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