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204 Cards in this Set
- Front
- Back
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Cover or Index Sheet |
Project Title Sponsor Consultants' names Index to drawings by title and sheet number Project location map Sometimes graphic key to drawing symbols |
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Existing Conditions Plan |
All existing site features: - contours and spot elevations, including ridges and swales - property lines with bearings, easements, setbacks, benchmarks - Buildings or other structures - utilities, above and below ground - total hectares existing vegetation - boring data |
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Demolition Plan |
Often overlaid on ex conditions plan All items to be demolished, removed, transplanted or relocated in order to prepare the site • Show utility location: such as, electrical, gas, oil, steam, communication lines,water, sewer, etc. • Construction fences shall be installed around the perimeter of the project priormoving to site construction, including areas of staging and storage. • All elements and materials no longer needed shall be broken down and removed.When possible, materials shall be reuse or recycle. • Any topsoil on site should be excavated and stored to be reused. (4” - 6” top layer) • Verify all utilities locations and carefully protect. • Specify where hand excavation is needed. (Around trees, utilities, foundations,etc.) |
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Soil Boring Location Plan |
shows the location where soil boring will be done, oftendenoted by a small simple symbol with an accompanying alpha/numeric code ( 1,A). Often times the boring will be done by a qualified soils engineer orgeotech, and the results used to site buildings and/or design appropriate footing/foundations. Purpose is to get information about the soil composition indifferent layers sometimes including depth to bedrock. |
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Stormwater Pollution Prevention |
site-specific, written document that Identifies potential sources ofstormwater pollution at the construction site. • Describes practices to reduce pollutants in stormwater discharges from theconstruction site. Reduction of pollutants is often achieved by controlling the volumeof stormwater runoff (e.g., taking steps to allow stormwater to infiltrate into the soil). • Identifies procedures the operator will implement to comply with the terms andconditions of a construction general permit. |
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Site Preparation Plan |
Shows proposed development in line drawing Indicates location of stockpiling areas, trees to be removed and thinned, limit of work, employee parking and construction road access, erosion control methods, concrete truck washout areas, staging areas, storage areas, trees to be protected, location of dewatering trenches or construction siltation ponds |
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Site Protection Plan |
A site protection plan helps protect the natural resources of a project site andadjacent areas and achieve compliance with local laws and codes. The site protection plan’s basic elements include: - A protection plan for vegetation/trees and healthy soils - A tree rescue plan for those trees and plantings that must be removed - A site access plan (ingress/egress controls like tire scrubbers) - Storage areas for salvaged materials and collection areas for recyclable - Defined sensitive areas where staging, stockpiling, and soil compaction areprohibited- Waste water runoff and erosion control measures - Measures to salvage existing clean topsoil on site for reuse - Plans to mitigate dust, smoke, odors, etc.- Noise control measures - Designated wash-down area for construction equipment |
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Mitigation Plan |
Hazard mitigation is any cost-effective and sustained action taken to reduce thelong-term risk to human life, property, and infrastructure from hazards. measurestaken to avoid, minimize, or reduce the severity of environmental impacts. Hierarchy: avoidance, minimization, reduce |
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Layout and Materials Plan |
Shows proposed development superimposed on the existing conditions plan Proposed design is located horizontally on the ground using bearings and distances, station offsets, and coordinate points Materials are identified and keys to details and blow ups are indicated Contractor uses this drawing to calculate quantities of materials |
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General Notes |
General conditions: conditions the work shall comply, summary of work, scope,location and verification, limitation of the site. Site demolition notes: items to be removed, conditions and instructions ofremovals, contact info and requirements for local agencies, etc. Layout notes: contractor instructions etc. Landscape planting notes: source of plants, special instructions for location,excavation, pruning, alignment, etc. Soil preparation notes: instructions prior installation of landscape, soil storageand disposal, etc. Tree protection notes: special instruction, tree preservation notes, root pruning,soil compaction, etc. Irrigation notes: installation, location referrals. - Table of abbreviations - Energy code compliance - Special inspections - Water efficiency |
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Grading and Drainage Plan |
Property lines, match lines, limit of contract and benchmark All site features including: roads, parking, walks, walls, steps, etc Existing contours and spot elevations Proposed grading including: high points, low points, ridge and swale CLs and grades, spot elevations at all changes in gradients, walk ends and inlets; spot elevations at top and bottom of all walls, steps and ramps; floor elevation of every access level of each structure - subsurface drainage network - existing building, auxiliary structures and trees to be retained - protection for trees that will be affected by grading - cut and fill calculations and/or profiles |
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Planting Practices, Plans, Notes and Schedules |
Planting plan shows locations of all proposed plant materials, names, sizes, any other characteristics to assist the designer in specifying the precise specimen required Plant list or schedule indicates quantity, botanical name (genus, species, variety), common name, size (height, spread, caliper), spacing, special requirements Include note that plan takes precedence over list in case of discrepancies Also show: - property lines, match lines, limit of contract - paved areas, terraces, walls - surface and subsurface utilities - location and sizes of ex plant material - location/type/size of proposed plant material - areas to receive seed or sod - planting list or schedule - existing and proposed topography - location of decorative lighting features - irrigation (if not part of the utilities plan) |
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Utility Plan |
- stormwater drainage: surface and conduit system - subdrainage: tile fields, footings, etc - sewerage: sanitary sewer and septic systems - water distribution: drinking, irrigation, fountains, fire control - electrical layout: lighting and outlets - buried cables: telephone, electrical, optical, cable TV, etc - special waste drains: chemical/acid, petroleum, etc - fuel lines: natural gas and petroleum |
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Site Details and Sections |
Convey specific methods of construction Achieved through sections usually drawn from 1:10 to 1:20 Helpful to group details of like subjects |
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Plan Enlargements |
Used as needed to show detail design layouts in courtyards, entrances, etc Can show dimensions, grading, material pattern, planting, etc. Typically 1:200 or 1:100 |
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Road Profiles and Sections |
Road profiles show a profile section along the road CL and designate finish and existing grades at 10-100m stations along that line Horizontal scale is usually the same as that of the plan, and vertical scale is exaggerated at least 4:1 but more commonly 10:1 Profile sheet shows location and length of: 1. all vertical parabolic curves 2. Horizontal curves by symbol 3. Superelevation 4. High and low points 5. top of curb 6. bottom of gutter lines |
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Code Requirements |
• The appropriate consultant familiar with the local conditions and coderequirement shall be consulted and incorporate the comments to the drawingswhen appropriate. • Local code requirements shall be added in the general notes and appropriatedrawing sheets or specs. • All drawings submitted to support the plans must be in accordance with themunicipal codes and must be signed and sealed by the design professional. • Special inspections required by the local authorities shall be included in thecontract documents. |
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Summary of Quantities |
• A bid price is estimated based upon the cost of implementing all of the provisionsof the working drawings and specifications within the framework of the generalconditions and the agreement. • The bid price represents the contractor's cost summary for: Preparing the site to receive the design elements, Furnishing and installing all materials as specified, Providing the necessary equipment and labor crews for the required period oftime, Operation overhead expenses and Profit. |
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Site Infrastructure Plan |
a major component of a residential development isinfrastructure. This primarily includes roads, utility easements, and other right-of-way, also includes other elements such as accommodations for public structures. Infrastructure quality is important to neighborhoodresidents and businesses. It is also perhaps the least controllable aspect ofneighborhood development, particularly where city officials have not beeninvolved in the neighborhood planning process. |
