test pit will add to the cost so a balance has to be struck. – Municipalities have guidelines with regards to minimum number of bore holes/test pits. 14 Importance Of Borehole Locations (Page 12 of The Geotechnical Report) 15  3) Cone Penetration Testing (CPT) Involves pushing a cone-shaped penetrometer into the ground at a constant rate and measuring the resistance to penetration. Provides continuous data throughout the depth of the test, allowing for detailed profiling of soil properties. It is a faster and modern method of investigation as compared to the conventional borehole drilling or test pit excavation. 16 Inside View Of Cone Penetration Testing Machine 17  Comparison Of Bore Hole Drilling With CPT Borehole Drilling Cone Penetration Testing (CPT) Provides information at specific depths, Offers a continuous profile of soil and the extent of investigation depends properties, making it suitable for on the number and spacing of boreholes. assessing soil behavior over the entire depth of the test. Can be more expensive due to the need for drilling rigs, drilling fluids, and additional personnel. Generally more cost-effective than borehole drilling because it requires fewer personnel and equipment. Relatively time consuming to collect samples and then take to laboratory for Faster because laboratory sampling testing. requirements are greatly reduced for added cost savings. Disturbance of samples is unavoidable and can compromise sample integrity. Superior accuracy and precision and Error may be caused during sample lesser chances of sampling error. extraction, handling, transportation to laboratory and testing in laboratory. 18  Comparison Of Bore Hole Drilling With CPT Borehole Drilling) Cone Penetration Testing (CPT) Takes longer due to the drilling process Generally faster than borehole and the need to extract soil samples at drilling, as it provides continuous different depths. data without the need for frequent interruptions. Can encounter difficulties in certain soil conditions, such as cohesive soils that Effective for a wide range of soil may stick to the drill pipe. types, including sands, silts, and clays. 19  Recommendations of the Geotechnical Report & Their Implementation on Site 20 Recommendations of the Geotechnical Report & Their Implementation on Site The Geotechnical Report normally contains recommendations on the items of work that relate to or are supported on the soil, some of which are given below. The site superintendent must implement these recommendations on site. a) Bearing capacity of soil and types of footings to be used and their depths. 21 Recommendations of the Geotechnical Report & Their Implementation on Site 22 Recommendations of the Geotechnical Report & Their Implementation on Site b) Type and location of perimeter drainage to be provided. Perimeter drainage Compaction of backfill 23 Recommendations of the Geotechnical Report & Their Implementation on Site c) Type of floor slab and moisture barrier Slab on grade / Structural slab Compacted granular underneath slab d) Types of back fill materials to be used: For trenches For raising the floor slab level 24 Recommendations of the Geotechnical Report & Their Implementation on Site e) Type of equipment used for backfill f) Lift height Sheep foot roller being used for the compaction of sub- grade. 25  Recommendations of the Geotechnical Report & Their Implementation on Site g) Whether the site soil may be used as structural / engineered fill or not a) Engineered / Structural fill is that material that can be compacted and can carry load. b) The geotechnical report recommendations will decide whether the site soil may be used as structural fill or not. h) Type of pipe bedding materials for storm & sanitary drains. 26 Recommendations of the Geotechnical Report & Their Implementation on Site i) Types & thicknesses of pavement to be used Light duty / Heavy duty Compaction equipment 27  Compliance With The Geotechnical Report Recommendations During the building permit approval process, the City staff will review the geotechnical report along with the project design documentation and will examine/study to ensure: – that the scope of the investigation undertaken by the geotechnical consultant adequately addresses the geotechnical issues at the site. – the guidance provided in the geotechnical report has been fully incorporated and adequately addressed in the detailed design by the consultants. – If not, objections will be raised by the City staff which shall have to be addressed by the consultants. 