Financially troubled South Korean construction firms are expected to refinance a large sum of debts due in April, industry data showed on Tuesday, raising concerns that their already shaky footing could further worsen. According to the data, a total of 5.23 trillion won (US$4.86 billion) in debts sold by 24 local construction companies are due this year, around 1.26 trillion won, or 24 percent, of which are scheduled to mature next month.