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THE SOUTHERN AFRICAN INSTITUTE
OF STEEL CONSTRUCTIONWorking alongside our members since 1957
to promote the use of steel in construction
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For over 20 years, B&T Steel (an SAISC member)
has specialised in the design, detailing, fabrication and
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News

28/01/2019 /
SAISC Commentary January 2019
Events and Training

16/01/2019 /
Basic Connection Design Course
Featured Content

15/02/2019 / Technical Articles,
Popularity of Steel Frame Buildings On The Rise
What does the Southern African Institute of Steel Construction do?
The SAISC provides technical support to its members
With over 60 years worth of local, Southern African project case studies and access to experienced and qualified individuals, the SAISC is well placed to assist with technical queries relating to Steel Construction and Structural Engineering. Assistance with technical queries is a service offered to our professional individual members and company members.
The SAISC voices the concerns of all of its members when lobbying government, policymakers and industry stakeholders
As a neutral party with members in all functions and levels within the Southern African steel construction industry, the SAISC strives to achieve its goal of a sustainable, healthy and wealthy industry for all players. This is sometimes a challenge as well as a delicate balancing act, as members are likely to have opposing views and objectives. We endeavor to facilitate opportunities for members to engage in an open, respectful and robust discussion where the end goal is for the industry as a whole to survive and thrive.
We invest great time and effort in engaging all levels of government on behalf of the steel construction industry to ensure that our members’ concerns are escalated and that policymakers are made aware of practical implications.
The SAISC runs training and events for members and non-members
The SAISC has a wide range of CPD credit-bearing training courses aimed at young engineers. These courses incorporate face to face workshop sessions, video modules, and practical assignments. Public training dates are arranged based on the number of delegates interested in a particular course. If you have 8 or more delegates interested in a particular training course, an onsite course can be held at your premises on a date suitable to you. Download our course catalog here.
In addition to our training courses, we host business breakfasts, networking cocktail events, golf days and of course our annual Steel Awards gala events.
While all events are open to the public, special discounted rates are enjoyed by our members.
The SAISC provides marketing and publicity support services to its members
Since the association’s inception in 1959 as the “Structural Steel Publicity and Advancement Association”, our primary objective has been to sing the praises of all players in the industry, while extolling the virtues of structural steel.
Our members are the kind of people who put their heads down and get on with the job. Their focus is completing a project with excellence, not necessarily on promoting their achievements. Using our Steel Construction Journal, our website, our social media platforms and press releases to other respected industry publications, we tell those success stories. Foundational marketing and publicity services are available to members as part of their annual membership fee. More comprehensive marketing services including video, photographic and audio recording services are available to members at a special discounted rate.
Some of the great work our industry produces
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Structural Steel Roof Over Blue Downs Swimming PoolThe Blue Downs swimming pool was developed in response to the City of Cape Town’s wish to provide a high-quality indoor public swimming pool to serve the Blue Downs community. It is intended that the pool should serve as both a general community facility as well a sporting facility for use during swimming competitions. The design of the structural steel roof comprises a main roof over the swimming pool area, as well as adjacent subsidiary roofs over two separate public seating areas, an administration block and a lifeguard tower. The requirements of the architectural design were furthermore that the main roof should be supported only at the four corners, standing 35 metres apart on circular concrete water storage ‘silos’ (the silos are for storing rainwater run-off from the roof for use in the pool). Due to the architectural requirements and the large spans involved, it was considered that no other structural medium other than structural steel would be feasible. The original architectural design called for a rounded double barrel-vault roof over the main swimming pool area, in accordance with which a thin shell-type roof structure was designed. Due to financial constraints and difficulty in engaging suit-able local steel fabricators prepared to carry out the work, which required extensive use of curved members, the design was subsequently revised during construction to the current pyramid shape. In carrying out the re-design, the new design was constrained to an extent by the configuration of the supporting reinforced concrete structure already constructed. Because of the highly corrosive swimming pool environment, a duplex system of corrosion protection consisting of both hot-dip galvanising and painting was adopted. As the components of the toblerone trusses were too large for the galvanising bed, zinc metal spraying was used for these elements in lieu of hot dip galvanising. Inspection and testing of the zinc spray application was carried out by the Hot Dip Galvanizers Association in order to ensure compliance with the speci-fications. The main roof as per the revised design and as constructed comprises the follow-ing main structural elements: Pitched ‘toblerone’-type