Recently, a citizen reported to the Yangtse Evening Post that at the construction site of the expansion factory building of Nanjing Sifang Barrel Making Co., Ltd. in Zhongshan Science and Technology Park, Luhe District, Nanjing, the pipe pile supplier Anhui Shangneng Pipe Pile Co., Ltd. actually altered the markings printed on the pipe piles. The original marking was "PHC500-100", which was manually altered with a black pen to "PHC500-110". A difference of one digit concerns building safety.
　　Although under the witness of the reporter, on-site measurement showed that the wall thickness of these altered pipe piles was indeed 110mm, such problems reflect deficiencies in the rigor of Shangneng Pipe Pile Company's management. The Quality Inspection Station of the Luhe District Construction Bureau stated that an investigation has been launched into this matter, and a testing center has been arranged to conduct comprehensive tests including breaking piles on the company's pipe piles to ensure that the pile foundation engineering quality meets relevant requirements.
　　Citizen's Tip-off
　　Pipe Pile Specifications Altered at Construction Site
　　Under the guidance of this citizen, the reporter found the construction site inside the wall of Sifang Barrel Making Company in Dachang Zhongshan Science and Technology Park. At the west corner, a pile driver was in operation, and a half-driven pipe pile was still standing on the site. On the flat ground nearby, there were three stacks of pipe piles, each containing dozens of piles, all 11 meters long. In two of the stacks, the reporter indeed found anomalies.
　　At one end of these pipe piles, the manufacturer, production date, and related specification numbers were printed in bold black characters. The reporter saw that in two of the stacks, more than ten pipe piles mixed in had traces of alteration. The "PHC500-100" on several pipe piles had been changed to "PHC500-110", i.e., one "0" was painted over with a black pen to become "1". Judging from the font, it was very irregular and clearly manually altered. The reporter learned that PHC is the abbreviation for prestressed high-strength concrete pipe piles, which are hollow cylindrical concrete precast components made by pre-tensioning, centrifugal molding, and steam curing at about 10 atmospheres (1.0 MPa) and around 180°C. According to the specifications, these pipe piles should be 11 meters long, 500mm in diameter, and 110mm in wall thickness. That is to say, if the alteration is true, then its wall thickness was changed from 100mm to 110mm.
　　"Pipe piles are driven into the foundation to support above-ground buildings. If the specifications of the pipe piles do not meet the design requirements, their bending and shear resistance will be greatly reduced. The most direct result may be uneven settlement of above-ground buildings, which may cause houses to tilt or even collapse." a construction engineering expert told the reporter.
　　Reporter's Investigation
　　On-site Measurement: Pipe Pile Wall Thickness is 110mm
　　Construction Party Says Problem Already Noticed, Supplier Says Printing Error
　　Just as the reporter was searching the site for these altered pipe pile markings, two men came over to stop the reporter's search. When asked why these markings were altered, a man who claimed to be from Shangneng Pipe Pile Company said he did not know the situation. The quality inspection station in Dachang had already sent people to measure, and specific details should be asked to the construction party, Shaanxi Construction Machinery Construction Group.
　　The reporter found the project department of the construction party, Shaanxi Construction Machinery Construction Group, several hundred meters away. After a middle-aged man asked in detail about the reporter's identity, he claimed that the reporter did not need to know the process of the matter and that they would handle it themselves. At the reporter's request, a manager Hu in charge of quality management at the project department told the reporter that they were actually aware of the situation and had measured these pipe piles with altered markings, finding them all qualified. "The staff of the Dachang Quality Inspection Station also came specifically to measure the day before yesterday after receiving a complaint, and there was no problem," Manager Hu said.
　　Subsequently, at the reporter's request, Manager Hu brought a tape measure to the site of the pipe piles and measured the wall thickness. Several altered pipe piles indeed showed 110mm.
　　"We also consulted the supplier Shangneng Company. They said that workers made a mistake when marking the product; it should have been 110mm but was mistakenly marked as 100mm, and then it was manually changed," Manager Hu said, adding that there was no problem with the product. As for the testing issue, Manager Hu told the reporter that their project leader had gone to the Luhe quality inspection department to submit materials, and the relevant situation explanation and testing would be carried out together.
　　Not That Simple: Pipe Piles Must Be Subjected to Destructive Sampling Inspection
　　Have Similar Pipe Piles Entered Civil Building Construction Sites? This Newspaper Will Investigate
　　The reporter learned from an informed source that the construction site planned to use more than 10,000 meters of pipe piles, and the "Nanjing Prestressed Concrete Pipe Pile Quality Supervision and Management Regulations" clearly stipulate: "Qualified products after factory inspection shall have a qualification mark on the end of the pipe pile, and the mark content shall be clear and complete." In addition, "for pipe piles with external defects upon entry (dimensional deviation, cracks, concrete damage, incomplete or unclear markings, etc.)," the quality supervision department should conduct supervised sampling inspections.
　　Station Chief Li of the Quality Inspection Station of the Luhe District Construction Bureau told the reporter that they are investigating the matter of Shangneng pipe piles involved in the construction by Shaanxi Construction Machinery Construction Group, and relevant testing is also underway. "They are going through the relevant procedures, which have not been completed yet, and we are also investigating this matter," Station Chief Li replied to the reporter. Regarding whether this batch of pipe piles was reported to the quality inspection station, and whether construction before completing the testing procedures is compliant, Station Chief Li repeatedly emphasized that the procedures are being processed, and the piles currently being driven may be test piles, which are allowed.
　　"There are many tricks in pipe pile production, and some even engage in low-price competition. Only destructive testing can reveal them. For example, for Type A piles, the main reinforcement must be 9.0mm as required, but some pipe pile companies use 8.0mm 'slimmed steel bars'. Also, the end plates at both ends of the pipe pile should be 18mm according to regulations, but some use 16mm, which is hard to see with the naked eye and must be measured with a vernier caliper. In addition, the spacing of spiral reinforcement inside, the thickness of concrete end plates, etc., can all be tampered with and covered up by a glossy appearance," the informed source told the reporter. Pipe piles must be subjected to destructive sampling inspection to reveal these problems, and at the same time, it is necessary to prevent some pipe pile companies from custom-making pipe piles for inspection.
　　As to whether problematic pipe piles have flowed into civil building construction sites in the Nanjing market, this newspaper will continue to follow up.