Baakens Valley Pedestrian Bridge

 

 

The Baakens Valley Pedestrian bridge is an iconic structure in Port Elizabeth. As part of the Mandela Bay Development Agency’s plan for the precinct, the bridge is a key part of rejuvenating the area.

By extending and connecting the inner city to the Baakens Valley, the bridge plays a crucial part in creating a world class precinct for the community.

The iconic structure is a composite design that makes extensive use of circular hollow sections.

PROJECT OVERVIEW
Physical address of the project
Street Address
Town
Province		 16 Lower Valley Rd
Port Elizabeth
Eastern Cape
Google Maps link  
STRUCTURAL STEELWORK
Completion date of steelwork 05/06 July 2019(On site); 20 July2019 Crane Lifted
Completion date of full project 12 December 2019
Tonnage and steel profiles used 14.8 tonnes – CHS Profiles & 2-profiles
   

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.

The new replacement swing bridge, V&A Waterfront

 

The V&A Waterfront (V&A), situated in South Africa’s oldest working harbour, is a mixed-use development for both residential and commercial, offering visitors from near and far a world-class experience when it comes to entertainment, shopping, dining and accommodation.

The V&A already had a swing bridge that was well-used and well-loved. It was an efficient structure that opened and closed up to 60 times a day, carrying up to 2.4 million people per year. It was, however, 22 years old: a lifetime in the context of the V&A and the 2 m wide walkway, which once seemed appropriate, could no longer cope with the rising numbers of pedestrians.

The team was therefore commissioned to design a new wider bridge

The engineering brief

The challenge set by the client was:

  • The new bridge had to be equally quick and efficient, effective and reliable as the existing;
  • The construction cost had to stay within a tight budget; and
  • The works had to limit the disruption to the public, the V&A and the environment.

Both steel and FRP were considered at the early stages of the project as the only materials that were light enough to limit the loads on the moving mechanical parts and to limit the foundation size. However, as the design progressed the use steel was the obvious choice. Its advantages were:

  • Its strength enabled the creation of a stiff yet slender pylon as well as a relatively shallow central spine beam.
  • The material is robust and can withstand some impact.
  • It created a relatively light weight structure that limited the power needed to move the bridge.
  • The local expertise to fabricate the bridge was readily available in Cape Town.
  • It enabled the bridge to befabricated offsite and easily assembled on site and lifted into place.
  • It gave great opportunity to sculpt a beautiful structure.

Structural framing

The new swing bridge has a span of 40 m. The deck is cable-stayed with a single plane of 4 locked coil cables connecting to a central, upstand spine beam. The spine beam is a 500 mm wide fabricated box with a total depth of 800 mm, but only 470 mm protrudes above the top of the deck. The reclining pylon is in the continuity of the main central beam and its stiffness transfers the cable loads into the piled substructure. The steel with timber deck is rotated on a slewing bearing, which is stressed down onto a doughnut-shaped pile cap by 34 vertical Freyssibars.

The steel deck comprises cantilevering cross beams that are fabricated I-sections; a longitudinal edge beam that is a triangular closed section; and bracing members that are standard angle and T-sections.

The end beam houses the bridge wheel assembly and is a box section to resist the loads at the deck tip.

The pylon is a fabricated box that has been sculpted to provide strength and stiffness where required. The stay cable anchorages are discretely housed within the top of the pylon with an access panel at the back to allow for stressing and inspection.



Challenges

This was a very challenging build. The bridge is over 40m long and 3m wide with the mast section extending over 10m into the air.  Once completed it weighed more than 40T.  In the workshop the eccentric shapes of the individual sections (some as big as 16T) created big challenges with regards to the moving and rotating for the welding and fabrication.

One of the project objectives was to limit disruption to the V&A. Hence, the bridge was assembled on a nearby jetty. Once completed the bridge was carefully craned onto a barge and towed to its final position. The bridge was then lifted off the barge and mounted onto the slewing bearing. It was an amazing process that took 2 days and careful co-ordination and it was a first for many to see a completed bridge sail away.

The interface between the bridge and the circular slew bearing was a critical joint that required very tight flatness and dimensional tolerances. If not achieved the bearing’s working life might be reduced or worse the fit-up with the bearing might have been compromised. The bridge 3.5 m diameter ring beam that connects it to the bearing was fabricated from heavy plate sections to resist the forces needed to prestress it down onto the bearing. The dimensional control required in fabricating this element was a significant challenge and required all the skills of the welding team.

The architectural intent was for the pylon to be a continuation of the central upstand beam. As such, it is a very slender element. The fit up of the stiffeners and diaphragms as well as the various fabricated pieces of the pylon, ring beam, spine beam and deck elements had to be carefully considered to ensure that the required welding operations were practical. The sequence of closing the hollow box sections and of jointing them on-site also presented several conceptual problems. The 3-dimensional Revit model developed by the design team was essential for testing this aspect of the design. The modelling work done undoubtedly saved time in the fabrication yard and on-site.