trusses forming the four corners of the pyramid shape, edge girders, and sloping secondary trusses. The toblerone trusses are the primary structural elements, spanning diagonally across the pool between the supporting silos, and intersecting at the roof apex. The trusses work in combined bending and axial loading and rely on the lateral resist-ance provided by the four support points. The trusses support the ends of the purlins, the ends of the secondary trusses, and the translucent sheeting forming the facetted corners of the roof. Because of the potential for buckling in the slender axially-loaded trusses, diagonal bracing was provided in the plane of the roof to provide lateral stability. The edge girders are placed along the perimeter of the main roof. Besides support-ing the side cladding and the outer sections of the roof, the edge girders assist in resisting the lateral support reactions from the sloping toblerone trusses. The edge girders on two sides of the structure also support the top edges of the subsidiary roofs over the seating areas. The secondary trusses support the roof purlins, and are in turn supported at their top ends by the toblerone trusses and at their lower ends by the edge girders. In addition to supporting the roof loads, the secondary trusses are also used to provide lateral support to the chords of the edge girders. The architectural requirements were for the structural steelwork to be exposed and to make use as far as possible of circular tubular members in order to be aestheti-cally pleasing. All main structural elements with the exception of purlins and sheeting rails, and including all knee braces and diagonal bracing, have therefore been fabricated using circular hollow sections. With the numerous intersecting members, welded connections between intersecting tubular members were in some cases rather complex, requiring careful fabrication. A number of technical challenges had to be overcome in both the design and the erection of the roof structure. Due to the large span of the main roof, vertical midspan deflections of almost 60mm could be expected in the four edge girders. The interface between the main roof and the side roofs therefore had to be designed to accommodate this relative movement. In the case of the roofs over the administration building and lifeguard tower, this was accomplished by separating the side roofs from the main roof, and accommodating the movement by provision of sliding flashing joints in the cladding. The erection sequence was established in consultations between the engineer and the steel fabricator, taking cognisance of the requirements of the design. The edge girders and toblerone trusses intersect at common corner elements, and these elements had to be installed at the beginning of the erection process. The corner elements had to be accurately placed in order to ensure proper fitting of the various trusses and girders. Because the toblerone trusses rely on the edge girders to withstand the lateral support reactions, the four edge girders had to be erected beforehand. This meant that the toblerone trusses had to be installed while working over the edge girders. One of the toblerone trusses was installed, remaining temporarily propped until the intersecting truss could be installed to provide stability. Once these main members were in place, the secondary trusses and other structural elements such as bracing members and purlins could be installed. Because the design allows little tolerance for dimensional discrepancies, a high level of input was required by the steel fabricator in order to achieve the required accuracies. Project Team Developer/ Owner: City of Cape Town Architect: ARG Design Structural Engineer: Bergstan South Africa Quantity Surveyor: LWA Quantity Surveyors (R/A Waterson & Hoosai cc) Project Manager: ARG Design Main Contractor: Tempani Construction (Pty) Ltd Steelwork Contractor: Mazor Steel (Pty) Ltd
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MacEdwards House ExtensionThe Deep Flute Floor System is a floor system characterized by its steel permanent formwork. The steel acts alone to carry the construction loads - without any support within its span.The steel formwork also serves as the mould giving the concrete the shape required of it to act as part of the Engineered floor system.
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Victor Daitz Mathematics CentreThe King Edward VII Mathematics Centre is located at King Edward VII School in Johannesburg. The project is a classroom facility with a hockey pavilion comprising both an upper viewing deck with kitchenette facility and lower area of team ablution/change facilities, as well as a larger ablution facility for scholar use.
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V&A Grain Silo Complex façadeThe V&A Grain Silo was built in the 1920s to store grain for export out of South Africa. This industrial heritage complex was rejuvenated as the central feature of the world class green Silo District development. Heatherwick Studio was engaged to conceptualise the redevelopment that is now occupied by The Zeitz Museum of Contemporary African Art (MOCAA) and The Silo Hotel.
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Rosebank LinkAt 15 stories above the ground, the building consists of two basement parking levels, a ground floor or public/retail level, five parkade levels, and nine stories of offices from a podium level. It will allow everyday pedestrians to traverse without barriers from the Gautrain through to the adjacent malls.
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RCL Foods Head Office, WestvilleThis project was undertaken in the framework of an extraordinary collaboration of the developer/landlord/contractor, tenant, architect, interior designer, branding alchemist and technical team. Somewhat of a 'rescue operation', we engaged by the developer to redesign a new corporate head office for RCL Foods after construction had commenced on the site in Westway Office Park.
