APS_Brea OH (11-19-13) - Laserfiche WebLink

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BRIDGE ADVANCE PLANNING STUDY BREA OVERHEAD (WIDENING) (Br. No. 55-0482) General Description The existing Brea Overhead (Br. No. 55-0482) was constructed in 1971 and is a 3-span cast-in- place reinforced concrete girder bridge. The existing structure is currently undergoing a widening on the northbound side, resulting in a structure that will carry 13 lanes of SR-57 over an abandoned UPRR track in the city of Brea. The existing structure is approximately 173 feet long and will be approximately 191 feet wide upon completion of the northbound widening. The existing structure has a skew angle of approximately 18.2 degrees. The existing structure would be widened to the west as part of the Lambert Interchange project alternatives 7A and 9 to accommodate the proposed southbound on-ramp alignment. The proposed widening would range from 25.55 feet to 26.40 feet to accommodate a new alignment of the southbound SR-57 on-ramp at Lambert Ave. The proposed bridge geometry includes adequate width to accommodate a future southbound widening for an additional lane plus full standard width lanes and median shoulder. The span configuration would remain as 3- spans, totaling 173’ in length. Structure Description The proposed structure would be a 3-span cast-in-place reinforced concrete girder bridge of 4’- 6” in depth and a skew of approximately 18.2 degrees. The abutments would be diaphragm type approximately 5 feet tall at abutment 1 and 4.5 feet tall at abutment 4 (measured from soffit of superstructure to bottom of diaphragm) with an expansion joint between the diaphragm and supporting footing to allow the new structure to match the existing bridge movement and rotation characteristics. The two new bridge bents would both utilize single 4’ diameter concrete columns founded on a pile and pile cap foundation. The columns would be detailed as fixed bottom columns. Falsework and Minimum Vertical Clearance The bridge crosses an abandoned railroad line currently utilized as a pedestrian trail. Pedestrian access would be maintained along the pedestrian trail during construction as required by the city of Brea. This would require the construction of a protective cover. The existing structure vertical clearance to the dirt trail is 37’-8”. With the only limitation for falsework under the proposed widening an 8’-0” minimum vertical clearance for pedestrian access, a cast-in-place construction is the preferred method of construction.