Get to know Portland's bridges: Burnside

• Because it serves as an official emergency transportation route for the tri-county area, it was chosen as the first bridge to get an earthquake-ready upgrade — even though there have been several delays since.

Flashback: Built in 1926, the Burnside Bridge is a 2,241-foot long, double-leaf, Joseph Strauss-designed bascule bridge. Its two-leaf drawbridge pivots upward to allow marine traffic to pass below.

• As part of the 20th century "City Beautiful Movement," the bridge was adorned with Italian Renaissance operator towers and ornate spindle-type balustrade railings.

The intrigue: It's one of the heaviest bascule bridges in the country and the first to rely on concrete for its movable span.

• Plus: The bridge's piers are hoisted up by 380 tree trunks driven into the riverbed and reinforced with steel and concrete, but they were not built to withstand prolonged shaking in the event of a massive earthquake.

Follow the money: The bridge cost $4.5 million to build — far less than the estimated $900 million cost of its soon-to-be replacement.

The latest: In March, Multnomah County, which owns the bridge and is tasked with its replacement, announced it would delay construction by one year, to 2028.

• The county board approved an inverted Y-shaped design for the bridge's future look last year.

What's next: If we ever make it to the construction phase, all traffic will be detoured to other bridges.