How to Estimate the Cost of a Water Main Installation in a City Street CPE Candidate No. 0114217 June 15, 2014 4 How to Estimate the Cost of a Water Main Installation In an Urban Environment Table of Contents Section 1 Introduction Page 6 Section 2 Types of Methods of Measurements Pages 6-­‐11 Section 3 Project Specific Factors to Consider Affecting Takeoff and Pricing Pages 12-­‐15 Section 4 Overview of Labor, Material, Equipment, Indirect Costs and Pages 15-­‐18 Approach to Mark-­‐ups Section 5 Special Risk Considerations Page 18 Section 6 Ratios and Analysis – Tools Used to Test the Final Bid Page 19 Section 7 Miscellaneous Pertinent Information Pages 19-­‐21 Section 8 Sample Plan and Profile View Pages 21-­‐22 Section 9 Sample Trench and Restoration Detail Page 22 Section 10 Sample Estimate-­‐ Takeoff and Pricing Sheets Pages 23-­‐25 Section 11 Terminologies – Glossary Page 26 Section 12 References & Copyright Releases Page 27 5 Section 1 Introduction This technical paper is focused on providing the reader with a general understanding of the necessary steps and procedures to complete a construction cost estimate for the installation of an underground water main in an existing city street. Unlike residential or commercial projects conducted in previously undisturbed virgin soil, water main installations in existing urban environments can present a great potential for difficult obstacles such as unforeseen utility conflicts, abandoned utilities, contaminated or hazardous soils, existing asphalt and roadway improvement restoration, traffic control, etc., which will require the cost estimator to consider much more than the labor, equipment and materials for the project. The basis for this technical paper is: Main CSI (Construction Specifications Institute 2004 Master Format) Division Division 33 Utilities Main CSI (Construction Specifications Institute 2004 Master Format) Subdivisions Subdivision 33 10 00 Water Utilities Subdivision 33 11 13 Public Water Distribution Piping Subdivision 33 12 13 Water Service Connections Subdivision 33 12 00 Water Distribution Equipment Section 2 Types and Methods of Measurements After the Estimator has conducted a thorough review of the contract documents and determined that the project falls within the guidelines of company policy to proceed with the estimate, he/she will need to conduct a quantity survey. The quantity survey or takeoff is one of the most important steps that the estimator will take in the process of developing the cost estimate. If the estimator is not careful in taking off the project quantities, it could lead to a costly error, which could detrimentally affect the price of the bid and result in a significant financial loss on the project. Before starting the quantity takeoff, the estimator will want to become very familiar with the trench section details and pipeline profiles for the watermain. The trench section details will provide the minimum depth and required cover of the watermain, minimum trench width, bedding, backfill material requirements 6 and asphalt thickness and restoration limits. If available, the pipeline profile should show the pipeline design depth and vertical alignment of the waterline from start to finish. A contract for a new watermain is typically bid by the unit price. The contract bid package will typically include a bid form that will include the engineer’s quantities for the various bid items. The contract bid form will list such items as Mobilization –Lump Sum, Traffic Control-­‐Lump Sum, Water Main-­‐Lineal Foot, Tee-­‐Each, Gate Valve-­‐Each, Signal Detector Loop-­‐Each, Asphalt Restoration-­‐Square Foot, etc. with estimated quantities. The estimator will use this bid form to submit the estimated prices to the project owner. The bid form will also serve as a helpful guide in preparing the estimate. However, the estimator must be careful to always confirm the quantities and not assume that the contract bid item quantities provided by the engineer or owner are correct. If one of the bid items is presented as a final pay quantity, there will be no chance to receive additional compensation for actual quantities that exceeded the engineer’s bid estimate. Further, there are many appurtenances that will need to be included with the installation of the watermain, which may not be included on the bid form. The design engineer may have omitted a blow off assembly or air relief valve that will need to be included per the contract description of bid item or written specification. Vertical pipe offsets under existing utilities may not be included in the engineer’s estimate and should be considered. A cathodic protection system may need to be installed with anode bags and test stations. When these types of issues are discovered during the bid process, it is prudent for the estimator to submit an RFI (Request for Information) to the Owner or Agency for a clarification or revision of the contract scope to include any additional items that were not called out on the bid form or specifications. The Estimator can takeoff the project plans by utilizing several methods that can be manual tools including an engineer, architect or metric scale ruler or measuring wheel, and electronic devices consisting of a digitizer or onscreen takeoff system software. The information gathered in the quantity takeoff will become the basis for determining the required labor, material and equipment in 7 the cost estimate. The quantity takeoff for the new water main will start with the