28 Important Considerations For The Site Superintendent Relating To The Geotechnical Report Since the geotechnical report is based on samples retrieved from a select number of boreholes dug at site, there can be significant variations in other areas of the site, therefore the site superintendent has to remain vigilant in this regard during grading and excavation works. Additional geotechnical testing must be systematically used by the site superintendent to confirm the bearing capacity at various locations prior to placing of footings, so that the conditions at the site can be confirmed in regards to the findings of the original investigation, especially for the footing and related works. 29 Important Considerations For The Site Superintendent Relating To The Geotechnical Report It is thus the responsibility of the site superintendent to coordinate with the geotechnical consultant during construction for review and inspection of the project, to verify and document the adequacy of the geotechnical aspects of footing and other related works. 30  Limitations In The Geotechnical Report Typical “Limitations” in a Geotechnical Report include: – Report is meant to be used only for the client named in the report and not for any other third party. – The recommendations of the report are based on the bore hole locations and sub-surface site conditions (water, type and thicknesses of soils, etc. ) may vary significantly at other locations. These Limitations are meant to act as a safeguard for the author of the report against liability issues, especially when third parties such as Contractors rely on the report for Tendering & Bidding purposes. The report does not reflect the environmental aspects of site. 31 Environmental Site Assessments 32  Environmental Site Assessment (ESA) Contaminant means any substance that can have an adverse effect on human, animal and plant health as well as on the environment (air, soil, water, sediments, etc.). Contaminants can include : – Toxic compounds, – Chemicals, – Salts , – Radioactive materials, or – Disease causing agents, – Etc. 33  Environmental Site Assessment (ESA) Other sources of contaminants include: o Indiscriminate use of fertilizers; o Indiscriminate use of pesticides, insecticides and herbicides; o Dumping of large quantities of solid waste on the soil; o Urbanization  Plant & animal wastes  Papers  Wooden pieces  Plant twigs, leaves & mulch  Cloth wastes  Non biodegradable materials such as plastic bags, plastic bottles, plastic wastes, glass bottles, glass pieces, stone / cement pieces, etc.; 34 Sources of Soil / Groundwater Pollution (Contamination) o Chemical releases during major fires; o Dumping of contaminated soil on the site; o Leakage of underground storage containers; o Drips and spills on the site or in the adjoining areas; o Chemicals released by industrial wastes and industrial wastes; o Decomposed and partially decomposed materials of sanitary wastes 35  Purpose Of Environmental Site Assessment (ESA) The purpose of environmental investigation of a construction site is to find out about the levels of contaminants present on the site, in the: – Soil – Groundwater – Sediments ESA is a mandatory requirement for all construction sites and must be carried out before a project will be approved by the government authorities. ESAs are regulated by the Ministry of Environment (MOE). 36 Environmental Site Assessment (ESA) Site contamination also has very serious financial implications for a site such as loss of value of the property and the cost of remediating the property. Prospective purchasers may want to know whether they are assuming unforeseen financial liability on a land transaction. Banks often require an investigation prior to financing a property to ensure no hidden liability exists from contamination. 37  Types Of Environmental Site Assessments As per MOE rules, the Environmental Site Assessment is carried out in 3 stages, namely: – ESA Phase 1 Visual investigation without sampling – ESA Phase 2 Detailed investigation based on sampling & laboratory chemical analysis and comparison of the results with MOE Tables provided in the Environmental Protection Act – ESA Phase 3 Remedial measures and Remedial Action Plan (RAP) 38 Types Of Environmental Site Assessments Types Of Environmental Site Assessments must proceed in sequence and each next phase is required only if the earlier phase report recommends so. 39 ESA Phase 1 40  ESA Phase 1 The purpose of a Phase I investigation is to look for any visible signs and likelihood of contamination on the site and is carried out by means of: a) Site inspection and visual observations b) Review of historical databases c) Interview with related persons 41  ESA Phase 1 a) Careful visual site inspection, of the site and any facilities existing on the site, by an environmental professional, usually accompanied by someone familiar with the property, to look for the following: Property use Hazardous materials Unidentified substances Storage tanks and containers Odours 42  ESA Phase 1 Potable water supply Special