Impressive technical aspects of this project

A moving bridge project is unique in itself and for the design team the greatest technical achievement was the combination and integration of mechanical, structural, marine, geotechnical, construction and architectural expertise to create a simple but beautiful structure that moves. The use of a slew bearing was a technical innovation not seen before in Africa and the design team had to undertake detailed research and modelling to validate it could be used for a bridge of this type.

Having to manufacture the bridge on one side of the harbour, ship to across the harbour and offload it onto the bearing on the other side of the harbour introduced elements that we never normally deal with. Ensuring the bridge didn’t fall off the barge and into the sea was always in the back of our minds.

How this project demonstrates the benefit of steel as a material

As mentioned above steel offered the opportunity to create a relatively lightweight and slender structure that could be sculpted into a single attractive form. It’s proven robustness and strength is unrivalled.

The bridge was fabricated into a single sculpted form. It is not a collection of parts; deck, mast, beam. It is rather a bridge with its own identity that can be recognized as a landmark. The use of steelwork has enabled architecture and structure are integrated together. The curves and sculpting of the various box elements create a beautiful bridge that seemingly rotates and supports itself by unseen parts.

How the project team worked together

The core design team: SMEC South Africa, Stefanutti Stocks, Eadon Consulting and the V&A Waterfront came together 4 and a half years before the bridge was finally open to the public. The early contractor involvement, the dedication from the client and the passion from all the designers involved throughout the design and construction processes ensured the success of the project. The vision to create something beautiful for Cape Town to be proud of was shared by all those involved and fuelled good working relationships.

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 ProvinceV&A Waterfront, New Swing Bridge (connecting the Pierhead Precinct with the Clock Tower Precinct)
Google Maps link 
STRUCTURAL STEELWORK
Completion date of steelworkAugust 2019
Completion date of full projectAugust 2019
Tonnage and steel profiles used46.3 tonnes, Ex Plate 25 – 100mm
  

 

Project Team Company
Nominator Anchor Steel Projects
Client/ Developer Waterfront Properties
Architect Coasite Craft of Architecture
Structural Engineer SMEC Engineers
Engineer SMEC Engineers
Quantity Surveyor SMEC Engineers
Project Manager Steffanutti Stocks Coastal
Main Contractor Steffanutti Stocks Coastal
Steelwork Contractor Anchor Steel Projects
Steel Erector / Project Coordinator Anchor Steel Projects
Cladding Manufacturer  
Cladding Supplier  
Cladding Contractor  
Corrosion Protection  
Galvanising Advanced Galvanising
Corrosion Protection MRH Shot Blasting and Corrosion Control
Paintwork Contractor MRH Shot Blasting and Corrosion Control
Photographer, Photo competition Anchor Steel Projects
Photographer, Other submitted images Anchor Steel Projects

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.

The Viper Elevated Woodland Walkway

A comprehensive and very accurate 3-D cloud survey of all the trees and their branches in the forest was done, so that the route of the walkway could be designed    and refined to meander through the wood without a single tree being affected

Since disturbance of the tree roots was also to be kept to a minimum, conventional concrete bases were not an option and the structure is thus supported on steel piles driven into the ground, with positions carefully chosen so as to miss all roots.

Each column is fixed onto a tripod, with  its three ends each supported on a pile. After installation the pile top positions were accurately surveyed again, and the tripods all manufacture to exact, bespoke dimensions, so that each column base would be in precisely the correct position and at the correct level, ready for the column to be fixed onto it.

SUPERSTRUCTURE STRUCTURAL CONCEPT

Since no diagonal members are allowed in the UK above deck level (to prevent climbing over the handrail), the handrails could not be used as the upper chord of a truss, as we have done on previous structures. The main structural members are thus all below the deck level, comprising a central box section plus two side box sections, with the stanchion ribs above not forming part of the main structure and thus designed as delicately as possible, only 15 mm wide at the top. All the box sections are welded up from plates profile cut to  the correct curves.

The central box is joined to the two outer box sections with diagonal ribs that are angled on plan, so at to provide horizontal stiffness.

The shapes of the stanchion ribs and the lower ribs have a continuous, even outer curve that flows  from the handrail all the way around to the central box section. The stanchion and lower rib  inner edge curve is also continuous until it becomes horizontal in the centre. The outer box sections have vertical sides but the top and bottom surfaces are sloped to follow the curved lines of the stanchions and ribs.

The superstructure was built in 3 sections: the central main box section with the lower ribs welded to it, and the left and the right balustrade sections. All components were made up in lengths of roughly 5 m, so that they could easily be lifted into their  final positions on site with a light crane.