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Phasing Plan |
In order to ensure the implementation of large-scale regeneration projects, theyneed to be broken down into manageable project components. hand-over process must account for the complex set of interdependenciesbetween the large-scale investments and construction projects, such as majorinfrastructure (utilities, transport, park systems, brownfields cleanup), and themicro-delivery of commercial and residential projects that need to establish a“sense of place” and completion. |
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Irrigation Plan |
Design Criteria: Climate, soils, plant material site layout, and economicconcerns all influence irrigation strategies Every foot of elevation change causes a 0.433 PSI change in water pressure. If yourpipe is going downhill add 0.433 PSI of pressure per vertical foot the pipe goesdown. If the pipe is going uphill subtract 0.433 PSI for every vertical foot the pipegoes up. |
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Lighting Plan |
Lighting Layout, Schedule, and Details Requirements: - Fixtures type and location, including any important location dimensions. - Remote transformer designations and schedules - Control load designations and schedules- Fixture control group designations and schedules - Schematic wiring diagrams - Custom or modified fixture details - Special systems such as neon or fiber optics- Installation details - General notes: provide information about the overall project while numberednotes provide information about a specific situation or location on thedrawing. Sheet notes refer to information specific to items on that sheet. - Photometric data and calculations |
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Site Furnishings Plan |
• Site furnishings and other features should be made of nonflammable materialsuch as metal, brick, or stone. • Structures made of wood should be avoided in fire-prone sites. Likewise, use ofwood-based mulches should be avoided in this zone, and gravel, recycled glass,or other nonflammable material should be used instead. |
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Signage and Wayfinding Plan |
Groups of outdoor information: 1) Directional; 2) Locational; 3) Identification; 4) Display The Information should be formatted and placed within easy view of either thepedestrian or the motorist. The primary mode of transportation, whetherpedestrian or vehicular, will determine the optimum location and size of signs. |
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Traffic Control Plan |
Five basic requirements that a traffic control device should meet to be effective, itshould:- Fulfill a need- Command attention- Convey a clear, simple meaning- Command respect of road users- Provide adequate time for response |
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Emergency Access Plan |
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Stormwater Management Plan |
Identify watersheds relative to stream flow Identify watersheds relative to localized runoff- roof runoff- pavement- turf- planting areas Identify direction of drainage Raingardens- configuration- plant materials- drainage |
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Shop Drawings |
Provided by the contractor when required by the designer Can allow for more efficiency when contractor is given latitude to design features requiring experienced craftmanship LA needs to review drawings before materials are ordered |
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Record (As-Built) Drawings |
Record drawings created to properly maintain a project after construction Contractor is required to keep track of all changes and amendments to the original construction docs so LA can create an official record of the built project |
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Construction Activities |
1. preliminary surveying 2. tree protection, temporary conditions, erosion control, transplanting 3. clearing, grubbing and demolition 4. Topsoil stripping and stockpiling 5. Rough grading 6. Finish grading 7. Installation of site improvements 8. Planting and seeding |
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Specifications |
Present detailed information on the materials required, the fabrication procedures, and the application of products and materials Establish the scope of the work and clearly spell out the criteria for altering the scope (changes orders, deletions, etc) Drawings establish dimensions and ID materials to be used, and specs establish procedural and performance standards required to construct the design as shown on the drawings |
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Notice to Bidders (public projects) |
1. Notice must be given in advance of the bidding - placed in newspapers, magazines, trade publications. Info included: - nature and type of project - location of the project - type of contract for construction - bonding requirements - dates in which to perform the work - terms of payment estimated construction cost (some specifically exclude this) - time, manner, and place to submit bids - location to obtain bid docs - deposit required on bid docs - owner's right to reject any and all bids - requirements regarding wage rates 2. Invitation must be posted in public places and distributed to the local construction community 3. All bidders must be treated alike and offered opportunity 4. Prequalifications may be required |
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Advertisement for bids in the private sector |
No well-defined rules. Most owners follow procedures similar to public 1. owner may select contractor by any means 2. public ads often used to obtain benefits of competition 3. Owner may select to negotiate a contract with a particular contractor. Most common in residential and industrial construction 4. Most common approach is for owner to select a few prime contractors - Select Bidding List |
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Public Bid Process (Design-bid-build) |
Design must be complete before bidding can occur, and bidding is completed prior to start of construction. Advantages include: 1. competitive marketplace 2. appearance of being impartial 3. process fully embraces fundamentals of free market system 4. only viable method for some government agencies Disadvantages: 1. accurate costs cannot be known until design is completed 2. bids that exceed owner's budget cannot be readily accommodated without jeopardizing the project 3. various parties tend to be adversarial under this process 4. errors and omissions in the design may lead to costly change orders |
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Negotiated Contract |
Eliminate some of the disadvantages of design-bid-build but compromise some of the advantages associated with competitive bid projects |
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Prequalification |
May be a requirement imposed by some owners - bidders restricted to firms that have been prequalified - select bidders list Generally consists of submitting specific info about the types of projects successfully completed by the firm, current workload, personnel employed by the firm, experience of the personnel to be assigned to the project, financial stability, other info Owner is responsible to show that a contractor is not qualified |
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Value engineering |
Specific procedure carried out to analye the various aspects of contract documents in relation to the owner's objectives, to determine if alternative methods or materials may be more appropriate May result in variety of changes in contract docs that may reduce costs, improve or maintain project quality, and/or decrease duration of construction Can be conducted either in design phase or during the construction phase |
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Constructability Review |
assessment of contract docs prior to bidding phase to identify problem areas and identify solutions (problems include any aspect that may present obstacles to the efficient construction of a project) |
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Decision to Bid |
Once a contractor is informed about a project that is to be bid, a decision must bemade about whether the company will be one of the bidders. Depends on several factors: • Bonding capacity• Location of the project• The owner• The owner’s financial status• The architect/engineer• Nature and size of the project• Probable competitors• Labor conditions and supply• Availability of in-house staff• The company’s need for work |
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Bidding (Estimating) Period |
What is often referred to as the bidding period is actually the estimating period,which culminates with the bid. The bidding period does not begin untilthe plans and the specifications are completed. |
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Instructions to Bidders |
Rules by which project will be bid. Concern the bid itself and the project during construction. Typically include the following: 1. Typical instructions relative to the procedure for writing and submitting thebid include the following issues:Bids must be submitted on the forms furnished.Erasures must be initialed by the signer of the bid proposal.All items in the bid schedule must be priced.Alternatives are not considered unless called for.Discrepancies between the unit price and the extended amount (how handled)are discussed.Are mailed bids accepted and considered?Can bid modifications be made (if or how)?The submission policy (sealed, marked, and addressed as directed) is specified. 2. The contractor may be required to submit an experience record to demonstratethe capability to perform. This is used for postqualification. 3. The instructions clearly list all the documents that are part of the bid documents (drawings, specifications, alternates, instructions to bidders, etc.). 4. The construction time period is carefully spelled out in the instructions. Thisincludes the start date and the number of calendar or working days allotted forproject completion, or it may permit the contractor to state the constructiontime required. 5. The instructions usually indicate who is responsible for the subsoil data, testborings, errors in the plans, and so on. Site visits by the bidders are usuallyrequired in the instructions.6. The requirements of a bid guarantee are outlined. 7. The insurance to be provided by the contractor is stipulated. 8. The bonding requirements are given. 9. Conditions for handling bid irregularities are often stated. 10. Where and when to deliver the bids are stipulated. 11. Closed or public opening of the bids is indicated. 12. A prebid conference may be described. |
