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<br /> Development of the Project Study Report Equivalent (PSRE)
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<br /> will require the preparation of a bridge Advance Planning ~ ~
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<br /> Study (APS) for Santa Ana Grade Separation Improvements. ~ ~ ~ "
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<br /> The purpose of Advance Planning Study is to evaluate ~ „ ~ ~ ~ .;A . ~
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<br /> feasible structure types, understand City, County, OCTA, , , ~
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<br /> SCRRA, and Caltrans requirements, identify constraints, ~ ~ , ~ ~ "w,r ~ ~
<br /> and develop associated cost estimate summary for the i ~ I~~~~L N ~ ~ _ ti, r.; ; ~ ~
<br /> structure work involved. Additional APS's will be re ared as a"~ ~ ~ ~ ` ~ y
<br /> appropriate to consider alternative structure types. ~ ~,r-~i~~~~~ ~ ~ ~ ~ r,,~~~~,-~~~~~
<br /> A com rehensive desi n memo must be re ared to ~ ~ ~ ~
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<br /> summarize and document the following key items:1) ti
<br /> important, or unusual, design assumptions or structure ~ ~ ~ ~
<br /> features, particularly any deviations from standards .,.u..: ~ ~ ~ ~ :
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<br /> to accommodate the site constraints, 2) discussions
<br /> with City/County/OCTA/SCRRA/Caltrans/Stakeholders/ ~ ~ I:~~.
<br /> Resource Agencies concerning any key assumptions, 3) I~.,I.~,,, ~.~~~~,-n,~,~ ~,r~~r°~'~~~il~'11
<br /> cit re uirements such as aesthetics im rovements in the The span length required to span the Santa Ana Boulevard
<br /> y q p roadbed is approximately 134'. The typical span range for
<br /> vicinity of the structure, or other obstructions, 4) special this type of construction extends to about 150-ft under
<br /> foundation requirements, special excavations such as Type Cooper E-80 loading. Therefore, even though the required
<br /> A, Type D (if ground water is shallow), and/or hazardous span is nearing the upper limit of the typical structure span
<br /> or contaminated material, shoring adjacent to the tracks, length, this structure type is suitable for construction of new
<br /> 4) special construction requirements, including limited underpass. The total structure depth for the replacement of
<br /> site accessibility, 5) stage construction, and 6) SCRRA the double track would be approximately 13'-6". Provisions
<br /> Requirements (closure windows, flagmen etc.). can be made in the bridge design so that is capable of
<br /> The information identified in the APS as listed above supporting a future third track, should this become a
<br /> and preliminary structure costs are used as a part of the requirement of OCTA/SCRRA. To support a possible third
<br /> evaluation to select the best project structure alternative, track, the through girder, on the either left or right side of
<br /> which will be carried into the design phase along with the the underpass, will be required to have a structure depth
<br /> preferred roadway alignment alternative. approaching 15' in order to support the full weight of a
<br /> Cooper E-80 live load.
<br /> Two structure alternatives are presented and discussed in
<br /> detail in the ensuing sections. The abutments will be precast type and will be supported
<br /> on drilled shafts (the shafts can be constructed under
<br /> Construct Through Girder Underpass on-site and Roll normal, single track weekend closures prior to the 56 hour
<br /> into Place for Final work window, while the abutments would be placed as one
<br /> This structure alternative has the distinct advantage of of the first operations during said window). The through
<br /> constructing the bridge in place without long-term disruption girder underpass structure can be constructed in the
<br /> of Metrolink's service operations, thereby eliminating the staging areas near the project site. Once the substructure
<br /> need of shoofly tracks and station modifications, and work is completed, and the 56 hour work window has been
<br /> minimizing the time for the vehicular traffic to be detoured implemented, the bridge superstructure can be placed on
<br /> around the construction site. While the traveling public has rollers and moved from the staging area location to the
<br /> been moved to a detour road, this completed structure can finished main line alignment.
<br /> be rolled into place over a 56 hour weekend work window, Special details will be required, including jacking stiffeners
<br /> from Friday night to Monday morning, when train service can in the through girders where the bridge jacks are to be
<br /> then be restored. What will remain will be the construction placed for raising the bridge off of its bearings, and bearing
<br /> of the depressed roadbed for Santa Ana Boulevard, in a "top stiffeners at the locations where roller bearings are to be
<br /> down" construction sequence, that is to build the walls first, placed in order to support the bridge and roll it from the
<br /> and then excavate the roadway in front of the wall to final staging area to its final installation location on the main line
<br /> grade. Upon completion of roadway construction, traffic can alignment. In addition, a system must be constructed to
<br /> resume the normal pattern on the new facility. This method support the dead load of the bridge superstructure on the
<br /> for construction of the bridge has been done successfully, roller bearings and guide its movement from the staging area
<br /> previously in 1994, for the double track bridge over the Santa to its final installation position. The bridge bearings used to
<br /> Ana River. I"" ~ shows the general plan sheet of this support the bridge at the staging area can be removed and
<br /> proposed structure type, and the construction sequencing placed on the finished abutment seats in the final installation
<br /> associated with buildingthis structure. location.
<br /> Construct Precast Prestressed Box Girder Underpass
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