A Tall Storey (a BIM app)

Dangling from a cradle 40 stories high, clip board tethered to a wrist, scaling up and down the side of a building, weather permitting, inspecting joints, seals and glazing. This job has to be done for the life of the tall building; lives and rent are at risk.

Nearly all major cities around the world have tall buildings. When we walk through those landscapes we may marvel at our achievements, or not, but take a closer look. These are aging buildings expensive to build and potentially expensive to maintain. We all know that weather erodes the landscape and buildings are not immune from the wind, rain and toxins from our industrial civilisation. The building fabric has to be inspected, assessed and maintained otherwise we risk, in the worst case scenario, death by falling objects; reputations are at risk if tenants move out and a large monolith starts to deteriorate.

So how are these buildings inspected and maintained? It isn’t some remote drone technology scaling the walls and electronically determining the quality of seals. That technology, whilst used in the depths of the ocean, isn’t cost effective and available to the building maintenance community. No, you need the experienced eyes of an individual who knows what to look for and isn’t scared of heights or working outside in a variety of weather conditions.

The scale of the task varies, for example one of London’s iconic tall buildings originally known as the Nat West Tower, has over 4,000 panels. Built between 1971 and 1980, officially opened in 1981 by the Queen, costing £72 million and is 183 meters high. The building, with many others was damaged in the 1993 IRA bomb blast, demolition was considered but rejected as too expensive and a £75 million refurbishment programme pursued which involved completely recladding the façade, reopening in 1996. This grade A office building is now in multiple occupancy and called Tower 42 after the 42 cantilevered floors.

The building façade is surveyed every 5 years and the rate of weathering damage is assessed so that remedial work can be planned in the most efficient way. Most tall buildings are assessed this way; some building owners may use a specialist firm or their own personal, the risk of failure could be fatal and that is certainly a driver to make sure the maintenance is carried out.

About 8 years ago we (activeplan) were approached by the owners to see if we could help with interpreting the data from the cladding surveys. They had been following our work with other property developers and our skills in turning data into meaningful information through a web portal environment. The survey data was being recorded on paper and then transcribed into spread sheets but there was a problem in human interpretation of the spread sheets in relation to the elevation and floor. They wanted a solution that authorised personal could view and also author alterations to the data. We proposed folded out elevations of the façade as the most practical view of the building façade together with plan models. Had we just built a 3D model of the building then they would need specialist software and skills to navigate as the building is not a rectangular shape, they would not be able to produce printouts to easily understand the issues as orthogonal elevations would obscure panels. Our building information model is a database and that means we can store attribute information against any element of the building down to the component level. This information can be visualised in abstract ways such as the folded out elevations, something 3D models cannot readily achieve.

With our foldout elevations each panel is shown flat on, and by navigating the faults recorded the panels can be displayed in context or you can click on a panel and see the full range of faults for any survey. PDF outputs and panel reports can be generated for documentation. That was the first pass, 5 years later the client came back with the next set of survey data and wanted to know which panels had got worst, stayed the same or been repaired. This was a process of importing the survey data and then allowing the user to compare surveys viewing the traffic lighted coloured folded out elevations or plans.

As with most problems you learn more as you explore more and the client asked if there was an easier way for them to input the data matching the method the surveyor is using to capture the data. We favoured an offline mobile solution to be used by the surveyor in the cradle. However, it is not easy to implement new technology, as many surveying companies will testify with older experienced staff. This does not mean you don’t pursue it but it will take longer so a compromise was reached by developing a web desktop version first, the prototype for the offline version waiting for that more tech ready surveyor. It wasn’t designed quite like the paper based system but around how the surveyor navigates the building using drops and levels and recording the faults on the sides of the panels straddling the cradle rail. So the surveyor records 2 halves of each panel per drop. This is specific to this type of cradle and may not suite all buildings.

Is this building information modelling? Yes, I think so, because we are using the same database for storing all the other information about the building, as and when it becomes needed, providing the infrastructure to build a comprehensive BIM cost effectively gradually. We are now building apps around the BIM in a pragmatic way which can be applied to all the buildings in the system. So now I’m pondering the architecture of such apps how they will address their primary purpose with on/offline synchronisation and integration to the rest of the BIM apps. Some apps will be generic in nature and applicable to most buildings some will be specifically designed but they will still use the same BIM model structure. This means that the BIM data model can be transferred from owner to owner who can then use their own preferred systems. That’s a future which will be many years in the making.

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One thought on “A Tall Storey (a BIM app)

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