AUSTIN (KXAN) — Main lanes of Interstate 35 at the Slaughter Creek overpass in south Austin will close between 9 p.m. and 10 a.m. Friday and Saturday nights.

All southbound lanes will be closed Friday night and all northbound lanes will be closed Saturday night, as Texas Department of Transportation crews erect concrete beams for reconstruction of the bridge — weather permitting.

Traffic will be detoured to the frontage roads in both directions at exit 226. Ramps and lanes will be reopened as construction work is finished.

Drivers can cross I-35 at either Onion Creek Parkway or Slaughter Lane during the closure. TxDOT says the Slaughter Creek overpass was demolished last June to make way for a new, wider bridge, including a south-to-northbound U-turn.

Crews will also widen the southbound I-35 frontage road to two lanes through the Slaughter Creek intersection, as well as install safety lighting from Slaughter Lane to Onion Creek Parkway.

The $9.2 million project to replace the nearly 60-year-old structure is being undertaken by contractor Capital Excavation, TxDOT said in a statement.

Drivers who would normally use I-35 during the closure times should plan a different route or expect potentially long delays. TxDOT will be posting traffic updates on their Twitter and at DriveTexas.org.