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Radisson Hotel at Silo 6The Radisson Red hotel located in Silo 6 has art, music and fashion at its core. It is an upmarket hotel that caters to business travellers, international travellers and families. This 252-room Hotel, recently completed, is the first in South Africa of a new offering by the Radisson Group. The vibrant 4-star brand, Radisson Red, caters for a younger, trendier segment of the tourist market. Situated immediately adjacent to the precinct’s Centrepiece, MOCAA (museum of Contemporary African Art), this project occupies a critical position. With MOCAA as the focus, and the existing BOE building on the opposite side, Silo 6 was designed to complement this composition of three buildings. Conceptually, the building is a ‘wall’ building that defines the outer edge of the precinct and in mirroring the scale of the BOE building, showcases MOCAA as the focal point. Architecturally, the wall concept is expressed literally through the creative use of rendered brick construction on the East and West facades while the North and South facades reflect the Dockland’s industrial heritage using Steel and Glass. The punctured fenestration on the East and West facades reflects the rational floor layout of rooms and is expressed using a custom designed protruding Aluminium frame. Juxtaposed against the rough brickwork, this device is a key contemporary insertion in the architectural expression of the building. The building has been awarded a 5-star Green Building status. The project site had an existing super basement that was designed to accommodate a generic building on top of it. During the time when the basement was constructed, the client (V&A Waterfront) wasn’t 100% sure whether the building would be a hotel. The Rezidor Hotel Group/ Raddison Red later become the operator of the Radisson Red Hotel at Silo 6. The Radisson Group has their own design requirements for creating a hotel and the brief to the architects was to adhere to their standards and to create a hotel that would maximise the number of rooms as well as fit into the Silo District, which has become a landmark in South Africa’s Mother City. To create a commercially viable hotel, stay within the brand standards and requirements, and maximise keys of the third Radisson Red hotel in the world, the design team had to think out of the box. Not only did they have to respond to an existing structural grid that didn’t relate to a hotel configuration, but they also had to carefully consider how the north façade of the hotel would complement the Silo 6 district. The structural gymnastics that the team employed included introducing V-columns to create a layout that would accommodate a hotel, and the north façade of the hotel included interesting steel solutions and careful placement of cladding pannels to create a playful ‘random’ rhythm within the framework. There is a concrete frame structure with steel elements clipped onto the façade. The north façade is articulated with balustrading and channels that are fixed to the concrete structure with steel. The façade articulation speaks to the notion of an industrial area, which is appropriate for the context of the Silo 6 precinct which includes a working shipyard, a museum and other landmark buildings. The design team fixed vertical flat plates to the concrete frame structure in a series of angles to frame the balustrade modules. The beta fence panels (fencing panels) were then fixed to tubular sections. The concrete slab was then finished a C-channel that is fixed to the concrete edges, which created a unique and beautiful façade articulation. Red cladded panels create privacy for guests on their balcony. Bright red was an aesthetically pleasing way to introduce colour into the north façade while speaking to the operator’s brand, and created a seemingly random pattern on the façade. One of the challenges that the design team encountered was a manufacturing error that led to an incorrectly sized balustrade height. The calculation error led to the design team having to adjust the design to avoid remanufacturing of the balustrade modular panels. The architects inherited a restrictive structural grid which informed a very constrained north suite façade configuration and the design team was tasked with articulating the north façade to create a playful ‘random’ rhythm in the framework. The balcony spaces vary in size due to the staggering of the red panels, which creates a beautiful façade. The challenge of the manufacture height was successfully overcome by the design team and the contractor working hand in hand to deliver the project on time and within budget. The team were able to collaborate to look at ways to achieve the desired results by modifying the fixing detail. Cladding profile/ type used Klip-Tite & IBR Cladding area/ coverage 270m2 Cladding tonnage 1,4 tons Project Team Project Team Role Company Nominator Global Roofing Solutions Client/ Developer Not provided by nominator Architect Peerutin + Design Space Africa Structural Engineer Arup South Africa Engineer Not provided by nominator Quantity Surveyor MLC Cape Town Project Manager Not provided by nominator Main Contractor Not provided by nominator Steelwork Contractor Not provided by nominator Steel Erector Not provided by nominator Cladding Manufacturer Global Roofing Solutions Cladding Supplier Global Roofing Solutions Cladding Contractor Chartwell Roofing Corrosion Protection Galvanising Not provided by nominator Corrosion Protection Paintwork Contractor Not provided by nominator Photographer, Photo competition Not provided by nominator Photographer, Other submitted images Not provided by nominator 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.
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Ngezi LoungeWhen brothers Moses and Selby Mdaka approached Aura Entle to install a floor for their restaurant the team saw the project as an opportunity to carry out its practice of giving opportunity to unemployed youths. The Ngezi Lounge Project is located in the township of Letlhabile, in the North West Province.
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Discovery Head OfficeThe Project entails the development of the new Head Office for Discovery Health in the Sandton Precinct and consists of three towers with glass façades and large skylight roofs on the two larger towers and required extensive steelwork support for the facades at roof level and between the three towers.
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33 Baker StreetBaker Street at its core was an upgrade of a current concrete building that was to be equipped with new structural steel to accommodate impressive looking glass and facades with paneling on the exterior. Essentially the overall appearance of the building was to be modified. The problem was getting accurate and existing concrete dimensions from site to work with the new Engineering/Architectural changes.
