Abstract:
Steel brackets have a renowned potential of being used in bridge constructions as a load-bearing
element. Due to the higher consumption of steel in bridge constructions, the emission of Carbon
Dioxide (CO2) gas is increased when manufacturing steel components. CO2 is one of the main
greenhouse gases prompting the increase in global warming. Moreover, excessive material
usage in bracket manufacturing will lead to expensive constructions and increased embodied
energy consumption. Another concern is that, though the material usage is to be reduced, the
strength, stiffness and stability of the structure should be preserved. Hence, engineers have
identified that structural optimisation is the best solution to address this global problem, and
they have been practising structural optimisation principles on the structural components
recently to achieve sustainability during the service life. In other words, their ultimate target is
to apply sustainable concepts to the construction principles. Although many researchers have
studied various structural optimisation tools and presented novel designs, applications of those
designs in the construction industry are still limited due to the complex geometries of the
optimised designs. Nevertheless, the advantages of optimised designs are more powerful than
the manufacturing challenges. The recent developments in additive manufacturing extend
higher flexibility and efficiency to the fabrication of these structures by overcoming the
manufacturing challenges. However. nowadays, these novel and eco-friendly techniques are
getting more attention all over the world because of their merits in the ever-evolving field of
Civil Engineering.
To circumvent the above-mentioned challenges, this research demonstrates a novel approach
for producing an optimum and sustainable steel bracket for a pedestrian bridge construction.
Among several structural optimisation methods, topology optimisation is used as the tool of
choice in this work, which has a proven record of arriving at the highest stiffness to weight
ratio. This study uses an existing steel bridge bracket in Castleford Foot Bridge, England as a
study case. The bracket is optimised under several volume fractions and ultimately, the
optimum design is selected based on both simulation results and practical considerations.
According to the results, the optimised model with a 30% volume constraint is selected as the
optimum design which leads to the manufacturing of cost-effective and sustainable structure.
Considering the manufacturing possibilities, the optimised model from the finite element
software is converted into a manufacturable parametric Computer-Aided Design (CAD) model
using the Rhinoceros software package for further post-processing and analysis. The modified
CAD model is re-analysed using finite element software and its structural performance is
verified. It is shown that a considerable amount of material could be saved without sacrificing
the strength and stiffness requirement of the bridge bracket. Similarly, further optimisation
could be performed in terms of the shape of the geometry which is identified as a potential
future work that stems from this study.