A visual look inside construction of new Vulcan office tower New South Lake Union tower climbing at average pace of one story every two days

Iron worker Jake Lucas balances as he negotiates a beam on the 11th floor of Vulcan's Block 45 Project in South Lake Union. The building is being assembled faster than most as two tower cranes are being used on the project. When finished the building will be 12 stories tall and almost 500,000 total square feet. Photographed on Thursday, October 2, 2014. less Iron worker Jake Lucas balances as he negotiates a beam on the 11th floor of Vulcan's Block 45 Project in South Lake Union. The building is being assembled faster than most as two tower cranes are being used on ... more Photo: JOSHUA TRUJILLO, SEATTLEPI.COM Photo: JOSHUA TRUJILLO, SEATTLEPI.COM Image 1 of / 42 Caption Close A visual look inside construction of new Vulcan office tower 1 / 42 Back to Gallery

Buildings are going up fast in South Lake Union. The collection of massive, yellow tower cranes methodically working over the neighborhood can easily clue you in on that.

But one building in particular, Vulcan's Block 45 project, is rising over the neighborhood at a much faster pace than most.

Because of the building's elongated shape, occupying most of the block, contruction crews were able to use a pair of the tower cranes for assembly. Usually only one of the cranes is used for a building.

The synchronized cranes, swinging and lifting in tandem, have been able to help crews build the structure at an average of one new floor every two days — twice the pace of a single-crane approach. Managers schedule the cranes to work in different project zones so they don't interfere with each other, said Christopher Heger, project manager for Turner Construction.

The job also utilizes computer-based building models that translate into points on a GPS-like device. The high-tech construction equipment measures the assembly of prefabricated pieces with near-perfect precision.

Much of the building was actually built elsewhere. "The assembly is happening here," Heger said during a tour of the site on Thursday.

When finished, Block 45 will include about 300,000 rentable square feet and will be 12 stories tall.

Take a look at our collection of photos to see some of what it takes to put together a modern office tower.

Visit seattlepi.com's home page for more Seattle news. Contact Seattle photographer Joshua Trujillo at joshuatrujillo@seattlepi.com or on Twitter as @joshtrujillo.