PSI - Issue 64

Tom Argyle et al. / Procedia Structural Integrity 64 (2024) 1376–1385 Argyle et al./ Structural Integrity Procedia 00 (2019) 000 – 000

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Fig. 11. (a) grout removal and hammer tap surveys (b) chase cutting with saw track (c) NSM Rod installation (d) pigmented binder

During the works Octavius and their specialist supply chain implemented a number of improvements to their approaches for the substrate preparation and chase cutting as well as proposing the use of a pigmented binder course instead of indicator studs to control the risks relating to future planning and resurfacing during operation. 8. Conclusions The implementation of a NSM CFRP Rod solution has provided the required design strength for the structure with all strengthening to be below the top of deck level that allows a flat continuous bridge deck waterproofing system and full surfacing depth to be applied to improve the durability of the solution. The scheme has also demonstrated the benefit of a collaborative approach to design with ECI to support the scheme development and give confidence in the buildability of the proposed solution. The main lessons learnt from the construction of the Swanley East bridge can be summarised as follows: • NSM Rods were found to be easier to install than recessing CFRP plates to achieve a flat surface below concrete. • Accelerated curing, whilst possible, becomes unviable for long length / large cross sections required for Swanley I/C structures. • Compatibility between Resin and Waterproofing was found to be acceptable, with the use of a kiln dried sand applied to the wet resin. • Continued operation of the Junction 3 roundabout required a staged sequence and assessment of the residual capacity of the structure. • Continued operation also required a review of the anticipated strains under the single lane operation and subsequent reduction in strength of the completed system as per the requirements of TR55. • Concerns exist over the effectiveness of the NSM Resin in hogging zones during surfacing. A sequenced approach was required for the binder course placed directly on the resin, but trials and 2D thermal modelling demonstrated that the binder course provided adequate insulation for the application of the surface course.