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Addenda |
Formal changes or clarifications issued by the owner or owner’srepresentative to all identified bidders during the bidding period. When modifica-tions are not included in the original bid documents, the issuance of addenda is aprocess by which bidders can be updated on design changes and clarifications. Ifsuch changes or modifications were made after the contract award, these items ofwork have to be addressed as changes. Issued during the bidding or estimated period. Should not be issued up to the time for submitting bids. Bidders need to acknowledge number of addenda that were received |
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Alternates |
For lump sump contracts: alternates are modifications to the base bid. They may consist of changes in the structure of aproject, changes in the quality of the material to be furnished, the inclusion of additional items of work, the deletion of specified work items, etc |
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Bid Form/Schedule |
Form on which bids are to be submitted. Form will facilitate analysis and comparison of the bids to make it easy to detect irregularities. For contractors, ensures accuracy in providing necessary info and prevents the possibility of having omissions in the bids. Common requirements to include on the form: - Price (lump sum or unit price) - Time of completion (often given by the owner) - Bid surety - Agreement to provide contract surety - Acknowledgement of having reviewed addenda - List of contractors used in the final bid - Experience record, financial statement, plant and equipment inventory - Declaration regarding fraud and collusion - Statement regarding site examination - Signature |
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Lowest responsible bidder |
The Bidder who fully complied with all of the bid requirements and whose past performance, reputation, and financial capability is deemed acceptable, and who has offered the most advantageous pricing or cost benefit, based on the criteria stipulated in the bid documents. |
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Contract Award |
After the low bidder is determined on the bid opening day, that bidder is in-formed of his or her apparent status. The owner also expresses the desire to enterinto a contract with that bidder. The unsuccessful bidders should be informed ofthe status of their bids |
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Construction Contract Documents |
May include the construction agreement, drawings, general conditions, sup-plementary provisions, technical specifications, and addenda. These documentsare prepared by the designer and become the vehicle through which the owner andthe contractor communicate. |
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Drawings |
The drawings, also known as the plans or blueprints, are the primary vehicle bywhich the physical, quantitative, or visual description of the project is conveyed.The drawings are organized in a fashion that follows to some extent the physicalsequence in which the construction work will be performed. |
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Project Manual |
Consists of the bidding documents, general conditions, supplementary provisions, and technical specifications. These documents are oftencontained within a single binder or “book.” This simplifies the handling of thedocuments and provides greater assurance that some items are not misplaced. |
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General Conditions |
Often referred to as the boilerplate, augment the con-struction contract and outline the rules under which the project will be built. Establish the rights, authority and obligations of the contracting parties: theowner, the owner’s representative, and the contractor. Standard GCs have been developed by different groups |
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Supplementary Conditions |
Also known as special provisions or special conditions, supplementary conditionsare more specific to the job being constructed. SAmend/augment the general conditions and tend to be more specific. Topics include the following: • The number of copies of the contract documents to be received by the contractor. • The type of surveying information to be provided by the owner. • Which materials the owner will provide. • Specific information about material substitutions. • Changes in insurance requirements. • Requirements concerning the phasing of construction. • Examination of the site. • Start date for construction. • Requirements for project security. • Requirements for temporary facilities. • Specific procedures for submitting shop drawings. • Cost-reporting requirements. • Job schedule requirements. • Special cleaning requirements. • Traffic control requirements. • Discovery of artifacts of cultural or historical value. |
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Specifications |
The term specifications is often used very broadly to include all the contract docu-ments, with the exception of the drawings. This would include the following: • Invitation to bid • Instructions to bidders • General conditions • Supplementary conditions • Bid proposal form • Bid bond form • Contract bond form • List of prevailing wages (may be part of the supplementary conditions) • Noncollusion affidavit • Technical specifications |
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Technical Specifications |
Needed to cover the qualitative items of a project - info not easily shown on the drawings, which are morequantitative in nature. The technical specs are written descriptions of the quality of the various aspects of the construction project.Technical specs will generally follow a standard format of providing the followinginformation: • General: stipulates ground rules for the work to be performed and defines thescope of work to be performed within the specification section. • Products: describes the product or products (materials, equipment,accessories, components, fixtures) and the development and manufacturingprocess to be used in producing them. • Execution: describes the preparation, workmanship, installation, erection, andapplication procedures to be employed along with quality requirements and performance criteria that must be satisfied. |
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Priority of Documents |
1. Agreement between the Owner and the Contractor 2. Definitions 3. Supplementary Conditions 4. General Conditions 5. Division 1 of the Specifications 6. Technical Specifications 7. Material and finishing schedules 8. The Drawings (Drawings of larger scale shall govern over those of smaller scale of the same date, dimensions shown on Drawings shall govern over dimensions scaled from Drawings, later dated documents shall govern over earlier documents of the same type) |
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Organization of Technical Specifications |
With the exception of the drawings, most of the contract documents will beincluded in one binder, which is often referred to as the specifications. In thisbinder, the technical specifications will be in the later portion (technical specifications are the last items included, generally consisting of more thanhalf the book) The organization of the technical specifications, like that of the drawings,follows the general order of the construction process. The technical specsusually begin with the site-type items and conclude with the finish items.As with the drawings, the technical specs are separated into sections forquick reference. |
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Basic criteria for specifications |
• Technical accuracy and adequacy. • Definite and clear stipulations. • Fair and equitable requirements. • A format that is easy to use during bidding and construction. • Legal enforceability. |
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Design specifications |
Also called material and workmanship specifications,method and materials specifications, and prescriptive specifications. In this type ofspecification, a particular kind or type of material is to be used, a particular dimen-sion is required, and the installation instructions are given. If the specconcerns a method, it will state in detail exactly what the contractor is to do to satisfy the requirement. * By using this type of spec, the owner warrants by implication that the specswill produce the desired results if they are followed by the contractor.* |
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Performance Specifications |
The results or the performance of the finished product, rather than the specific methods and materials used to construct theproduct, are specified. The product satisfies the spec as long as it does the job.Since this spec focuses on the end product rather than the means of getting theproduct, this form of spec is growing in popularity. This specification does not stipulate the method to be used to obtain the de-sired results. However, the spec may offer suggestions that may be employed toobtain those results. Of course, the contractor is not obligated to accept the suggestions. * if designer on a project gives specific verbal directions onhow a task is to be done, the specification then becomes a design specification. |
