Relocatable buildings / Prefabricated Buildings / Transportable Homes - an Insight

Factors Considered in the Design of Buildings for Transport and Relocation

Transport Considerations: Unlike conventional structures that are constructed and remain in a fixed location for their entire design life, relocatable structures must be planned and designed with transportation challenges in mind. These structures may need to be installed in remote areas, where limitations on the maximum size and weight that can be transported to the site are often critical factors in determining how to design these structures.

Handling Considerations:  Relocatable structures experience the greatest stress during lifting and transportation. Choosing appropriate lifting points and mechanisms is essential for efficient handling. Conversely, a poorly designed lifting plan can complicate the process, potentially damaging the structure and posing health and safety risks.

Site specific characteristics: When relocating a structure, it is essential for the designer to consider the change in environmental factors that may affect the structure's performance depending on its new location. Common environmental factors requiring assessment include changes in soil conditions, wind loads, and seismic loads. Additionally, the durability aspects of the structure may need validation based on these environmental considerations.

AB Consulting Engineers - Experience with Relocatable/Prefabricated buildings in NZ

Relocatable Water Treatment Plants

AB Consulting Engineers were engaged by a leading Australian-New Zealand company specializing in water treatment plants to design a relocatable structure for housing a potable water treatment facility.

AB Consulting Engineers have developed the design for single-story buildings measuring 8 m x 4 m x 3.5 m in height, with nine such buildings already installed and operational. These structures were intended for remote locations with challenging construction access.

Consequently, AB Consulting Engineers collaborated closely with the client to create a relocatable building that can be manufactured off-site and transported. Given the necessity to install the plant prior to transportation, a cast-in-situ concrete slab was provided, the concrete slab was cast in the precast yard, with the entire building, including the plant, assembled before transporting to the site.

The distinctive features of these relocatable buildings are:

• The buildings are classified as Importance Level 3 (IL3) structures, designed to remain operational following an Ultimate Level Earthquake to ensure the provision of safe drinking water to remote communities.

• They are engineered to endure wind and seismic loads specific to their intended installation locations.

• The buildings feature a 200 mm thick cast-in-situ concrete slab, necessary for accommodating the heavy equipment installed within.

• The entire building design includes strategically placed lifting hooks, facilitating transportation from the assembly shop to the remote sites where they are deployed.

Relocatable/Prefabricated Building - Installed on site

Relocatable Café

AB Consulting Engineers were engaged by a client to design a relocatable café. The buildings are to be manufactured and constructed in Hamilton, then transported to various locations nationwide in response to market demands, aiming to position them at sites with the highest anticipated foot traffic. The structure comprises a café space with an adjoining kitchen area.

Modular solution: The key challenge we faced in this project was that the overall size of the structure required by the client exceeded the dimensions that could be conveniently transported using standard shipping methods. This posed significant logistical issues, as transporting oversized structures often involves complicated arrangements and can lead to increased costs and delays. The limitations imposed by transportation regulations and the physical constraints of roadways and bridges further complicated the situation, making it clear that a different approach was necessary to ensure the successful delivery and assembly of the structure.

To address this challenge, we developed an innovative solution that involved designing the structure as two modular units. This modular approach allowed each unit to be constructed to a size that complied with transportation regulations, thereby facilitating independent transport without the need for special permits or extensive logistical planning. Each modular unit was meticulously engineered to ensure that it maintained structural integrity and functionality while being compact enough for transport.

Once the two units arrived at the site, the assembly process was designed to be straightforward and efficient. We incorporated a system of interlocking connections and pre-installed fixtures that enabled quick alignment and secure fastening of the units upon arrival. This minimized the need for extensive on-site labor and specialized tools, allowing for a seamless assembly process that could be completed in a fraction of the time required for traditional construction methods.

Furthermore, this modular design not only simplified transportation and assembly but also provided additional benefits such as flexibility in design and potential for future expansion. If the needs of the project evolve over time, the modular units can be adapted or added to without significant structural modifications. Overall, this solution not only addressed the immediate transportation challenge but also set a precedent for future projects where size constraints may similarly limit conventional construction practices.

Transportable/Pre Fabricated/Relocatable Building

AB Consulting Engineers possesses extensive expertise in the design of prefabricated, pre-engineered, and transportable homes utilizing timber, steel, and EPS panels. For further information, please contact us.