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Public Utilities Commission <br />Commission's Order Authorizing Construction of the Grade Separation <br />This work is not part of the Phase 1 Scope of Services, rather it shall be done during Phase 2. <br />Commission's Order Authorizing Alteration of the Existing At-grade Crossing <br />This work is not part of the Phase 1 Scope of Services, rather it shall be done during Phase 2. <br />Task 1.6 Structural Analyses/APS <br />Structures <br />Development of the PSRE and PSR will require the preparation of a bridge Advance Planning Study (APS) for <br />Santa Ana Boulevard Underpass. The purpose of the APS is to evaluate feasible structure types, understand City <br />requirements, identify constraints, and develop associated cost estimate summary for the structure work involved. <br />The APS General Plan (GP) clearly delineates all the structural elements identified in the PSRE and the PRE <br />typically using the minimum detailing necessary and basic dimensions, which will help develop a reasonable cost <br />estimate. As a minimum, the APS GP will show Plan, Elevation, and Typical Section views and will make note <br />of all critical assumptions. Additional APS's will be prepared as appropriate to consider alternative structure <br />types. The APS General Plan and APS Report will be prepared on the most current Caltrans APS formatted plan <br />sheet, and templates respectively. <br />Structure Preliminary Geotechnical Reports (SPGR) are required as part of APS to identify basic site parameters, <br />which may have a significant impact on the structure scope and cost. In addition, a comprehensive design memo <br />must be prepared to summarize and document the following key items: <br />Important or unusual design assumptions or structure features. <br />4. Discussions with City/OCTA/SCRRA personnel concerning any key assumptions. <br />,4 Modifications from Structure Maintenance Records recommendations. <br />-4? Seismic retrofit modifications. <br />,4? City requirements such as aesthetics, improvements in vicinity of the structure, airspace usage, or other <br />obstructions. <br />? Special foundation requirements, special excavations such as Type A, Type D, and/or hazardous or <br />contaminated material. <br />Special construction requirements, including limited site accessibility. <br />4- Stage Construction. <br />The information identified in the APS, as listed above, and preliminary structure costs are used as a part of the <br />evaluation to select the best project alternative. <br />Santa Ana Boulevard Underpass <br />It is proposed to construct a railroad bridge by lowering the Santa Ana Boulevard. <br />A 2-Span Structure Alternative would work very well at this location. This proposed double track railroad bridge <br />structure is approximately 126.7 feet long and 40.3 feet wide, with no skew to Santa Ana Boulevard. A Pier Bent <br />is needed in the median of Santa Ana Boulevard, which will result in the maximum span length of 63.3 feet, and <br />therefore a SCRRA Standard Precast/Prestressed (PC/PS) Double Cell Box Girder Structure can be used for the <br />structure type. <br />Precast units can expedite the construction schedule, helping to reduce impacts to both the rail and the road traffic. <br />In addition, a precast, simply supported structure is the preferred railroad bridge type because of its flexibility for <br />repair and replacement in the future. Significant shoring would be required around the construction area when <br />constructing the bridge. Retaining walls would be required for both the roadway depression and the raise of the <br />01Y o/ Santa :1 nu <br />25B-26