measurement of quantity of the new watermain by the lineal foot (LF). There are many varieties of material options for new watermain installations. The most common present day watermain materials specified by design engineers will include PVC, Cement Mortar Lined and Coated Steel and Ductile Iron. The PVC and Ductile Iron material is typically supplied in 20 LF lengths, while the steel pipe is commonly supplied in 40 LF lengths. Whether or not 20 LF of pipeline is being installed, the estimator must still include the additional material cost for purchasing a full length of material in the bid. Rounding up to the next full pipe section will be required to ensure an accurate material budget for the project. Horizontal and vertical changes in direction of the pipeline will require the use of fittings or bends, which are measured by the each (EA). Pipe fittings are typically designed as a 22, 45 or 90-­‐degree elbow configuration for PVC, cast or ductile iron. However, custom offsets and elbows can be fabricated out of welded steel and could be potentially added to the pipe system if allowed by the project Owner. Depending on the type of material system utilized, a fitting may be constructed of PVC, Steel, cast or ductile iron. Specification requirements may require that the non-­‐plastic fittings include special coatings that include fusion bonded epoxy, liquid asphaltic coat and cement mortar lining and coating. If the material is not supplied with the specified coating and lining, the estimator will need to source a coating company and provide the vendor with an estimated diameter, length and weight that will need to be coated to determine the appropriate cost. Often times the required coatings will be included in the supplier’s pipe package. In addition to the special coatings and linings, the estimator needs to fully understand the specified type of connection. The various types of connection could include slip on, flanged or mechanical joint. In some cases the connection type will also need to be restrained with a mechanical lug restraint for mechanical joint fittings or restraint harness systems for push on and flanged applications. Many project specifications require the restraint of the fitting with a concrete thrust block. An appropriate quantity of short load concrete will need to be added under the backfill 8 estimate for the pipeline. Special consideration should be taken here because it may not be possible to place a full load of concrete for all thrust blocks in a given day. Therefore, a higher concrete unit cost will need to be applied. The quantity of the concrete thrust block will be calculated by the cubic yard (CY). Water systems can contain a considerable amount of valves, fittings, accessories and appurtenances that need to be carefully considered by the estimator. Most of these items will be taken off by the each (EA). While most waterworks and pipe supply houses will prepare a materials list and package bid for a project, it is important to carefully analyze and verify what is being quoted and avoid plugging the low material bid amount into the estimate without carefully analyzing what is included in the total quote. Often times different supply houses will be quoting different manufacturers that may not be an equal to what the design specification has called out for. Assuming that the low price pipe package with a coating or restraint system that is not an equal to what has been called out in the specifications could be a costly mistake if not approved by the Owner. Once the total lineal footage of the watermain has been determined, the estimator can then use the trench section detail and profile to determine the quantity of trench excavation by the Cubic Yard (CY). The Cubic Yard calculation is three dimensional (Width X Depth X Length/27), and will require the estimator to determine the average depth of the pipeline, as well as the average width. Additional considerations for existing adjacent utilities, concrete structures or trench shoring will be required when determining trench width. The trench volume cubic yards can be converted to tons for an accurate estimate of required trench rock backfill or cement slurry. The backfill requirements can be verified in the project specifications, Agency Standard Specifications or contract drawings. It would be prudent for the estimator to consider a waste factor when calculating the needed quantity of materials. Thus, the ordered backfill material will be greater than the theoretical calculated bank volume. Further, the trench spoils from the excavation will need to be off hauled. The excavated spoils will swell once removed from the 9 trench. The estimator will need to apply a swell factor of 10% when calculating the volume of spoils, which will affect the total number of trucks and associated fees for trench spoil disposal. The estimator will need to include analytical testing costs of the soils before hauling to disposal site. Most land fills, developments or quarries will require documentation on the soil to ensure that is clean and free from pollutants and constituents of concern before accepting. It is advisable at bid time to review the bid documents to determine if soils information is available, or submit an RFI to Owner for more information. Once the quantity of excavation cubic yardage has been obtained, the estimator can then apply the calculated dimensions to determine the quantity of pipe bedding and cover which is typically calculated and purchased by the Ton (TN). The estimator can utilize a multiplier or weight conversion factor for the various types of bedding and backfill material that will be needed. As an example, the estimator can use the weight of 1.45 tons per CY as a multiplier to determine the needed tonnage sand bedding. For the ¾” CL II road base rock, a weight of 2 tons per CY can be used to determine the total tonnage of rock needed. Please note that the conversion multipliers referenced above also contain a shrinkage/compaction consideration. This is used because the material is sold and shipped loose. If the estimator only considered bank compacted yards in his/her material takeoff, it would be short of the actual material that will need to be ordered for the job. In addition to the material calculation, the delivery of the materials will also need to be calculated. Whether utilizing company owned trucks or an outside trucking company, the required size and type of truck to deliver the material will need to be considered to properly estimate the project cost. The most common options for hauling the aggregate material for an underground watermain project will be a 10 Wheeler Dump with a 12 TN capacity, a Semi Transfer Dump with a 24 TN capacity or a Semi End Dump or Side Dump with an equivalent capacity. The estimator will need to take the estimated total quantity of aggregate material needed and divide by the capacity of the selected haul truck to determine the approximate number of loads. (300 TN Material/24TN Truck Capacity = 12.5 Truck Loads). The estimator will then take the total number of loads and multiply by the haul time to 10 determine an approximate number of trucking hours for the estimate. (12.5 Loads X 2.5 Hr round trip = 31.25 Truck Hours). Other factors that will need to be considered will be whether or not the material can be stockpiled or if the area that the truck will be routed through can accept a full sized semi or will require a smaller truck. When using an outside trucking company, a four hour minimum charge will most likely apply, regardless of quantity hauled. So, it is important to properly account for this additional cost if one segment of the watermain will only allow for a small quantity of aggregate material to be placed on a given day. If the watermain is to be installed in a paved roadway, it will most likely require a crushed road base backfill up to asphalt pavement subgrade. Other times there may be a requirement to provide cement slurry backfill. The requirement for road base or cement slurry is to prevent future settlement in the roadway area by ensuring the contractor achieves 95% compaction. If the contractor were to backfill with native material, it is highly unlikely that the specified compaction would be achieved. The contract specifications will require a testing and flushing of the watermain to ensure that there are no leaks in the pipe system and to ensure that it is properly disinfected and suitable for transmission of potable water. The estimator will need to determine the quantity and cost of the required water to test and properly flush the watermain. By calculating the volume of the pipeline (pi X radius squared=area; multiply area x length = volume in CF) and then the estimator can multiply the total calculated cubic feet by the local water agency cost per hundred cubic feet (Ccf). One hundred cubic feet of water is equivalent to 748 gallons of water. The needed liquid chemicals or tablets can be estimated by assuming a ratio of gallons of chemical per CF of water volume or tablets per stick of pipe. Lastly, the estimator will need to determine if the flush water will need to be dechlorinated and whether or not the water can be discharged in to storm sewer system. In many areas this will not be allowed and will require a permit to discharge into the nearest POTW sewer system. The estimated permit fees and cost per gallon will need to be added to the estimate. 11 Section 3 Project Specific Factors to Consider Affecting Takeoff and Pricing The Estimator who will be responsible for the development of the cost estimate for the new water main installation will need to conduct a comprehensive review of the project scope, construction plans, details, specifications and Geotechnical Investigation. Often times the Geotechnical Report will not be included with the bid documents and specification book, but will be available for separate review over the counter at the Owner’s office. It is critical that the estimator review this information if the report is available. Considerations of season, weather and geographic location of the project are very important. While most contracts have an allowance for weather delays, it still may be required to complete some activities in raining or wet environments due to project schedule. An adjustment of production rate or additional contingencies may be required. When working in northern areas and higher elevations, freezing conditions may adversely affect trenching and pipe laying efforts. Production rates will be lower in these conditions and should be adjusted accordingly. The Soils Report contains valuable information regarding the present site conditions in the vicinity of the new watermain to be installed. Boring logs can be found as an exhibit in the soils report, which will indicate the types of soil layers, or rock that will be encountered during excavation. The boring log will indicate the asphalt thickness in the existing roadway so that the estimator knows how thick his replacement