## 1 Introduction  
High-strength concrete (HSC) has excellent compression resistance and is very effective for column members subjected to axial loads [1; 2]. Meanwhile, in terms of economic efficiency, normal-strength concrete (NSC) is mainly used for flexure-dominant members, such as slabs. However, when the HSC column and the NSC slab are used together, the load-transfer performance of the column is affected by the low concrete compressive strength of the slab. The current design codes (ACI 318-19; CSA A23.3-14) suggest that the effective compressive strength (\(f^{\prime}_{ox}\)) of the column can be used in such cases [3; 4]. ACI 318-19 [3] prescribes that when the concrete compressive strength (\(f^{\prime}_{cc}\)) of the corner or edge column exceeds 1.4 times the slab concrete compressive strength (\(f^{\prime}_{cj}\)), \(f^{\prime}_{cj}\) should be used as the design compressive strength of the column. On the other hand, CSA A23.3-14 [4] specifies that if \(f^{\prime}_{cc}\) exceeds \(f^{\prime}_{cj}\), \(f^{\prime}_{cj}\) should be used in the corner column, whereas 1.4 \(f^{\prime}_{cj}\) should be used in the edge column.  
Many experimental studies have been conducted on slab-columns with different concrete compressive strengths. [PERSON] et al. [5] performed a compressive-strength test using the compressive-strengths ratio of the column and the slab, and the confinement conditions of the slab (i.e., interior, edge, and corner columns) as variables. Based on the test results, the issue of the load-transfer performance of the HSC column, which is reduced by the NSC slab, was raised, and this research was reflected in ACI 318-63 [6]. After this, [PERSON] et al. [1], [PERSON] and [PERSON] [7], [PERSON] [8], [PERSON] and [PERSON] [9], [PERSON] and [PERSON] [10], [PERSON] et al. [11], [PERSON] and [PERSON] [12], and [PERSON] and [PERSON] [13] carried out experimental and analytical research and reported the effects of the compressive strength of the column and the slab (\(f^{\prime}_{cc}\) and \(f^{\prime}_{cj}\)), the column width (\(c\)), and the slab thickness (\(h\)) on the effective compressive strength of the column (\(f^{\prime}_{cc}\)). The effective compressive strengths specified in the current design codes (ACI 318-19; CSA A23.3-14) have often yet failed to properly reflect the effects of the many variables, and compared to experimental test data, they provide very conservative results with large scatters. Therefore, in this study, ANFIS (adaptive neuro-fuzzy inference system) [14], a combination of fuzzy theory and an artificial neural network, was introduced to propose an algorithm that can evaluate the effective compressive strength of the column with high accuracy. The ANFIS is a system that can solve complex problems in science, finance and engineering, which are hard to analyze in a numerical manner. It is advantageous in that it can provide an output with a high accuracy by considering the correlations between various variables. However, it can also suffer from overfitting and overtraining, so adequate datasets are required for training the ANFIS algorithm [15; 16; 17]. In this study, a simplified equation was developed by means of extensive parametric studies and dimensional analysis based on the ANFIS evaluation results. The accuracy of the proposed model was verified by comparison with the design codes and empirical equations proposed by other researchers.