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Performance and Design Specifications |
This type of spec is one in which the contractor is instructed how to do a task,and then told to warrant that the results will be satisfactory. |
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Closed Specifications |
Requires a specific item or system. The purpose of thistype of spec is to ensure that only products of a particular type are used. More frequently found in the private sector because it is inprinciple not legal on public works projects (eliminates the chance for competition) Can be either design or performance specification. In public works projects, at least three manu-facturers’ models must be named to avoid the designation of being closed. |
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Proprietary Specifications |
Type of closed specification. It specificallystates what is to be provided without any allowance for alternatives. This is aunique type of a design specification. It is common for a proprietary specificationto prescribe the use of a particular model of a particular manufacturer. |
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Multiple Proprietary Specifications |
May be an open or a closed specification. It is a design specification aswell. In a multiple proprietary specification the models of more than one manufacturer are specified. |
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Open Specifications |
Nonrestrictive in that they permit a wide variety ofchoices. Public projects should be bid under this type of spec, naming at leastthree manufacturers. The products of various manufacturers should be acceptablewhether or not they are actually mentioned by name. This type of spec is desiredby owners as it gives contractors the widest opportunity to get the lowest prices fordelivering the project. |
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Or Equal Specifications |
Modification of the proprietary specification in that it is aproprietary spec followed by the words or equal. Or equal specs should be avoidedby spec writers. The contractor could make a substitution and claim that the substitute is an equal. Resolving the conflict will be difficult. Ways to avoid conflicts that this type of specification frequently generates: • Name the specific acceptable brands and the model numbers and delete thewords or equal. (This may be a closed spec.) • Name many acceptable brands and models. This will require that the spec writerbe familiar with all the different models listed. • Let the contractor name an alternate. • Request substitutions up to a given time before the bid date. |
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Or Approved Equal Specifications |
These are open specifications in that they give all acceptable products an opportunity to be considered. The ideal form of this type of spec lists the brands andmodel numbers of various manufacturers followed by the words or approved equal. |
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Reference Specifications |
Found in the technical specifications and makeitems, established tests, or formal procedures a part of the contract documents byreference. It is common to have a specification that will establish the performanceof a product as measured by a standard or accepted test procedure. This can bepart of a design or performance specification. This type of spec is generally usedto ensure that a product conforms to industry-accepted test criteria (e.g, ASTM) |
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Standard Specifications |
Refers to an entire set of technical specifica-tions that have been developed by an owner - can beused for many similar types of projects (common in in highway, bridge, and utility construction) Will apply tothe entire industry - often adopted by state agencies and are modified onlyto satisfy unique conditions. Saves time in spec writing and requires contractors with several projects with the same owner to familiarize themselves with onlyone set of specifications. |
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Submittals |
Submittals may include cut sheets, working drawings, shop drawings, descriptive data, certificates, methods, calculations, materials samples, test data, schedules,progress photographs, procedural descriptions, and manufacturer’s instructions.The process of making submittals is streamlined considerably when the designeritemizes the specific items for which submittals are required. The actions of the owner on submitted itemsare generally to approve them as submitted, to approve portions of the submittal, togive a conditional approval, or to reject the submittal and require a resubmittal.Eventually, approval must be received on all items. The contract may require thecontractor to provide the entire file of approved submittals to the owner at projectcompletion. |
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Operating and Maintenance Manuals |
Projects that include mechanical equipment usually include a contractual require-ment for the contractor to provide operating and maintenance manuals for theequipment. These materials are for the owner’s benefit during the actual occupancyand use of the facility. Equipment for which such manuals are required should beclearly noted in the contract documents. The specific information to be included inthe manuals should also be stated. |
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Required info in a contract |
- Identify contractor, owner and designer - outline scope of work - reference to docs like specs and drawings - date construction needs to be completed (e.g, within x number of days after notice to proceed) - state how payments will be made (e.g, monthly) - base on which payment is made (unit price, cost-plus, lump sum) - signatures of the contracting parties |
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Unit Price Contracts |
Primary feature of unit price contracts is that the pricing for the various unitsof work is determined before the start of construction. For such contracts, theowner will estimate the number of units included for each element of work. When the extensions are made (quantity times unit bidprice), the sum of these extensions (the total) is used to determine the low bidder.The contractor must be careful when calculating the amounts to be bid so that allanticipated costs are included in the bid items (e.g, overhead and profit) |
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When to use unit price contracts? |
Used whenthe project is fairly well defined, but the actual quantities may be difficult orimpossible to estimate with accuracy until after construction has started (e.g, don't know total amount of earthworks required but get unit price for it) |
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Balanced Bid vs. Unbalanced Bid |
A balanced bid is one in which the anticipated costs for the various bid itemsare accurately reflected in the unit prices that are submitted. Unbalancing a bid isa method used by some contractors in which the unit prices of the various biditems are altered so that they do not reflect the true costs of those items (doesn't alter total bid amt) |
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Disadvantages of unit price contract |
- not sure of actual cost until project is completed - additional field staff required to verify in-place qtys |
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Cost-plus contract |
Contractor is reimbursed for most of thedirect expenditures associated with a particular project plus an allowance for overhead and profit. It is common for the allowance for overhead and profit to be based on a percentage of the costs. If the allowance for overhead and profit is reasonable, the contractor is almost assured of not losing money. Could also be "cost plus a fixed fee" (removes incentive for contractor to increase costs in attempt to increase overhead and profit allowance) |
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When to use cost-plus contract |
Usedwhen the actual costs of a project or portions of a project are difficult to estimatewith accuracy. This may occur when the plans are not complete, or when the project cannot be accurately portrayed. It also may occur when a project is to be completed within a fairly short time period and the plans and specifications cannot becompleted before construction starts. Another type of project for which the cost-plus arrangement is well suited occurs when the true nature of the project cannot be accurately described before construction begins. This may occur in remodeling or renovation projects that containmany unknowns. |
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Disadvantages of cost-plus contracts |
Does not lend itself well to competitive bidding. Thisform is used almost exclusively in the private sector.A cost-plus contract, unlike other forms of contract, does not place theowner and the contractor in an adversarial relationship. However, this form mandates that the contractor be trustworthy. |
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Lump Sum Contracts |
Most common type of contract used in theconstruction industry, particularly in building construction. Of the various formsof construction contracts, the lump sum, or fixed-price, contract is the simplest.The contract essentially states that the contractor will produce the project as designed for a stated specific sum. Often paid monthly - contractor isgenerally asked to break down the project into a variety of work items and to allo-cate the appropriate payment to be made for each item. This payment schedule, orschedule of values, will become the basis for all payments throughout the project. |
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When to use lump sum contract |
Plans must be fullycompleted so that the contractor can estimate quantities accurately.Owners with a limited budget prefer this form of contract because it is theonly one that yields a fairly accurate indication of the final cost of a project. Unless changes are made in the project, the amount stated in the contract will be theamount actually paid by the owner. |