attention items Surface stains or stressed vegetation Drains and sumps Topographic conditions 43  ESA Phase 1 Abandoned and existing wells Sewage and waste water disposal Pits, lagoons, ditches or standing water Presence of fill Roads , parking , right of way 44  ESA Phase 1 b) Review of the following historical databases (maintained by the site owner and regulatory agencies) to gather information about past and present uses of the site. » aerial photographs of the site » aerial photographs of the adjacent site » property use records » title search » previous environmental or geotechnical reports 45  ESA Phase 1 » regulatory information of the area » geological and soil maps` » topographic maps » agreements of sale and purchase » Environmental Risk Information Services (ERIS) report c) Interviews with persons knowledgeable about the site and its past uses. 46  ESA Phase 1 The risk of contamination is evaluated not only from on-site sources, but also from off-site sources, such as a neighboring gas station etc. which may have leaked contamination onto the owner's property. On the basis of the above mentioned three activities, an ESA Phase 1 provides recommendations whether there is a likelihood of contamination on the site or not and whether a Phase II investigation is required. 47 ESA Phase 2 48  ESA Phase 2 ESA Phase 2 is carried out on a site only if recommended by ESA Phase 1 and involves detailed site investigation based on sampling & laboratory chemical analysis and comparison of the results of the tested samples with Ministry of Environment (MOE) Tables 1-9 provided in the Environmental Protection Act. ESA Phase 2 investigation involves the following sampling and testing protocols: – Taking samples from the site and testing them in the laboratory to find out the chemical composition of soil, groundwater and surface water. 49  ESA Phase 2 – Sampling and testing of plants and/or aquatic species obtained from the site. – Testing of above ground storage tanks (AST) and under ground storage tanks (UST) found on the site for content and leakage. – Sampling for any asbestos containing materials (ACM) found on the site. – Using transportation models to evaluate the potential migration of the contamination to and from the site. 50 Ministry of Environment Tables and the Chemical Analysis Report 51  MOE Tables (1- 9 ) of the Soil, Ground Water and Sediment Standards for Use Under Part XV.1 of the Environmental Protection Act MOE has 9 Tables, based on various site conditions, that set allowable limits for various chemical constituents (~ 65+) in the soil, water and sediment on the site. In other words, each MOE table sets the amount of contamination that can be allowed in the soil, sediment and ground water on any particular site, based upon the: – site conditions and – the past and future intended land use of the site. 52 53 54 55  MOE Tables (1- 9 ) of the Soil, Ground Water and Sediment Standards for Use Under Part XV.1 of the Environmental Protection Act The various site conditions include: – Table 1: Full Depth Background Site Condition Standards – Table 2: Full Depth Generic Site Condition Standards in a Potable Ground Water Condition – Table 3: Full Depth Generic Site Condition Standards in a Non-Potable Ground Water Condition 56 MOE Tables (1- 9 ) of the Soil, Ground Water and Sediment Standards for Use Under Part XV.1 of the Environmental Protection Act – Table 4: Stratified Site Condition Standards in a Potable Ground Water Condition – Table 5: Stratified Site Condition Standards in a Non-Potable Ground Water Condition – Table 6: Generic Site Condition Standards for Shallow Soils in a Potable Ground Water Condition 57 MOE Tables (1- 9 ) of the Soil, Ground Water and Sediment Standards for Use Under Part XV.1 of the Environmental Protection Act – Table 7: Generic Site Condition Standards for Shallow Soils in a Non-Potable Ground Water Condition – Table 8: Generic Site Condition Standards for Use within 30 m of a Water Body in a Potable Groundwater Condition – Table 9: Generic Site Condition Standards for Use within 30 m of a Water Body in a Non-Potable Groundwater Condition 58  MOE Tables (1- 9 ) of the Soil, Ground Water and Sediment Standards for Use Under Part XV.1 of the Environmental Protection Act The various land uses in these tables include: – Agricultural – Residential – Parkland – Institutional 59 MOE Tables (1- 9 ) of the Soil, Ground Water and Sediment Standards for Use Under Part XV.1 of the Environmental Protection Act – Industrial – Commercial – Community – All other property types 60  Soil Chemical Analysis Investigation Chemical analysis of soil is a necessary requirement of Phase II site environmental investigation. However, soil chemical analysis is also done for sites which do not require Phase II site environmental