R L Alia Company 5/4/2017 - Laserfiche WebLink

I I 6-02.3(29) Siphon Headworks(SHW)Modifications Section 6-02.3 (29)is added as follows: The siphon headworks modifications are comprised of 1)demolition and removal of the above L ground concrete entry structure and, 2) internal structural hydraulic modification consisting of connection a new 72-inch inlet pipe; modification of concrete weir-walls; removal of a steel- liner from an existing concrete parshall flume, and applying an epoxy coating on new and existing internal concrete walls within the SHW 6-02.3(29)A General The Contractor shall be responsible for the stability of the structure during Construction. Submit a Construction and Demolition Plan,conforming to the requirements of Type 2 Working Drawings per Section 1-05.3, indicating methodologies, equipment, and work necessary to perform the SHW modifications as shown in the Plans. Do not undermine existing SHW components dueto excavation or removal of material. Provide full support to the existing CSO chamber during construction to avoid inducing additional loading on the SHW wall and provide details of support. If, at the Engineer's judgment, the SHW is loaded in such a way that the structural integrity may be compromised as a result of the proposed and/or actual construction methodologies, or if temporary falsework or bracing is required, the Contractor shall provide Type 2E Working Drawings, demonstrating the falsework design and any loading induced into the SHW is acceptable. Include in the Construction and Demolition Plan details and design of any temporary shoring required for excavation stabilization. Comply with Section 2-09 for submittal and design requirements of shoring and/or cofferdams. No construction vehicles shall be allowed on the roof of the SHW. Construction live load on the roof of the SHW shall be limited to 25 psf during construction. 6-02.3(29)B Siphon Headworks Entry Structure Demolition Prior to contractor demolition, the City will remove all existing electrical and ventilation equipment from the entry structure. The above ground entry to the below underground siphon headworks structure shall demolished and removed off-site. The roof and concrete walls shall be removed from the existing concrete top-slab of the underground siphon headworks structure. For any existing reinforcing steel that is exposed due to existing concrete removal, remove bar 1 inch beyond the surface of concrete and patch with an epoxy grout. Contractor shall cut opening in existing top-slab and fill the partial-slab void of the entry staircase opening as indicated on the plan to conform to proposed new access hatches. Contractor shall remove the above ground handrail and modify the hand-rail portion below the slab on the existing staircase.to conform to new hatch. Contractor shall provide two access hatches manufactured to fit the blockout dimensions as shown in the Plans. Hatches shall connect to a steel angle attached to existing concrete as shown in the Plans. Hatches shall be capable of supporting 90 psf pedestrian live loading and shall be aluminum, stainless steel, or galvanized steel. Submit details of hatch including connection detail to Engineer prior to fabrication. 6-02.3(29)C Trunk C Connection and Flow Modifications Contractor shall demolish portions of the siphon headworks wall and construct structural modifications to connect proposed 72-inch pipe and also remove and modify existing concrete weir walls within the siphon headworks structure inlet chamber of the siphon pipes, all as indicated in the plans. Contractor shall furnish and install new additional manhole access and an adjustable steel weir plate on new concrete weir wall as indicated in the plans for SRO3. I HAYES STREET REGULATOR February,2017 AND CSO CONTROLS (SRO1,SRO2,AND SRO3) WO No—UP3398-31 SP- 159