Static and Dynamic Mechanical Responses of CFRP-Reinforced Ultra-High Strength Steel (UHSS) Tubular Members

This thesis investigates how ultra-high strength steel (UHSS) hollow tubes behave under static loads and sudden impacts, and whether reinforcing them with carbon fibre-reinforced polymer (CFRP) sheets can improve their performance. Advanced detailed laboratory experiments and numerical finite element models were used to examine tubes made from different steel grades under compression, bending, and drop-weight impacts in both axial and lateral directions. The results show that CFRP reinforcement can improve the strength, stiffness, and resistance to buckling and impact damage, although the level of improvement depends on steel grade and loading conditions. The study provides practical guidance for strengthening steel tubular columns used in buildings and infrastructure to improve their performance under both static and impact loading.