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Disadvantages of lump sum contracts |
Construction of the project is delayed while the plans are being completed. Errors in the plans will be costly because they will result in extras. |
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Agreement Form |
A legally binding document endorsed by the owner and thecontractor which seals and initiates the contract. It contains a complete list of biditems, their respective quantities, and the unit pricing for each item with a priceprovision for adding or deleting a specific item after construction initiation. |
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Basic differences between types of contracts |
The fundamental differences lie in the ways that payment for services isestablished. Lump sum contract can only be used when scope definition is clear as demonstrated in acomplete design Unit price contracts are better suited than lump sum contractswhen the actual quantities (earthwork) cannot be accurately estimated. The cost-plus contracts can be utilized on any type of project, unless public policy forbidsthis type of contract. |
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Geomorphic grading |
The proposed grading blends ecologically and visually with the character of the existing natural landscape. Reflects natural patterns and aims to minimize amount of regrading needed |
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Naturalistic Grading |
Perhaps the most common type of grading, particularly in sub-urban and rural settings, but has also been used to great effect in the urban work of Frederick Law Olmsted, as in Central Park in New York City. It is a stylized approach in which abstract (or organic) landforms are used to represent or imitate the natural landscape. The design is so successful that the landscape is believed to be a product of natural forces. The way the landforms respond to the remaining bedrock leads many to the conclusion that the landforms are natural |
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Architectonic Grading |
Creates uniform slopes and forms, usually crisply defined geometric shapes - use where a strong contrast is desired between built and natural landscapes |
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Sculptural Grading |
Bridge between architectonic and naturalistic categories |
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Swale/valley contour signature - contours point uphill |
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Ridge Contour Signature - contours point downhill |
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Where are spot elevations necessary? |
1. Stairs 2. Ramps 3. Walls and fences 4. Rim elevation of drains5 . Beginning and ending of swales 6. Finish grade elevations of hardscape elements and structures 7. Existing trees to be saved 8. Finish grade of elevation of special landscape elements |
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Slopes of elements - minimum to maximum |
hardscape - 1% minimum to 5% maximum- softscape - 2% generally considered minimum to maximum of 3:1 direction of water flow-perpendicular to contour |
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roadway alignment |
horizontal - curve and super elevation relative to design speed ofroadway vertical - safety relative to entering and exiting slopes daylight a curve - clear sight distance |
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Erosion control measures |
(e.g., mulch, blankets, mats, vegetative cover) protect thesoil surface and prevent soil particles from being dislodged and carried away by windor water. It is usually easier and less expensive to prevent erosion than it is to controlsedimentation. |
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Sediment control measures |
Sediment control measures remove soil particles after they have been dislodged(typically through settling or filtration). |
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Common Stormwater Pollution Prevention Plan Objectives |
- Stabilize the site as soon as possible. - Protect slopes and channels. - Avoid disturbing natural channels and the vegetation along natural channels, ifpossible.- Reduce impervious surfaces and promote infiltration. - Control the perimeter of your site. “Divert the clean water, trap the dirty water.” - Protect receiving waters adjacent to your site.- Follow pollution prevention measures. Provide proper containers for waste andgarbage at your site.- Store hazardous materials and chemicals so that they are not exposed tostormwater. - Minimize the area and duration of exposed soils. Clearing only land that will beunder construction in the near future. |
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Principals of erosion and sediment control: |
1. Develop design to fit the site and the terrain.2. Protect and retain existing vegetation to the extent possible. 3. Protect/revegetate and mulch exposed areas. 4. Minimize steepness of slopes to manage both velocity and flow of runoff. 5. Schedule earthwork and construction to minimize soil exposure andenhance stabilization. 6. Protect new swales and drainage paths. Improve stabilization of existingchannels for increased flows and velocities. 7. Trap the sediment on the site. 8. Maintain site controls. 9. Develop contingency plans before they are needed. |
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Soil erosion and sediment control measures |
Buffer zone: a vegetative strip surrounding disturbed areas or along water bodymargins. Streambank stabilization: vegetative and structural practices to prevent orreduce bank erosion. Check dam: a temporary structure to control concentrated stormwater flows inchannels. Channel stabilization: the creation, improvement or stabilization of channels forsafe conveyance. Stream diversion channel: a temporary channel to conduct flow aroundconstruction in a stream. |
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Soil erosion and sediment control measures (2) |
Permanent downdrain: a concrete or half-pipe sectional flume to conduct flowssafety down slopes. Grade stabilization structure: a permanent structure designed to accommodatevertical grade change in natural or man-made channels. Level spreader: a zero gradient device used to convert concentrated flow intobroad overland sheet flow. Rock filter dam: a temporary or permanent dam used in streams or drainagechannels to filter sediment and slow flow velocity. Retaining wall: a structural method to reduce slope face exposure to erosiveforces. Storm drain outlet protection: rock or concrete device to reduce stormwatervelocity and channel erosion at pipe outlets. Vegetated waterway: a vegetated channel designed for stable nonerosive flows. |
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Silt fencing placement |
must be installed parallel to existing contours or constructed levelalignments. Ends of the fence must be extended 10ft, tracing up slope at 45degrees to alignment of the main fencing section. |
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Erosion Control practices |
1. Minimize disturbed area and protect natural features and soil 2. Phase construction activity 3. Control stormwater flowing onto and through the project 4. Stabilize soils promptly 5. Protect slopes |
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Sediment Controls |
1. Protect storm drain inlets 2. Establish perimeter controls 3. Retain sediment on-site and control dewatering practices 4. Establish stabilized construction exits 5. Inspect and maintain controls |
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Stormwater pollutants |
Primary pollutant: sediment Other pollutants: Nutrients, Heavy metals, pH (acids & bases), Pesticides &herbicides, Oil & grease, Bacteria & viruses, Trash, debris, solids, Other toxicchemicals. |
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Removals Plan and Plant Protection Plan |
removals plan is often combined with the plant protection plan (tree protection plan) unless the plan protection plan is more complicated.• Verify in field all dimensions and determine the limits of the project agreed by all parties • Special condition requirements for plant protection and removals plan: Confirmed location for trees, wells and tree islands, Areas requiring compaction mitigation, Pavements and materials to be removed, Location of potential tree erecting, pruning and guying, Location for vegetation protection • Demolition plan and removals plan are not the same. Avoid combining plant protection, removals and demolition together unless it’s a very simple project. • When combining plant protection and removal and also utilizing demolition plan, it is not necessary to show removed trees on the demolition plan as they should be removed already. |
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Mitigation - avoidance strategies |
Not undertaking projects or elements of projects that could result in adverseimpacts Avoid impacting environmentally sensitive areas Implementing preventative measures to stop adverse impacts from occurring. |
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Mitigation - minimization strategies |
- Scaling down proposals; - Redesigning elements of a project. - Employing supplementary measures to manage impacts. |
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Compensatory mitigation |
When adverse environmental impacts are unavoidable,strategies can be used as a “last resort” to offset impacts, such as: - Rehabilitation - Restoration - Replacement of the same resource values at another location. This could occurthrough mitigation banking or in-lieu fees. |
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Materials Plan |
