Engineers overreacted to the Cologne metro collapse by installing too much extra ground monitoring equipment, an expert close to the investigation said last week.
Extra ground and structural monitoring equipment installed following the disaster had to be scaled back because engineers were being swamped with data.
The city’s six-storey archive building and two neighbouring residential buildings collapsed into a deep shaft for a new subway on 3 March, killing two people (NCE 12 March).
“There was too much data − it is almost impossible to evaluate that amount.”
Roland Leucker, STUVA
Immediately after the accident, automatic measuring systems were installed to detect further movement, settlement and deformations of the shaft walls. Some of these monitors were read up to four times a day.
“There was too much data − it is almost impossible to evaluate that amount,” said German Research Association for Underground Transport Systems (STUVA) managing director Roland Leucker.
“You have to look at all the monitoring together. A small incident in one indicator and another small indicator from another monitor together can conclude the cause of an accident.”
Leucker was speaking at the NCE and Ground Engineering “Tunnelling 2009” conference last week. He said that after two months it was decided to cut the evaluation of data back to just one check per day.
Client Cologne Transit Authority KVB appointed STUVA in April to oversee further construction work on the city’s North-South Metro Line and investigate what led to the collapse.
At the conference, Leucker also confirmed that results of neither the technical nor judicial inquiries would be released before the end of 2010.
This is despite expectations that the investigating team would be ready to report its findings on the cause of the disaster by the end of this year.