|Manatee County Government Administrative Center Commission Chambers, First Floor 9:00 a.m. - April 3, 2014|
Agenda Item #12
1:30 PM Time Certain - Item 13 - Contract 14-1467MW, Lake Manatee Dam Rehabilitation, Phase 1A and 1B
Contact and/or Presenter Information
Mark Simpson, Water Division Manager, ext. 5258
Section 2-26-40c of the Manatee County Code of Laws
Chapter 255.20 1(1)(c)1a-c of the Florida State Statutes
On February 14, 2014 a press conference was held in the Board Chambers at which preliminary results were shared from a supplemental investigation by Carollo Engineers, Manatee County Utilities Engineer of Record, and their subconsultant AMEC Environment & Infrastructure which showed potentially serious conditions at the Lake Manatee Dam. Results from that investigations showed voids beneath the downstream spillway structure resulting from piping effects causing soil erosion. Additional testing was needed to define the scope and design for the needed repairs.
That additional testing has revealed issues with the clay core likely related to the original 1960’s design and construction of the core and earthen embankment. The core test samples identified loose material in areas within the core and loose material at and beneath the layer where the clay core is supposed to key-in to the naturally occurring clay. The core tests also revealed that an appropriate clay layer for the key-in was located approximately 40 feet below (deeper) than the original key-in layer.
AMEC Environmental & Infrastructure, Inc. has recommended the dam cutoff area be re-established in its most critical portion to stabilize this section in advance of the rainy season and Carollo Engineers concurs with the recommendation. The work involves repairing the existing dam cut-off core by installation of a cutoff wall constructed by using Trench cutting Remixing Deep (TRD) and Jet Grouting (JG) methodologies.
AMEC Environmental & Infrastructure recommends Hayward Baker, Inc. of Tampa, Florida to perform the stabilization work based on a number of factors (see HBI Recommendation attached). Hayward Baker, Inc. is one of the largest geotechnical contractors in the United States in the field of specialty foundation and geotechnical construction. Hayward Baker possesses technical and geotechnical expertise, financial strength and excellent risk and safety planning and management practices.
The proposal provided by Hayward Baker for the dam repair has been reviewed by County staff and its Engineer of Record and is found to be acceptable. In addition, AMEC has performed a cost reasonableness analysis and has determined that the costs for the stabilization work are in line with similar past work of this nature.
The work will re-establish the tie in between existing concrete structures and steel sheet pile cut-off with the clay core and will re-establish the core key-in to the natural clay layer along about 3,100 feet of the dam.
In addition to its creation of the form of Agreement used, and assistance in negotiation of the Agreement, the County Attorney's Office has advised the Administration that the facts in this case support the Administration's waiver of competitive solicitation, and its invocation of emergency contracting procedures.
The negotiated contract price for these improvements is $14,091,190. Phase 1A - the priority portion - includes the cutoff wall beneath the approach spillway and 400 feet on each side of the spillway, and will be substantially complete by June 1st. Phase 1B improvements are to be completed by October 31st. Phase II improvements not included in this contract will require remediation of the identified voids beneath the downstream spillway structures, unconsolidated soils next to the downstream training walls, and a pressure relieving drainage system for that area.
Budget Amendment B-14-049 appropriates $15,100,000 for this construction contract and design services for the project. Funding for the project at this time comes from Utility System Reserves. Long-term financing for the project will be considered in the 5 year Capital Improvement Program as part of the upcoming budget.
County Attorney Review
Other (Requires explanation in field below)
Explanation of Other
The form of Agreement used is the same form approved by the County Attorney's Office for Agreements of this type. Additionally, this specific Agreement was reviewed by, and relevant edits approved by Assistant County Attorney Robert Eschenfelder.
Instructions to Board Records
Please email a copy of the contract to Hayward Baker, Inc., firstname.lastname@example.org; and a copy of the stamped approved agenda package to: Mark Simpson, Utilities Department, email@example.com, and Melissa Wendel, Purchasing Division, firstname.lastname@example.org.
Please also send signed copies of the Budget Resolution to: email@example.com, firstname.lastname@example.org,
Cost and Funds Source Account Number and Name
401 099 002 599000 Utilities Operating Fund - Reserves
Amount and Frequency of Recurring Costs
Attachment: Hayward baker 100% plans - Lake manatee dam.pdf
Attachment: HB R057700_emergency prioirity phase 1 dam repair_memo to MWendel_033114.pdf
Attachment: HB Comparison with HHD Costs Revised 20140331.pdf
Attachment: HBI Recommendation Letter AMEC v1.pdf
Attachment: Hayward Baker Dam v4 apr 2 executed.pdf
Attachment: Budget Amendment Resolution B-14-049.pdf