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Home My WebLink About03.b. Change Order in the amount of $350,000 with Auburn Constructors, LLC to upgrade wet-weather bypass structure under influent pump; District Project 7328Page 1 of 6 Item 3.b. CDr EENI RAL SAN BOARD OF •' �J POSITION PAPER CENTRAL CONTRA COSTA SANITARY DISTRICT � � • MEETING DATE: MARCH 23, 2023 SUBJECT: REVIEW DRAFT POSITION PAPER TO AUTHORIZE THE GENERAL MANAGER TO EXECUTE A CONSTRUCTION CONTRACT CHANGE ORDER IN THE AMOUNT NOT TO EXCEED $350,000 WITH AUBURN CONSTRUCTORS, LLC TO UPGRADE THE WET WEATHER BYPASS STRUCTURE UNDER THE INFLUENT PUMP ELECTRICAL IMPROVEMENTS, DISTRICT PROJECT 7328; AND AUTHORIZE A BUDGET TRANSFER IN THE AMOUNT OF $800,000 FROM THE CAPITAL IMPROVEMENT BUDGET CONTINGENCYACCOUNT SUBMITTED BY: INITIATING DEPARTMENT: NANCY MOLINA, ASSOCIATE ENGINEER ENGINEERINGAND TECHNICAL SERVICES - CAPITAL PROJECTS REVIEWED BY: EDGAR J. LOPEZ, CAPITAL PROJECTS DIVISION MANAGER DANEA GEMMELL, PROVISIONAL DIRECTOR OF ENGINEERING AND TECHNICAL SERVICES KENTON L. ALM, DISTRICT COUNSEL ISSUE Authorization from the Board of Directors (Board) is required to execute a construction contract change order in an amount greater than $200,000 and transfer more than $500,000 within the Capital Improvement Program. BACKGROUND On July 16, 2020, the Board awarded a $6.5 million construction contract to Auburn Constructors, LLC (Auburn) for the Influent Pump Electrical Improvements, District Project 7328 (Project). This Project includes major electrical and controls, mechanical, and instrumentation improvements at the Headworks facility in the treatment plant (plant). Major Project elements include: • Replacement of five existing variable frequency drives; • Refurbishing five pump motors; • Installation of a new bypass pump, Pump No. 6; • Switching Pump Nos. 3 and 4 to increase pumping capacity resiliency during wet weather; and • Installation of hydraulically actuated isolation gates within Wet Wells 1 and 2. March 23, 2023 Special EOPS Committee Meeting Agenda Packet - Page 39 of 44 Page 2 of 6 In general, this Project has increased the daily reliability and resiliency for handling wastewater flows entering the plant, especially for wet weather conditions. To date, the Project is substantially complete with minimal contract work remaining due to delivery delays. The new systems installed under the Project were fully tested and operated as designed during the recent storm events since December of last year. These systems experienced incoming flows of 240 million gallons per day (MGD) with the bypass pumps handling up to 100 MGD at peak times. However, staff has identified upgrades needed to the existing Bypass Structure to allow Operations the ability to bypass flows more reliably. The Bypass Structure is located west of the Headworks facility as shown in Attachment 1. This structure is used for bypassing flows and diverting wastewater from Headworks to the wet weather basins within the plant. The Bypass Structure functions as a discharge location for the bypass pumps and allows for the flows to gravity through the plant and to the gunite channel on the north side of Imhoff Drive. The gunite channel is used to feed the wet -weather basins. After the new bypass pump (80 MGD) was installed, it was apparent to staff that the added hydraulics conflicted with the existing bypass pump (45 MGD) operations. Although both pumps are functional, the change in hydraulics allows flows to re-enter the discharge piping for the smaller pump, thus, allowing recirculation when the pump is not in use. Currently, both bypass pumps need to be in operation to avoid recirculation since the piping systems were not built to self isolate, or be required to. Staff is recommending executing a construction contract change order in the amount of $350,000 with Auburn Constructors, LLC to upgrade the Bypass Structure as soon as possible to eliminate the recirculation issue by next winter. Operations is fully aware of the issue and the Project team has worked with them to develop action plans in case of emergency situations, or failures associated with the bypass pumps. I n addition, Operations staff has been supplied the equipment and training necessary to prevent recirculation if the smaller bypass pump is out of service. However, these measures are for emergency use only, and have significant impacts on how the plant responds to peak wet weather flows. Upgrading the Bypass Structure includes additional piping, supports, coatings, metal systems, and other work needed to modify the structure to handle the flows. Working within the Bypass Structure and the type of work required to perform the upgrade is within Auburn's expertise and contract scope for the Project. Therefore, adding the