Proposing New Standard and ANFIS Calculation Approaches for Precast Concrete Connections with Steel Tube Elements: Lessons from Experimental Studies

The importance of establishing a proper method for calculating newly studied structural elements and primarily translating the results of experimental and numerical analyses into practical standards poses a significant challenge for structural researchers. In this study, which focuses on the importance of previously studied connections for the precast industry as a case study, two approaches are proposed for calculating the capacity of elements connected by rectangular steel tubes. The first approach involves a step-by-step calculation for analyzing the forces and capacities of different steel tube or concrete section parts under bending and shear, aiming to establish a standard calculation approach. Despite its complexity, the standard calculation approach has proven its accuracy by successfully solving examples with features similar to those of the experimental tests describing the process. The second approach relies on a look-up table generated from experimental data, developing an Adaptive Neuro-Fuzzy Inference System (ANFIS) for interpreting the data. ANFIS not only facilitates the evaluation of the capacity of non-experimentally tested elements but also resembles the calculation process. Evaluating ANFIS’s performance concerning the original results underscores its remarkable capacity to analyze experimental data. With a maximum calculation error of only 13% when compared to the experimental tests, ANFIS demonstrates considerable accuracy and user-friendliness. Following the initial internal force evaluations, the proposed standard calculation method requires eight specific control inputs, and comparing these inputs with experimental tests further confirms the effectiveness and safety of this approach for connection design.