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<br /> <br /> <br /> <br />BRIDGE ADVANCE PLANNING STUDY <br />LAMBERT ROAD UNDERCROSSING(WIDENING) <br />(Br. No. 55-0492) <br />General Description <br />The existing Lambert Road Undercrossing (Br. No. 55-0492) was constructed in 1971 and is a <br />single span cast-in-place prestressed concrete box girder bridge carrying 10 lanes of SR-57 over <br />Lambert Road in the City of Brea. The existing structure is approximately 177 feet long and <br />approximately 144 feet wide. The existing structure has a skew angle of approximately 2 <br />degrees. The existing structure would be widened to the east as part of the Lambert Road <br />Interchange project Alternative 7A to accommodate a new northbound loop on-ramp. The <br />proposed bridge geometry includes adequate width to accommodate a future northbound truck <br />lane widening that would cause a shift to the proposed loop on-ramp. <br />The proposed widening would range from 37.5 feet to 52.75 feet to accommodate a 12 feet wide <br />ramp lane, 10’ wide right shoulder. The span configuration would remain as a single span 177’ <br />long. Lambert Rd would be lowered about 12 inches to provide a minimum clearance of 15’-0” <br />under the existing bridge and widened portion. <br />Structure Description <br />The proposed structure would be a single span cast-in-place prestressed concrete box girder with <br />6’-9” in depth with a skew of 2 degrees. The north abutment would be a diaphragm type <br />approximately 3.5’ feet tall and with a pin bottom to match the existing movement and rotation <br />characteristics. At the south abutment, the proposed roadway and sidewalk would be widened to <br />within 5 feet of the abutment diaphragm. It is proposed to use a seat abutment with a drop cap. <br />The drop cap height would be about 3.5’, to provide a pin at the approximate location as the <br />existing structure. The abutment footing would be located 2’ below the proposed roadway <br />surface. A special type 5 wall would be placed in front of the abutment to provide a constant <br />width sidewalk. Additionally, a ground anchor wall would be needed under the existing south <br />abutment. The wall types and costs were prepared under a separate APS within the Project <br />Report, and are not included in this APS cost estimate. <br />Falsework and Minimum Vertical Clearance <br />The existing structure vertical clearance is 14’-9”, thus Lambert is proposed to be lowered to <br />improve the existing vertical clearance to the minimum of 15’-0”. The 52.75’ widening at the <br />existing cross slope of 1.5%, the maximum bridge depth of 6’-0” would be required. At this