Lean Construction with BIM Level 2 and Beyond - Tools for reduced waste


Architecture, engineering and construction (AEC) industry has seen the fall of its productivity and work efficiency over last 50-60 years. Key statistics on the official website of UKGBC quotes “About 400 million tons of construction material is delivered to the construction site each year, out of which almost 60 million goes straight to waste due to inappropriate ordering or damage.” To general contractors and construction engineers, this is not only a concern of materials wastage but also their planning and time management. It consumes additional time to plan the schedule and timings with new ordering.
 
So how can general contractors and construction engineers get out of this vicious circle of planning and re-planning? Obviously, trying and implementing a method that has already been proven to be a success elsewhere, such as practicing principles of lean manufacturing for building construction projects. 

Attaining Coordination & Eliminating Redundancy

With implementation of BIM Level 2, lean practices come invariably. BIM implementation for construction project will eliminate most of the redundant tasks causing waste of time and planning. However, the current situation of annual waste statistics for the UK, as mentioned above, indicates that this isn’t the case. 

For any building element, the ways of looking, perceiving and designing is different for various discipline and hence the design will have as many versions as the disciplines. Say for example, for an architect the building wall is about the outer look and finishing; for a structural engineer it deals with the steel and concrete material for strength; and, for a facility manager it is to see the maintenance to have it sustained the way it was built originally. Thus, one building element has several ways of perception and as many drawings in several different software.

With design coordination on a common platform, as offered in BIM Level 2; differences in designs are viewed from a holistic approach. BIM solutions would integrate various steps of design detailing and coordinating construction processes. 

BIM solutions for building construction projects focus on creating a 3D model, incorporating details from all disciplines; architectural, structural and MEP. It helps with a collaborative approach for quantity takeoffs to avoid any mistakes in planning. Designs for fabrication, from such BIM-ready 3D models essentially, integrate cost and scheduling data. It eliminates repetitive tasks of evaluation and empowers site managers to manage construction activities efficiently. 

Well organized schedule is must for Lean Approach

Most of the waste results from rework that takes place, due to improper alignment of activities, on any building construction site. The solution to eliminate waste lies in implementing BIM enabled construction sequencing with lean construction principles. It allows creating and maintaining work orders across construction phases and also during later stages of facility management.

Simulating construction process in a digital environment empowers general contractors to maintain and control supply chain by accurately planning the logistics. The knowledge of exact location and expected time of delivery of pre-fabricated building elements gives these contractors a sense of better judgement of delivering the ordered quantity at correct construction site location. Efficient and safe operations can be guaranteed by eliminating unnecessary delays due to idle time or reworks during the entire project.

To justify this, reduction of 30-35% in budget was observed resulting from reduced waste and reworks by using BIM with LOD 300 during the construction of a hospital in Egypt. Instead of going the traditional way, the construction firm decided to move ahead with BIM and the engineers at design support firm developed architectural, structural and MEP plans and developed a BIM ready model for the hospital. Information pertaining to construction from such intelligent BIM 3D model resulted in achieving proper coordination of activities.  

Adopting Efficient Construction & Installation Process

When building elements are assembled, key aspect to be considered by site engineers is about logistics and installation process. The comprehensive understanding is necessary in order to optimize the methods with minimum rework and follow lean construction approach. Transportation, shipping weight and their charges; formworks, etc. are some of the many key factors deciding construction processes. Say for instance, offsite prefabrication of building elements has proved to be efficient in terms of productivity and costs. 

Ideally, MEP connections as part of BIM process, in the designed layout are the most difficult to manage and install on site. But prefabrication of partially completed MEP panels can aid well and manage installation easily. It is because of weight difference in partially and fully fabricated panels; and the panels serve as formwork on their own. Near site fabrication and a final on site installation can eliminate the issues related to space, transportation, and risk to damage during transportation, etc.; thereby reducing the waste. 

Conclusion

Today, most of the leading construction firms have adopted BIM as several governments have mandated BIM, and Netherlands is following the footsteps.  What needs to be done is implementing the idea to focus more on the construction process leading to fine & efficient facilities. Adapting the principles of lean manufacturing to construction alongside BIM can create wonders in reducing the waste currently produced in the industry.  

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