- Identify existing materials and elements- Identify proposed materials, with different symbols, hatches and patterns. - Label and dimension planters, planting walls, tree pits, planting boxes. - Clarify materials and plants species. - Label and dimension furniture, seating, water features, walking paths. - Label lighting fixtures, gates, boulders. - Include accessibility features if necessary. - Include callout details of all elements proposed. - Include notes of specific materials, sources, locations or any additionalinformation needed to complete the project. |
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Considerations for irrigation |
Climatic factor of greatest importance: water deficit - difference during growing season btwn natural precipitation and amt of water required for satisfactory growth Windy areas have greater evaporation rate - set timers to irrigate when wind is minimal or heads with lower trajectories and large orifice sizes |
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Objectives of conventional irrigation system |
applywater at a rate that the soil can accept., without causing runoff. Station timingcan be adjusted according to the percolation rate of the soil and theprecipitation rate of the sprinkler. With drip irrigation systems, it is important todetermine the extent of the root zone to be irrigated and then to design the areaof wetness to envelop that zone. |
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When is the best time to irrigate |
Early morning hours are usually the best time to water because wind speeds aretypically low, evaporation is at a minimum, and plant leaves do not remain wetfor long periods of time. |
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Spacing for different types of irrigation systems |
Most small system designs use square spacing unless area is irregularly shaped Large areas like athletic fields are typically designed for triangular spacing |
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Sprinkler Irrigation |
Only option for lawns Sprinklers should spray low to avoid evaporation Should not spray directly into plant, building or other structures atclose range because of possible damage and to prevent a void from occurringon the opposite side of the disrupting object. |
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Quick Coupler Irrigation System |
Include a valve which is opened when a key is inserted.A hose or sprinkler head can be attached to the key to distribute the water asrequired. They are often used in combination with automatic systems to providesupplemental water access. |
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Drip Irrigation System |
Increasingly being designed into landscape projects because of efficiency Small orifices that can become clogged if improperly designed For permanently irrigated landscapes, use drip irrigation wherever possible. Dripsystems waste very little water, as they deliver water directly to the roots. This alsopromotes deeper root systems and leads to fewer problems with insects anddiseases that are fostered by wet leaves and stems. |
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Effective Irrigation |
harvest rainwater from roofs, etc, run downspouts into planting beds, grade pavement to run into lawns/beds, terrace steep slops to collect rainwater, use collection swales at the foot of slopes |
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Recommendations for all forms of irrigation |
- Irrigate deeply and infrequently to promote resilient, deep root systems. - Calibrate rate and duration of water delivery to minimize runoff. - Monitor irrigation consumption and adjust monthly to meet changing conditions - Allow for regular maintenance of irrigation systems. |
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Rainwater Harvesting |
collection, storage, and reuse of runoff fromimpervious surfaces. Functional components: • Catchment area• Conveyance system• Storage element• Roof-wash system• Delivery system • Water treatment |
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Roofing materials for water capture |
• Avoid organic materials, asphalt, zinc coated and lead.• Use stainless steel, galvanized steel with baked-on enamel, or lead freefinish. When the water will be used only for irrigation, a roof wash system combinedwith leaf screens installed at downspout inlet may be adequate. |
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Rainwater harvesting uses |
• Fire suppression storage • Toilet water • Mechanical cooling • Irrigation |
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Graywater Uses |
Graywater comes from sinks, showers and washing machines • Toilet uses• Irrigation• Aquifer• Washing machines• Not for potable use |
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Landscape Lighting Objectives |
Safety: Avoid injury. Landscape lighting should provide a clear view of anypotential obstacles in the environment Security: Avoid intrusion by trespasser. Light can be a deterrent to an intruderand it adds psychologically to an inhabitant’s feeling of protection Aesthetics: Allow enjoyment of the environment. Lighting the exterior canprovide a view from the interior out into the landscape, psychologicallyenlarge the interior space by visually fusing it with the landscape and providefor activities such as entertaining and sports. |
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General lighting design principles |
- able to make distinction between major and minor roads, paths etc by varying distribution and brightness as well as height, spacing, colour of lamps - clear lighting pattern reinforces circulation, delineates intersection, visual cue to conditions ahead - minimize glare (no exposed light sources/under-lighting) - security is created though even spacing, peripheral lighting, vertical illuminance levels, good colour-rendering |
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Distance to which light should extend |
key is to “place lighting in such a way that it allows people to be recognizedfrom 25 feet away” and to avoid creating harsh shadows and contrasts betweenlit areas and unlit areas. Brightly lighting paths with a sharp drop-off to darknessin the adjacent planting areas should be avoided. |
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Lamp characteristics and Lighting Effects |
Selection of a lampinvolves trade-off between lamp size, optical control, efficacy, appearance,color temperature, color rendition, lamp life, costs, and maintenance - Illumination data tor lighting fixtures are illustrated by photometric chartsprovided by the manufacturer. These charts illustrate light patterns onhorizontal and vertical planes - Uniformity of illumination is described by a ratio of the intensity values in lux |
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Steps and staircase lighting |
lighting must provide enough light to identify thepresence of the stairs and to differentiate between the risers and treads. |
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Light fixture selection |
fixtures can be divided into two basic types: those thatserve as part of the decoration of the landscape and those that providelighting effects from hidden locations. |
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Perception of Slope |
Impacted by: texture (rough looks less steep) relationship to surrounding grades 2% or more is visible in pavement Horizontal reference lines increase awareness of slope |
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Convex Slope |
More abrupt foreshortening Sense of height accentuated from uphill side Contours lines spaced at decreasing intervals in downhill direction Slopes flatter at higher elevations |
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Concave slope |
More graceful from downhill side Contour lines spaced at increasing intervals in downhill direction Slope is steeper at higher elevations |
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Spatial considerations for slopes |
Enclosure: containment, privacy, screening, safety Separation: separate activities to reduce potential conflicts Channeling: direct/funnel circulation and control viewing angles |
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Environmental Considerations for slopes |
Stormwater mgmt habitat enhancement (e.g, recreate meandering forms) Microclimate modic\ficaiton: enclosure, snow drift control, reduce wind |
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Environmental Development Constraints |
Topography: locate HPs and LPs, slope %, extent of level vs steep areas Drainage: conform as closely as possible to existing to reduce negative impacts Vegetation: changes to drainage can impact, stay out of root zone Soils: bearing capacity, angle of repose, shear strength, permeability, erodibility, frost action, pH Erodibility: minimize erosion by reducing area of disturbance |
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Negative impacts of development |
Increased impervious surfaces, channelization, floodplain encroachment = decreased water table, increased fluctuation, increased flood hazard |
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Soil considerations for grading |
Avoid/remove: loose silts, soft clays, soils with high organic content Other critical conditions include high water table Evidence of earth movement include landslides, subsidence, creep Need to know history of site |
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Land Subsidence |
gradual settling or sudden sinking of the Earth's surface due to removal or displacement of subsurface earth materials |
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Temporary Erosion and Sediment Control Plan |
Indicates measures to be taken during construction as well as permanent measures that will be included once complete Need to strip and stockpile ex topsoil layer properly to avoid loss Erosion is impacted by slope (degree and length) - erosion potential increases as either of these increase |
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Functional Development Constraints |
Restrictive conditions: legal controls and physical limitations, need to tie in at PL Bld and zoning regulations Utility systems - elevations of existing system needs to be lower than proposed, need to have enough capacity |
