Construction World December 2017

SOL PLAATJE UNIVERSITY LIBRARY

Not only does this development celebrate Kimberley’s diamond-mining legacy, it was designed to be the central showpiece of the Sol Plaatje University district which, in turn, is already stimulating the rejuvenation of the larger Kimberley central business district (CBD). Situated on the main student pedestrian walkway that connects the development to the larger CBD, the building is immediately noticeable by its angular shape and origami- like roof structure with each corner at a level that corresponds with the neigh- bouring buildings. However, it is the structure’s concrete façade that appears as if floating 2,4 m off the ground that bears testament to the expertise and skills of the main contractor, Murray & Dickson Construction, and structural engineer, Aurecon. AECOM is the principal agent, while credit also has to go to the client, Sol Plaatje University, which demonstrated its willingness to work closely with the professional team to achieve this technically complex outcome. Seamlessly blending in with the roof of the structure, the façade is a three- will continue to showcase the extent of expertise and capabilities of South Africa’s built environment fraternity for many years to come. Sol Plaatje University’s new Library and Student Resource Centre can be described as an engineering marvel that

dimensional concrete envelope that is functionally, structurally and technically separated from the inner core of the building. The void created between the external envelope and floor plates along the perimeter of the building acts as a thermal duvet between the non-insulated external shell and its habitable building, while facilitating all vertical movement, houses the services and allows natural light to all floors. While there were more cost-effective and practical ways to construct the façade, they all had their limitations that would compromise the high-quality finish that was required by both architect and client. A cast in-situ ‘liquid-stone’ façade was therefore considered the only available option to achieve the demanding end result, despite the high risks involved, especially in Kimberley. The 220 mm-thick walls were climb- formed by Murray & Dickson Construction Group while supported eccentrically off slender steel columns. As the wall progressed, it was tied to the floor slabs by steel struts which resist the overturning nature of the design and ultimately create the illusion of a façade that is floating off the ground. Considering the high risks involved, the contractor and engineer embarked on a six-month-long planning phase to refine the process ahead of the actual construction, while work commenced on the core of the structure. Specialist supplier, Lafarge, helped design a concrete mix with the necessary low-shrinkage properties. The design also incorporated 600 mm-wide shrinkage pour strips that would run the full vertical height of three sides of the building and remain

open for 90 days afterwards. This enabled unrestrained movement of up to 50% of the expected shrinkage movement in the walls. In addition, Murray & Dickson Construction Group would follow a stringent concrete- curing regime which further limited the effects of drying shrinkage. This high-slump concrete mix with a smaller-sized aggregate would have to be carefully vibrated in-and-around the closely-spaced reinforcement and other embedded cast-in elements. Once the design and construction process had been validated, Murray & Dickson Construction built a 1:1 scale ‘sample’ wall to test the process. Special attention was also paid to the complicated interface of the shuttering panels with the sloped roof of the structure, as well as ensuring consistent concrete flows. Murray & Dickson Construction has extensive experience in off-shutter concrete finishes and, therefore, only minor refinements to the proposed construction process had to be made at this stage to achieve the desired end result. By involving the building contractor early during the design phases of the façade, Murray & Dickson Construction Group was able to share critical insights on shuttering, staging technology and construction sequencing. Murray & Dickson Construction also demonstrated its extensive capabilities in the building of the two striking internal in- situ concrete A- frames. These relied upon an intricate construction sequence, starting with building of the large temporary support columns.

PROJECT INFORMATION

• Company entering: Murray & Dickson Construction

• Client: Sol Plaatje University • Contract value: R142-million • Start date: November 2015 • End date: September 2017 • Main contractor: Murray & Dickson Construction • Architect: Design Workshop SA

• Project manager: AECOM • Quantity surveyor: KDM • Consulting engineer: Aurecon

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