investigation and is done in this case to ascertain the environmental quality of soil for: – On site soil management – Off site soil disposal location 61  Soil Chemical Analysis Investigation For chemical analysis of soil, samples of soil are taken from the site to the laboratory to ascertain the quantity of each chemical constituent of soil. These results are provided in a tabular form in the report as Certificate of Analysis (as shown in the next slide). The results of the chemical analysis are compared against the Ministry of Environment (MOE) Tables to determine which MOE table shall apply to the site. 62 63  Onsite Soil Management Based on Chemical Analysis Report Based on current and future intended uses of site, the MOE guidelines will determine which MOE table shall apply to a particular site. The Chemical analysis carried out on a site shall confirm whether the site soil conforms to the required Ministry table for that type of site or not. Only soil which conforms to the Ministry applied table is allowed to be used on that site. 64  Onsite Soil Management Based on Chemical Analysis Report If the existing soil on the site does not fall in the specified Table , then it either has to be replaced by soil that conforms to the Ministry prescribed table or remediated to bring the contaminant levels within the prescribed limit or replaced with soil of the proper table. 65  Onsite Soil Management Based on Chemical Analysis Report If soil is to be disposed off from any site, it can only be taken to a dump site which is legally authorized to accept soils of that particular table type. Conversely if soil is to be imported to a site, only the soil belonging to the correct table type for the site may be imported. The above can have huge cost implications for grading contractors for the site. 66 ESA Phase 3 67  ESA Phase 3 ESA Phase 3 is required when a ESA Phase 2 investigation has been completed for the site and the Phase II determines that the site is contaminated and remediation needs to be undertaken. Remediation is described as an improvement carried out on a contaminated site, in order to eliminate, minimize or mitigate the potential damages to human health or environment , by bringing the contaminant levels within the MOE criteria as prescribed in MOE Tables. 68  ESA Phase 3 Carrying out remediation for a construction site can have huge cost implications. ESA Phase 3 provides the Remedial Action Plan (RAP) for the site and lists: – Various remedial options for the site and their feasibility. – Site management and monitoring to be undertaken while Remedial Action Plan is being implemented. 69 Contaminated Site Management 70 71  Closure Report Upon implementation of the remedial action plan on the site as per ESA Phase 3, to remove contamination, a Closure Report is prepared by the Environmental Consultant to inform the Ministry of Environment regarding successful implementation of the remedial measures at site as proposed by the Remedial Action Plan. Closure report has to be provided to the MOE before any construction may be allowed on site. 72 Record Of Site Condition (RSC) 73  Record Of Site Condition (RSC) A RSC is filed with the Ministry of the Environment and Climate Change (MOECC), by the Environmental consultant, and summarizes the environmental condition of a property at a particular time, based on the environmental site assessments (ESAs) done to date by the Environmental consultant. RSC’s can be publicly viewed and searched on the following registry (https://www.ontario.ca/environment-and- energy/records-site-condition). 74  Record Of Site Condition (RSC) Most commonly, a RSC is required when changing the land use (zoning) of a property to a more sensitive land use. – For example, a developer who purchases a property currently being used as an automotive repair shop with the intent of redeveloping the property as a residential building, would be required to file a RSC because the residential land use standards for soil and groundwater are more stringent than commercial/industrial standards, and consequently the completion of ESAs are required to ensure that a property meets the appropriate standards. 75  Record Of Site Condition (RSC) A RSC can take approximately four to six months to complete, depending on the complexity of the ESAs. A RSC may contain a Risk Assessment report to address any contamination. A Risk Assessment is the development of site-specific standards for a property and is typically completed when there is contamination on site and there are economical or physical restrictions for remediation. 76  Record Of Site Condition (RSC) Once the environmental assessments are completed, the RSC is submitted to the MOECC. When the MOECC has provided their approval, the RSC is filed in a registry. 77 Questions? 78