section of asphalt will be and can estimate that cost accordingly. The boring log will also indicate whether or not there was refusal during the borehole drilling. Refusal is the point at which the drilling stops and cannot continue due to obstructions such as rock or an unforeseen structure. Further, the boring log will indicate at what elevation ground water was encountered, if any. Knowing whether or not the excavation for the new watermain will be through rock can be a serious cost impact that could significantly affect the type of equipment utilized and production rates 12 estimated. Type A soils will be cohesive and less likely to cave in, or slough off into a trench, while a Class C soil will contain granular, sandy material, which is most likely to slough off into a trench. With this information, the estimator can make the best determination of excavation equipment and shoring to be used. Ground water is also a very serious risk on a project that must be considered. If ground water is present, temporary dewatering with submersible trash pumps must be conducted to remove the water from the excavation. In these wet areas the subgrade will be very unstable and not ideal for installation of pipe bedding and rock. Proper stabilization methods, which should be indicated in the plan details and written specifications, will usually call for the use of clean drain rock wrapped in geotextile fabric to stabilize the subgrade. The trench stabilization will be an increased cost of material, trucking and labor time that will need to be accounted for separate from the rest of the watermain installation. Sometimes this unforeseen stabilization cost will be paid for under an allowance item for unforeseen conditions. However, this is rare and will likely not be found in most contracts. In some instances, it may be required to install a temporary dewatering system to draw down the water table before trench excavation can begin. In addition to the slower crew production in these types of conditions, the estimator needs to also include the temporary dewatering system pump or well point rental costs to contain the groundwater in tanks, obtaining a groundwater dewatering permit from the local governing authority and have the water tested for constituents of concern before discharging at an approved location, which could be a POTW or waste facility. In some instances the ground water can be discharged overland but will require special approval. Under the specification section for trench backfill, the estimator will need to carefully review and determine if there are compaction requirements and whether the contractor or Owner will be responsible for compaction testing for the backfill. The estimator should consult with a materials testing company to determine the minimum hourly charges for compaction testing and the costs for 13 running a compaction curve at the testing laboratory. Once the estimator has determined the number of backfill days for the project, an estimated number of compaction testing mobilizations and budget of testing hours can be determined. When installing a watermain or any underground utility in an existing city street, a special consideration needs to be made regarding traffic control. Many cities will require a traffic control plan to be submitted before work can begin. In some cases, a basic markup of a site plan showing the location and spacing of traffic signs may be considered adequate. However, many cities and agencies will require a professional traffic control plan stamped by a Professional Engineer to be submitted. This could be a significant cost that will need to be added to the bid. To avoid liability, many contractors now subcontract traffic control services to a specialty subcontractor. However, this adds additional costs and markup to the project cost estimate that may make the estimate less competitive. The specialty subcontractors are well trained and certify all of their personnel in traffic safety. If a contractor is considering the utilization of their own onsite crews, they will need to include the costs for any special training requirements and certifications that their personnel will need to have. There is a large cost difference between water main installations with a shoulder closure versus a full traffic lane closure. Further, there will be even larger cost impacts for a watermain installed on a two-­‐lane road that requires a full lane closure and two-­‐way traffic control. The traffic control subcontractor will require the number of working days calculated in order to provide an estimated cost. Whether the traffic control is subcontracted or performed by the contractor’s own forces, the duration of traffic control required work will need to be calculated. When dealing with unit price contracts it is important for the estimator to understand that spreading overhead, indirect and direct project costs over an estimated quantity of 1000 LF of pipeline will result in a considerably lower unit price than when those costs are spread over 100 LF. The estimator will need to pay careful attention to how these line items are paid for and whether or not a unit price adjustment will be allowed for significant additions or deletions in the contract. The author of this paper has had first hand experience with an Owner who had deleted 90% of a bid item 14 quantity and expected the unit price to remain the same due to a note on the project plan! Material changes in scope and quantity will warrant an equitable adjustment