Everything was pre-assembled in the workshop, then galvanised and painted, so that it would fit perfectly when bolted together on site, with only minor paint touch-ups required.

The Oak timber joists, Balau transverse decking slats and the Oak handrails were also pre- fabricated in sections, before being fitted in their exact positions on site.

COLUMNS

The columns are up to 11 meters long, and have to resist substantial moments at their bases. They also need to be stiff to reduce the horizontal walkway deflections. They are star shaped in plan, made of 6 radial T sections. They taper from a 265 mm diameter below the walkway to a diameter of up to 460 mm where they are bolted onto the tripod top plates.

An interesting detail was devised for this connection, to allow for any possible angular orientation between the column and the tripod. This was achieved by having 12 slotted holes in the column baseplate and 24 round holes in the tripod top plate. As the column is rotated around the common centre point (which also has a bolt for initial erection purposes, 12 bolts will always fit through the 2 plates.

The columns were made up in sections of max 6 m long and the detail where these sections are bolted together is also interesting, with no protrusion of the flange plates beyond the column edges and the bolts hidden between the T-sections.

COLLABORATION

The Architect and Structural Engineer have worked very closely together to sculpt all the details of the walkway deck and its supporting structure, to ensure that that every component is tidy and aesthetically optimal.

Furthermore, the entire walkway and all the columns were fabricated by a Cape Town steel fabricator before being shipped to the UK, achieving a considerable saving for our Client. A UK steel contractor fabricated the tripods supporting the columns and did the onsite erection of all the steelwork. The close collaboration achieved between the consultants and contractors in Cape Town and those in the UK has been one of the highlights of the project.

INTERESTING FACTS AND NUMBERS

Total length                           130 m

Width                                    1.4 m for most of the bridge, 3 m in one zone

No of spans                          12

No of columns                       12

Typical span length                10 m Max height above ground    12 m

Steel mass of bridge             31 tonnes Steel mass of columns 14 tonnes Steel mass of tripods 12 tonnes

Nearly all the steelwork was CNC plasma cut from plates and welded together

CONCLUSION

We feel that the Viper Walkway at Emily is an excellent example of how steel can be used to create something of amazing and enduring beauty. The facility is bound to provide a lot of pleasure to many people for a long time to come. Steel is a material with very special attributes and qualities, no matter where it is fabricated or where it is erected.

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 Team Role

Company

Nominator

Henry Fagan & Partners

Client/ Developer

Emily Estate (UK) Ltd

Architect

Mark Thomas Architects

Structural Engineer

Henry Fagan & Partners

Quantity Surveyor RSA

Bernard James & Partners

Quantity Surveyor UK

Synergy

Project Manager

Stonewood Design Architects

Main Contractor

Beard

Steelwork Contractor  RSA

Prokon Services

Steelwork Contractor  UK

MJ Patch & Co

Steel Erector   UK

MJ Patch & Co

Timber Work Contractor

HG Holliday (Pty) Ltd

Corrosion Protection
Consultant

KVB Associates

Corrosion Protection
Galvanising

Advanced Galvanising 

Corrosion Protection
Paintwork Contractor

MRH 

Photographer: competition

fotohaus

Photographer: other images

Henry Fagan & Partners

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.

Hazendal Wine Estate – New Educational Play Center

The Educational-Play Center at the Hazendal Wine Estate in Stellenbosch is a new building forming part of the redevelopment of this heritage wine estate. The facility is named Wonderdal.

After various designs were proposed to the three heritage bodies involved in this building’s approval, the final design of the building was agreed upon. These heritage bodies did not have a unified vision and what was preferred by one was not accepted by another.

The close proximity of the new facility to the historical building had to be considered. The new building design had to respond in a sensitive manner to the scale and not dominate the existing old structure.

The nature of the building programme, that of a play center, suggested that the design of the new facility should be a simple Box Shed. This building type was approved by one heritage body but rejected by another. Therefore, to reduce the impact of this Box Shed, two new barns similar in scale to the historical buildings where introduced. This formed a rhythmic streetscape where the space between the barns formed courtyard spaces for entrance and deli spillover seating. The shed roof that floats over these barns forms the main double volume required for the play center’s apparatus and functions. Where the floating roof and barns meet, they are connected with glass. This new building also houses the main kitchen which serves as the farm’s new Deli Restaurant which is located in the attached old historical barn.

Architect Interview:

The façade and parts of the roof of the building consist of white concrete panels and large glass windows which afford little space for vertical bracing to resist high lateral wind loading the open farmland. The lateral deflection of the building had to be minimized to prevent cracking of the glass facades. This was resolved by designing all columns and bases to act as vertical cantilevers.

All roof beams were fixed to the columns with moment connections to further enhance the lateral stiffness of the building. In order to achieve neat inconspicuous connections, the top flange at the beam ends was cut away to allow a small workspace. All bolts, end plates and stiffer plates were fixed on the inside of the square hollow sections (refer to the attached details).  

