Los Angeles is bracing for "Jamzilla," a massive traffic backup on the Presidents Day weekend because of lane closures on northbound Interstate 405 through the Sepulveda Pass.

As part of the construction, all northbound lanes will be closed overnight from Feb. 14-18 and traffic restricted to just a few lanes during the day along the stretch from Getty Center Drive to Ventura Boulevard so crews can repave lanes and shift the freeway to a new configuration.

The 80-hour closure is unprecedented, even for the project that led to Carmageddon — the 2011 53-hour closure between two of the city's busiest interchanges — and Ramp Jam, the closure of the Wilshire Boulevard off-ramp that caused backups and headaches for nearly two months last fall.

But project managers say after the long weekend work, the bulk of the headache-causing closures will be over as they work toward a summer completion date for the three-year, $1 billion overhaul of the busy freeway.

“It will be a lot of work, but once it's done, we hope this will be the last big one,” said Krishniah Murthy, executive director of transit project delivery for Metro. “After this, we will still have some landscaping and other things to work on, but the lanes will mostly be open and the major work done.”

Murthy said the lengthy closure is necessary because of the many composite layers that go into the concrete that forms the roadway, each needing its own period of time to dry and set.