Solomon Islands is home to over 720,000 people who rely on bridges to connect to communities and access economic opportunities. Like many countries in the Pacific region, Solomon Islands is highly vulnerable to the impacts of climate change and natural hazards. Each year, natural hazards destroy or severely damage critical infrastructure such as bridges, leading to loss of life, injury, and disruption to social and economic activity. Maintenance delays can also strain infrastructure, leaving them more vulnerable to damage.
In 2019, we began a study, funded by the World Bank, investigating the implementation of innovative bridge technologies in the Pacific. Our study included an assessment of long-term design life modular bridge options available for implementation in the Pacific.
Modular bridges comprise pre-cast concrete or prefabricated steel bridge sections, ideal for short, single-span bridge crossings between ten and 20 metres. Their standardised components can be rapidly assembled and easily replaced if damaged in a natural disaster.
Through this study, we shortlisted modular bridges appropriate to meet the Pacific region’s infrastructure needs and enhance resilience. The project also included performance monitoring of a pilot project in Solomon Islands and Vanuatu.
Our project team combined technical engineering specialists with members of our International Development team with a strong contextual understanding of the region. Our assessment considered bridge spans, design standards, vehicle loading, number of lanes, design life, exposure conditions, supply, installation, and constructability.
Using our findings, we supported the publication of a World Bank Technical Guidance Note on Implementation of Innovative Bridge Technologies, focusing on the Solomon Islands pilot and providing the methodology and lessons learned from the study for other Pacific countries to consider when implementing modular bridges.
2 Pacific countries considered for the pilot projects
19modular bridge options assessed
3bridge sites visited by our team
Learning with Solomon Islands
Our team travelled to three bridge sites in Solomon Islands to work with government and industry stakeholders to share our desk-top study findings. During this visit, we co-created contextual selection criteria to assess bridges within Solomon Islands with stakeholders through a capacity building and pilot study review workshop. In this workshop, we identified vital criteria for bridge project success in Solomon Islands including logistics, ease of transport, construction, hydrology, future land use and planning, scale of infrastructure work and identification of local suppliers.
The challenges faced in Solomon Islands can be different from experiences elsewhere, for example, transporting bridge components requires an access road that can handle the weight of the vehicles and construction equipment. Modular bridge components are lighter and easily supported by existing infrastructure in Solomon Islands.
Enhancing resilience through modular bridge use
Modular bridges open new avenues for addressing post-disaster situations by facilitating the rapid reopening of permanent critical infrastructure. Their speed of construction helps communities restore the transport connection much faster than a traditional bridge, increasing the community's resilience.
Our assessment noted if a modular bridge is damaged during a natural disaster, its standardised modular nature will allow road authorities to order replacement parts or have them on hand quicker than traditional construction methods.
The research has created awareness of the potential to apply modular bridge technologies within other local contexts in the Pacific with some key lessons learned to guide others through the process.
Our research is also being put into action with two modular bridges being constructed in Malaita, Solomon Islands, under the Solomon Islands Roads and Aviation Project, and planned construction for two more modular bridges in Santo, Vanuatu under the Vanuatu Climate Resilient Transport Project, both funded by the World Bank.