and will require the estimator to negotiate a new unit price that will cover the costs, overhead and markup for the modified scope of work. A site visit will be needed, as well as a careful review of the Contract General and Special Provisions. The Estimator will need to assess the anticipated start date and expected completion date of the project to determine if the needed manpower and equipment will be available in time for the project. Will the project involve night work or weekend work? Will there be time restrictions in any of the work areas? Many Cities have working hour restrictions due to commute traffic or schools. Will the contract be a unit price or lump sum? What is the payment frequency? If the contract is for a unit price bid, will the contract allow for unit price adjustment if more than 15% of the work scope is increased or decreased? Some contracts do not allow for a unit price adjustment and will only compensate the contractor for actual quantities installed. Careful consideration of these items will need to be evaluated before proceeding with the estimate. It is not uncommon for an estimator to decide to not proceed with bidding on a project due to any one of these factors not being favorable or inline with company policy or too risky for the company. Section 4 Overview of Labor, Material, Equipment and Indirect Costs and Approach to Markups Once the estimator has completed the project takeoff, he/she can begin to prepare the cost estimate. The cost estimate will include all costs for the needed subcontractors, materials, labor and equipment with an appropriate markup for overhead, profit, escalation, contingency and bonds. The estimator will need to send out the generated material takeoff lists to suppliers for a job specific quotation on the required materials. It is imperative that the estimator read the contract specifications for each material that is being quoted. There are many material prices that will tend to be repetitive, especially if the estimator bids in the same city or geographic area continually. The 15 estimator needs to ensure that he/she has read the material specification, and avoid “plugging” average historical estimated materials costs without obtaining a new job quote. This should be avoided because it could lead to a very costly mistake if the project specification for the material was changed due to special job conditions and requirements. Tax, freight and minimum order quantities will also need to be taken into account in the determining of an accurate materials cost budget for the estimate. In order for the estimator to determine the labor and equipment costs for the project, a production rate will need to be applied to the various tasks on the project. The production rate utilized can be determined through the use of historical company cost data tracked by a Labor Distribution Report, or could be determined by published production rates through means, etc. Once the production rate has been determined it will be applied to the total water line length to determine the number of days or man-­‐hours required to complete the watermain. Labor and equipment costs will be determined by applying the calculated total number of man and equipment hours for the work by a composite crew labor rate, individual crew craft rates and equipment rates as shown below: COST ITEM
QTY
OPERATING ENGINEER FOREMAN
OPERATING ENGINEER- GROUP 2
LABORER - PIPE LAYER
CREW TOOL TRUCK - 1 TON
FOREMAN TRUCK - 1 TON
CAT 314 EXCAVATOR
CAT 235 EXCAVATOR W/WHEEL
1
2
4
1
1
1
1
TOTAL HOURLY COST
TOTAL DAILY COST (8 HR DAY)
UNIT
HR
HR
HR
HR
HR
HR
HR
UNIT COST
$88.95
$78.95
$58.95
$17.00
$17.00
$65.00
$58.00
TOTAL
COST
$88.95
$157.90
$235.80
$15.00
$15.00
$65.00
$58.00
$635.65
$5,085.20
If the project is being bid for a public agency, there will be a prevailing wage requirement to adhere to. The prevailing wage requirement, required by the Davis Bacon Act, will be automatically met if the bidding contractor is a union contractor who is signatory to the appropriate unions such as Operating Engineers or Laborers union. If the contractor is not a union contractor, he/she will need 16 to reference the local prevailing wage rates, which should be included in the bid documents and include the appropriate listed rates in the cost estimate. The Public Agency will verify that these prevailing wage rates are paid to the employee by requiring the contractor to submit a weekly certified payroll report. The project direct costs, which include materials, can be generated from the quantity survey for the project. The estimator will need to ensure that all pipe material; fittings, valves and appurtenances have been counted and included in the appropriate items of the estimate. The estimator will solicit suppliers for quotes on the needed materials and will need to ensure that all taxes and freight are included. Typically, suppliers of construction materials will leave freight and tax out of the bid to ensure that the contractor can easily compare the bottom line total against the competing material supplier bid package. Aggregate materials and quarry locations will need to be verified to ensure that the trucking hours have been calculated appropriately. Most likely there will be subcontracted work on the project. Subcontractors may include traffic control, asphalt pavement restoration, concrete sidewalk, curb, gutter and valley gutter replacement, electrical and signalization contractors for traffic loop replacement, surveying, landscaping and