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Three types of structural foundations |
Slab foundation: horizontal plane with relatively thin profile, least amount of grading flexibility - depending on length of building, slopes up to 3% can be achieved along face Continous wall foundation: forms a line that provides for moderate flexibility depending on ht of foundation wall, grade changes of one storey or more can be achieved Pier/pole foundation: most flexibility, least ground disturbance, poles form points where they meet the ground |
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Minimum distance below siding |
Grade at the foundation should be minimum 8" below siding material |
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Street layout configurations |
Street parallel to contours: if bld long axis is parallel to road it creates a block for drainage - work around by terracing (cut on uphill side), normally results in easy access btwn circulation system and bld Street perpendicular to contours: most common practice to place long axis of bld parallel to road, makes it easier to direct SW around; problems include the gradient of the road becoming to big, awkward relationshop that may result at access points from street (cross slope), may need grade changes between blds Place street diagonally across contours: more efficient storm drainage, better relationship btwn access and structure, less steep than perp. arrangement, least disturbance Layout impacted by: type/vol/speed of traffic, local climate and ex topography, specific activities |
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Grading for sports fields |
Baseball: grade twd outfield Courts: crown from centre or sheet flow Playing fields: crown at centre, split to both sides |
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Desirable slope ranges |
Public streets: 1-8% Private road: 1-12% Parking area: 1-5% Courts: 0.5-1.5% Field: 2-3% Terrace seating: 1-2% Grass bank: up to 33% Planted bank: up to 50% |
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Economics and maintenance post construction |
optimum: balance cut and fit - if not possible excess of cut is less costly mowing is a primary concern in northern climates steep slopes on circulation routes may increase snow removal and excess salt and sand (be mindful of solar orientation) |
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What to know in order to calculate slopes |
Scale, direction of slope, contour interval (assume accuracy to 1/2 of interval) |
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Characteristics of Contours |
1. all points on contour are at same elevation 2. every contour is continuous and eventually forms closed loop 3. need 2+ contours to define 3D 4. steepest slope is perpendicular to contour lines - greatest vertical change in shortest horiz distance 5. water flows perpendicular to contour line 6. for same scale and contour interval, steepness of slope increases as space btwn contours decreases 7. equally spaced contours = constant/uniform slope 8. contour lines never cross except where there is an overhanging cliff, natural bridge 9. in natural landscape contours never divide or split |
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Stairs |
Minimum width 900mm - min width for passing 1200mm 2R + T = 24-26 in (600-660mm) Common: 6in (150mm) riser with 12 in (300mm) tread 5 in (127mm) riser with 15in (381mm) tread Minimum 3 risers - max 10-12 risers for a set of stairs More than 12 need to include landing Handrail required for more than 5 risers Treads pitch min 1% downhill Cheek walls commonly used along the edge for safety and maintenance - contours only drawn to outside edge of cheek wall Grades at top and bottom indicated w spot elevations |
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Ramps |
Typically 20:1 - 12:1 for pedestrian access AODA says max 6.67% Min 1200 width Handrails required for 20:1 or greater Max rise 30 in (760mm) with landing every 30 ft (9m) May be graded to slope perpendicular to direction of travel or preferably cross sloped (max 50:1) |
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Cordonata |
Combination of stairs and ramps (stairs > ramp > stairs) |
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Retaining walls |
Allow for greatest change in elev. over shortest distance - most expensive proper drainage: build up of water pressure behind wall - need drainholes/weepholes near base of wall and lateral drain behind wall for excess groundwater Saturation of soil under the wall reduces bearing capacity - intercept runoff on uphill side with swales or drains to prevent it flowing over the top Indicate TW and BW at ends and corners Contours drawn to face of wall |
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Slopes |
to be visually significant should not be less than 5:1 (H:V) Planted slopes shouldn't exceed 2:1 Paved slopes can be up to 1:1 or greater Mowed lawn shouldn't exceed 3:1 but 4:1 preferred Dependent on design intent, soil conditions, erosion, type of surface cover - stabilize with veg or mech. to avoid erosion |
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Terraces |
relatively flat intermediate levels to accommodate a change in grade could be visual, structural, or functional, can be with slopes, walls or both when slope and bench are small in area and grade change can pitch bench in downhill direction with big change need to pitch bench back from slope to reduce ersoion Need to deal with SW runoff from bench to prevent saturation at toe of uphill slope (can cause slump) |
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Collecting topographic data |
Typically collected by placing grid pattern over site (usually 10, 20 or 30m squares) 2 rows of stakes along each of 2 sides, rod person locates remaining intersections by aligning leveling rod with two pairs of stakes |
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Cross Slope |
Slope across a structure, pathway, drive, etc Positive drainage, prevents ponding, carries water to gutter Perpendicular to path of travel - typically 2% |
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Road Crown |
difference in elevation between edge and CL of road purpose is to speed up stm runoff from road and visually separate landes expressed in inches or inches/foot (total crown ht calculated by multiplying 1/2 road width by rate of change) |
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Road Crown sections |
Parabolic: commonly used in asphalt construction - change in slope direction achieved through rounded transition - contour lines point in downhill direction Tangential section: most often found with concrete construction since easier to form, CL emphasized due to intersection of sloping planes, contour lines point downhill but are V-shapedReverse crown: may be parabolic or tangential, typically used in laneways/where you don't want water going to edges, contour lines point uphill like valley*not all roads are crowned - some are banked on curves to counteract overturning forces) |
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Curb |
Vertical separation at the edge of the road Usually 6" (150mm) but ranges from 2" (100mm) to 8" (200mm) Directs/restricts SW runoff and for safety |
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Swale |
Constructed or natural drainage channel that has a vegetated surface (gutter is paved surface) Depth is measured as difference in elevation between CL and point at edge of swale on a line perpendicular to CL Contour signature similar to valley Intercepts, directs, and controls runoff |
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Saddle of swale |
dividing point for two swales sloping in opposite directions - simultaneously a high point (parallel to direction of swale) and a low point (perpendicular to direction of swale) |
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Contour signatures of planar areas |
One plane requires 2X elevation to drain the area as crown or reverse crown more low points = smaller grade change required for drainage (requires more drainage structures |
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Slopes for surface drainage |
move water away to: avoid leaking, avoid soil saturation, avoid adverse effects of moisture on bld materials |
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Positive drainage |
draiange away from a structure |
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Diversion |
channel with supporting ridge on lower side constructed across slope to suitably stable outlet |
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Grading Process |
1. Site Inventory and Analysis of development program: existing physical and cultural conditions, evaluate opps/cons/conflicts 2. Design Development: concept w one or mre solutions, grade changes must be purposeful 3. Design implementation: drawings and specs |
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Grading Plan Development |
1. Develop section criteria 2. Application of section criteria 3. Develop slope diagrams 4. Evaluate slope diagrams |
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Five elements for a grading plan |
- written/graphic scale - north arrow - notes (general/explanatory, description of unique elements, source of ex condition data, benchmark and ref data) - legend/symbols and abbreviations - title block |
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Impacts of soils on construction |
- max steepness depends on shear strength of exposed soils - where walls are necessary their design will be based on soil properties - fill operations include methods of soil placement and methods of compaction depend on soil type |
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Footings and Foundations |
weight of structures supported by soils underneath - footings transfer weight to soil shallow foundations generally used with firm soils deep foundations (piles/caissons) used where weaker surface soils are underlain by mroe stable soil |