The choice of materials and structural design of details resulted in a steel frame with a neat non-industrial appearance.  

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.

STRUCTURAL STEELWORK
Completion date of steelwork May 2018
Completion date of full project March 2019
Tons of structural steel used 44.2 Tons
Structural profiles used 200x200x6 SHS, 203 x 203 x 46 H, 203x133x30 I
PROJECT TEAM COMPANY
Nominator Michael Hackner Architects
Client/ Developer Hazendal Wine Estate
Architect Michael Hackner Architects
Quantity Surveyor Prodigious
Project Manager  
Main Contractor R + N Master Builders
Steelwork Contractor TGS Concepts
Steel Erector TGS Concepts
Corrosion Protection
Galvanising		 Galvatech
Nominator Michael Hackner Architects
Client/ Developer Hazendal Wine Estate
Architect Michael Hackner Architects
Structural Engineer JTL Structures cc
Quantity Surveyor Prodigious
Main Contractor R + N Master Builders
Steelwork Contractor TGS Concepts
Steel Erector TGS Concepts
Corrosion Protection
Galvanising		 Galvatech
Photographer, Photo competition Michael Hackner Architects

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.

IRPTN Pedestrian Bridges

In 2013, the City of Ekurhuleni Metropolitan Municipality embarked on an upgrade of their existing transportation route planning and infrastructure in the form of an Integrated Rapid Public Transport Network (IRPTN). The City is now set to kick off the first official run of its IRPTN service, Harambee, as part of the implementation of its Phase lA operations.  The limited service will run eight buses in mixed traffic along the 38 km service route, with 33 kerbside stops, between Tembisa and Isando.


The full roll-out of the Harambee Phase lA service includes the introduction of new elements into the system until it is ready to operate as a fully-fledged BRT (Bus Rapid Transit) scheme. Integral to the project is the construction of nine new BRT Bus Stations (see the Station layout in Figure 1 below) which run into the heart of Tembisa. These new Bus Terminals and pedestrian bridges are the projects submitted here for consideration.

The overall project scope includes the upgrade of the existing road facilities, to add new BRT lanes with sidewalk and median, as well as the construction of nine new station facilities. Due to the overall road width increase, several structures are required to be extended and upgraded – these include a road culvert water crossing and several rail culverts that cross the main road (Andrew Mapheto drive) that traverses through central Tembisa.

With the exception of the pedestrian bridges, the typical layout model that has been deployed throughout the project is similar to that which has been used in the Johannesburg CBD and Cape Town BRT systems. The Stations represent central node points that facilitate the easy access of pedestrians into the BRT system, and the brief to the Architect was to design an aesthetically pleasing solution that provided such access.

The elements generally incorporated into a typical Station are the following:

  • A median area where passengers are noused in a dedicated enclosed structure that provides direct access to the bus route and BRT lane,
  • the pedestrian bridges that cross over the road intersections, allowing pedestrians the ability to gain safe access to the median area,
  • the various interlinking walkways and stairs,
  • the lift shafts that allow users to transition from the Ground level to the First-Floor level and back

The original concept developed by the Architect and Structural Engineer is very similar to the final design that is currently under construction, which involves a curved steel truss type arrangement, made out of mostly circular hollow sections. Structural steelwork was envisaged on this project due to its ease of use for the required spans, the ability for easy erection over existing roads, as well as the overall slim look and feel that arises out of its use in the design.

The bridges incorporate a composite structural steel/reinforced concrete slab design. The top and bottom girder chords are constructed from circular hollow sections and the design has a curved top chord that is set at an angle relative to the main floor structure, making the bridge took “open” as one travels from one end to the other. Due to deflection requirements, the bridges are given a slight vertical preset to allow the deflections to normalise under dead and live load conditions. The vertical girder members are given outward curved radi, and a similarly radiused plexiglass f de is attached using aluminium mullions – the fac;ade envelops the entire truss frame, giving the bridge an aesthetically appealing look and feel, To facilitate drainage on the bridges, a longitudinal fall is provided between deck interface platforms and full-bore outlets are used on the bridge ends to facilitate the discharge.

The longest pedestrian bridge has a span of 36m and therefore it is long enough for vibration considerations to play a role. A LUSAS model was therefore developed to simulate the effects of pedestrian crowds as well i:IS single dynamic pedestrian users moving over the bridge. The analysis showed that that the maximum accelerations developed on the bridges are not in excess of the 0.5m/ s2 allowed by the relevant Codes. Acceleration results were further compared with the SETRA Pedestrian Bridge design guide as well as the TMH7 guidelines.