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St JohannModul8 was built in Gauteng in a controlled environment & then transported to Lesotho & placed on a prepared soil platform. A steel ring beam at the top & bottom, together with square steel posts act as a rigid frame which can be picked up from the top to load on a truck, transport to site & dropped off on a pre-prepared foundation. 150dia Round Tubular Steel columns with 32dia tubular steel cross bracing was selected for the foundations. The columns were prepared (manufactured) in the factory off-site, and the bolted to a rock plate covering the entire stand, with 4 of M16 threaded rods, fastened to the rock plate with epoxy which can harden under water. The roof structure was also pre-manufactured in the factory in Gauteng, complete with double glazing & lifting brackets, in order to have minimal work to be done in the harsh weather conditions on site. The roof structure was placed on the Modul8 units by the same crane mounted on the truck horse, after which the 90mm thick PU foam SIPs were placed on the frames on site as an all-in-one roof covering, ceiling & insulation. A neat rectangular angle serves as finishing to the edges of the roof SIPs as well as drip to the lower end of the roof. The roof/wall glass & steel structure act a unit & is cross-braced through the use of Structural silicon between the double glazing & steel frame as well as the use of the roof SIPs A corner niche was also manufactured in the factory in Gauteng, trucked to site together with the Modul8 units & placed in position by the same crane mounted on the horse of the truck. The corner niche can also be picked up from the top and is bolted straight to the corner of the kid’s bedroom. A cantilever ‘landing’ grid was chosen for the front door, only held in place by hinging it to the short end of the Modul8 bottom ring beam & a 32dia round tube profile ‘arm’ to hold it in the horizontal position. This grid helps to keep mud & snow out of the ski chalet, as mud is dropped through the grid when stepping on it before entering the front door. Green building rating/ environmental or sustainability considerations Many environmental & sustainable considerations were employed as are shown in Point 3 & 4 (Please read point 3 & 4 together with this section) Because the Modul8 units are manufactured off-site, there is no damage to the site or the surroundings during the construction process, as no construction takes place on site accept for the foundations. The foundations are also of a lesser scale as the inherent strength of the Modul8 units and the shipping containers are already built into their structure, needed when transporting the units, thus the foundations do not have to be that strong. As the building is pre-manufactured off-site & then brought to site, the buildings can also be taken away again & the site can be totally rehabilitated. As the Modul8 units are modular, materials were optimised to their modular size, resulting in very little to no cutting, resulting in no waste of materials, labour, equipment, tools or time. All Modul8 units are ‘properly’ insulated, made in a controlled environment with strict quality control procedures and of high-quality materials & finishes, resulting in less heating- & cooling costs, as well as less maintenance Low maintenance to no maintenance materials were chosen to reduce maintenance costs in the long run, as well as reducing the materials, cleaning & maintaining agents which will go with maintaining a building Because the Modul8 units are movable (transportable), they can be reused or up-scaled when they have reached the limit of their current use, e.g. if not required as a ski chalet at Afriski anymore, it can be moved to the coast as a beach cabana. A Modul8 building can be ordered to be totally off-the-grid, as it can contain its own solar/wind/gas power generation and/or water heating mechanisms in order for it to be totally self-sustainable and/or in hard-to-reach and un-serviced locations. Solar water heating backed up with gas, is used for domestic water heating as well as for hydronic underfloor heating. The ski chalet is lifted off the ground by placing it on the round tubular steel columns, for a few reasons: 1 There are more than 400 natural water springs on the resort, of which two flow from underneath the position of the ski chalet. By lifting the chalet above the ground, the flow of the water is not restricted to flow downhill and cause damage to the structure. 2 If or when the ski chalet is moved to a new location, for instance as a retirement cabin at the coast, the site can be easily rehabilitated to its original state. Many years of design, various prototypes, extensive structural-, wind- & fire tests were done to get to the current design model: Steel, in various forms e.g. Light Gauge Steel Frames, Hot rolled steel & cold rolled steel, galvanized bent plate, SIPs, etc. was chosen for its many positive attributes like strength-to-weight ratio, flexibility, cost-to-strength ration, durability, low maintenance, etc. Many hours & details went into designing a structure which can be manufactured & assembled in a factory, can be lifted from the top, (instead of through the frame or with belts under the frame), is under 3 tons in weight in order for ‘standard’ truck cranes to lift the Modul8 units onto a truck & off again on site, flexible enough to withstand the current South African (and rest of Africa) road conditions on a truck, and last many decades on site to be even moved again at a later stage. Modul8 is currently designed to be stacked 3 stories high, but with nominal steel sizes or wall thickness increases, this can be increased to many more stories. Usually, 1-3 days on site are enough to place the Modul8 units, connect them to each other, waterproof them & connect the services to the units if necessary. Weight was a major consideration when designing modular units, as well as the lifting method, as both have an influence on the transport of the units: It was thus critical to keep the weight lo, while retaining the strength & flexibility of the units. Strey Architects paid a lot of attention to designing for the maximum allowed size to fit on a truck withouta police escort, as well as to stick to standard sizes of materials