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Pile |
vertical structural member made of steel or concrete and driven into ground |
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Caisson |
constructed by drilling holes into ground and filling with concrete - constructed to bedrock or to depth where bearing capacity is enough |
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Soil Drainage |
Sandy/non-cohesive = more erodible, more permeable Clay-ey = more erosion-resistant, less permeable Stratified (layers of coarse and fine) = may present complex situation (e.g, sandy soils w clay beneath may hold water or transmit laterally) |
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Soil Phases |
accumulation of solid particles generated from physical and chemical weathering of parent material containing network of voids that may be filled with gas or fluid Soil has 3 phases - solids, water, air Total volume of soil (V) = volume of solids (Vs) + volume of voids (Vv) Volume of voids (Vv) = Volume of water (Vw) + Volume of air (Va) Total weight of soil (W) = weight of solids (ws) + weight of water (Ww) |
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Physical soil properties |
particle size/shape/minerology structure, texture, colour, organic content, pH density, moisture content and specfic gravity |
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Unit weight and bulk density |
weight of soil/volume of soil = g/cm3 |
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Water content |
amt of H2O impacts degree to which it can be worked or compacted as water increases soil will move from solid > semi solid > plastic > liquid when all voids are filled with water soil is saturated |
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Specific gravity |
ratio of unit wieght of soil solids to unit weight of water values range from 2.5 - 2.8 depending on soil minerology, typical value of 2.65 |
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USDA textural classification |
sand: 2 - 0.05mm silt: o,o5 - 0.002mm clay: >0.002mm 12 textural designations |
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AASHTO soil groups |
based on suitability for roadway subgrade |
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Unified Soil Classification System (USCS) |
coarse-grained: gravels and sand find grained: silts and clays organic |
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Grain-size analysis |
cobble, gravel, sand, silt, clay (no 200 sieve) |
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Atterberg Limits |
liquid limit: boundary between plastic and liquid plastic limit: boundary btwn semi-solid and plastic Shrinkage limit: boundary btwn solid and semi-solid |
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aring capacity |
what a soil is able to support - expressed in N/m2 or lbs/sq ft hard-sound rock = highest saturated organic = lowest If soil can't support it needs to be removed and replaced or other methods used (piles, spread footings, floating slabs) |
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Shear strength |
stability of soil and ability to resist failure under loading result of internal friction (resistance to sliding btwn soil particles) and cohesion (mutual attraction btwn particles due to moisture content and molecular forces) Shear strenght of sand and gravel increases in relation to normal pressure so degree of slope doesn't need to decrease with height increase Slope failure occurs when shear stress > shear strength |
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Frost penetration |
silty soils/soils w even distribution of particle sizes are subject to frost action movement of soils with freeze or thaw = decreased bearing capacity depth of freezing depends on temp, soil structure, presence of capillary water |
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Soil shrinkage/swell |
clay soils/soils with clay fines shrink as they dry and swell as water content increases degree of change depends on minerology and degree of water change high plastic w very fine (colloidal) that change = expansive clays can sometimes be c\good to seal reservoirs |
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Structural soils |
Cornell University: gap-graded angular crushed stone, clay-loam and hydrogel Carolina State: stalite, sandy clay loam Davis: lava rock and loam soils |
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Structured soil volume |
modular structure to support structures and create void for topsoil (2 ways - steel or CIP conc, or off the shelf modular unit) |
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Lightweight Soils |
how to support plants over structures fabricated from range of components Lightest weight: soil-less, aggregate, negligible organic - best suited for alpine plants heavier loads: sand, slow releasing fertilizer, lime, organics |
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Geotextiles |
synthetic fabrics with physical and engineering properties used to enhance soil properties or improve structural performace woven or non-woven fabrics of syntehtic polymer fiber subset of geosynthetics Properties: tensile strenght, elongation, puncture resistance, UV resistance, apparent opening size, permeability |
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Geotextile Applications |
drainage: convey water within plane of fabric, thicker and non-wovern Filtration: allow water thru plane of fabric while preventing movement of soil, apparent opening size, permeability Reinforcement: distributes imposed loads to underlying soils (e.g, roads) Separation: prevent mixing of separate materials |
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Construction Sequence for Grading |
1. site prep 2. bulk excavation 3. backfilling and fine-grading 4. finish surfacing |
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Placing and Compacting Soils |
subgrade material for structure/roadway is closely controlled fill is spread in uniform layers called lifts, each layer compacts material held to a uniform moisture and consistency |
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Compaction |
densificaiton of soil by decreasing voids - increased bearing capacity and shear strength moisture content plays role: dry means particles rearranged and crushed to fill voids, moist - need enough water to facilitate mvmt without filling all fo the voids |
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Standard proctor vs. modified proctor |
differ in amt of energy applied MPD is higher energy and more compaction |
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Compaction equipment by soil type |
vibratory steel drum for sandy soils Heavy rubber tired roller for fine sands/non-plastic silts Sheepsfoot roller (kneading) best for clay soils |
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Earthwork specifications |
must describe materials and placement procedures: topsoil removal, bulk excavation, structure excavation, earth fill, structure backfill, final shaping and grading Need to define scope and limits of excavation, used or disposal of material, placement and compaction reqs, finish grading reqs, how work will be evaluated as basis for approval and payment Critical issues: performance and safety, on-site testing, reference standards where needed, incorporate safety reqs |
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Finished Grade |
final grade after all works done usually indicated by spot elevations/contours |
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Subgrade |
Top of the material that surface material is placed on Represented by the top of a fill situation and the bottom of a cut situation Compacted subgrade - must attain a specific density Undisturbed subgrade - soil that hasn't been excavated or disturbed in a ny way |
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Base/sub-base |
Imported material (normally coarse/fine aggregate) typically placed under pavements |
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Finished Floor Elevation |
elevation of the first floor of a structure but may be used to designate the elevation of any floor relationship of FFE to exterior finished grade depends on type of construction |
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Cut/cutting |
process of removing soil Proposed contours extend across existing contours in the uphill direction |
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Fill/Filling |
Process of adding soil - proposed contours extend across existing in the downhill direction |
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Topsoil |
Normally the top layer of a soil profile, may range in thickness from 25mm to more than 300mm High organic content, subject to decomposition - not an appropriate subgrade material for structures |
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Grading Operations |
Option 1: Balance cut fill Option 2: import or export (preferable to export vs. import - cheaper to export, fill condition is generally less stable) |
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Average End Area Method |
Best for lineal construction Volume of cut or fill btwn two adjacent cross sections is the average of two sections multiplied by distance between them V= [(A1+A2)/2]XL Take cross sections at predetermined intervals Each xsection indicates existing and proposed grades - measure area between existing and proposed Keep cut separate from fill |
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Borrow Pit/Grid Method |
For complex grading projects/urban conditions 1. lay grid out over site and determine ex elevations at each grid intersection 2. determine proposed elevations at each intersection through interpolation 3. Calculate difference between elevations (use F or C to signify fill or cut) 4. Apply method cell by cell - find average change in each cell by finding DE for each corner - add together then divide by 4 Find volumes by adding all averaged values together (keep cut and fill separate) then multiply by area of one grid cell |
