Wugu-Yangmei Overpass cracks most likely due to poor construction: expert
By Adam Tyrsett Kuo, The China PostTAIPEI, Taiwan -- An expert has slammed the Taiwan Area National Expressway Engineering Bureau's (TANEEB) suggestion that cracks which have appeared on the Wugu-Yangmei Overpass (五楊高架) may have been caused by rapidly rising underground water levels due to Tropical Storm Trami.
August 24, 2013, 12:00 am TWN
New Taipei City Professional Civil Engineers Association head Yu Lieh (余烈) blasted the bureau and said that its explanation was “nonsense,” adding that the cracks were most likely caused by poor construction.
The cracks were most likely caused by contractors not following soil compaction requirements, Yu said, adding that the cracks may have also been caused by contractors using the wrong soil type.
Regarding the bureau's decision to invite third-party investigators to probe the case, Yu said that the question of whether or not he is invited to take part in the investigation will not affect his suspicion that the cracks were caused by poor construction.
Later in the afternoon, Yu traveled to the site in question for further inspection.
The section of the overpass sits on 8 to 9 meters of backfill, Yu said.
Ideally speaking, each layer of soil should be 35 centimeters and be compressed by machinery before another layer is placed on top of it, Yu said, adding that soil density after compaction should reach 95 percent.
Citing figures released by the Central Weather Bureau, Yu said that the section of the overpass saw 413 millimeters of precipitation over the course of three days during Tropical Storm Trami's arrival, Yu said, adding that relatively speaking that wasn't a lot of rain.
The Wugu-Yangmei Overpass has been open to traffic for roughly four months. On Thursday, three cracks were observed on the overpass, one of which reached 30 meters in length. Sections of the overpass were closed off for emergency repair. The sections were re-opened to traffic by noon yesterday.
In response to accusations of poor construction, TANEEB chief Tseng Dar-jen (曾大仁) said that according to his bureau's investigation, construction work on the overpass was completed in accordance with contract regulations, and that the supervisory bodies had left a complete record of data.
If further probes show that there were any faults, actions will be taken in accordance with the contract, Tseng said. The bureau will not protect its own, Tseng added.