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The Afriski Backpackers LodgeThe original Backpackers at Afriski was built with shipping containers as they seemed appropriate for the low cost, weather proof, indestructible and quick accommodation qualities at the time. With the extended & reworked Backpackers factory manufactured modular units called Modul8 was built in Gauteng in a controlled environment & then transported to Lesotho & placed on a prepared soil platform. A steel ring beam at the top & bottom, together with square steel posts act as a rigid frame which can be picked up from the top to load on a truck, transport to site & dropped off on a pre-prepared foundation (a soil mattress platform in this case). The smallest possible cellular beams were utilised in the floors to support light weight textile concrete, to save weight & to thread services through the holes of the cellular beams Round tubular steel profiles were used as ‘tree’ columns in the courtyard, supporting lipped channel purlins to carry the relatively large span (for the element sizes used) over the courtyard in order to ‘feel’ like or simulate a ‘picnic’ area under ‘trees’ on a ‘lawn’ (It was an interesting exercise as the one will not stand without the other (‘trees’ & purlins) and the roof sheeting serves as cross bracing) Rectangular & square tubes were utilised for the double glazed roof & wall structure facing the ski slope, as it was easier to pre-manufacture & test erect in a factory environment and could easily be bolted together on site in a relatively short period in adverse snowy conditions. The double glazing lets in sun & light during the day which heats the concrete floor which in turn emits the heat at night, gained during the day. The roof/wall glass & steel structure act a unit & is cross braced through the use of Structural silicon between the double glazing & steel frame The combination (Hybrid) of materials & building methods utilised makes this project unique: The Modul8 units (6 off) used for the project are a vast improvement on ‘traditional’ shipping containers. The original Backpackers’ shipping containers were reused, although flawed, as they are too narrow to accommodate & be practical for much more than small bedrooms or bathing ablutions. Also, if you cut holes in shipping containers you take away their inherent strength and need to reinforce the frame with more steel, which make it actually very uneconomical. Modul8 pre-manufactured, modular units were design & manufactured off site (in a factory in Gauteng) to improve on all the inherent flaws of shipping containers but still utilise all the advantages of shipping containers. They insulated, wider, higher, longer, more flexible & lighter than shipping containers. They can be flat packed and transported in numbers on one truck if assembled on site. These were pre-assembled, together with the courtyard roof & glass roof/wall system in a factory in Gauteng, (without the shipping container units which were already utilised on site for some years), before being disassembled & transported to site for placement & completing the project. A simple & cost effective IBR roof was screwed to lipped channel purlins (a very light structure was designed to be handled by manpower only), and the sods which used to cover the site & was placed to one side for re-use, was place on the roof sheets to help act as insulation (and greenery), together with insulation board, for the roof. Because the entire envelope is insulated, heat cannot escape easily. This was critical as sometimes temperatures of -20 C are reached in winter. A 20’ shipping container was also utilised as a hot water storage tank. Polyuria was used to waterproof the inside of the container, and board insulation for thermal proofing, in order to use the container to store heat generated through arrays of vacuum tubes on the roof to heat water. The hot water is then used in the ablutions as well as to pump through the concrete floors to create a fly wheel effect of heat being released during the cold nights all year round, (and days during the winter). Zink/Aluminium panels (Zincalume Structural Insulated Panels) were used to the Modul8 units around the covered interior courtyard for its aesthetic appearance, strength & longevity. Green building rating/ environmental or sustainability considerations Because the Modul8 units are manufactured off site, there is no damage to the site or the surroundings during the construction process, as no construction takes place on site accept for the foundations. The foundations are also of a lesser scale as the inherent strength of the Modul8 units and the shipping containers are already build into their structure, needed when transporting the units, thus the foundations do not have to be that strong. As the building is pre-manufactured off site & then brought to site, the buildings can also be taken away again & the site can be totally rehabilitated. As the Modul8 units are modular, materials were optimised to their modular size, resulting in very little to no cutting, resulting in no waste of materials, labour, equipment, tools or time. All Modul8 units are ‘properly’ insulated, made in a controlled environment with strict quality control procedures and of high quality