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This study investigates the effectiveness of modified graphene (MGE) for developing novel structural adhesives and their application in concrete beam reinforcement. The research aims to reveal the mechanism of MGE and evaluate the effect of different reinforcement methods on the flexural performance of concrete beams. Two adhesive formulations – original structural adhesive (OSA) and functionalized graphene-based structural adhesive (FGSA) – were examined alongside two reinforcement methods: the grouting reinforcement method and the adhesive fiber-reinforced polymer (FRP) method. The results show that the increased spacing of the functionalized MGE flakes improved their dispersion in epoxy resin, enhancing cohesive forces through bonding interactions and leading to the enhancement of the basic mechanical properties of FGSA by 6% to 12%. Compared to OSA, the application of FGSA improved the flexural properties of concrete beams, with the degree of improvement depending on the reinforcement method, while the failure mode of the beams remained unchanged. In addition, the FGSA/FRP combination showed the most significant improvement in the fracture parameters (220% to 480%) compared to the unreinforced control, highlighting its efficiency and cost-effectiveness as a reinforcement method. These findings offer valuable insights into reinforcement strategies for concrete beams, addressing the limitations of structural adhesive bond strength and optimizing reinforcement techniques. [ABSTRACT FROM AUTHOR]

A new adjustable and combined reinforcement method consisting of arch rib and steel beam is proposed in this paper. The principle is to redistribute the internal forces of the structure through the support of the arch rib and to form a combined structure by using steel and concrete. Symmetrically loaded bending tests were carried out with five different combined strengthening schemes. The analysis of the test process was conducted adopting a FEM model, and the equations for calculating the RC beam's load capacity under combined strengthening were derived while considering the slip effect. The experimental results indicated that the combined reinforcement method had a synergistic effect when the ultimate load capacity had increased by more than 95% after reinforcement. As the size of the arch ribs and profile beams increased, a better reinforcement effect was seen. However, beyond a certain range, the RC beams had already broken down and had failed before the reinforcement material could yield. The combined reinforcement method changes the force system of the original RC beam, resulting in a smaller angular inclination trend of the cracks in the original purely curved section and a smaller crack extension. The non-linear finite element results are generally consistent with experimental loads, displacements, and ductility, while the average ratio of experimental to calculated ultimate Load capacity is 0.95, demonstrating that non-linear finite elements and theoretical formulas are accurate. [ABSTRACT FROM AUTHOR]

In order to ensure the safety and stability of the construction process of the bidirectional outward inclined arch tower cable-stayed bridge, the optimization design method of construction measures is put forward. The objective function of optimization is the safety and economy of construction measures. The stress safety of cable-stayed bridge in each construction stage is the constraint condition. The construction method of cable-stayed bridge is optimized by determining the position and structure form of construction measures. The prestressed concrete cable-stayed bridge with single tower and double cable plane in the shape of golden camellia is taken as the engineering background. The position and causes of the hidden danger in the construction of the bridge are analyzed. This method is applied to optimize the construction method, and three cross bracings are to be set up in the construction stage of the main tower. The optimized construction method is applied to actual construction. The results show that this method can design better construction measures. The optimized construction method effectively controls the stress and line shape of the main bridge during the construction phase. The maximum tensile stress of the main tower is controlled at 1. 67 MPa, and the maximum horizontal displacement of the tower top is maintained at 14. 50 mm. The stress state of the main bridge construction can meet the safety requirements. The measured stress of the main tower is consistent with the finite element calculation, and the error is within 5%. This method scientifically and effectively guides the construction and achieves good results. [ABSTRACT FROM AUTHOR]