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HomeMy WebLinkAbout03.b. Review draft position paper to authorize the General Manager to execute a construction contract change order in an amount not to exceed $350,000 with C. Overaa & Company for additional bypass work under the Mechanical and Concrete Renovations, Dist Page 1 of 5 Item 3.b. CENTRAL SAN BOARD OF DIRECTORS POSITION PAPER DRAFT MEETING DATE: SEPTEMBER 3, 2019 SUBJECT: REVIEW DRAFT POSITION PAPER TO AUTHORIZE THE GENERAL MANAGER TO EXECUTE A CONSTRUCTION CONTRACT CHANGE ORDER IN AN AMOUNT NOT TO EXCEED $350,000 WITH C. OVERAA & COMPANY FOR ADDITIONAL BYPASS WORK UNDER THE MECHANICAL AND CONCRETE RENOVATIONS, DISTRICT PROJECT 7351 SUBMITTED BY: INITIATING DEPARTMENT: EDGAR J. LOPEZ, CAPITAL PROJECTS ENGINEERING AND TECHNICAL SERVICES- DIVISION MANAGER CAPITAL PROJECTS REVIEWED BY: JEAN-MARC PETIT, DIRECTOR OF ENGINEERING AND TECHNICAL SERVICES ISSUE Authorization from the Board of Directors (Board) is required in order to execute a construction contract change order in an amount greater than $200,000. BACKGROUND On November 15, 2018, the Board awarded a construction contract to C. Overaa & Company (Overaa) in the amount of$10,604,000 for the Mechanical and Concrete Renovations, District Project 7351 (Project). This Project generally consists of concrete structure rehabilitation, major mechanical replacement and improvements in the Influent Structure and Primary Sedimentation Tanks (PSTs), safety repairs, and work within other critical structures at the treatment plant (plant). To complete rehabilitation of structures and to facilitate replacement of critical gates, the Project includes two major bypass pumping efforts; the first at the Influent Structure and the second at the PSTs effluent structures. The bypass for the Influent Structure has been completed with successful results. However, the current bypass at the PSTs has been challenging and cannot meet all the safety and reliability needs for the proposed work under the Project. It should be noted that while the Influent Structure bypass was successful and staff resolved all the issues related to that scope of the project, bypassing the Influent Structure and PSTs has never been done at Central San. Although the PSTs bypass system as currently installed can be used to perform some of the planned work, a large portion of the rehabilitation work cannot safely proceed unless the bypass system is modified. Staff, Overaa, consultants, and the bypass subcontractor(Rain for Rent), have exhausted all September 3, 2019 Special EOPS Committee Meeting Agenda Packet- Page 5 of 15 Page 2 of 5 options available, including revising the work sequence, operational changes, flow diversion, and modifying the bypass system design to consider all scenarios. In the end, the best and safest bypass approach would be to change the piping configuration and discharge point from its current location at Structure C to the secondary selector channel, which is a further distance away. This change would require two additional 30-inch temporary pipelines, restraints, other equipment, and modifications to the pump discharge. The selector channel is approximately 950 feet away and will impact access through the plant. The value of all the repairs and mechanical work during the bypass is approximately$2.5 million. Time is of the essence; if the proposed work is to proceed this fall as scheduled, then a change order or work directive will have to be issued as soon as possible. Staff is negotiating the change order with Overaa and plans to have a refined cost estimate by the time the Engineering and Operations Committee meets on September 3, 2019. ALTERNATIVES/CONSIDERATIONS Alternative No.1: Proceed with the authorization as proposed, which is the recommended alternative. One consideration and advantage of the additional bypass system, if approved, would be the ability for staff to investigate and perform a condition assessment of the 72-inch primary effluent channel that feeds the primary effluent pumps. Like several structures under this Project, the 72-inch primary effluent channel has been in operation since its inception and has never been out of service. This alternative would allow for potential concrete repairs of the 72-inch effluent line, which already shows signs of corrosion at the adjoining structure. Staff would strongly recommend the condition assessment of this critical passageway. Alternative No. 2:Another alternative is to reschedule the portion of rehabilitation work that cannot be accomplished with the current bypass, which would be the case if the Board elects not to authorize the change order. The rehabilitation work is necessary and delaying to a future project would be more costly since it would require reinstallation of the proposed bypass pumping system. The postponed rehabilitation work includes repair of a critical bypass valve, Structure B gate, and other adjoining concrete structures. The current estimated cost for the postponed items is $2.5 million, which would include the bypass costs valued at over$1 million. Staff does not recommend postponing the work or this alternative since the work is needed within the next two-three years which will not be able to happen due to several other conflicting plant projects, including the Outfall Improvements-Phase 7 project. Alternative No. 3: Do nothing approach, which means do not complete rehabilitation. Some of the structures are used by Operations on a daily basis, and others are needed for critical bypassing of the PSTs during emergencies or future project/maintenance activities. This alternative is not recommended. FINANCIAL IMPACTS The costs to include the additional bypass system is estimated at$350,000, which includes temporary piping, labor, equipment and materials needed to perform the bypass safely and reliably.At award, the project contingency was set at$1 million. To date, staff has issued approximately$102,000 in change orders and with this proposed work would reach $452,000.Approximately $548,000 project contingency would be remaining under the Project. COMMITTEE RECOMMENDATION The Engineering and Operations Committee reviewed this matter at the September 3, 2019 meeting and recommended September 3, 2019 Special EOPS Committee Meeting Agenda Packet- Page 6 of 15 Page 3 of 5 RECOMMENDED BOARD ACTION Authorize the General Manager to execute a construction contract change order with C. Overaa & Company in an amount not to exceed $350,000 under the Mechanical and Concrete Renovations, District Project 7351. Strategic Plan Tie-In GOAL TWO: Strive to Meet Regulatory Requirements Strategy 1 - Strive to achieve 100%permit compliance in air, water, land, and other regulations GOAL THREE: Be a Fiscally Sound and Effective Water Sector Utility Strategy 2- Manage costs GOAL FOUR: Develop and retain a highly trained and innovative workforce Strategy 3- Meet or exceed industry safety standards GOAL FIVE: Maintain a Reliable Infrastructure Strategy 2- Facilitate long-term capital renewal and replacement, Strategy 3- Protect District personnel and assets from threats and emergencies ATTACHMENTS: 1. Project Reference Photographs September 3, 2019 Special EOPS Committee Meeting Agenda Packet- Page 7 of 15 Page 4 of 5 Reference Photographs Mechanical and Concrete Renovations, District Project 7351 - HUinEY���11��R�i�y�:.➢ aJ- • r. Primary Sedimentation Tanks (PST) Bypass System as of August 27, 2019 September 3, 2019 Special EOPS Committee Meeting Agenda Packet- Page 8 of 15 Page 5 of 5 . r L ........... YLS�M L4fr }4 Current Construction Activities in PST Nos. 3 and 4 September 3, 2019 Special EOPS Committee Meeting Agenda Packet- Page 9 of 15