Development of a novel pultruded FRP-lightweight concrete hybrid beams

  • Offiong Orok Etim

Student thesis: Doctoral ThesisDoctor of Philosophy


Fatalities resulting from building collapse are further exacerbated by dead-weights of structural members particularly, in geographical areas easily prone to natural disasters. Beyond these concerns, there is a growing need for lightweight structures aimed at significant reduction to transmissible foundation loads and general savings in materials used for construction and the built environment. The purpose of the current research is to promote the use of lightweight structural elements by publishing experimental findings on the performance of a newly fabricated hybrid composite beam comprising of Glass fibre reinforced polymer (GFRP) material and lightweight aggregate concrete (LWAC).
GFRP had been limited to the aerospace industry until recently when it found significant purpose within construction and the built environment. Nevertheless, its application in construction remains limited owing to scarce publications on its performance both as a single structural element and/or a structural composite element.
Locally sourced GFRP wide flange (WF) sections are compositely fastened onto pre-characterised LWA concrete made of Lytag aggregates fashioned after conventional steel-concrete composites. The composite connection is experimentally tested using the push-out test method described Eurocode 4 for determining interfacial shear performance and appropriate configurations for the design of the hybrid composite beam. The developed hybrid beam of an estimated 400kg (about 60% less than the conventional steel-concrete counterpart) was investigated under the four-point loading test carefully
setup in the light structures laboratory. Experimental test results are validated against results from numerical modelling deploying the ANSYS Finite Element (FE) software.
Hybrid structural composites involving the use of GFRP and LWAC showed comparable flexural response to that of conventional steel-concrete counterparts but with a deviation in the characteristic lateral shear failure modes evidencing dominant bearing failures around clearance holes. Shear characterisation of composites reaffirm the single curvature yielding of steel studs for GFRP composites earlier deduced by Hicks (2019) taking the height/diameter characteristics of the stud as a metric for determining their
performance. Whereas 19mm studs of equal height showed 22 % (and above) higher capacities over their 16 mm counterpart. The study adopted 12 mm which had 17% lower capacities to the 16 mm studs. The novel hybrid beam can retain up to 66 % reserve capacity against ultimate failure under serviceability state.
Date of Award15 Sept 2022
Original languageEnglish
Awarding Institution
  • Coventry University
SupervisorAlfred Gand (Supervisor) & Messaoud Saidani (Supervisor)

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