Temporary works, while a vital part of the construction process can often be overlooked at the Strategy Stage of a project. However, introducing temporary works digitally from the very beginning of a project delivers many benefits, including the ability to help teams win tenders by providing more buildable solutions.
Here, Duncan Reed, Digital Construction Process Manager at Trimble, discusses the factors that need to be considered in the context of the Digital Plan of Works, in particular the benefits of incorporating digital temporary works processes on a project.
The design and management of temporary works is covered by the BS5975:2019, which gives recommendations and guidance on the procedural controls to be applied to all aspects of temporary works in the construction industry. This standard describes temporary works as ‘providing an "engineered solution" that is used to support or protect either an existing structure or the permanent works during construction, or to support an item of plant or equipment, or the vertical sides or side-slopes of an excavation during construction operations on site or to provide access’.
Temporary works are often designed by a separate engineering team to the permanent works, so it is vital that both sets of engineers should collaborate efficiently from the beginning of a project to ensure that the most appropriate temporary works scheme is designed, to enable the permanent structure to be erected. One way that this can be achieved is for both parties to work digitally and for temporary works requirements to be properly considered throughout the overall plan of works. The RIBA Digital Plan of Works (DPoW) does not currently consider temporary works at all, but it gives a potential framework as to how design teams could work together better so this could be achieved:
0 - Strategic Definition
The start of any project begins with defining the scope at a strategic level and looking at which option is best to be progressed to fulfil the needs that have been identified; new build, an extension or refurbishment works. In all three cases some form of temporary works will be required. Therefore, the need for temporary works expertise will likely be needed from the outset. However, the appointment of a Temporary Works Coordinator (TWC) does not normally take place until a contractor is in place. So, should the need for some form of a TWC, in an advisory or consultative role be required from the start, as a contributor to these strategic decisions?
In digital terms, the temporary works design can be considered as conceptual modelling. Volumes or placeholders can be used to indicate where required temporary works may be necessary. These can also provide an indicative schedule of the scope of temporary works required on a project.
1 - Preparation and Briefing
Having outlined that there is a need for temporary works, the involvement of a TWC or temporary works professional to guide the preparation of an adequate design brief will benefit any project greatly. This brief will define the scope of the works and also the information needed to verify the works. This can be defined digitally in the Exchange Information Requirements (EIR) as the temporary works deliverables for the Project Information Model (PIM), as well as linking with the requirements of The Construction (Design and Management) Regulations.
Similarly, the amount of information to make a decision can be defined as the Level of Information Need, aligning the temporary works requirements to the digital processes defined in the new BS EN ISO 19650-1:2018 standard. Determining information requirements in this way ensures that just the right data is defined from the start.
2 - Concept Design
On larger or more complex schemes, the appointment of potentially multiple TWCs makes things more complicated. Therefore, at this point it becomes even more important that the distribution of information is accurately managed. This is where another regularly used digital tool for permanent works designers should be opened up to accommodate the developing temporary works design – a Common Data Environment (CDE). When temporary works information is created digitally and held in a CDE, filters can be applied to ensure that only the relevant information is available to the TWCs. An example could be if parts of the scheme are not yet approved for erection (so not Published data), or it is simply a part of the project that a TWC is not responsible for supervising.
The use of authorised signatories can also be assigned to standard digital forms to ensure that the scheme is signed off by the correct member(s) of the temporary works team. For example, by implementation, risk or design check categories.
3 - Spatial Coordination
As humans we generally see in 3D, our world is 3-dimensional. So, it therefore follows that 3D geometric information can give a much better understanding of a design than 2D information. By developing a temporary works scheme using 3D information, it ensures that all the data is combined in one digital model, providing benefits such as:
- Calculations can be embedded or linked to a 3D model
- Digital models can be viewed from any angle; isometric views to explain the details of the design to the TWC and the team responsible for erecting the temporary works solution. In fact, by sharing the 3D model, the viewing options are infinite allowing the TWC or erection team to inspect any part of the scheme from any angle.
- Drawings are still a vital data exchange mechanism for the industry. Using 2D drawings that derive from the data in a 3D model ensures that the information is completely coordinated.
