CABLE-STAYED HOUSTON SHIP CHANNEL CROSSING

The bridge crosses the Houston Ship Channel 20 miles east of Houston between the cities of Baytown and LaPorte, Texas. It is the first dual superstructure cable-stayed bridge, and its total dcek area of about 350,000 sq ft makes it one of the largest cable-stayed bridges to date. Each of the dual cable-stayed bridges has a composite superstructure girder with a main span of 1250 ft and a navigational clearance of 175 ft. The twin concrete towers with a double diamond shape configuration rise 426 ft above the ground. In the transverse direction they carry the loads by truss action, in the longitudinal direction they are fixed to the foundations and elastically supported by the stay cables. Each of the two girders is 78 ft 2 in. wide and consists of a 5 ft 3 in. deep steel grid. Exterior main edge girders and transverse floor beams at 17 ft spacing are plate girders with an 8 in. composite concrete roadway slab. An additional wearing surface is 4 in. thick. The roadway slab was designed for composite action under dead and live load. The stay cables vary between 19 and 61 strands of 0.6 in. diameter. Their corrosion protection consists of Polyethylene (PE) pipes with cement grout. In addition, they are wrapped with a white weather-resistant tape. Construction started in 1987; completion of the bridge is anticipated in 1992.