
In the aftermath of the devastating 7.3 magnitude earthquake that rocked Port Vila, many residents are understandably scared and fear for their safety, particularly regarding tall buildings.
Structural engineer and owner of BI Consulting, Bikenibeu Efosi Ieremiah, emphasised that to ensure safety, everything must be done correctly from the planning stage. He advised that people planning to build houses should first consult a structural engineer to ensure their plans comply with building standards.
Ieremiah explained that Vanuatu’s Building Act, enacted in 2017, is primarily based on Australian and New Zealand building standards.
He highlighted a concerning issue: those responsible for checking whether building plans meet the standards outlined in the Act often lack the knowledge needed to perform thorough reviews. As a result, some plans receive approval without proper scrutiny by a structural engineer.
“This is something that really needs to be sorted out,” Ieremiah stated.
He added that a team is currently working to improve the building code, as Vanuatu’s existing code, drafted in 2000, needs updating to align with modern designs. The revised building code is expected to be ready before the end of 2025.
Ieremiah also noted weaknesses in building inspections, where inspectors often fail to ensure that construction aligns with approved plans.
He emphasised the importance of conducting a geodetical investigation before construction to assess the soil conditions and ensure the foundation is suitable for the environment. For instance, rocky soil requires a foundation design that reflects those conditions.
Ieremiah observed that many draftsmen neglect these considerations, leading to foundations that do not align with soil textures—a significant issue.
Regarding the implementation of the Vanuatu Building Code, Ieremiah pointed to a gap in understanding among those tasked with enforcement. The technical nature of the document poses challenges for builders and the general public, resulting in widespread non-compliance.
Damaged buildings
Addressing the collapse of the buildings that resulted in fatalities, Ieremiah noted there is no single factor behind such failures.
He referred to the collapse of the Billabong building in Port Vila’s Central Business District (CBD), describing it as an old structure built to outdated material specifications. Standards have since evolved; for example, 500-grid bars are now standard, offering greater strength and flexibility compared to the 450-grid bars used in the past.
Ieremiah stressed the necessity of having a site engineer present during construction to ensure concrete mixtures meet specified standards.
While standards for steel and concrete structures exist, Vanuatu lacks guidelines for composite buildings—structures combining steel and concrete. This is problematic because steel and concrete vibrate at different frequencies during earthquakes, potentially creating stress points depending on how the materials are integrated.
Building lifespan
Ieremiah explained that steel structures are susceptible to rust and typically require inspection after 20 years. If corroded, the structural integrity is compromised, necessitating demolition. Concrete structures, however, can last much longer if built to standards and maintained.
He warned that moisture exposure can cause concrete cancer, leading to corrosion and structural failure during cyclones or earthquakes. Regularly patching cracks is vital to protect the reinforcement and prolong the building’s lifespan.
For steel structures, Ieremiah emphasised inspecting bolts and joints after 20 years to address potential corrosion. Failure to do so compromises safety, requiring the building’s demolition.
SOURCE: VANUATU DAILY POST
