02-05-2002 RA RPT 05 - Laserfiche WebLink

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CITY OF RIVERSIDE Riverside tze.d All-America c; , 1111" AGENCY MEMORANDUM People Serving People 1998 HONORABLE MAYOR AND AGENCY MEMBERS DATE: February 5, 2002 ITEM NO: 5 SUBJECT: PILOT STRUCTURAL REPAIR PROGRAM BACKGROUND: Integrated Design Services, Inc. (IDS) was retained by the Agency to complete a structural evaluation of the condition of Parking Structures 1 and 2, with specific attention to structural damage and corrosion. This initial Agreement was for $16,000. Originally designed by T.Y. Un International in 1961, Parking Structures 1 and 2 are located at Orange Street, between Mission Inn Avenue and Ninth Street. The two structures consist of cast-in-place post-tensioned concrete slabs and beams. They are one of the earliest post-tensioning constructions in Southern California. This technology has been refined over the years and today is widely used in the construction of large-span concrete parking structures. IDS' strategy of repair focused on three repair measures. The first measure was to ensure the structural integrity of the closure strips. The second measure was to repair the corroded post-tensioned strands as needed. The third measure was to limit exposure of the strands and the steel hardware to water leakage and other corrosive factors with the objective of preventing future occurrence. In the Preliminary Structural Evaluation Report, IDS identified that the closure strips at the middle of the parking structures have been damaged several times during the life span of the structures. As post-tensioned strands and their anchors are exposed to weather and water, corrosion becomes more progressive. The problem is aggravated as more corrosion results in more concrete spalling, which leads to more exposure to moisture. The original design of the expansion joints in the structures is obsolete, and no longer used in today's construction. Vehicle pounding at these joints is a main contributing factor of the spalling and cracking of the concrete near the joints. CURRENT ISSUE: IDS has noted many uncertainties of the existing conditions in both parking structures, and are recommending a Pilot Structural Repair Program at a limited area of a parking slab. The objective of this program would be to, (1) verify existing conditions of a typical section of the damaged area, (2) verify the feasibility and effectiveness of the repairs, (3) provide a more accurate estimate of the construction cost and time of construction of the project, and (4) provide a more defined construction document that would be easily bid. The seismic performance of the connection between the walls and the slabs in the parking structures will also be tested to determine its adequacy to transfer seismic loads, and evaluate its behavior. IDS is best qualified to perform these services based upon their completion of the structural evaluation. FISCAL IMPACT: IDS has submitted a proposal for $16,000 to perform the Pilot Structural Repair Program. Funding is available in the Parking Professional Services Account 2830810-421000. 5-1