The Lift Tower shafts and their supporting structure represent key structural elements that directly interface with an unusual curved supporting element that takes the bridge load directly down to the foundation level after first wrapping its way around the Lift Shaft Tower. The lift shaft itself is also enclosed in an aesthetic plexiglass facade, providing cover to users of the lift as well as protection for the lift equipment. Louvered vents through the facade are also required due to the heat-build inside the Lift Shaft Tower structure.

From a design point of view, the interfacing of the plexiglass facade with the bridge structure required several Iterations to ensure that a robust and workable solution was arrived at. One of the challenges of designing with plexiglass material is that all the connections to the structure need to include a gasket sealing material and gaps are required in connections to allow for a certain degree of plexiglass movement. Interfacing with the 11ft contractor also required a thorough understanding of the details of the levels and falls on the site to ensure that the lift exit and entry points corresponded with the deck slab and ground levels.

The open frame design of the bridge girder members meant that careful attention had to be paid to the stability of the main girder structure in the transverse direction –  this meant that any member splicing along the lines of the main transverse framing action required the use of stiff moment connections.

A significant number of Shop drawings were required to be generated for the entire project. 3-D Tekla models were used by the steelwork contractor to facilitate the rapid development and approval of shop drawings. Due to aesthetic requirements, welding for the splicing of main longitudinal members was done on site under carefully controlled conditions.

For each bridge site, road closures were required for the erection of each bridge – this required a significant amount of coordination with the local traffic authorities who were fortunately very obliging. Some 32 tonnes per 36m span were lifted, and a typical station involved the erection of approximately 115 tonnes (Including the Lift Towers) per station.

For this project, the two main Contractors on the project (Stefanutti Stocks and King Civils) were required to think of solutions to the problem of how and when to  Install the concrete deck slabs whilst allowing for the concrete creep and shrinkage to occur. This produced a set of interesting and varying opinions, and ideas suggested varied from precast concrete to  in­ situ concrete with permanent formwork.

The design of the Station Bridge structures that are required to harmonize with Lift Shaft Towers presented an interesting challenge to the SMEC South Africa bridges design team. The project demonstrated that there is still a significant preference for the use of structural steel for pedestrian bridges in this country.

STRUCTURAL STEELWORK
Completion date of steelwork ± September 2018
Completion date of full project ± April 2019
Tons of structural steel used 725 Tons
Structural profiles used Chs, Ub, Uc, [, Angle
PROJECT TEAM COMPANY
Nominator Khombanani
Client Ekurhuleni Metropolitan Municipality
Structural Engineer Smec South Africa
Engineer Lte Consulting
Engineer/Project Manager Lte Consulting
Main Contractor Stefanutti Stocks / Khombanani Steel JV
Main Contractor King Civils
Steelwork Contractor Khombanani
Steel Erector Onpar Steel
Cladding Manufacturer Global Roofing Solutions
Cladding Supplier Global Roofing Solutions
Cladding Contractor Roofline
Corrosion Protection
Paintwork Contractor		 Dram Industrial Painters
Corrosion Protection
Paintwork Contractor		 RSC

Naspers Skybridge

The Naspers Skybridge is a pedestrian link between the CTICC 2 building and the Naspers building. The client tasked the architect with designing a new bridge between the new CTICC 2 building and the NASPERS building. This would aid in daily access for Media24 staff, as they did not have enough parking of their own and could then utilize some of the parking bays in the CTICC buildings. This new bridge had to link CTICC 2’s Second Floor with NASPER’s Fourth floor, roughly 13.5m above the road level.

The architects developed various concepts for the design of the bridge. Inspiration was taken from the shape of a tree, interpreted in different architectural expressions. Through workshops with the client (both CTICC and NASPERS) and the professional team, multiply small-scale physical models were built to convey the different design ideas, including an option of steel laser cut panels that form a sculptural support and leaf-pattern balustrade, and another version with steel support “branches”. Ultimately, the design was refined to form a simple yet “raw” aesthetic, with the architectural and structural logic informing the details. A composite wood decking floor in a staggered pattern was used to enhance the “raw” aesthetic, with Rheinzink roof sheeting chosen for aesthetic and practical reasons due to the slanted and curved roof. Panoramic views of the city can be experienced through the full-height glass façades.

Due to the location of the entrances to the buildings, the bridge curves for about half of its length. This creates an interesting architectural experience as one crosses the bridge, while making it possible to see the bridge’s exterior from the inside. Structurally the challenge was to support the curved section only on two columns, with the end part at the CTICC not being able to be supported by the existing building (thus creating a large cantilever that had to have minimal movement at the façade entry point).

The bridge was always envisaged as being constructed out of steelwork – to allow maximum views to the sides and to enable construction with minimal disruption to the street below. The bridge structure comprised mainly Universal Beam and Column sections, with some angles added to support the flooring and a CHS safety rail for window cleaning.

