Optimization-based strut-and-tie model generation for reinforced concrete structures under multiple load conditions

Strut-and-Tie modelling (STM) has been widely applied to design D-regions of reinforced concrete structures. For economic and environmental reasons there is a need for optimized Strut-and-Tie models. How to optimize Strut -and-Tie models considering multiple load combinations has not been investigated extensively in the literature. In order to address this gap in this paper, we propose a method to generate multi-load optimization-based Strut -and-Tie (MOST) models to design D-regions under multiple load combinations. The proposed generation method involves the determination of basis vectors for the load combinations and generation of the corre-sponding optimization-based Strut-and-Tie models for each of the basis vectors by topology optimization and truss extraction. The generated model is then used to design D-regions under multiple load combinations. In order to check the effectiveness of the proposed method, three alternative approaches for multiple load com-binations are investigated and discussed. These approaches comprise: (1) using manually created Strut-and-Tie models, (2) adopting multi-load topology optimization resulting in a single Strut-and-Tie model, (3) generating individual Strut-and-Tie models for each of the considered load combinations. In this paper, three 2D and one 3D D-regions are investigated to compare the effectiveness and applicability of the different methods. It is found that the proposed method results in more economical designs than the three alternative approaches.

Automated summary

This paper proposes a method to generate multi-load optimization-based Strut-and-Tie (MOST) models and compares the effectiveness and applicability of three alternative approaches for multiple load combinations. The results show that the proposed method is more economical than the other three methods.