Progressive collapse of modular buildings

This project explores the progressive collapse of modular buildings made from composite shear walls (in the form of concrete sandwiched between two steel plates) and composite columns (in the form of concrete filled steel tubular tubes (CFST)) via simulation approach with ABAQUS. More information about this project can be found in the PhD thesis by Dr Swami [1].

Firstly, a novel three-layered shell element was developed in ABAQUS to capture the nonlinear behaviour of composite shear walls used in modular tall buildings. The proposed shell element can capture well the load-displacement behaviour of composite shear walls under static and cyclic loadings. The benefits of using this shell element compared to conventional solid elements are its computational efficiency, and this makes the modelling of high-rise composite buildings more efficient. Detailed information of this element can be found in Ref. [2].

Next, the proposed shell element was then used to simulate the progressive collapse of composite modular tall buildings. A dynamic amplification factor (DAF) of 1.2 was also proposed for composite modular tall buildings based on the findings from a comprehensive parametric study. This value is much smaller than the value of 2.0 proposed by general service administration (GSA) for conventional buildings. This means that modular buildings with composite shear walls and CFST columns have better structural robustness than conventional buildings. Detailed information of this study can be found in Ref. [3].

The roles of inter-module connections and CFST columns in structural robustness of composite modular buildings were also examined for a 10-storey building. To reduce the computational cost, the B31beam element with rebar option in ABAQUS is used to model the composite section of CFST columns. This will reduce significant computational time compared to the conventional method using solid element. This numerical study indicated that the use of CFST columns can enhance significantly the robustness of modular buildings against gravity-induced progressive collapse. The study also indicated that the gusset plate plays a critical role in developing the alternative load path to transfer the load to adjacent columns/modules. Please see Ref. [4] for more information.

Finally, design recommendations for structural robustness design of modular buildings were also provided in Ref. [5] based on a numerical study of steel modular building.

References

[1] Swami G. Robustness analysis of tall composite modular buildings. PhD Thesis, The University of Melbourne 2024.

[2] Swami G, Thai HT, Liu X. A novel shell element for modelling composite shear walls. Submitted.

[3] Swami G, Thai HT, Liu X. Robustness analysis for innovative tall composite modular buildings with composite shear walls. Submitted.

[4] Swami G, Thai HT, Liu X. Structural robustness of composite modular buildings: The roles of CFST columns and inter-module connections. Structures 2023;48:1491-1504.

[5] Thai HT, Ho QV, Li W, Ngo T. Progressive collapse and robustness of modular high-rise buildings. Structure and Infrastructure Engineering 2023;19(3):302-314.