Engineer Interview

Challenges arose due to the weight of sections, which made moving these sections a challenge during both fabrication and erection. The bridge sections were assembled into just two pieces adjacent to the road, allowing these two large pieces to be erected using a 440t crane during a road closure on a Sunday. The two parts had never been spliced together before erection, with all dimensions being theoretical. The first real fit was therefore on site, and everything fitted perfectly.

Another challenge was erecting the bridge on a windy and rainy day, forcing the contractor to wait for a lull before lifting.

Since the bridge was modelled in 3D, an IFC export was provided to the contractor to aid them in the shop drawing process. In turn, they provided their fabrication model in 3D for approval by the engineer and architect, which ensured that the aesthetic intentions of the professional team could be met.

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.

STRUCTURAL STEELWORK
Completion date of steelwork October 2018
Completion date of full project March 2019
Tons of structural steel used  
Structural profiles used UB, UC and CHS sections
CLADDING
Completion date of cladding No cladding
Cladding profile/ type used Rheinzink
Cladding area/ coverage and tonnage 165m2
PROJECT TEAM COMPANY
Nominator Anchor Steel Projects
Client/ Developer Cape Town International Convention Centre
Architect Osmond Lange Architects + Planners
Structural Engineer Sutherland
Quantity Surveyor Turner & Townsend
Project Manager Lukhozi Engineers
Main Contractor Superway Construction
Steelwork Contractor Anchor Steel Projects
Steel Erector Anchor Steel Projects
Cladding Supplier Two Oceans Metal
Cladding Contractor Naturally Slate

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.

CTICC Skybridge

The CTICC Skybridge was intended as an above-ground link between CTICC 1 on the West of Heerengracht Street and CTICC 2 on the East. The client asked the Architects to design an enclosed pedestrian skybridge to connect the Cape Town International Convention Centre (CTICC 1) with the CTICC East Expansion (CTICC 2) across the busy Heerengracht Street. Development of the CTICC skybridge was considered critical in enabling the two buildings to function as a single integrated international events hosting venue and providing a seamless visitor’s experience.


The curved skybridge with its slender slanted steel columns has an unusually dynamic aesthetic from outside. The curved route inside provides a dynamic visual experience as one moves across the bridge in anticipation of an obscured end destination. The indirect travelling direction guides the visitor’s gaze outwards and across the historic Heerengracht Street and allows the bridge to become a unique destination in its own right. This purposefully iconic structure pays tribute to CTICC’s core purpose of ‘connecting people’.

The bridge was always envisaged as being constructed out of steelwork – to allow maximum views to the sides and to enable construction with minimal disruption to the street below. Universal Beam and Column sections were chosen to frame the concrete floor and roof, which were both cast in sections in between these steel members, with support provided by Bondek sheeting. Universal Column sections were also chosen for the Vertical members, in order to frame the glass panels.

Circular hollow sections, however, were chosen for the diagonal members to minimise the disruption of the view. The same members were also used for horizontal bracing at the roof and floor level, to keep the section sizes down. Large circular hollow sections were also used for the slanting support columns.

Engineer interview:

Challenges arose due to the weight of sections, which made moving these sections a challenge during both fabrication and erection. The bridge sections were assembled into

just two pieces adjacent to the road, allowing these two large pieces to be erected using a 440t crane during a road closure on a Sunday. The two parts had never been spliced together before erection, with all dimensions being theoretical. The first real fit was therefore on site, and everything fitted perfectly.

Another challenge was the temporary support of the bridge during erection. This was overcome by introducing the temporary towers, which made the installation much simpler and safer.

Since the bridge was modelled in 3D, an IFC export was provided to the contractor to aid them in the shop drawing process. In turn, they provided their fabrication model in 3D for approval by the engineer and architect, which ensured that the aesthetic intentions of the professional team could be met.

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.

STRUCTURAL STEELWORK
Completion date of steelwork September 2018
Completion date of full project November 2018
Structural profiles used UB, UC and CHS sections
PROJECT TEAM ROLE COMPANY
Nominator Anchor Steel Projects
Client/ Developer Cape Town International Convention Centre
Architect Convention Architects – a JV between Makeka Design Lab cc, SVA International (Pty) Ltd and van der Merwe Miszewski Architects (Pty) Ltd
Structural Engineer Sutherland
Quantity Surveyor Turner & Townsend
Project Manager Lukhozi Engineers
Main Contractor Superway Construction
Steelwork Contractor Anchor Steel Projects
Steel Erector Anchor Steel Projects

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.

No.1 Silo Bridge

The requirement for a pedestrian bridge link between two office buildings was borne out of the need of Allan Gray’s expanding workforce as they out-grow their head office capacity at No.1 Silo building in the V&A Waterfront. Allan Gray and the V&A Waterfront together with the architect and engineers developed the idea of a linking bridge between the No.1 Silo building and the adjacent Clock Tower building to allow the internal flow of employees between the buildings.

