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HomeMy WebLinkAbout01-09-2008TO: Members of the Sebasti ty Council FROM: Al Minner, City Maria RE: COLLIER CREEK E DATE: Wednesday, January , 08 As advised via e-mail on Friday, January 4, 2008, Dave Fisher and I conducted a meeting on Tuesday, January 8th regarding a construction alternative for the Collier Creek Canal Project. Upon review of the bids, additional information was brought to our attention, which indicates that wall construction may, indeed, be a potential. Unfortunately, the true additional cost is not yet available. However, it seems that this option may be within affordability. For the last several years this option, in my opinion, was always the preferred alternative. Nonetheless, every bit of data we collected indicated that wall construction was unaffordable, which lead to the rip -rap design, It has not been until the Collier Creek Project bid opening, that (1) significant changes in the market place have been fully realized; and, (2) information from contractors was received that indicates that wall construction may be significantly less expensive than estimated. Noted in my e-mail of January 4th, I believe this office has a fiduciary responsibility to investigate the market place. To that end, this memo is provided to update Council on the January 8'h meeting. With regard to engineering the proposed alternative, the meeting identified that the alternative proposal to construct walls from CR 612 to the Barber/Lake Street Bridge for $3.6 million was incomplete. It was incomplete for several engineering questions that concern the following: SAFETY FACTOR: In engineering terms, design criteria include a safety factor for any given project. To prevent wall failure, CDM calls for a safety factor of 1.5. The contractor proposal safety factor was 1.0. CANAL WATER LEVEL: In a schematic of wall structural integrity, the contractor proposal has an incorrect water level. GEOTECHNICAL REPORTS: It was proposed that the walls be "jetted" into the soils in front of existing walls. This is a process were water cuts a small trench in which the new wall is set. The analysis of geotechnical data is critical to the design of an installation back-up plan. This was not dealt with thoroughly enough in the alternate proposal presentation. SCOUR DEPTH: No allowance for scour was included in the proposal. After discussion, it was agreed that a minimum of 6" scour depth needed to be included in the analysis. WEEP HOLES: An unclear/incomplete analysis was provided on wall weep construction. This is important for ground water escape, as water retention (on the outside of the canal) could lead to wall failure. SURCHARGE: A full analysis was not done on surcharge. In other words, additional data and information needed to be considered to account for the pressures caused by dirt, slops, storage and other improvements on the outside of the canal. CROSS SECTION: The provided cross section was typical but did not include a 12-foot total sheet length as the cost estimate indicated. A different cross section of the canal, which includes wall depth; surcharge and other engineering issues need to be computed to identify more accurate wall deflection data. CONCRETE CAP: It was determined that without cross bracing, a concrete cap was the best method of completing the wall. The concrete cap was not computed in the $3.6 million estimate. While all the above engineering data seems ominous, the major general consensus from the January 8th meeting was that if all the above changes are made, a wall project might still be affordable. Moving forward is tricky. The biggest concern is that a very good proposal for rip -rap construction has been received and may be lost in search of a wall option. In other words, we have a "bird in hand" with the rip -rap project, but there may be "birds in the bush" if we continue down the wall path. At this stage Dave Fisher and I believe there are at least three options going forward: 1. Negotiate a project modification with value engineering (to support and sign -off on wall construction with a professional engineer) with all four rip -rap bidders only. All value engineering would be reviewed by a City Engineer/Consultant (i.e., CDM). 2. Retain City Engineer/Consultant (i.e., CDM) to prepare a value -engineered Collier Creek Wall RFP. 3. Retain a City Engineer/Consultant (i.e., CDM) to redesign a wail project and start a completely new procurement. Note, that this option is not favored at this time, pending a review of additional information requested. Obviously one major concern is to preserve the integrity of the bid process, as well as its costs. To date this has been accomplished and the bids are good until April 16, 2008. Currently, the City Attorney is researching legal ramifications concerning the above -mentioned options. Other concerns at this time: FINANCIAL - Should additional money be required, 1 would propose use of DST money. This may cancel already scheduled projects and use the bulk of unallocated DST funds. In any case, provided the walls do not exceed affordability, I believe there may be a way to shift financial blocks and pay for the potential increases. TRANSPORTATION/STREET MAINTENANCE - There is some argument that as rip -rap construction occurs, significant truck traffic will impact streets, bringing additional cost that could be avoided by not using rip -rap. Please note, based on a sludge disposal site, truck traffic still could be an issue with wall construction, but far less than if we are also hauling in rip -rap. For the last four years, the City has moved methodically to ensure a successful capital project amid much debate and emotional public input. As a result, the City has gone the extra mile to please all, while sometimes pleasing no one and having a "compromised project". A final reward of walls seems to indicate moving forward rapidly to capitalize on market conditions is now a very reasonable approach. In summation, we are waiting on additional information and legal updates. As these are presented, I will come before Council with a formal recommendation.