Jan. 27–The JW Marriott will reach a milestone Tuesday when the final steel beam is hoisted atop the building, marking the structural completion of the shell of the $300 million convention center hotel under construction on Congress Avenue downtown.

Community leaders and city officials, including Austin Mayor Lee Leffingwell, will attend a ceremony at the Headliner’s Club on the 21st floor of the Chase Tower downtown to watch the “topping out” of the 34-story luxury hotel.

The hotel is scheduled to open March 1, 2015. Construction began in 2012, and is running about three weeks ahead of schedule, Jay Spurr, the hotel’s director of sales and marketing, said during a media tour Monday. About 600 construction workers are on site now — a number that will peak at about 700 in the next month-and-a-half.

“This is an exciting day for Austin,” Leffingwell said in a statement. “A few months after becoming mayor, I gave a speech calling for a convention center hotel to be built in downtown Austin. The topping out of this tremendous project represents how this vision is now a reality.”

With nearly 1.3 million square feet space, the hotel will be the city’s largest, and the biggest JW Marriott in the United States. It is one of several hotels either under construction or proposed for downtown, which combined would add more than 3,200 hotel rooms during the next three years. That would be about a 40 percent bump in the existing downtown room supply of about 8,000.

With 1,012 guest rooms and more than 112,000 square feet of meeting, banquet and exhibition space, city and hotel officials say the JW Marriott will help Austin attract larger conventions. Currently, Austin has one convention hotel, the 800-room Hilton Austin downtown.

“Austin is increasingly an international destination, and the addition of this international-caliber hotel helps secure our city as a premier world destination,” Leffingwell said.

So far, more than 286,000 rooms rooms have been booked, with first groups due to arrive the day the hotel opens. Those bookings are about 20 percent above projections for this time, Spurr said.

“We are excited to be one step closer to showcasing Austin as a meetings and convention hub for businesses and organizations worldwide,” said Bob Lander, president and CEO of the Austin Convention & Visitors Bureau. “To already have more than 280,000 rooms contracted shows the demand for this hotel and the desire businesses have to come to Austin.”

Among the large conventions booked through 2020 are the annual meetings for the Specialty Tools and Fasteners Distributors Association; the Association of American Medical Colleges; the South by Southwest music, film and interactive festival; and the 2017 Professional Convention Management Association’s Convening Leaders annual meeting.

The latter one is a coup, because its attendees are the meeting industry’s leading planners, who often return to the area for their own meetings, Spurr said. The 2017 meeting will attract an estimated 4,000 attendees.

“We would never have been able to bring that meeting to Austin if it wasn’t for the JW Marriott,” Spurr said.

The hotel will employ 750 people when it opens. It is expected to generate more than $16 million in taxes annually, with an estimated $5 million to $6 million going to the city.

Randy McCaslin, a hotel industry consultant, said the hotel “is a missing piece in the downtown lodging market package — much, much overdue.”

“The current high occupancies in downtown Austin make it almost impossible to block enough rooms for a decent sized convention,” McCaslin said. “The new JW Marriott, teamed with the Hilton, will enable Austin to have enough hotel rooms dedicated to the convention market to bring new visitor dollars into the Austin economy.”

Last year, the Austin City Council revoked $3.8 million in incentives for the project, amid claims by construction workers that they were not getting paid the wages promised by hotel developer White Lodging. In September, White Lodging sued the city in federal court over the cancelled incentives.

In addition to the JW Marriott, another convention hotel — a $350 million Fairmont with 1,035 rooms — is planned for downtown at Red River and East Cesar Chavez streets by Manchester Texas Financial Group. Although several anticipated start dates have come and gone, president Doug Manchester told the American-Statesman on Monday that site work began late last year, and “will continue as designs are completed, construction costs are nailed down, and our final decisions with respects to financing are made.”