SURFSIDE, Fla.—Florida officials are working on plans to tear down what’s left of a partially collapsed oceanfront condominium building after concerns about the structure’s instability prompted a 15-hour halt to the search for survivors. After rescue efforts resumed Thursday evening, officials said they had started planning for the likely demolition of the remaining structure even as searchers continue to comb the rubble pile beneath it. Scott Nacheman, a FEMA structures specialist, said engineers are looking at different methods for the demolition and how to proceed “to make the site safe for ongoing rescue operations.” Nacheman said that if the building comes down, there initially will be a slowdown in the rescue operation. But he said the demolition of the structure would create a safer working environment that could allow more personnel on the site and accelerate the pace of the work. He said it would likely be weeks before officials …