COUNCIL WORKSHOP ITEM

Transcription

1 COUNCIL WORKSHOP ITEM ITEM: Recommendation to Purchase a Pavement Milling Machine DATE: 6/5/01 PREPARED BY: Jack J. Bajor, Jr., Director of Public Works Rick Ebel, Pavement Division Manager PURPOSE: Street Pavement Maintenance BID AMOUNT: $ 184, BUDGET AMOUNT: $ 190, DISCUSSION: Beginning in the mid-nineties the Public Works Department began discussions on methods of improving the effectiveness and efficiency of our in-house patching and pavement work. Discussions quickly turned to milling or grinding pavement patch areas to a depth of two (2) inches, rather than doing full depth patches of the pavement surface. Pavement thicknesses in Downers Grove are quite variable commonly ranging in depth from six (6) to ten (10) inches. So for a pavement patch of a 10 X 20 area, we are removing and replacing approximately 100 to 167 cu.ft. of material with each full depth patch, while the grinder would remove only 33.3 cu.ft. of material for the same 10 X 20 patch. Table 1 compares the material volume differences of three patch sizes for full depth patching verses milling. Obviously, if we are taking a greater volume of material out, there is a greater need for the re-installation of new asphalt. On average a three to one reduction can be realized by moving from full depth patching to milling. Additionally, the process to remove a full depth patch is much more labor intensive as the area is first saw cut, then broken out and finally loaded on to a truck with a backhoe. A grinder can complete all three of these steps as it works, again in about a third of the time. There is also the issue of the material taken from the patch site. The broken up asphalt from a full depth patch is land filled at a cost of $50.00 to $70.00 a truckload. The asphalt removed with the milling machine is commonly referred to as grindings. Disposal of these grindings is more attractive as they are a usable commodity. For example, they can be recycled back into asphalt. Asphalt plants frequently take grindings from regular customers at no charge. Grindings can also be used as base material under some circumstances. In 1999 Martam Construction used our grindings as base material along Main Street during Phase II of the CBD Street Project. Being able to recycle in this manner would save the Village approximately $4,000 in disposal charges each year. In 1997, in a move to improve our program we budgeted to rent a pavement grinder for a week as a trial. Our initial plan was to find an equipment dealer who would rent us a grinder on a weekly basis. At about this same time, having seen the DuPage County Highway Department running a new grinder on 63 rd street we inquired into their machine. We found that they had recently purchased the unit and were open to renting it to us with an operator when they had unscheduled machine time. We decided to rent the machine from the county for a week instead of the equipment rental company. We immediately realized that we could dramatically increase 1

2 the amount of area that we could patch by using a milling machine. That year we did patching on Curtiss Avenue, from Belmont west to Walnut Avenue; Fairview Avenue, 59 th Street to 63 rd Street: and Maple Avenue, the railroad tracks east to Fairview. We would not have been able to patch, as much area on these roads using the old method of patching which would have been removing full depth pavement. In all of these cases, these road sections were going to require in As a result of this work we have been able to delay any resurfacing work on these sections of roadway through this year and possibly next. These roads are all 6-10 or more in thickness. After seeing the increase in production and efficiency, we increased the budget amount to $9,000 in fiscal year 1998/1999 for a rental period of two weeks. That year we milled 81 patches in two weeks with a total of 8, square yards of asphalt installed. The best other two-week period for the year was 5, square yards. By fiscal year 2000/2001 we had increase the budget figure again to $18,500 to rent a larger machine for a month s time. As we found this method to be much more effective in patching pavement surfaces, so have many other communities. This has resulted in far fewer opportunities to arrange rental of DuPage County s machine as our neighbors also have started milling programs. During this time the County has also raised its rental charge. This coupled with the ever increasing difficulty we have had in scheduling a time to secure their machine, caused us to rent from an equipment supplier during the fiscal year. This too has presented some scheduling challenges as this is not the type of item that a firm will have several available for rental, so to a degree, you must work from a point of equipment availability, always gambling that the weather will cooperate. In light of our experiences with such increased efficiencies and production, a milling machine was placed in the Fleet Plan with pre-funding beginning two years ago. While it is impossible to make an exact comparison of how much of an increase in production milling represents over our current method of full depth patching, it is staff s opinion that it is at a minimum of double what could be done currently if a machine were to be purchased. In fact, we feel that a three-fold increase in production is not unachievable. The value of this potential two to three fold increase in pavement patching production, if it were to be is shown in the following table. This information is based on the 1996 construction year data. Est. potential increase Sq. yrds. Patched* Est. volume increase Contractual cost of increase** Asphalt for these this area*** Est. contractual value of milling work w/grinder 2X increase $41, $8, $33, X increase $83, $16, $67, * 1996 the last year in which we did not rent a grinder a total of 2, yards were patched ** Square yard cost used to est. value of 2" patch; milled and replaced $14.00 *** Current asphalt cost is $25.50/ton The resulting increased material need would be met by the reduction of asphalt needed per patch generated by the change from full depth patching to milling. While there are many variables in this estimation, we are comfortable with our determination of this significant expectation. Any time you consider an equipment purchase of this value an immediate question is how much will it be used. To best address this point consider that there is an approximate thirty (30) week 2

