For more than two decades, Boksán Projects CC (Boksán) has been involved in the fabrication, supply and erection of a variety of specialised bridge building projects, as well as steel pedestrian and pipe support structures throughout southern Africa.
In more recent years, Boksán has also carried out bridge refurbishment projects for bridges needing structural repair and corrosion protection from environmental elements. This skill set has become increasingly important on many historical bridges, as they age and require refurbishment, mainly as a result of structural damage or due to new requirements to suit contemporary conditions.
The Bruma Lake Bridge is an iconic feature of the Johannesburg East area and many members of the local community and some further afield see the bridge as holding sentimental value. The bridge has remained in its original state since the 1980s and is mostly used by pedestrians crossing over the Jukskei River to access the Bruma Lifestyle Centre. However, over the past three decades, natural elements have caused a significant amount of corrosion.
As part of the rehabilitation of the Bruma Lake business precinct, Boksán partnered with the main contractor, Basil Read & ARQ Consulting Engineers, who were the driving force behind giving the Bruma Lake Bridge its much needed facelift. Boksán then looked to Prokon Software Consultants not only as their Autodesk® Reseller, but also as trusted advisors on the project.
“The challenge was to make use of existing structural elements as much as possible to manage project costing,” says Wayne Page, a Structural Detailer at Boksán. “It’s therefore important to maintain the original structure of the bridge, which is a cambered profile suspended from steel cables with balustrades that have a unique design, rolled-profiled hand-railing and shaped stanchions. The concrete pillars and other parts of the bridge can be refurbished to restore the bridge to its former glory as well as ensure that the natural elements would cause minimal corrosion in the years to come.”
“We were able to design all the bridge parts quickly on this software because of the programme’s diverse functions.”
Another common problem with the refurbishment of old buildings and structures is that the original architectural drawings are paper-based hand-drawings that can get damaged or lost, which mean that years later, contractors need to recreate the drawing to carry out any repair work required. Detailed drawings are crucial to the success of construction projects, because they ensure accuracy, while also enabling the planning of other details like transporting and lifting the structure.
Bridge detailing always presents a challenge to architects, as each bridge is unique. To manage the redrafting of the bridge’s plans, Boksán used the technology offered by the Advance Steel™ 2015 package from Autodesk® on the AutoCAD platform. Advance Steel™ detailing software helps accelerate design, steel detailing, steel fabrication and steel construction. It also improves accuracy and enables a more connected workflow.
Prokon Software Consultants provided Boksán with all the training required to use Autodesk® Advance Steel™ to its fullest potential and continues to provide Boksán with technical support to ensure that their part of the project runs according to plan. “With Autodesk® Advance Steel™, we were able to model the existing bridge structures with little complication. The 3D model generation made for easy viewing of the external design of the bridge as well as the fitting of internal members with regards to practical connections,” says Page.
“The steel detailing, draughting and creation of shop drawings in Advance Steel™ is quite easy in comparison to other packages I have reviewed. So we were able to detail cambered plates quickly and all the other bridge parts on this software because of the programme’s diverse functions. Other software options in the market don’t have the advanced pillar functions. It is quite amazing what can be done with plating on Advance Steel™,” he adds.
Much of the structure is pre-assembled in a controlled workshop environment. The bridge was trial assembled off site in the factory in Olifantsfontein to ensure a seamless and correct fit, as no mistakes can be afforded on site. “The advantage, of course, is that much of the structure is pre-assembled in a controlled workshop environment and less time is wasted on site when erecting the bridge,” explains Page.
Once it is completed, the bridge will be transported to the building site. This will be done after dark, when there is less traffic on the roads. It will be assembled piece by piece, using scuffling bolts under the bridge to support it, two to three parts at a time. Upon erection, the metal surfaces of the bridge will be painted with a specialised heavy duty anti-corrosion paint system that can withstand harsh environmental elements.