Not far away from the site of the bridge is the defunct Collier Jetty that has a steel gantry structure along its length, historically used to convey coal and later grain. The gantry is constructed from conventional bolted angle trusses – the inspiration behind the truss form of the bridge with matching diagonal angle sections. 

The brief was thus to design and construct a bridge that would allow people movement over the 12,5m span. While it is a relatively short distance the challenge lay in designing a structure that would deal with the movement between the two buildings that are built on separate floor plates by catering for differential lateral and horizontal movements of up to 20mm.


Architect interview:

The Allan Gray building has a fully glazed double-skin façade supported off long cantilever fins which are sensitive to additional loads. The bridge, therefore, had to be fixed on one side only, and cantilever without physically touching the glazed façade. As such columns were introduced to support the bridge at the glazed façade allowing unimpeded movement against it. The two columns, 219mm CHS, are braced by 254x146mm universal beams forming a ‘portal frame’ on which the bridge rests and on the other side, it is bolted to the reinforced concrete frame of the Clock Tower building by way of a shear key detail.

Engineer Interview:

To maintain the view corridor between the two buildings, toward the working harbour, the architects motivated for a crossing at second-floor level. Limited space between the buildings, the delicate glazed façade and the limited crane load that could be applied on the podium level between the buildings meant the structure could not be erected in its entirety and craned into position – it needed to an on-site assembly, erected on a scaffold deck.

A rectangular girder comprising 200x100mm RHS sections was designed as the most efficient steel structure to span from the Clock Tower building to the ‘portal frame’ and cantilever a further 1,7m to the Allan Gray floor plate. A spliced connection along the length of the top and bottom chords created parts that could be handled on site. Rigidity is provided by expressed diagonal bracing visible externally as a structural ‘exo-skeleton’, painted red. 

The design team devised connection details between the various parts that expressed the junction of the steel members, in keeping with the industrial, maritime aesthetic. 100x100mm equal angles bolted to gusset plates brace the vertical SHS posts on  the sides of the bridge. 100x100mm SHS brace the underside and the roof level, expressed externally on the soffit and internally below the ceiling finish. Spigot connector splice details were required on the bracing diagonals to cater for the erection sequence.

Where the bridge passes through the double skin façade a flexible EPDM membrane allows for the required movement but also a weather seal. The membrane is protected by overlapping aluminium flashings.

The bridge links offices on two different floor levels – this is achieved by a sloping timber floor within the girder structure. Steel cleats on stub columns welded to beams along the length of the bridge support timber joists at varying heights.

Main Contractor Interview: 

Sidewall cladding is Snap Lock profile in Armour Grey colour, selected for its broad pan and narrow flutes with wide rib spacing. Set behind the diagonal bracing, the industrial aspect of vertical sheet cladding further ties the bridge to its maritime setting. Snap Lock is also used for the roof sheeting and in conjunction with a stepped aluminium flashing detail it creates a crisp silhouette of the bridge spanning between the two buildings. 

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.

STRUCTURAL STEELWORK
Completion date of steelwork 05 / 09 / 2018
Completion date of full project 14 / 12 / 2018
Tons of structural steel used 8.1 tons
Structural profiles used RHS, SHS, CFLC, CHS

CLADDING
Completion date of cladding 10 / 10 / 2018
Cladding profile/ type used SnapLock
Cladding area/ coverage and tonnage 48m²

PROJECT TEAM COMPANY
Nominator Loudon Perry Anderson Architects
Client/ Developer V&A Waterfront Holdings (Pty) Ltd
Architect Loudon Perry Anderson Architects
Structural Engineer Sutherland Engineers
Facade Engineer Arup Engineers
Services Engineer Solution Station
HVAC Engineer Arup Engineers
Quantity Surveyor MLC Group
Project Manager Principle Agent  Architect
Main Contractor R+N Master Builders (Pty) Ltd
Steelwork Contractor Prokon Services (Pty) Ltd
Steel Erector Prokon Services (Pty) Ltd
Cladding Manufacturer Bluescope Steel
Cladding Supplier Youngman Roofing
Cladding Contractor Metro Roofing 

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.

Kusile Coal Bridge from Kusile Boiler 5 to Kusile Boiler 6

Shanahan Engineering was successful in securing an erection only contract to erect Secondary and Tertiary Structural Steelwork for Kusile Boiler 3 for Mitsubishi Hitachi Power Systems Africa in 2013.

Shanahan delights in providing well supervised and productive construction crews for all of our customers. This positive attitude during the execution of our contract at Kusile quickly led to the company securing the erection contracts for Kusile Boilers 4 and 6 as well as the Primary Coal Feed Conveyor for Kusile Boiler units 4, 5 and 6, the Steel Erection contracts for PJFF units 4 to 6 and the Coal Bridge between Boilers 5 and 6.

