Development of Precast Concrete Boat Ramp Planks Reinforced with GFRP Bars

Cooper, Dean (2018) Development of Precast Concrete Boat Ramp Planks Reinforced with GFRP Bars. [USQ Project]


The corrosion of the internal galvanised steel (GS) reinforcement is the main factor which causes the deterioration of precast reinforced concrete boat ramp planks (RC planks). In Queensland alone, the economic loss associated with the expenditures for the repair, rehabilitation, and maintenance of corrosion damaged RC boating infrastructures, including that of RC planks, is approximately $10 million per annum. Glass Fibre Reinforced Polymer (GFRP) reinforcement bars are an ideal solution to replace the corrosion prone GS reinforcement. Therefore, this project aimed to determine an optimal GFRP RC plank design. This was achieved through evaluating the similarities and differences in the manufacturing processes and structural performance of RC planks reinforced with either GS or GFRP bars, in attempts to determine if GFRP bars can be a cost-effective reinforcement for RC planks used throughout Queensland.

Two types of GFRP RC plank reinforcement designs were created. The first plank design consisted of a single layer of GFRP reinforcement (single layer GFRP RC planks), which was identical to that of the standard GS RC plank reinforcement design, incorporating a concrete cover of 65 mm. The second plank design type consisted of two layers of GFRP reinforcement (double layer GFRP RC planks), where the top and bottom reinforcement layers were placed as close as possible to the plank surface, incorporating a reduced concrete cover of only 30 mm. This was possible due to the non-corrosive property of GFRP bars. This particular design resulted in a larger effective depth and slightly lesser amount of GFRP reinforcements compared to that of the GS RC planks.

The manufacturing processes for the single and double layer GFRP and single layer GS RC planks were then identified, documented, analyzed and compared through a comprehensive motion and time study. The results of the analyses revealed that the main differences between the manufacturing of GS and GFRP RC planks was the mesh fabrication and the mesh installation into the plank formwork. GS mesh had a faster fabrication time than that of single and double layer GFRP mesh, where on the other hand, single and double layer GFRP mesh installation was more efficient than GS mesh installation. In terms of resources required, GFRP mesh fabrication and installation required lesser manpower and equipment than GS mesh fabrication and installation. More importantly, the GFRP bar assembly is almost 60 kg lighter than that of the GS bar assembly. Alternative mesh fabrication methods, such as reducing the quantity of reinforcement ties, were also investigated to potentially increase the efficiency of GFRP mesh fabrication.

Flexural testing of the manufactured RC planks revealed that due to the effective utilisation of the high strength properties of the GFRP bars, double layer GFRP RC planks outperformed single layer GFRP and GS RC planks in terms of initial cracking moment, crack width development and ultimate load capacity. It was determined that the main structural advantage of using two layers of GFRP reinforcement was associated to the reduced concrete cover, which allowed for the inclusion of a second layer of reinforcement, and also allowed for an increase in the effective depth of the bottom layer of reinforcement. The optimal double layer GFRP RC plank design was then remanufactured and subjected to further motion and time studies, in attempts to evaluate its mesh fabrication process using previously identified alternative mesh fabrication methods. Results highlighted that due to the inclusion of lean fabrication methods, double layer GFRP mesh fabrication time was significantly reduced. It was concluded that with further task repetition and practice, the double layer GFRP mesh fabrication time could equal that of, or be less than the standard GS mesh fabrication, whilst still requiring lesser resources.

At the conclusion of this project, it was identified that a GFRP RC plank design is easier, requires lesser resources and is potentially more time efficient to manufacture than the standard GS RC plank used throughout Queensland, whilst also being structurally superior and completely corrosion resistant. The non-corrosive property of the GFRP reinforcement material will significantly prolong the lifespan of RC planks, potentially saving millions of dollars in future RC plank maintenance and rehabilitation costs, which is a significant outcome of this project.

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Item Type: USQ Project
Item Status: Live Archive
Faculty/School / Institute/Centre: Historic - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying (1 Jul 2013 - 31 Dec 2021)
Supervisors: Manalo, Allan
Qualification: Bachelor of Engineering (Honours) (Civil)
Date Deposited: 01 Sep 2022 23:53
Last Modified: 27 Jun 2023 04:56
Uncontrolled Keywords: boat ramps; precast reinforced concrete; deterioration; Glass Fibre Reinforced Polymer (GFRP)

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