- Specifications do not need to be separate from the main design, as they would have been previously. Instead, specifications can be linked to a 3D model, which means that they can never be lost; the information is there for anyone to check at any time. For example, in Tekla Structures, specification data is automatically generated as components are chosen, such as geometric data or steel and timber grades. Additional information, like classification data (such as Uniclass Tools and Equipment codes) can also be added by means of User Defined Attributes (UDAs) within Tekla Structures. What’s more, product data sheets in PDF formats can also be tagged to objects in models hosted in Trimble Connect and shared, so they are accessible to anyone (for free) without the need to have access to the original 3D authoring software.
4 - Technical Design
Independent checking is a vital process for temporary works. Reviewing the 3D information and data can explain the design and loading assumptions. Equally a design produced digitally has the potential to be checked far more quickly and accurately than by trawling through reams of handwritten or printed calculations.
Analysis software can provide a visual indication of the loads on a structure, which allows quick initial checks to be carried out; letting the Temporary Works Designer (TWD) review the most highly loaded areas in more detail.
To ensure that the independent check is only carried out at the appropriate stage, the use of a CDE and changing the status of the design from ‘Work In Progress’ to ‘Shared’ would be the trigger for an independent check. In these digital workflows the design check certificate remains the fundamental requirement for each and every temporary works item on a project. The creation of a digital certificate is the gateway to allow the transfer of the data associated with a temporary works design to be moved within the CDE from ‘Shared’ to ‘Published’.
5 - Manufacturing and Construction
Risk assessments and method statements are a crucial part of every temporary works scheme. The sequence of hold points such as erection, loading or dismantling are fundamental parts of any temporary works design process and are unique to this part of the industry. Using the model to provide views or even animations for a TWS to refer to, such as the erection and dismantling sequence (which may not be the same) allows transparency that may be lacking in a word heavy document. Visual method statements break down the barriers of language too, allowing method statements created in one country to be used anywhere in the world.
By creating a constructible model of the proposed scheme, it is also possible to ensure the accurate procurement of the specific materials for the temporary works structure. This could be the volume of aggregate required for a piling mat or the number of components for a scaffolding scheme. By defining the Level of Information Need required at each stage of the works, it is possible to have an accurate bill of materials available from a model.
6 - Handover
Whilst in the RIBA DPoW Handover relates to practical completion of an asset, I would argue that for temporary works this actually could relate to when the installation of the temporary works structure is completed. This is probably the most critical part of the temporary works process, as it is when the approval to place loads onto the temporary structure is given. It can only take place following the issue of a permit to load. In order to issue this, the TWC or the TWS must be satisfied that the installation is in accordance with the design. When this can sometimes be a large scaffold or inaccessible falsework, the confidence to know the scheme is right can be a daunting task to check. However, when temporary works have been created in a digital format it is now possible to use Augmented Reality (AR) applications to overlay the digital model onto the physical works and check the installation in detail. Even without AR technology the increased adoption of mobile devices on sites, together with the use of QR codes or barcodes attached to the temporary works structures, allows the TWC or TWS to inspect the physical structure with the Published digital record to enable easier checking.
Issuing the permit to load through the CDE also gives all parties greater confidence in the temporary works processes on the project.
7 – Use
The in-use phase of a temporary works scheme is very different from that of the permanent works. For example, structural integrity checks are required on a regular basis and these must be recorded for legal purposes. Having these processes digitised, available via mobile devices and linked to the projects CDE, allows for far greater rigour to be applied to these processes than paper-based systems ever allowed. Real time updates directly from the field, perhaps supplemented with sensor data, provide a much greater level of confidence and the ability to share the information in easily digestible project dashboards.
Finally, at the end of the requirements for the temporary works scheme the permit to dismantle can also be issued through the CDE to trigger the removal of the materials on site.
Although the DPoW is usually applied to just the permanent works of a project, there is no reason why there couldn’t be a Digital Plan of Temporary Works. Applying this eight-stage plan with defined data requirements ensures that all the participants understand the status of the temporary works information on a project. While some schemes may move through several of these stages in a few hours, the transparency that is created by aligning the temporary works scheme against these eight DPoW stages provides confidence to all parties involved in a project. What’s more, the common terminology of the DPoW stages allows the rest of the team to understand how far the temporary works design had progressed by defining it in terms commonly understood.
Whilst BS5975 does not have the same eight stage plan, this article shows that the actual requirements of the temporary works standard can be aligned to the DPoW relatively easily. It is also possible to develop digital processes in accordance with BS5975 that are not only aligned to the DPoW, but which can be replicated and easily implemented across the wide range of temporary works solutions required on any project.