3 construction season each year. For the Pavement Division those 30 weeks generally break down as follows: 3 weeks of crack sealing 2 weeks of special event activities 3 weeks of road shouldering 4 weeks of concrete work 2 weeks of alley restoration and repair 11 weeks of patching activities 7 weeks of miscellaneous activities During the 11 weeks of patching and 2 weeks of alley work a milling machine would be used consistently. Additionally, we would attempt to use it during breaks in the winter weather season to address pothole issues. We feel that during these times we could mill out the pot hole to a depth that would hold the cold mix more effectively, greatly reducing the problem we see now of reoccurrence of the same pot hole for the entire winter as the thin layer of cold mix applied is quickly pushed out. This is a total of thirteen plus weeks or over three months of active use. When considered in light of an expected 15 year service life and a minimum $18,500/month rental cost, the value of this machine can be measured. On May 8, 2001 bids were opened for the purpose of securing prices for the purchase of a pavement-milling machine. Three bids were received as shown below: Bidder Unit Bid Bid Price Auto-Lube Option Finkbinder Equipment Wirtgen, W1000L $182,000 $2,700 Wirtgen America, Inc. Wirtgen, W1000L $189,000 $3,800 American State Equipment Co., Inc. Wirtgen, W1000L $185,900 $3,500 Should the Village proceed and purchase a pavement-milling machine, we certainly would be open to renting it to other municipalities during times not scheduled for our use. Doing so however has a couple of hurtles. First, is that like the County, it would be advisable to only rent with a Village operator as part of the deal. This then may create a difficulty with staffing levels for other Pavement Division activities. The other challenge is the transport of the machine to these potential community users. This recommendation does not include a trailer or other method for moving this unit outside of Village streets as we intend to just drive it from site to site, however this would not be a practical option to other communities. Thus it would be the renter s requirement to secure appropriate transportation for the machine. Storage of the machine when it is not expected to be used for several weeks will be at the 71 st St. water tower. ATTACHMENT: Attached are: Brochure of the proposed unit to be purchased Table 1: Patching Method Comparison 3

4 RECOMMENDATION: With reference to the operational and financial reasons stated above, the Public Works Pavement Division is recommending the purchase of a 2001 Wirtgen W1000L Pavement Milling Machine from the Finkbinder Equipment Company, of Burr Ridge, IL., with the inclusion of the Auto Lube system bringing Finkbinder s bid to $184,700. The bid meets all details of the specifications and is under the amount in the Fleet Plan for this purchase. Additionally, the bid unit model is a type we have rented and found to be very effective for our uses. The Village has rented several machines from Finkbinder and found their service to be excellent. Fleet Service has reviewed the bids and is in agreement with this recommendation. An optional lease to purchase program was included in the bid document and could be considered. 4

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