Investigation on the flexural behavior of UHPC I-beams reinforced with steel plates
Xuanyi Shen, Qiuhan Kong, Jun Wang, Yueyue Tang, Qirui Pei, Fengjiang Qin
Abstract
This study proposes a novel ultra-high-performance concrete (UHPC) I-beam reinforced with steel plates. The flexural behavior of these composite beams was systematically investigated through experimental tests, numerical simulations, and theoretical analysis. Firstly, the four-point bending test was carried out on four specimens with steel ratio and reinforcement ratio as variable. The results revealed that under the same steel ratio, replacing a part of steel rebars by the 3 mm thick steel plate restricted the development of crack width and exhibited an increase in yield load and ultimate load by 22.8 % and 25.2 %, while it has little effect on improving the cracking load. As for the specimens reinforced with steel plates, when the steel ratio increased by 33.33 % and 75.00 %, the yield load increased by 16.10 % and 31.52 %, while their ultimate load increased by 17.81 % and 39.25 %, respectively. Subsequently, finite element models of the composite beams were established based on the experiment, which were verified to be applicable for the parametric analysis with an error less than 5 % compared with experimental result. The parametric analysis revealed that the flexural bearing capacity increased nearly linearly with the increase of the total steel ratio. Furthermore, considering the strain hardening characteristics of UHPC, the calculation method for the flexural bearing capacity of the steel plate reinforced UHPC I-beam is derived and is verified that the error between theoretical, analytical and experimental value was under a limit of 7 %. In summary, reinforcing UHPC I-beams with steel plates improves yield and ultimate strength while controlling crack propagation. This method offers a cost-effective solution for broader UHPC beam applications.