saw cutting which should be solicited for a written proposal to be included in the bid file. The estimator should be careful when analyzing and considering subcontractors to include in the estimate. More than one subcontractor should be solicited. Each proposal should be checked and verified for accuracy of scope and inclusion of all required items. A subcontractor that cannot perform what has been quoted could be a significant project risk. After including direct labor, equipment, material and subcontracted items, the estimator will need to determine the appropriate overhead costs for the project. Overhead can be divided into direct and indirect overhead costs. Direct overhead costs will include bid, performance and payment bonds, workman’s compensation, builder’s risk, equipment floater and property damage insurance, permits, site supervision, mobilization, etc. Direct overhead costs include advertising, depreciation, office rent 17 and associated costs, payroll taxes, professional fees, etc. The direct and indirect overhead costs can be added to the project as a percentage of the total cost of the project. Contingency and escalation should also be considered if appropriate for the project. A contingency for unforeseen and unexpected conditions that may be encountered on the project may be prudent. Although unforeseen conditions on the jobsite should be compensated for as a legitimate change order, there are always unexpected situations such as lost or damaged materials, jobsite specific problems, etc. Adding cost for escalation protects the contractor from increase in material and labor costs if they are expected before completion of the contract. After all direct costs and overhead have been included in the estimate, the estimator will need to add mark up. Markup represents the return on money invested in the project and business operations after all costs are paid. Competition typically dictates the amount of mark up that will be included in the estimate. While the contractor may want to realize a 25% markup on the project, depending on the number of competitive bidders, location, risk, difficulty and amount of contractor’s backlog, it could be significantly lower. The markup variable will vary from project to project. The estimator and executive management will carefully analyze the risks and opportunities of the project and set the markup accordingly. Section 5 Special Risk Considerations Construction of underground utilities in general presents a contractor with a great deal of risk. Coupled with the challenges and complexities of installing an underground watermain in an existing urban setting has a potentially unlimited amount of risk and liability. Unlike a green field commercial or residential site that is in previously undisturbed soil, the existing urban setting includes potential for unforeseen utilities that include abandoned or unmarked gas, storm drain, sewer and electrical ductbanks, concrete structures, contaminated soils, asphalt pavement and concrete restoration and traffic control. The estimator has to consider and include all of the above referenced costs in addition to the labor, equipment and materials to complete the installation. 18 Section 6 Rations and Analysis-­Tools Used to Test the Final Bid Quality assurance and control of the prepared bid estimate is critical in identifying errors and discrepancies before the estimate is submitted to the Owner. The estimator is responsible for potentially hundreds of mathematical computations and conversions in the preparation of a cost estimate. It is very easy for there to be an oversight that may not be completely obvious. In other trades such as concrete work, it is possible to utilize unit prices to check the estimated bid quantity costs or bid units to determine if they are within range of the standard unit prices. Unfortunately, due to the unique risks and considerations inherent to installing an underground watermain in an existing city street, it can be difficult to compare the estimated cost of the watermain installation to a developed standard unit price. However, the estimator can utilize past watermain installation costs as well as tabulated bid cost data from bidders for previous water main projects in the location that the watermain is being constructed for comparison. The estimator will need to make adjustments for material and labor prices based on the time period that the tabulated bid data was for. While the estimator may not have the ability to check the estimate based on bid costs for all bid items, he/she can check the production rates assigned for pipe trench excavation, pipe laying and backfill. There will be a range of reasonable production that should be assumed on a watermain in an existing urban environment. If the estimator rechecks the estimate and notices that the number of days calculated is a production rate based on 500 LF per day, when the best cast scenario would be 200 LF per day, the estimate will need to be corrected. It is recommended that a peer or supervisor run through the estimate and carefully look at all production rates assigned for the project at a minimum to avoid potential errors in the bid. Section 7 Miscellaneous Pertinent Information A common theme that has been reiterated throughout this paper is the fact that the estimator has much more to consider in his/her estimate than the basic costs for labor, equipment and materials. The project Owner could be a public utility, city or county that has the project set up