During early 2018 Boxer Superstores recognised that the operational requirements at their Regional Distribution Centre at Cato Ridge were rapidly outgrowing the current facility.  The Developer was able to offer a new site at Ibhubesi Industrial Park, Lynnfield, relatively close by and adjacent to the N3 Durban-Johannesburg highway.  The Developer was the Main Contractor, and a full project team was assembled from personnel and firms with whom previous similar projects had been successfully completed.

Structural Engineering

The design brief centred around the storage capacity required (which was in terms of number of “pallet slots”) and the floor area required for the receiving and dispatch staging logistics (loading/off-loading space).  The Industrial Park provided the required access roads.  A four-hectare platform was constructed to provide for adequate traffic circulation, with the bulk earthworks commencing in October 2018.  This civil work, plus the foundation works were carried out in parallel with the main structural design.

The main superstructure was configured around the racking layout and the receiving/dispatch staging areas which were determined in conjunction with Boxer Superstores Operations Management.  The central section houses the racked storage section – the height determined by category of reach-truck to be used along with operational constraints & costs, plus floor slab design/construction costs.  The two staging areas were then run along each side with a lower roof height, the length of the building. An off-loading tunnel covered area was created on the receiving side and covered loading bays (at-grade and container platform) on the dispatch side.

Structural steel was identified by the Design Team as the optimum material for the superstructure – this provides a degree of flexibility (it is common to have design adjustments during a project of this nature), and fabrication is carried out off-site whilst foundation works are underway.  Steel also provides for speed of erection and closure of the building envelope for floor construction and installation of the various services.

The Structural Engineer and Steel Fabricator deemed that the basic cross-section of the building should follow a portal frame configuration.  It was initially considered to use cellular beams for the main portal frames but, at the time, long lead times for supply pushed to the use of castellated beams to suit the construction programme.

The two principal challenges in the design process were

(i) generating lateral stiffness across the building cross-section for wind loading without cross-bracing (which could not be fitted within the racking and staging areas), and

(ii) to ensure the stability of a partially erected superstructure to provide “lock-up” to allow roof sheeting and vertical cladding to proceed without full completion of the superstructure frame.

The main challenge to the steel fabricator was to fabricate portions of the building to facilitate the sequential erection working from one end of the building, ie. it was necessary to complete fabrication of all elements for specific sections of the building to tie-in with the construction sequence/programme, rather than just manufacturing the total number of each component for the entire building, with erection only commencing after all steelwork was fabricated.

This project demonstrates the large clear spans that can be achieved using structural steel for industrial buildings where clear floor space is a major priority, along with a degree of flexibility for design changes, and speed of erection.

The Project Team worked together from the outset with input on all the necessary aspects for the facility, including design time, supply time of materials, construction times and sequence, steel fabrication time, critical stage completion for further construction stages, and overall project completion.

Architectural and Cladding:

A single, large, steel sheeted Warehouse was designed by the Architects with steel cladding being the main aesthetic. The use of steel structure allows for wide spans to achieve the required uncluttered interiors essential for large scale economical storage. The steel structure is split along the centre to allow light to enter. The warehouses being approximately 6 700m2 in total, was envisaged to be done in steel with sheeting as it was designed around the possibility of future racking and stacking heights. The most optimum type design or structure was for this to be a sheeted and structural steel warehouse. Hot-rolled I beam sections, lattice girder trusses, cold-formed purlins, and girts were used in the construction of this warehouse. The crisp, clear nature of this simple steel building on the horizon can be appreciated from far off.

The sheeting for the structures was Safintra’s Saflok 700 0.53mm AZ150 Zincal on the roof and Widedek 0.47mm AZ150 Seaspray for the cladding. The total amount of steel required in order to complete this project was 32 tons of material. Due to the excessive lengths that were required to sheet the roof portion of the buildings, on-site rolling had to be done with Safintra’s Saflok 700 Mobile Mill. This required both space, planning and lifting onto the roof from ground level. Different sections were milled at different areas of the site so as to help with ease of erection, traffic requirements on a congested site and to minimise double handling of the sheets on site. The sheeting was hoisted to the roof from the side of the building.

Conclusion

Overall the team of professionals working on the Boxer Warehouse project worked well together and had a great understanding with each other. With this, it helped achieve what was set out to be done, and provide a suitable working environment for the client.

In conclusion, this project is a fine example of what may be achieved by co-ordinated design and construction team work.  The design team worked in liaison with the construction team to provide design information in accordance with the construction programme.  The use of steel in the building contributed significantly to the fit of the superstructure around the racking, it provides the clear span space required by Boxer for their operations and allowed for speed of erection of the building envelope – approx. 22 000 square metres roofed area, 548 tonnes of structural steel.  Steel erection commenced in April 2019 and was completed in July 2019.  Overall project completion was achieved in October 2019, twelve months after commencement of the bulk earthworks.

Project motivation editorials are provided by the project nominator. If any technical details, company names or product names are incorrect, please notify the SAISC so that the error can be corrected.

PROJECT OVERVIEW
Physical address of the project
Street Address
Town
Province
Ibhubesi Industrial Park R103 Lynnfield Park
Near Pietermaritzburg
KwaZulu Natal
GPS Co-ordinates 29.693S / 30.475E
Google Maps link 
STRUCTURAL STEELWORK
Completion date of steelworkJuly 2019
Completion date of full projectOctober 2019
Tonnage and steel profiles used548 tonnes
  
CLADDING (If applicable)
Completion date of cladding25 June 2019
Cladding profile/ type usedRoof:  Saflok 700 AZ150 0.53 Zincal Cladding:  Widedek AZ150 0.47 Seaspray
Cladding area coverage 6 700 m2
Cladding tonnage32 Tons

Nominator

Safintra SA (Pty) Ltd

Nominator

Martin & Associates Consulting Engineers

Client/ Developer

Afroprop Natal (Pty) Ltd

Architect

 

Structural Engineer

Martin & Associates Consulting Engineers

Project Professional Engineer

Martin & Associates Consulting Engineers

Project Manager

Afroprop Natal (Pty) Ltd

Main Contractor

Afroprop Natal (Pty) Ltd

Steelwork Contractor

Cousins Steel

Steel Erector

Pro-Erect Steel Riggers

Cladding Manufacturer

Safintra SA (Pty) Ltd

Cladding Supplier

Safintra SA (Pty) Ltd

Cladding Contractor

Cladco

Photographer, Photo competition

Kierran Allen Photography

Photographer, Photo competition

Afroprop Natal (Pty) Ltd

Photographer, Other submitted images

Martin & Associates Consulting Engineers

If you were a part of this project, and your company details are incorrect or missing – please notify the SAISC so that the error can be corrected.