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According to the Ministry of Construction, the reason many electric poles were “knocked down” before the last storm No. 5 is due to deficiencies in design, production, construction, installation and maintenance, and they have not complied with regulations. . .
As for the hundreds of post-tensioned centrifugal concrete electric poles that were “knocked down” before Storm No. 5 recently, The Ministry of Construction has sent documents to the Ministry of Industry and Commerce and various related units on the quality control of centrifugal reinforced concrete electric poles used in power transmission.
Specifically, said the Ministry of Construction, through the survey, this ministry found that the system of medium and low voltage networks nationwide uses reinforced concrete electrical poles, including reinforced concrete poles. Centrifugal is invested and built by many different actors, taking place in many stages. The current design standards and technical instructions are basically quite comprehensive.
The failure of reinforced concrete electric poles, including prestressed centrifugal reinforced concrete electric poles produced in recent times, has many causes.
For objective reasons, the number of reinforced concrete electric poles is very large, with many different origins, built by many subjects in many stages and due to adverse effects such as fallen trees, landslides. land.
“The subjective cause is due to deficiencies in the design, production, construction and installation, maintenance, and non-compliance with the regulations; lack of calculation, checking the bearing capacity of the reinforced concrete posts according to the current standards for the design of structures ”- Information from the Ministry of Construction.
The Ministry of Construction also requested the Ministry of Industry and Commerce and the State Capital Management Committee of the company to instruct Vietnam Electricity (EVN) to review, evaluate and classify the existing power poles in operation. in the system; have the appropriate measures, plans and routes to reinforce, repair and replace the columns that are at risk of not guaranteeing the safety of the bearings before the rainy season.
The Ministry of Construction also noted that EVN stipulates that units that design, manufacture, build and install reinforced concrete columns, including centrifugal reinforced concrete columns when fabricating, selecting and constructing, must comply with current national standards on structural design and foundations (including TCVN 5574: 2018 – Concrete and reinforced concrete structures, TCVN 2737: 1995 – Loads and impacts …).
The Construction Ministry also said that it is necessary to consider assigning an experienced and qualified consultant to perform the structural calculations and draw up the typical design drawings for reinforced concrete power poles to ensure safety. complete and synchronous.
Previously, according to the EVN report, on the network damage caused by the storm, in Quang Binh, Quang Tri, Thua Thien-Hue, Da Nang, Quang Nam provinces, there were 616 power poles broken, falling and inclined. , of a total of 531,135 electricity poles in the aforementioned provinces and cities. In which, 304 columns broke (representing 0.06%), 169 columns collapsed, 143 columns tilted.
Of the 304 broken columns in the provinces and cities mentioned, there are 34 post-tensioned concrete columns and 270 smooth concrete columns. Particularly in Thua Thien-Hue province, there were 272 broken columns, of which 30 were prestressed concrete columns. The above statistics show that the proportion of prestressed concrete columns constitutes a very small part of the total broken electric poles.
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