The work to be done generally consists of the replacement of two existing bridges with single span concrete PC/PS wide-flange girder bridges and reconstruction and realignment of the approach roads to each bridge, located along Marsh Creek Road, approximately 4 miles apart, in Contra Costa County southeast of Clayton, site 1, and in Contra Costa County southwest of Brentwood, site 2. The reinforced concrete bridge abutments are supported with CIDH concrete piles. Work includes: clearing and grubbing, tree removal, grading, bridge removal, single stage bridge construction, roadway construction in stages, construction of drainage facilities, storm drainage pipes and outfalls, relocation of a CCWD waterline, relocation of above ground and underground utilities, and pavement