The execution of our contract for the latter – the Coal Bridge between Boilers 5 and 6, is the reason for our contention at the 2019 Steel Awards.

As the name suggests, the Coal Bridge feeds coal into the Boiler Mills for use in the boiler combustion process. The coal travels up to Boiler 4 via the Primary Coal Feed Conveyor and then across two bridges from Boiler 4 to 5 and then from Boiler 5 to 6 before being fed into the Boiler Mills.

The bridge was assembled at Ground Level before being lifted as a single piece construction, to its final resting place, 50 m above ground level. The total weight of the bridge is 450 tons and is therefore too heavy to be lifted by means of a Mobile or Lattice Boom Crane.

The Engineers therefore designed a system of strand jacks comprising of a series of winches, and cables that are fixed to the 4 corners of the Coal Bridge. When all necessary load and safety checks have been checked and double-checked, the winches are activated in a controlled manner to lift the Coal Bridge up before being fixed by means of bolted connections, into position.

The lift can only be performed in near-perfect weather conditions. This is due to the large surface areas that are in play which would make windy and wet conditions more hazardous for the lift.

Prior to the Coal Bridge being ready to lift, the Shanahan Construction Team had to request for all the necessary components to be delivered to the erection site for the bridge to be assembled at Ground Level. The erection drawings are reviewed and a parts list was made that comprised 1556 steel sections and 11863 bolts and nuts. Some of the steel sections were quite light whilst others weighed tons. These parts lists were passed onto the Materials Handling Contractor who delivered the requested components to the erection site. On any mega – project like Kusile, there will be parts that are either incorrectly fabricated or missing, this invariably delays the process of erection due to the engineering queries that result. This process was managed closely by the Construction Team together with the Materials Handling Contractor and the Main Contractor so as to ensure the minimum possible impact to project schedule.

In this case, the Shanahan Construction team spent 10968 manhours to complete the assembly of bridge to be ready for lifting into position. The Strand Jacks were then fixed to the 4 corners of the coal bridge and the Construction Team were ready to erect by the afternoon on 7 December 2018. Weather conditions were checked and due to a favourable forecast (dry conditions and little wind), it was decided to perform the lift early the following day, 8 December 2018.

The lift started at 08h23 on 8 December 2018 following a special safety briefing which started at 06h30 earlier that morning. In the picture below you can see the 450 ton bridge section still on its trestles at Ground Level. By 15h40 on the same day, the Bridge had reached its final position. The lift took just under 7 hours and 20 minutes to complete which was just under 5 hours faster than any of the previous Coal Bridges.

Shanahan achieved a perfect Safety record during the Assembly and lifting of the Coal Bridge with no incidents having been recorded from start to finish.

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.

STRUCTURAL STEELWORK
Completion date of steelwork 08/12/2018
Completion date of full project In progress
Tons of structural steel used 450
Structural profiles used Miscellaneous
SA content – if this is an export project  
PROJECT TEAM COMPANY
Nominator Shanahan Engineering
Client/ Developer MHPSA
Structural Engineer Genrec
Main Contractor MHPSA
Steelwork Contractor MHPSA
Steel Erector Shanahan
Cladding Manufacturer Global Roofing Solutions
Cladding Supplier Global Roofing Solutions
Cladding and Roofing Global Roofing Solutions
Cladding Contractor Southey

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.

KZN Suspension Bridges

After heavy summer rains in KZN there are many rivers that come down in flood. This makes crossing dangerous and has resulted in sufficient incidents to have motivated KZN Transport to erect suspension bridges with a standardized design in numerous places. These hot dip galvanized bridges are user-friendly to erect in the most rural of areas.

A truly great community spirited project, this bridge is so much more than just another footbridge. For starters, we usually think of a pedestrian bridge placed in a city over some busy road or railway line……not so these bridges

If ever a bridge was placed to be of maximum benefit to the local community, to really save lives in flooded conditions, these bridges did just that. Can you imagine what this peaceful stream might look when in full spate?

Placed in rural locations, to service quite small communities, these bridges represent what service delivery by any of the 3 tier government sectors should be about.

Identify a need in many places, methodically come up with an excellent modular engineering solution that largely fits all situations, make a few small modifications to suit local conditions, and hey presto we get a cost-effective stable suspension bridge that is a win-win for both the developer, KZN transport and the community.

Now most of us think of a suspension bridge as a swing bridge……and this is where the good engineering comes into this solution, the multiple cables, the diagonal members, the standard modules and and and net result, very little by way of a swinging motion on these bridges. Hot dip galvanizing eliminates the need for future maintenance for a long time….

A truly deserving project to be recognized with a special commendation in the community development category, the KZN Rural suspension bridges.