Issue 74

E. Sharaf et alii, Fracture and Structural Integrity, 74 (2025) 262-293; DOI: 10.3221/IGF-ESIS.74.17

S ENSITIVITY INVESTIGATIONS

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ensitivity analysis was conducted to evaluate the influence of the main design parameters on the fundamental vibration period of RC moment-resisting frame (MRF) buildings. This investigation is based on numerical results of 125 building models, where the primary parameters are shown in Tab.11. They include the number of stories, total building height, typical storey height, span length, cross-sectional beam and column sizes, model mass, and concrete modulus of elasticity. The results of the sensitivity analysis are outlined in the following subsections. Geometric parameters The building's geometrical configuration is essential in determining its dynamic features, specifically its fundamental time period. The building's height and span length are among the most significant characteristics, as they directly affect the structure's overall stiffness and mass distribution. This subsection provides a comprehensive examination of how various elements affect the fundamental time period. Effect of building height Relative comparison provided in Fig. 15 (a-c) contrasts accuracy of different formulations in estimating the fundamental time period of moment-resisting frames having different spans (5 m, 6 m, and 7 m), with Finite Element Method (FEM) results. The equations considered are those given by [5, 6, 23] and a new expression developed in the present work. In Fig. 15a, for 5 m span frames, the proposed equation is in very good agreement with FEM-based calculations with R² = 0.999 and RMSE = 0.02 s. Aninthaneni and Dhakal's equation [23], however, has R² = 0.60 and RMSE = 0.67 s, indicating a moderate relationship with some scatter. Goel and Chopra's formula [5] exhibits suboptimal performance, yielding an R² of 0.36 and a root mean square error (RMSE) of 0.84 s, whereas Salama's formula [6] is more accurate (R² = 0.78, RMSE = 0.49 s) but less than the proposed model. For Fig. 15b, for a frame with a span of 6 m, the proposed model maintains high predictive fidelity (R² = 0.999, RMSE = 0.013 s), underscoring its robustness across structural configurations. Aninthaneni and Dhakal's equation [23] shows some improvement (R² = 0.66, RMSE = 0.55 s), but yet maintains a very high margin of error. Goel and Chopra [5] approach is still imprecise (R² = 0.38, RMSE = 0.76 s), while Salama's formula shows quite good agreement (R² = 0.83, RMSE = 0.40 s), though not as good as the suggested expression.

Figure 1 5 : Comparison of fundamental periods for buildings with varying models at different spans: (a) 5 m, (b) 6 m, and (c) 7 m.

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