Investigators use a model of highway in sinkhole report. Investigators use a model of highway to present sinkhole report.

Engineers say culvert was cause of sinkhole

An appropriate drainage system had not been put in place either

Replacing a damaged culvert would have prevented the sinkhole that appeared on the Cuernavaca Paso Express on July 12, an independent group of engineering experts has determined.

An analysis of the incident was completed by a team from the Morelos and Mexico City Colleges of Civil Engineers.

At a press conference yesterday to present the findings, hydraulic engineering expert Humberto Marengo Magallón said, “We wouldn’t be here if the culvert had been inspected carefully and the appropriate decision to change it had been made.”

Residents warned officials about the culvert prior to the disaster that killed two people and demanded that it be replaced.

Marengo indicated that video footage taken inside the culvert on July 16 showed that it had sustained severe damage including cracks and rusting. He added there were design and supervision errors from the beginning of the project.

“. . . An exhaustive inspection of the culvert should have been done to determine its state and on the evidence of the damage it should have been replaced with a new one of a sufficient diameter. If it had been changed to one of a larger size in good condition, the sinkhole problem would not have occurred,” he stated.

Marengo also said that companies working on the construction of the highway had failed to collect garbage from water channels and had not put an appropriate drainage system in place.

The engineer also raised the possibility that work during construction of the highway to repair a collapsed embankment caused by heavy rain may have dislocated the culvert, and that a further investigation is needed into the repair of a retaining wall damaged by erosion.

He asserted that despite a concrete reinforcement of the wall, it continued to erode due to heavy rains and when the sinkhole appeared, it was evident that repair efforts had not been effective.

“It didn’t need a car to go by or even a fly, the embankment on which the highway was supported had already lost structural resistance and that caused the sudden collapse.”

However, Marengo said assigning blame would be difficult.

“. . . it’s very difficult to determine the responsibility of each of the 14 companies that participated in the construction of the Paso Express, as well as local, state and federal authorities.”

Both the Communications and Transportation Secretariat (SCT) and the Public Administration Secretariat will review the report. SCT highways director Clemente Poon Hung said he would work to establish who was responsible and consequently impose sanctions, adding that contracts with Aldesa and Epccor, builders of the highway, are still current.

Those two companies previously said that since the culvert was 15 meters under the highway it was not part of the construction project.

There is also an ongoing investigation into three officials who allegedly didn’t respond in a timely manner to warnings about risks from residents and state and municipal officials.

Source: Milenio (sp)

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