materials & finishes, resulting in less heating- & cooling costs, as well as less maintenance Low maintenance to no maintenance materials were chosen to reduce maintenance costs in the long run, as well as reducing the materials, cleaning & maintaining agents which will go with maintaining a building Because the Modul8 units are movable (transportable), they can be reused or up-scaled when they have reached the limit of their current use, e.g. if not required as a ski chalet at Afriski anymore, it can be moved to the coast as a beach cabana. A Modul8 building can be ordered to be totally off-the-grid, as it can contain its own solar/wind/gas power generation and/or water heating mechanisms in order for it to be totally self-sustainable and/or in hard-to-reach and un-serviced locations. Many years of design, various prototypes, extensive structural-, wind- & fire tests were done to get to the current design model: Steel, in various forms e.g. Light Gauge Steel Frames, Hot rolled steel & cold rolled steel, galvanised bent plate, SIPs, etc. was chosen for its many positive attributes like strength-to-weight ratio, flexibility, cost-to-strength ration, durability, low maintenance, etc. Many hours & details went into designing a structure which can be manufactured & assembled in a factory, can be lifted from the top, (instead of through the frame or with belts under the frame), is under 3 tons in weight in order for ‘standard’ truck cranes to lift the Modul8 units onto a truck & off again on site, flexible enough to withstand the current South African (and rest of Africa) road conditions on a truck, and last many decades on site to be even moved again at a later stage. Modul8 is currently designed to be stacked 3 stories high, but with nominal steel sizes or wall thickness increases, this can be increased to many more stories. Usually 1-3 days on sire are enough to place the Modul8 units, connect them to each other, waterproof them & connect the services to the units if necessary. Weight was a major consideration when designing modular units, as well as the lifting method, as both have an influence on the transport of the units: It was thus critical to keep the weight low, while retaining the strength & flexibility of the units. Strey Architects paid a lot of attention to designing for the maximum allowed size to fit on a truck without police escort, as well as to stick to standard sizes of materials. The biggest challenge with Afriski is the inclement weather conditions, the altitude & the location of the site. Because of the altitude people inherently move & work slower. Because Afriski is located in a bowl, (less sun means more snow), the days are actually also shorter as the sun rises later over the East ridge & sets earlier over the West ridge. There are thus less daylight hours & the temperatures drop steeply when the sun disappears behind the Western ridge. Four seasons during the day is common, and it is known to snow in December & in April every year (there are weather records for the past 50 years). The distance of the site (Afriski) to the nearest town with most type of hardware & building supplies is at least a day (round trip) away, so one cannot ‘forget’ anything or construction will stand still. Developing a pre-manufactured building system, which is built in a controlled factory environment have the following advantages, apart from the ones mentioned in Point 2-8: Workers return to their own accommodation each night so there is no need to house & feed the construction workers The weather does not influence the building process Better quality control can be adhered to Less to no waste and no waste needs to be removed from site Longer (normal) working days & working hours can be adhered to The innovative use of several different types of steel products, and the combination thereof creating a hybrid & practical solution to the challenge, is noteworthy
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Midax House Zinkwazi BeachThe Midax House Zinkwazi Beach project entailed the addition of a second level to an existing house situated on the beachfront. Founding conditions were basically beach sand and the addition, therefore, had serious limitations in structural weight. In addition, the architecture required clear view lines, large open plan areas and quirky overhanging rooms, all which required large spans and cantilever structures. The design had to be exactly matched to the existing ground floor brickwork structure. This was achieved by using a duplex coated structural steel skeleton structure, lightweight roof, and floor, as well as some composite material cladding. The following aspects of the project make this an exceptional project and use of structural steel: The structural steel skeleton and lightweight cladding allowed acceptable foundation loading and hence, in essence, made it possible to affect the build. The structural steel allowed the key architectural elements of open plan areas, uninterrupted views, quirky overhanging rooms, and modern lines to be built. The steel structure saved considerable construction time and the use of CAD technology and modern laser measurement techniques resulted in a very successful build on to a complex shape existing structure. The property is situated in an environmentally sensitive area (within 100m of the highwater mark) and the steel construction allowed for a clean and neat build process with no damage to protected milkwood trees. The structural steel skeleton allowed for proper services planning in a “hollow floor” and also for the integration of add-ons such as facia mountings, gutters, and glass balustrades. Midax Investments Pty Ltd acquired a beachfront property known as Magai Drive 45 in Zinkwazi Beach in June 2013. At the time the 1970’s designed house