A major addition to urban Honolulu’s affordable-housing supply is about to get started, after a South Korean development company blessed the site Wednesday for a predominantly affordable condominium tower near Ala Moana Center.

SamKoo Pacific LLC held the blessing and groundbreaking ceremony at which praise was heaped on the company by city and state leaders. They congratulated the development firm for trying to address Honolulu’s critical shortage of affordable homes in a prime area with the $225 million project called Kapiolani Residence.

Timothy Yi, company president, said construction should begin next month and that interest from prospective buyers was incredibly strong at an initial homebuyer seminar two weeks ago when prospective buyers took close to 1,500 information packets.

“That’s way more than what we expected,” he said.

More seminars are planned, including one Saturday for which there are already between 800 and 900 registrants.

Kapiolani residence is slated to rise at 1631 Kapiolani Blvd. on 1.3 acres immediately mauka of the Ala Moana Hotel, a parcel that SamKoo bought in 2007 for $15.5 million.

The tower is designed to have 485 units ranging from 400-square-foot studios to 1,230-square-foot homes with three bedrooms. About 60 percent of the tower, or 292 units, will be reserved for residents with low to moderate incomes and priced to be affordable under federal guidelines. The balance of the units will be sold at market rates.

Overall, prices are expected to range from $272,000 to about $350,000 for studios, from $308,000 to about $600,000 for one-bedroom units, from $418,000 to the upper $700,000s for two-bedroom units and from $587,000 to $990,000 for three-bedroom units.

For the affordable units, buyers cannot earn more than 120 percent of the annual median income for Honolulu, which equates to $84,480 for a single person and $120,600 for a family of four. Some units also will be reserved for households who earn no more than 80 percent of the median income, or $56,320 for a single person and $80,400 for a family of four.

Sales have not yet begun through brokerage firm Locations, and will involve a lottery drawing for the affordable units sometime this fall. Applications for the affordable units are due by Aug. 31.

If construction goes as planned and is finished in about two years, SamKoo expects to then start construction on a second condo tower with predominantly affordable homes on a nearby site on Kapiolani Boulevard adjacent to a planned city rail station, Yi said.

SamKoo obtained approvals and assistance for its first tower from the city and state. The contributions included exemptions from city zoning rules, city permitting fees and the state general excise tax.

The zoning exemptions allow the tower to rise 400 feet high, which is in line with what the city envisions for sites close to rail stations that include the Kapiolani Residence site, but is 50 feet higher than the standard limit.

The tower also is going to be built closer to streets and property lines than ordinarily permitted, and will be about 2-1/2 times more dense. Under the tower’s approval by the City Council, the city will waive about $17 million in fees for permitting, park dedication and other things.

Initially the city Department of Planning and Permitting objected to some of the breaks, which contributed to “trials and tribulations” that City Council Chairman Ernie Martin said endangered the project but were fortunately overcome.

“To their credit and through (Yi’s) leadership and SamKoo’s commitment they actually came back with a better project,” Martin said.

“It was a difficult time,” Yi said. “But we finally were able to come through and bring this project forward.”

Gov. David Ige commended SamKoo for helping address a shortage of affordable housing in Honolulu that contributes to the city’s overwhelming homeless population.

“Providing housing for our people is one of the biggest challenges for us all,” he said. “This project is a great example of what can be accomplished when city, state and federal incentives really work together to make a project that is truly affordable for our community.”

Mayor Kirk Caldwell also acknowledged the “incredible challenges” involved with affordable housing in Honolulu, and praised SamKoo for building some in a prime area so close to the state’s biggest shopping center and not far from Waikiki.

“It’s so exciting to see what’s happening on this piece of property,” he said.