The manufacture of steel reinforcement rods is endangering the safety of construction projects in China, reported worldarchitecturenews.com.
The website says that a ‘stretching’ factory in Zhengzhou, where steel reinforcement rods used in a number of construction projects had been pulled to a thickness below regulatory standards has become the latest organisation to be found carrying out this practice.
A 10mm wide rods can be easily stretched to a thickness of 8.5mm, creating many additional metres of metal then sold on for profit.Despite countless assertions from experts that pulling these essential building components to inadequate diameters will weaken a structure and endanger the lives of its users, construction companies in China are still being found operating under such measures. A number of manufacturers have been ordered to stop this practice.
Thinning reinforcement rods is not illegal but when practiced to excess can lead to a reduction in the effectiveness of the metal. Fan Zhong from the China Architecture Design and Research Group told the website: “Over-stretching the steel bars will cause them to become brittle and weak, and less resistant to earthquakes,” a point confirmed by Wu Chengcai, General Engineer at the Shaanxi Provincial Building Research Institute, who comments: “When a building suffers great external force such as an earthquake, the stronger, standard steel bars will ‘stretch’ as the building suffers the damage, thus slowing the process of its collapse for people to escape. However, the buildings with the substandard, thin steel bars will collapse very quickly.”