Determining Material Properties of a Historical Industrial Steel Frame Structure

Canada is beginning to follow the European trend of shifting toward the reuse of existing structures to reduce environmental impacts. This shift has created a new culture of structural conservation and the need for engineers to understand the procedure of structural assessment of existing buildings. Historical structures are a specific niche of existing structures that require a closer assessment. A historical structure should not be damaged during assessment and is defined as a building or group of buildings that has been formally recognized for its esthetic, historic, scientific, cultural, social, or spiritual importance or significance for past, present, and future generations. The designation causes challenges in the testing available for data collection of material properties. Testing is limited to nondestructive (NDT) and minor destructive testing (MDT). Advances in technology have made nondestructive testing more reliable and easily accessible. Tests like laser scanning can map out the geometries of a structure, while ground penetrating radar (GPR) can confirm reinforcement details. NDTs are effective in confirming assumptions of structural properties and/or determining its material properties. Minor destructive testing relies on a sample of the structure to perform basic material property tests to gather information on strength, stiffness, and chemical microstructure. X-ray diffraction, scanning electron microscopy, Rockwell hardness testing, and tension/compression tests are all forms of MDT. The material properties determined from the above NDT and MDT can be used in finite element models (FEMs) to assess structural capacity. The FEMs allow engineers to determine possible failure modes of the structure and determine whether strengthening of members or buildings is required to increase the safety of the building. A case study was conducted to determine the material properties of the absorption building located in the historic Turner Valley Gas Plant (TVGP) in Alberta. The absorption building was constructed in the 1930s from structural steel piping and concrete. The NDT and MDT results were sufficient to determine the building’s material properties and eventually the structural capacity. The recommended NDT and MDT should be standardized to guide engineers when conducting structural assessments on historical structures.