The monitoring of structures is one of the most difficult challenges of engineering in the 21st century. As a result of changes in conditions of use, as well as design errors, many building structures require strengthening. This article presents research on the development of an externally strengthening carbon-fiber textile with a self-sensing option, which is an idea is based on the pattern of resistive strain gauges, where thread is presented in the form of zig-zagging parallel lines. The first laboratory tests showed the system’s high efficiency in the measurement of strains, but also revealed its sensitivity to environmental conditions. This article also presents studies on the influence of temperature and humidity on the measurement, and to separate the two effects, resistance changes were tested on unloaded concrete and wooden samples. The models were then placed in a climatic chamber, and the daily cycle of temperature and humidity changes was simulated. The research results confirmed preliminary observations of resistivity growths along with temperature. This effect is more visible on concrete samples, presumably due to its greater amount of natural humidity. The strain measurement with carbon fibers is very sensitive to temperature changes, and applications of this method in practice require compensation.

Monitoring of structures is one of the engineering challenges of the 21st century. At the same time, as a result of changes in the conditions of use, design errors, many building structures require strengthening. The article presents research on the development of the external strengthening carbon fiber textile with an option of self-sensing. The idea is based on the pattern of resistive strain gauge, where thread is provided in a zig-zag of parallel lines. Already the first laboratory tests showed the high efficiency of the system in the measurement of strains, but also revealed the sensitivity of measurement to environmental conditions. The article presents studies on the influence of temperature and humidity on the measurement. To separate those effects, resistance changes were tested on unloaded concrete and wooden samples. The models were placed in a climatic chamber and the daily cycle of temperature and humidity changes was simulated. The results of the research confirm preliminary observations. Resistivity growths with the temperature. This effect is more visible on concrete samples, presumably due to its greater natural humidity. The strain measurement with carbon fibers is very sensitive to temperature changes and application of this method in practice requires compensation.