was somewhat run down, but the location right on the beach and the sea views offered warranted the investment. The plan at the time was to add onto the house so as to create a beach house where a 3 generation family could holiday together. The property is however located within the environmentally sensitive area within 100m of the high water mark. As such footprint extensions were, at the time, limited to 50sq meters. This forced planning to consider the addition of a second level. In addition, the existing cement tile roof was very dilapidated and as it was considered to be unsafe, the plan for replacing the very heavy roof (some 20tonnes) with a second level living area became very appealing. Structural engineer Rob Young who, at the time was involved in another Zinkwazi project (the 2015 winner) was approached to act as consulting engineer on the re-build of 45 Magai. Following soil testing and inspection of existing foundations, Rob advised that it would be possible to add a second level provided that the design stayed within 25-30 odd tonnes of weight on the existing foundations. Architect David Mealin, a Zinkwazi resident, was appointed to design the largely “new” house. He produced a very modern concept which maximised the views, contained large open plan living areas and some quirky features such as overhanging “glass box” bathrooms. He also incorporated the client’s wish for a large veranda at ground level, the roof of which doubled as a large (100sqm) deck for the upper levels. The structural engineers were therefore faced with the following challenges: Engineering a reasonably lightweight structure which would allow the uninterrupted sea views, large open plan areas and quirky design elements Engineering a very corrosion resistant structure capable of withstanding the highly corrosive KZN North coast environment Fitting the structure to a fairly complex existing ground floor wall layout. Rob Young suggested a steel structure with a light-weight wooden floor and light-weight aluminium roof for the new upper level. At this point, it must be pointed out that Piet Coetzer, the director of Midax Investments, is also a major shareholder in the Structa Group of Companies, which is one of the larger manufacturers of steel structures in South Africa. Piet has often advocated the use of more steel in buildings in South Africa and here he was presented with an opportunity to practice what he had been preaching. Being a structural engineer himself he duly accepted the challenge and through Structa Konsult, he participated in the design of the staircase and bathroom boxes, while Rob Young designed the primary structures. In essence, the structure consisted of the following elements: A concrete ring beam cast onto the existing ground floor walls at the rear of the house Fabricated girders spanning window openings on the seaward side of the building and serving as the seaward portion of the ring beam An array of I-beam floor beams spanning from the concrete ring beam (where they are anchored), cantilevering over the forward fabricated steel girders to form the deck Roof support columns I-beam front and rear roof carrier beams Wing style roof consisting of pointed I section trusses and lip channel purlins Thin-skinned box girder 3CR12 sections forming overhanging bathroom structures GRP “sandwich” side walls closing off overhanging bathroom boxes A “floating” staircase A mezzanine portion of the floor suspended from the roof to give clear view lines In the entrance Most of the seaward fabricated beams were not clad externally so as to express the nature of the structure. Where cladding was used the following materials were employed: Plasterboard on internal surfaces Brick walls on the rear wall Brick infill on some seaward fabricated girders Nutec board The structure was detailed using the TEKLA system. This was performed by C.I.S Engineering (a Structa Group subsidiary), who was appointed as manufacturer. TEKLA details were used as direct input for plasma cutting and beam cutting and drilling. In order to achieve an “exact” fit to the existing ground floor walls, these were measured up using sophisticated laser measurements (performed by Richard Logan surveyors). The layout model developed from the laser measurements was imported into TEKLA and the structural steel layout superimposed to ensure a proper fit up. An anchor bolt drilling template was developed on the same layout. The TEKLA model was also used to fully integrate the building, structure, and services. Where possible the structural elements were modified to incorporate add-ons such as: Facia mountings Service channels Gutter recesses GRP sandwich mountings Channels for the deck and mezzanine frameless glass balustrades Corrosion protection was achieved by employing a duplex coating of hot dip galvanising and a two-part epoxy paint. The first component to arrive on site was the anchor bolt drilling jig. This was assembled and put into place on the existing walls and concrete ring beam. Key anchor bolt positions were marked and drilled, thus ensuring proper fit-up of the steel structure. Construction of the steel structure and logistics had to be carefully planned and synthesized with mobile crane presence on site which had to be minimised (55t mobile crane with 30m reach). The structure was delivered in 3 loads from Gauteng. The loads carried items prioritised to suit the build. The build was subcontracted to WPM Construction and completed within 14 days of the first steel arriving on site. In total only 3 days of mobile crane presence were required. The long reach of the 55-ton crane allowed sub-assemblies to be lifted in position without damaging any of the protected trees on the site. From this point onwards the conventional build proceeded up to end March 2016.