under an OCIP 19 program (Owner Controlled Insurance) that will require the bidder to remove the project insurance costs from their proposal because it will be covered by the Owner under its own policy. These types of contracts usually entail a considerable amount of additional requirements for safety representatives and special safety training for foreman and crewmembers to be OSHA compliant. These additional costs should be considered and added to the estimate. Further, the timing on receiving the safety certifications may prohibit the estimator from bidding on the project if it is determined that the crew or foreman will not be able to obtain the safety training or certification in time for the start of the project. When working in existing city streets, there can be a large amount of unmarked and unknown utilities. While it is the requirement of every excavation contractor to call USA (Underground Service Alert) 48 hours in advance of any excavation so that existing utilities can be identified and marked, it can be expected that there will be some utilities that will not be marked or will be mismarked. It is good practice to include the costs for an underground utility locating service in the estimate to survey the work area and mark out all utilities behind the USA before starting work. It is a very small price to pay for insurance that the crew does not hit a live existing utility while excavating. Further, having knowledge about potential obstructions and unforeseen issues before starting will save considerable time on the project by allowing the estimator and project manager to assess the potential additional cost impacts and come to an agreement with the Owner before proceeding. Many pubic agencies and utilities require diversity participation in their contracts. The project documents will typically provide a participation goal, which will need to be met in order to be considered a responsive bid for the project. The diverse contractor will be a qualified subcontractor or supplier that is a Woman Business Enterprise (WBE), Minority Business Enterprise (MBE), Disabled Veteran Business Enterprise (DVBE) or Small Business Enterprise (SBE). There is usually a stringent specification that informs bidders how to solicit and recruit diverse contractor participation. Sometimes it is not possible to find a diverse bidder for the project due to lack of subcontractors in the area or general interest in the project. Proof of solicitations to all potential 20 diverse subcontractors will need to be provided to the Owner in order to still be considered responsive without listed diverse subcontractor or supplier participation. Section 8 Sample Plan and Profile View Figure 1 This page depicts a typical plan, profile and detail of a 10” water main and pressure reducing valve installation in an existing city street. The estimator can utilize the presented plan to determine the quantity and length of needed water piping. He/She can easily see the existing adjacent sewer, water and gas utility lines, needed traffic control considerations and existing concrete sidewalk, curb, gutter and asphalt striping that will be affected by the new work. The profile view indicates the minimum depth and amount of cover for both the upstream and downstream side of the new 21 pressure reducing valve as well as depth of existing utilities that will be in the vicinity of the installation and tie in to existing water main. Section 9 Sample Trench and Restoration Detail Figure 2 This page depicts a typical trench section and asphalt restoration detail that provides information for the estimator regarding asphalt restoration, trench bedding and shading, road base section, etc. He/She will utilize Figure 1 to determine the pipeline depth from the pipeline profile. Minimum trench width if not indicated in the trench section view may also be found in the contract specifications. 22 Section 10 Sample Estimate –Takeoff and Pricing Sheets 23 24 25 Section 11 Terminologies – Glossary Construction Specifications Institute 2004 MasterFormat 6 Divisions – is a reference to the 16 divisions of construction that is defined by CSI (Construction Specifications Institue) MasterFormat. The MasterFormat was updated in 2004 and has been expanded to 50 divisions. This standard format and specification itemization is utilized by owners, designers, engineers, builders and contractors to organize and arrange construction contract documents. Class A, B & C Soil Classification – The Occupational Safety and Health Administration (OSHA) uses a
measurement called “unconfined compressive strength” to classify each type of soil. Type A is cohesive
and is the most stable to excavate in. Type B soils are less stable than A soils and include angular gravel,
loam and silt. Type C is the least stable being a low unconfined compressive strength material with little
cohesion.
Owner – A person or entity who would award a construction contract to the contractor and pays for
services defined in the contract.
Trench Shoring – A method of bracing and supporting walls of trench excavation to prevent collapse.
26 Section 12 References & Copyright Releases Reference: Roberts, D., 1951, 1997 Third Printing, Pipe & Excavation Contracting, Craftsman Book Company, Carlsbad, CA. Copyright Release: The watermain drawings and details shown in Section 8 and 9 were available through the City of Modesto, CA Public Works Department. Since these documents are considered public domain, no copyright releases were required. 27