The barkers who used to line 14th Street NW downtown, drumming up business for the row of strip-tease nightclubs known as the Strip, were replaced by demolition workers yesterday as crews went about reducing most of the Strip to rubble.

The giant Texas-based developer Trammell Crow Co., owner of several buildings near the southeast corner of 14th and I streets, is clearing the site to build a 12-story office tower. Benny's Home of the Porno Stars, the Californian Steak House and The Cocoon and Butterfly clubs have been reduced to twisted steel and shattered bricks.

Because of zoning laws in the area, it is unlikely such a concentration of sexually oriented businesses will ever again be assembled -- a fact that police officials applaud.

"A lot of people don't understand the impact a concentrated area of adult entertainment has on a city," said Lt. Robert Poggi, who heads the city's prostitution task force.

"Our experience has been that sexually oriented businesses are fronts or contact places for prostitution," Poggi said, adding that without a concentration of adult entertainment clubs, potential customers "won't have the incentive to drive downtown."

As some sexually oriented 14th Street businesses have closed in the last few years, nights have grown quieter, Poggi said. A few years back, motorists "were almost involved in traffic jams" because of the number of cars and the tendency of prostitutes to run into the street to solicit business, he said.

He also mentioned that drug sales, drunk driving, accidents, assaults and robberies are associated with a flourishing sex scene. Criminals see easy targets, he said, because "people who are out looking for prostitutes are reluctant to report minor crimes."

Rose Lindsay, manager of the new, upscale Mingles restaurant at 1400 I St. NW, said the establishment has not had problems with crime since it opened in February. "But having these buildings come down is a great thing," she said, adding that she hopes evening business will pick up as the Strip vanishes. "We're thrilled."

Ron Cohen, managing editor of United Press International, located upstairs at 1400 I St., said the closing of the clubs "has diminished traffic and the number of people being abusive," but added that the street is still active after dark. "We have a 24-hour operation, and our people are still very careful when coming to work at night."

Sex has not vanished from 14th Street; several adult businesses remain, mostly bookstores and peep shows. Developer Jeffrey Cohen, who began purchasing buildings in the area in the late 1970s and sold them all to Trammell Crow last year, said these establishments, too, eventually will be purchased for development. But it might take years, he said, because these small, old buildings are not easily assembled into a viable parcel.

D.C. zoning rules allow sexually oriented businesses to locate only in high-density commercial zones. Within those zones, they cannot locate within 600 feet of schools, churches or homes, or within 300 feet of each other. Because establishments already operating at the time of enactment were excluded from the rules, the 14th Street clubs could have operated indefinitely if no other violations had been prosecuted.

"It kind of evolved from a good, high-class entertainment area, into a kind of a place for soldiers on leave, into a pornographic area," said Thomas Lodge, a founder of the Logan Circle Community Association and a neighborhood resident since 1952.

In the 1950s, "the top entertainers in the country" performed there, Lodge said; in the early '60s, a combination of bookstores and go-go dance spots appeared; but in the 1970s, "overt drug sales and overt prostitution" took over, bringing with them "pure, absolute sleaze."

In 1978, developer Cohen bought the adjacent Parkside Hotel on I Street, and over the next few years he purchased the other properties he sold to Trammell Crow in 1985.

Around the same time, efforts began to make the area respectable for office development. The Franklin Square Association, a group of investors and developers with interests in the area, hired several private investigators whose miniature cameras caught evidence of liquor and zoning code violations in the clubs, as part of a campaign to clean them up or get rid of them.

Eventually, the Butterfly and The Cocoon were closed when Abraham and Isidore Zaiderman of Potomac pleaded guilty to using them as a front for fencing and prostitution. In 1984, "This is It?" lost its liquor license for a variety of violations, so it offered soft drinks and female Jello wrestling matches. Now, it is closed, and a sign in the window announces that "All This is It? Girls now working at Adam & Eve" next door.

In 1984, Herbert C. Cole, former proprietor of Adam & Eve and the Casino Royal, pleaded guilty to income tax evasion and racketeering, and went to federal prison with his wife Mary, who pleaded guilty to tax evasion.

Art Schultz, executive director of the Franklin Square Association and mastermind of its 14th Street makeover, has watched the demolition closely. "It is so gratifying to see this," he said.

Roger W. (Roddy) Simkins, who operated Benny's Home of the Porno Stars before it closed in 1984, takes the change in stride. "I think that certainly there were people who got their start there, one way or another. And some characters don't have a focal point to congregate anymore," he said. "But I don't think the city has lost anything."