The six-lane Hernando Desoto Bridge, built in the late 1960s, is 3.3 miles long with 164 spans, 160 piers and 10 abutments. It carries about 60,000 vehicles daily over the Mississippi River. The main bridge consists of two 900-ft-long steel tied arch spans over two shipping channels. Five 330-ft to 400-ft steel box girder sections complete the main crossing. Approaches and ramps are of precast concrete girders and plate girders spans.
Seismic. Structural steel, bearings and joints will help I-40 crossing hold up in a big earthquake.