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Granger Bay Demountable ParkingThe Granger Bay Demountable Parking (GBDP) project arose out of the V&A Waterfront’s urgent need for additional parking. The site consisted of an open area on approximately 12 to 15m of fill material with a gravel surface approximately level with the roads around its perimeter. It was selected for this project due to its close proximity to the Victoria Wharf Mall; however, it had been earmarked for a substantial development at some stage in the future, possibly five years’ time. For this reason, the V&A Waterfront Development Team decided to consider a temporary parking solution such that the land could be used for parking in the medium term and then developed as planned in the future. Initially, the V&A investigated importing a proprietary system. When considering the full project cost, the proprietary system would have cost more than a traditional concrete parking garage of the same size, although it would have had residual value after five years since it could be re-used elsewhere. The V&A Waterfront then approached LH Consulting Engineers to develop an alternative scheme using local technology. Together with the Quantity Surveyor, Union Steel, NMC Construction and Portland Concrete, this scheme was developed to suit the following requirements: - The structure had to be easily demountable and able to be re-installed elsewhere - It had to be modular such that the structure – or parts of the structure – could be reinstalled in different configurations - It had to be sufficiently lightweight such that shallow foundations would be adequate (the fill material was not sufficiently consolidated to support conventional loading on shallow foundations) - The structure was to provide two levels of structured parking and be designed to receive a third level - The project had to be designed, developed and completed within a six month period, including obtaining the necessary Council approvals The cost for the local alternative came in at approximately 60% of the cost of the proprietary system. This option was therefore given the go-ahead from the V&A. The structure was set out on a 7.5m x 8.5m grid and consisted of a structural steel frame and precast hollow-core floor slabs bolted to the frame. Primary beams consisted of plate girders with a parallel flange channel section for the top flange. The precast floor slabs were designed to span the 7.5m between the primary beams. Curved plate sleeves were inserted into the ends of the hollow-core slabs to enable an angle section to be bolted to the underside of the slab at each end in the factory. Once the panels had been dropped into position on the structural frame, the factory- fitted angles were then bolted to the sides of the channel section top flange. The joints between the precast panels were then grouted to ensure load-sharing between panels and diaphragm action for stability purposes. No topping was required. The perimeter barriers spanned between columns and provided a threefold function of balustrade, parking barrier and support to the cladding system. As part of the development process, two full bays were constructed. After inspection by the Design Team, the mock-up was then completely disassembled and reconstructed. This prototype served to demonstrate that the structure could be taken apart and re-installed without difficulty and without damage to the components. The choice of materials allowed for off-site fabrication, which got underway while the Principal Contractor prepared the platform and constructed the reinforced concrete column bases. The modular design resulted in a high degree of standardisation of components, which enabled a fast- track detailing and fabrication process. With careful planning of the installation sequence, the two levels of structure were fully installed over the 90m x 50m footprint in 49 working days. To comply with building regulations, the structure was required to provide 30 minutes fire stability. The precast floor slabs inherently met this requirement, but the structural steel required additional protection. This was addressed by means of intumescent paint, which was applied in the factory to save costs and time. Although this was intended to be a temporary structure, corrosion protection was a concern since the site is approximately 100m from the sea. A high specification paint application with a five-year warranty was chosen over hot-dip galvanising as this was more economical, met the design requirements and saved time. Drilling and fixing to the steelwork by follow-on trades was restricted and closely monitored to ensure that any damage to the paint system was carefully repaired. The cladding system had not been developed by the time the installation of the structure had commenced on site, so the support system had to be retrofitted. In light of the abovementioned restriction on drilling into the steelwork, it was decided that the cladding system had to be clamped around the paring barriers rather than relying on conventionally bolted brackets. Despite delays caused by external factors, the structure was completed in time for the end-of-year tourist season and provided a much needed additional 350 parking bays to the V&A Waterfront. When the time comes for re-development of this land, it is intended that the structure will be relocated elsewhere within V&A Waterfront. The potential for re-use of the structure is exciting from a sustainability point of view. The modular construction and component detailing allows for flexibility in re-use. The structure can be re-used elsewhere in its entirety, in part, in different formats and even for different occupancy classes if a topping and shear connectors are introduced. Project Team Role Company Client/ Developer V & A Waterfront Architect MLB Architecture Structural Engineer LH Consulting Engineers (PTY) LTD Quantity Surveyor BTKM Quantity Surveyors Project Manager NMC (PTY) LTD Main Contractor NMC (PTY) LTD Steelwork Contractor UNION STEEL Structural Steel Detailer UNION STEEL Steel Erector L&A Steel Erectors Corrosion Protection Paintwork Contractor Nu Nation Protective Coating
Steel Awards 2018
We’ve received an impressive 74 entries for this year’s SAISC Steel Awards! For more on the winning projects, click here. As always, we are delighted to have support in the form of sponsorship from companies in the industry, and look forward to celebrating the tenacity, ingenuity and excellent work produced by the steel construction industry of Southern Africa!
A big thank you to our sponsors: Pro Roof – Main Sponsor Gauteng Aveng Trident Steel – Main Sponsor Cape Town, Beverage Sponsor (National) ArcelorMittal South Africa – Digital Trailblazer Cadex Systems SA – Photo Competition ASPTM – Tubular Category Safintra SA – Factory and Warehouse Category Global Roofing Systems – Metal Cladding Category Safal Steel – Innovation Category NJR Steel – Partner Sponsor Macsteel – Partner Sponsor Stewarts and Lloyds – Partner Sponsor KRU Detailing – Gauteng photobooth sponsor