work is in accordance with the construction contract and does not violate any bidding policies since the work is used to correct an issue related to the work under the project. I n addition, there are significant items that are needed for the change order work, such as the piping and stainless -steel materials. Obtaining these materials is challenging and can take up to six months or more after shop drawing review and acceptance. As a result of the anticipated long lead times, conducting this work as a change order is needed to complete the work by next winter. ALTERNATIVES/CONSIDERATIONS The Board can consider the following alternatives or provide other directions to staff: Alternative 1 - Do nothing. This alternative includes not authorizing the change order or upgrading the Bypass Structure. This is not recommended as staff has identified a major risk for pumping wastewater during high wet -weather flows. Alternative 2 — Do not perform the work under change order, and add the upgrade to another project. This alternative is not recommended since it does not meet the timeline proposed by staff. If the work is not performed by change order, then the earliest the work can be completed would be in mid-2024 and staff would have to continue with the structure limitations for another winter. Staff does not expect any cost savings if the work is delayed. March 23, 2023 Special EOPS Committee Meeting Agenda Packet - Page 40 of 44 Page 3 of 6 FINANCIAL IMPACTS The additional cost to the Project is $800,000, which includes the $350,000 in change order costs, $150,000 for staff time, $200,000 for consultants, and $100,000 for contingency to close the project. The current project budget is $10,086,000 and includes $600,700 allocated for change orders and $500,000 for additional construction management. This Project was anticipated to be completed in November of last year, but due to delivery delays and the challenges associated with procuring electrical equipment, additional time was needed to complete the job, resulting in more staff and consultant costs. To date, the Project has used its budget and change order authorization. If the transfer is approved, the new total project budget will be $10,836,000, of which the new construction contract is $6,500,000 and $950,700 (14.6-percent) is reserved for change orders. Adequate funds are available within the Fiscal Year 2022-23 Capital Improvement Budget Contingency account; therefore, upon Board approval, a budget transfer in the amount of $800,000 would be completed to fund the change order and close out of this Project. COMMITTEE RECOMMENDATION The Engineering and Operations Committee reviewed this matter at its March 23, 2023 meeting and recommended RECOMMENDED BOARD ACTION Staff recommends the following: 1. Authorize the General Manager to execute a construction contract change order in the amount not to exceed $350,000 with Auburn Constructors, LLC. to upgrade the Bypass Structure under the Influent Pump Electrical Improvements, District Project 7328; and 2. Authorize a budget transfer in the amount of $800,000 from the Fiscal Year 2022-23 Capital Improvement Budget Contingency account to the Project. Strategic Plan re -In GOAL TWO: Environmental Stewardship Strategy 1 - Achieve compliance in all regulations GOAL FIVE: Safety and Security Strategy 2 - Protect Personnel and assets from threats and emergencies GOAL SIX: Infrastructure Reliability Strategy 2 - Execute long-term capital renewal and replacement program ATTACHMENTS: 1. Presentation March 23, 2023 Special EOPS Committee Meeting Agenda Packet - Page 41 of 44 Page 4 of 6 March 23, 2023 Influent Pump Electrical Improvements Project - Change Order Request District Project No. 7328 Engineering and Operations Committee Nancy A. Molina, P.E. Associate Engineer 1 System Description Headwork III��I \�1`o 1 9 Bypass Line„" 4' Bypass Structure 2 March 23, 2023 Special EOPS Committee Meeting Agenda Packet - Page 42 of 44 1 Page 5 of 6 Modifications Needed Scope of work includes: • Extending bypass piping on both pumping systems; • Additional piping and structural support systems; • Providing temporary systems to work in structure safely; • Limited access in structure for workers; and • Coatings and other work necessary to upgrade the system. 3 Schedule and Reason Verify and order materials as soon as possible. Long lead items for piping and stainless steel. Complete work by October of this year, prior to the next wet weather season. Change order being recommended to meet timeline and proposed work within Contractors ability and current construction contract scope. 4 a March 23, 2023 Special EOPS Committee Meeting Agenda Packet - Page 43 of 44 2 Page 6 of 6 March 23, 2023 Special EOPS Committee Meeting Agenda Packet - Page 44 of 44