In the eighth of our regular series of CPD modules, we look at Building Information Modelling throughout the construction process. This module is sponsored by Excitech
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With the recent growth of Building Information Modelling (BIM) across the design disciplines in both the building and infrastructure segments of the construction industry, a vast majority of contractors and construction management specialists are beginning to adopt these processes in order to realise the commercial benefits on offer.
Although the strategy to phase in the requirement for BIM on all public projects between 2012 and 2016 (outlined in the government’s report from May 2011) has undoubtedly had a catalysing effect in mobilising previously inert sections of the industry, many more are being driven to find better ways of working by the harsh realities of the current economic climate.
With contractors being repeatedly identified as being instrumental in taking BIM to levels 2 and 3 (as defined in Appendix 3 - BIM Maturity Levels of the Strategy Paper for the Government Construction Client Group from the BIM industry working group - March 2011), it is key that these benefits are realised across a number of key areas at each stage of the construction process. It can help the contracting organisation to drive these efficiencies through the supply chain, while decreasing overall construction cost and timescales; and ultimately improve the value being delivered to the industry’s clients.
Some of the key advantages of the BIM process for construction firms are as follows:
The benefits of BIM can be derived across the four main stages of the typical construction process, namely:
The ability to more rapidly produce compelling visualisations of the scheme, along with the ability to facilitate rapid cost analysis and present a shorter programme - which is likely to offer a significant edge during the bid process.
Automated estimation of the model at this stage provides rapid clarification of costs, while use of the model for planning can drastically improve the construction sequence, safety and sustainability of construction methods.
During the delivery phases, the use of integrated model data to facilitate a more thorough design review process will ensure that construction issues, such as clashing elements from different disciplines, are largely eradicated as an unforeseen additional cost.
The BIM process provides the opportunity to add accurate specification and validated as-built information to the model for handover - and subsequent maintenance - to the client organisation.
Although there will be subtle variations in how the principles of the BIM process can be applied during each of these stages, based on both experience of the organisation and the requirements of the project, there are common applications that are described in the sections that follow.
Some of the most immediate and obvious advantages of the BIM process should be realised during the initial bid stage, where costs need to be limited due to the speculative nature of this endeavour, yet the quality of communication is critical in highlighting the strength of the design response.
The benefits come from the ability to not only obtain cost estimates in a fraction of the time, but also produce these more rapidly by harnessing automated material takeoffs from the model. Additionally, these models facilitate rapid design visualisation for both the simulation of the construction sequence and for high-quality photo-realistic presentation graphics.
As the cost submitted as part of any bid will have such a major influence on the outcome, the benefits of using BIM are significant. The ability to collate the initial design models from the consultants will facilitate rapid quantification to reduce the time required by the estimators and reduce the risk of errors associated with the manual take-off process. Further cost savings can be realised through the early use of BIM-enabled planning solutions to compare alternative construction sequences and optimise the programme and reduce the level of waste.
The typical selection process relies heavily on the impact of visual communication and this can have a profound effect on those tasked with choosing the successful delivery team. Although traditionally perceived as a costly luxury, the use of BIM enables any organisation to produce quality visualisation for simulated construction through to fully immersive presentation-quality images and animations.
Prior to the start of construction activities on site, the design team should develop a more detailed and complete series of models that can be used to facilitate the planning and optimisation of the delivery schedule. This provides opportunities to accurately assess costs and further reduce the overall risk by providing a greater degree of certainty in key areas of the delivery process such as cost, schedule and co-ordination.
Construction planners have a critical role in ensuring that a project runs to time and budget. Using the design models, planners and schedulers should simulate the build process from start to finish. This not only helps identify any potential issues early enough to mitigate risks, it also allows for rapid evaluation of different sequencing options to help ensure that the best solution is used with respect to programme, resources, procurement and safety.
Using a more developed version of the model - along with the same solutions that were used to provide the accurate early cost estimates - construction cost planners should be able to drive efficiency into both the construction process and the selection of suppliers. With this more accurate model, it is possible to ensure that quantities are accurate enough to facilitate a more efficient ordering process. This in turn helps reduce the traditional waste associated with having too much material or the requirement for excessive on-site storage.
A lack of co-ordination is frequently cited as one of the main causes of cost and time overruns on projects. With a complete description of the building’s key elements in each of the primary disciplines’ design models, full co-ordination management should be achieved to aid a smooth, “clash-free” construction process. The available tools facilitate this from the development of the initial design models all the way through to the final co-ordination check before on-site activities proceed. The improved review and co-ordination abilities should be continued through the execution stage to ensure late design changes are incorporated with minimal impact and that opportunities for further process optimisation are not missed.
Although the foundations for a successful delivery will have been laid in the preceding stages, there is still much to gain during the on-site construction process by extending the application of the BIM philosophy. There is also scope to drive the automation of the construction - while also introducing higher levels of quality control and safety - through the method of digital pre-fabrication. This can enable large portions of the construction to be modularised off-site and then assembled with greater certainty for a faster and more predictable programme.
Building upon many of the techniques already deployed in winning and planning the delivery, continual refinements and cost savings should be realised by utilising the BIM data to aid communication with on-site operatives and to verify initial cost and scheduling on each work package in relation to current progress.
By adapting and extending the use of the BIM data beyond the design phase, construction professionals should harness the availability of accurate models that represent exactly what is to be assembled on-site. Repeatable architectural elements, such as room pods or specialist features, can be assembled in both the context of the designer’s BIM model or a manufacturing specific solution that would facilitate production through automation of parts and assembly instructions, or machining. Structural frames should be developed to include the steel connections and details of the concrete reinforcement. Building services design layouts should be swapped for fully accurate layouts using manufacturer components that the installation contractor can reference directly or that a pipe/duct fabricator could use to manufacture the required items.
By harnessing the ability to access BIM on-site through mobile tablet devices, field operatives can gain instant access to the latest information from the digital model and the latest documentation. BIM data can also be used for progress monitoring against the original construction schedule or obtaining up-to-date material lists. Other routine activities such as snagging, safety and quality reporting can all be facilitated more effectively by integrating this data digitally with the BIM database.
BIM provides numerous benefits to all parties, at all stages in the construction process. Your initial implementation of BIM should, after a short period and with good management, be seen to be delivering benefits, but as this article shows, the potential application areas are wider than many assume. As the recognised boundaries of BIM are pushed ever closer towards a full integration between design, construction and operations, each participant should be looking to extend their contribution beyond design to support the BIM approach through each stage of the process and to further the collaborative objects of the delivery team as a single cohesive entity.
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MODULE DEADLINE: 3 FEBRUARY 2012
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