The overconsumption and depletion of raw materials have increased pressure on the EU and the Netherlands to adopt policies aimed at achieving a fully circular economy by 2050. This transition has increased the demand for material reuse, and consequently the need for retrofitting technologies. End-of-life (EoL) steel elements experience damage that new elements do not, such as corrosion, cross-sectional loss, and fatigue cracking at riveted connections. The potential for lifetime extension of EoL structural steel elements through cold spray additive manufacturing (CSAM), particularly in bridges with riveted connections, was investigated using finite element modelling in ABAQUS.

First, the composite behaviour of an S235 steel substrate retrofitted with annealed 316L CSAM powder was studied, followed by an investigation into the effects of full bonding and no bonding between the two materials. The parametric analysis showed that structural performance is governed by the mechanical properties of the substrate, the retrofit volume, and the bonding quality at the interface. Retrofitted cracked specimens exhibited a 935% increase in allowable uniaxial load before fast fracture. However, ductile damage simulations revealed that mismatched material strengths can lead to premature debonding when loading is applied perpendicular to the interface, even when full shear interaction is assumed.

A life cycle assessment demonstrated that, due to the additional maintenance requirements of CSAM-retrofitted elements, replacing a fatigue-damaged steel connection with recycled steel is the most favourable solution. When rivets are used, the global warming potential (GWP) is lowest at 6.72 kg CO₂, without compromising structural stability. The CSAM-retrofitted connection only achieves the lowest CO₂ emissions (1.35 kg CO₂) when reusable bolts are used instead of rivets. Regardless of the bolt type, several assumptions must be validated or challenged before CSAM can be considered a structurally reliable solution.