Abstract
This study proposes a mixed-methods framework—combining Nondestructive Testing (NDT), Destructive Testing (DT), and expert surveys—to standardize the reusability assessment of structural steel. Validated on a 19-year-old, 1,900 m² warehouse in Thailand, NDT revealed structural irregularities caused by environmental wear and aggressive demolition. Subsequent DT tensile testing (benchmarked against ASTM, TIS, and Eurocode 3) confirmed that five major structural sections retained standard mechanical properties, whereas slender cold-formed sections failed due to severe geometric thinning. Ultimately, this framework provides actionable guidelines to advance sustainable infrastructure and Circular Economy adoption in Thailand.
Background
Thailand’s construction sector relies heavily on imported, virgin steel (>60%), contributing significantly to the nation’s ~248 million tons of CO2 emissions in 2024. Although reusing structural steel can cut carbon emissions by 80% and drive circular economy practices, widespread adoption is hindered by a critical lack of standardized assessment frameworks and criteria. To bridge this gap, this study evaluates salvaged steel from a demolished three-story warehouse in Thailand to develop a comprehensive, systematic framework for assessing structural steel reusability.
Objectives
- To review Thai and international standards to identify current methodologies for assessing structural steel reusability
- To evaluate salvaged steel from the real-world existing building to develop practical assessment
- To establish a comprehensive, standardized framework for structural steel reusability assessment
Methodology
As illustrated in Fig. 1, this study follows a five-phase methodology. It begins with a literature review to identify current standards and research gaps, followed by case study selection to uncover real-world assessment obstacles. Material data is then gathered through non-destructive (NDT) and destructive (DT) testing. These findings drive the development of a systematic structural steel reusability framework, culminating in practical, actionable recommendations for industry decision-makers.
1. Case study selection
The case study was selected to investigate practical constraints and provide a better understanding of the reusability potential of reclaimed structural steel members.
General building information and Structural system
The selected case study is a 1,900 m², 3-story warehouse in Thonburi, Bangkok demolished in 2026 after a 19-year service life. Functionally divided into open-span, partitioned, and service zones, the building utilizes a composite structural system where loads from welded secondary steel roof trusses are supported by a primary reinforced concrete (RC) framework.
2. Data collection and Material testing
Following the case study selection, data collection involved using a criteria checklist handbook to identify reusable structural members and observing their demolition and disassembly. Material evaluation was conducted in two phases:
- Non-Destructive Testing (NDT): Included visual inspections for environmental degradation (cracks, corrosion, surface condition) alongside caliper thickness and coating thickness measurements.
- Destructive Testing (DT): 6 samplings as shown in Fig. 1 were performed at the SIIT Concrete Laboratory using a Universal Testing Machine to determine the yield and ultimate tensile strength of the extracted steel members.
Results
As shown in Table 1, five of the six steel sections met both TIS 1227-2558 and EN1993-1-1 standards, confirming adequate strength and ductility for structural reuse. However, the slender S100 section failed; its geometry prevented the testing machine from recording an accurate yield strength, making standard ratios incalculable. Consequently, S100 is unsuitable for primary structures and should be strictly restricted to low-load applications.
