Structural efficiency of non-prismatic hollow reinforced concrete beams retrofitted with CFRP sheets

Ahmad Jabbar Hussain Alshimmeri, Esraa Kamal Jaafar, Lina Abdulsalam Shihab, Hadi Naser Ghadhban Al-Maliki, Ali Al-Balhawi*, Ben Zhang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)
4 Downloads (Pure)


Non-prismatic reinforced concrete (RC) beams are widely used for various practical purposes, including enhancing architectural aesthetics and increasing the overall thickness in the support area above the column, which gives high assurance to services that this will not result in the distortion of construction features and can reduce heights. The hollow sections (recess) can also be
used for the maintenance of large structural sections and the safe passage of utility lines of water, gas, telecommunications, electricity, etc. They are generally used in large and complex civil engineering works like bridges. This study conducted a numerical study using the commercial finite element software ANSYS version 15 for analysing RC beams, hollow longitudinally sectioned and
retrofitted with carbon fibre reinforced polymers (CFRPs), which were subjected to concentrated vertical loads. The numerical analysis results on the simulated beam models were in excellent agreements with the previous experimental test results. This convergence was confirmed by a statistical analysis, which considered the correlation coefficients, individual arithmetic means and standard
deviations for all the calculated deflections of the simulated beam models. A proposed numerical simulation model with the hypotheses can be considered suitable for modelling the behaviours of simple supported non-prismatic RC beams under vertical concentrated loads. The numerical results showed that altering the cross-section from solid to hollow could reduce the load carrying capacities of the beams by up to 53% and increase the corresponding deflections by up to 40%, respectively. Using steel pipes for making recesses could enhance the loading capacity by up to 56%, increase the ductility, and reduce the corresponding deflections by up to 30%, respectively. Finally, it was found
that bonding the CFRP sheets in the lower middle tensile areas of the hollow beams could improve the resistance and reduce the deformations by up to 27%. The failure patterns for all the numerical models were shear failure. The cylinder compressive strength could be used as a mechanical parameter for modelling and assessing the structural behaviours of the beam models, as its increase
could improve the load carrying capacities and reduce the deflections by 30–50%.
Original languageEnglish
Article number109
Number of pages23
Issue number2
Early online date23 Jan 2022
Publication statusPublished - Feb 2022


  • numerical simulation
  • reinforced concrete
  • non-prismatic beams
  • hollow sections
  • compressive strength
  • shear reinforcement
  • CFRPs
  • retrofitting
  • recess ratio

ASJC Scopus subject areas

  • Building and Construction
  • Architecture
  • Civil and Structural Engineering


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