BIM clash detection with 3D coordination techniques, foresees clashes at the initial stage of the project to help improve interdisciplinary collaboration, reduce delays, material waste and costly construction rework.
Rework and material waste contributes up to 7.25% to 35% of total project cost and also increases construction time. BIM clash detection tools like Navisworks, identify, inspect and report clashes from federated 3D models that are created by integrating various disciplines into a common platform. Detecting and solving clashes at the initial stage minimizes cost, effort and time.
Clashes delay construction until stakeholders coordinate together to fix the issue. This irreversibly impacts project cost and schedule. Clashes occur due to:
Hitech created a coordinated 3D MEP model with clash free plant room layout for European BIM consultants, enabling them to save costs and make informed decisions about issues to be resolved.
Using clash detection software like Navisworks, can facilitate 3D coordination between disciplines and generate clash reports by identifying and addressing areas of conflicts. Clashes identified prior to installation can be reviewed, approved and resolved before they move to the final construction stage.
Hard Clash comprises of two components sharing the same place such as a duct running through a plumbing line or pipework through a steel beam. Hard clash detection can be detected based on geometry or semantic and rule-based algorithms on the BIM object with embedded information.
For geometry based detection, tools like Navisworks identify clashes like a beam running through a pipe whereas the rule based clash detection on embedded object data eliminates the common mistakes likes pipe running through a wall or MEP against ceiling.
Clash-free MEP 3D model reduces costs; meets deadlines
A General Contracting Company in Muscat, faced challenges of rework on the new terminal building of an important international airport due to many clashes in the drawings that covered a large area of 350,000 mt. Hitech created REVIT model and coordinated with MEPF 3D BIM model in Navisworks, detected clashes with proper QC channel. The company not only met the stipulated project deadline but also a significant cost saving was observed due to clash free coordinated BIM model.
When an element is not given the spatial or geometric tolerance, it requires or its buffer zone is breached, it results in Soft Clash.
Spatial tolerance requirements are common in MEP services to facilitate maintenance at later stage. For e.g. an air conditioning unit may require buffer space from a beam for safe and easy maintenance access.
Soft clashes if left unattended can cause maintenance problems and safety issues. For instance, if a live wire passes by a plumbing line, there is always a risk of having issues of circuit completion or short-circuit.
Providing sufficient object related tolerance data to software like Navisworks can identify clashes as per applicable regulations and standards. This would especially apply to high occupancy places like malls, airports and healthcare facilities to ease operational maintenance.
Clash detection in BIM is extremely crucial and valuable. As per association of Construction and Development, it is estimated that, industry-wide, each identified clash saves about $17,000 on a project. On large projects, 2000-3000 clashes are usual. That is $34,000,000!
Workflow or 4D Clashes involve clashes of contractor scheduling, equipment and material delivery and general workflow timeline conflicts. Unlike hard and soft clashes, 4D clashes result from scheduling clashes of inter-disciplinary activities that eventually lower the efficiency of the entire construction firm. Since one clash has a cascading effect on several disciplines and can bring work to a standstill, contractors cannot afford 4D clashes; opting for BIM.
Developing a 4D construction sequencing timeline in Navisworks points out the start and end date of each activity and helps the contractor schedule the activities accordingly. A systematic step-by-step phasing in 4D BIM eliminates the possibility of encountering any workflow clash and avoids site downtimes to keep up the man-efficiency of the task force.
Various disciplines like structural and MEP engineers use the architect’s model as a starting point to produce their own independent model, to avoid clashes during Design Development Phase.
Clash detection on 3D coordinated models have the following benefits:
The models and data created by various disciplines can be integrated into a master model or in common data environment for better collaboration.
Using clash detection components in 3D modeling software ensures an error-less, consistent and technical perfect design, which can lead to an effective, profitable and reputable construction process, which is of great value to all stakeholders including owners, engineers, architects and contractors.
Keyuri Patel is an American Institute of Architecture associate, a LEED Green Associate and a Masters in Architecture from San Francisco, Keyuri Patel carries wide ranging experience in urban design, architecture and BIM projects. Her insightful industry coverage on building design and construction processes builds on her passion for technology and digitalization.
Harika Singh is an academician and published writer. Her passion for engineering and technology reflects in the in-depth coverage she provides on technology trends. 20 years of work association with institutes of repute across India and the US positions her to provide valuable insights to business stakeholders on achieving scalability and operational efficiencies through digitalization.
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Sep 6th, 2022 