07-19-2013 BPU RPT 06 - Laserfiche WebLink

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W A T E R E N E R G Y r RIVERSIDE PUBLIC UTILITIES Board Memorandum PUBLIC UTILITIES BOARD OF PUBLIC UTILITIES DATE: July 19, 2013 ITEM NO: 6 SUBJECT: REPAIR OF DETERIORATED VAULTS AND MANHOLE ON CHESTNUT STREET BETWEEN TENTH AND FIFTH STREETS -WORK ORDER NO. 1321782 ISSUE: The item for Board of Public Utilities consideration is approval of the capital expenditure in the amount of $111,000 for the repair of deteriorated vaults and manhole on Chestnut Street between Tenth and Fifth Streets. RECOMMENDATION: That the Board of Public Utilities approve the estimated capital expenditure of $111,000 for Work Order No.1321782 for the repair of deteriorated vaults and manhole on Chestnut Street between Tenth and Fifth Streets. BACKGROUND: As a part of General Order (GO) 165 a detail inspection in 2007 revealed deteriorated concrete and exposed corroded reinforcing steel at Vaults V-1045, V-1047, V-1048 and manhole M-1050 which were constructed in 1971. Work Order No. 0705869 was then initiated for the structural restoration of vaults V-1045, V-1047, V- 1048, and M-1050. The consultant proposed removal of rust from all exposed corroded reinforcing steel, applying a rust inhibitor to exposed surface of steel, patching up the spaces left by spalling concrete, and replacement of the roof slab. The removal of the roof slab would require excavation through the asphalt pavement that the Department of Public Works had rehabilitated earlier in the area. The planned construction was suspended for three years due to Public Works' policy that placed a moratorium on non-emergency street opening permits in newly paved areas. In 2011, a GO 165 detailed inspection confirmed that concrete deterioration was continuing. On September 20, 2012, the spalling concrete from the roof of vault V-1048 fell on one of the 12 kV cables causing the cable to fail which resulted in an outage affecting 838 customers for 33 minutes. In 2013, after reviewing the video, which was recorded during the 2011 GO 165 detailed inspection, on the interior of the vaults, the in-house design team decided that the roof slab can be structurally rehabilitated using certain polymer-modified cementitious material which has been used by other utilities in lieu of removal and replacement of the roof slab. The scope of capital repair work consists of contract crews which will: (1) prepare the areas where deteriorated concrete spalled, and corroded reinforcing steel; (2) apply the polymer-modified and finish the surface; and (3) inject pressurized epoxy to fill the cracks. Since the materials to be used are proprietary, the contract personnel as well as the in-house inspection personnel, shall be trained and qualified by the material proprietor.