The Dubai construction company that helped build the city's record-breaking Burj Khalifa and many other buildings in the United Arab Emirates says it lost more than $600 million last year as building slows amid a slump in oil prices.Arabtec Holding's preliminary results released Sunday show a loss of 2.3 billion dirhams ($626.7 million) in 2015. That compares with a profit of 215 million dirhams a year earlier. Sales fell 12 percent to 7.3 billion dirhams. Arabtec says results were hurt by "the continuing difficult environment ... and the challenging economic backdrop," as well as several "poorly performing projects."Backed by Abu Dhabi's state-run Aabar Investments, the company has cut costs following the abrupt departure of its then-CEO in 2014. It says it plans further cuts this year.