The Ministry of Housing and Urban-Rural Development recently reported on production safety accidents in housing and municipal engineering projects nationwide in the first half of the year. The accident with the highest death toll was the collapse of formwork support systems, which accounted for more than half of the total number of major accidents and total deaths.

　　In addition to being related to the construction characteristics of the formwork support system itself, the most fundamental cause of this phenomenon lies in the significant quality defects of the scaffolding that plays a key role, and the deeper reason is the unreasonable labor subcontracting system.

　　Tragic News: Frequent Accidents with Mass Casualties

　　During the concrete pouring of the central hall of the Phase I project of Shengyuan Wealth Plaza in Anqing, Anhui, a formwork support system collapse occurred, causing 8 deaths; during the concrete pouring of Workshop No. 6 of Fujian Fuqing Songyi Webbing Co., Ltd., a formwork support system collapse occurred, causing 4 deaths...

　　These are just a few examples of major safety accidents that occurred in the first half of this year, all caused by the collapse of formwork support systems. Moreover, in recent years, tragedies of construction workers falling to their deaths from scaffolding or scaffolding collapses causing mass casualties have frequently appeared in the news.

　　In the first half of this year, there were 13 relatively major production safety accidents in housing and municipal engineering projects nationwide, resulting in 53 deaths. Among them, 7 were formwork support system collapse accidents, causing 30 deaths, accounting for 53.85% and 56.60% of the total number of relatively major accidents and total deaths, respectively.

　　Ding Shuo has been engaged in project safety management for many years. He believes that the tendency of formwork support system collapses to cause mass casualties is determined by its own characteristics.

　　He stated that formwork support systems are mainly used during the pouring stage of components such as floor slabs and beams, with a large working area and requiring many workers. Accidents generally occur during the pouring process, so the proportion of mass casualties is relatively high.

　　However, this is not the root cause of the accidents.

　　Culprit: Thin-Walled Steel Pipes That "Kill" by Millimeters

　　The formwork support system includes formwork and a support system. Ding Shuo explained that formwork is used to shape concrete, while the support system is used to bear loads, which is what we commonly call scaffolding.

　　It is reported that the commonly used scaffolding types in current construction are bowl-buckle and fastener types, but regardless of the type, their quality and erection method are key to the safety performance of the formwork support system.

　　After reviewing materials, the reporter found that the "Scaffolding Code" JGJ130-2011 stipulates that steel pipes with an outer diameter of 48.3mm and a wall thickness of 3.6mm should be used. However, previously exposed accidents show that steel pipes with an outer diameter of 48mm have a wall thickness of less than 3mm.

　　Moreover, Ding Shuo stated that among the scaffolding currently used on construction sites, it is already fortunate if the actual wall thickness of steel pipes can reach 2.8mm, and very few fully meet the national standard. According to calculations by relevant technical departments, for steel pipes of the same diameter, every 0.5mm reduction in wall thickness results in a 15%-30% decrease in load-bearing capacity.

　　To reduce costs, cutting corners has long been an open secret in the scaffolding industry. Manager Zhu, a salesperson for a certain brand of scaffolding, spoke bluntly: "Many peers, in order to survive, risk taking the path of low quality, low price, and high risk." However, completely different from the construction companies' complaints about substandard scaffolding quality, the use of steel pipes with non-standard inner walls by construction units is driven by economic interests.

　　Manager Zhu stated that the purchase and rental of scaffolding steel pipes are calculated by tonnage, and steel pipes with thinner walls have an advantage in quantity over those with thicker walls.

　　The reporter also confirmed this with Ding Shuo, but it is not the construction unit pursuing economic interests, but the labor subcontracting units. This again attributes the problem to the labor subcontracting system that has remained unchanged in the construction industry for decades, which is precisely the deep-seated cause of scaffolding accidents.

　　Accomplice: The Subcontracting System Divides Safety Supervision

　　An industry insider from the China Infrastructure Materials Leasing and Contracting Association analyzed that, in addition to the quality defects of the scaffolding itself, the current non-standard erection of scaffolding and the weak safety awareness of construction personnel are also important causes of accidents, which are inevitably linked to the current multi-level subcontracting system in construction projects.

　　Zhang Feng has been engaged in construction technology work and currently serves as the technical department manager for a project. He stated that compared to labor teams, general contractors have stricter management of safety and quality. If the labor-only subcontracting method is adopted, the hidden risks are relatively small; if the comprehensive subcontracting method is adopted, everything depends on the labor team, as they are more likely to choose cheap materials, and the hidden risks increase accordingly.

　　He analyzed in detail that on-site technical personnel understand the current situation of the scaffolding industry, so they will increase the safety factor when preparing special plans to ensure the construction safety of the formwork support system. However, due to institutional problems, some labor companies do not have professional qualifications and therefore no technical personnel, and migrant workers do not understand the relevant regulatory technical requirements, making it difficult for labor companies to comply with regulations.

　　"Labor teams often rely on experience and habits, because a thinner wall thickness can save a lot of costs, and workers erecting fewer steel pipes saves a lot of labor time," Zhang Feng said. "But luck does not always favor them. Sometimes the omitted steel pipe is precisely an important member of the formwork support system, causing instability of the frame, tilting and deformation of the scaffolding, and ultimately collapse."

　　Zhang Feng also stated that it is undeniable that the occurrence of accidents is inseparable from the inadequate supervision of the general contractor, and there are still major loopholes in management.