Three types of clashes that can occur in the construction process:

In the construction process which requires collaboration between various disciplines namely architecture, structure and MEP there will be some clashes. It may be an air-conditioning duct running through a load-bearing wall, the lack of clearance around an important component or even a work scheduling conflict. When detected on site this would all result construction being halted and the overall schedule being impacted. The resultant effect on cost and time could be drastic and irreversible.

During the building process the breath of information that any project member must account for is substantial and very much vulnerable to human error. It is however, with BIM that information rich 3D models can be created prior to construction process. Virtual construction process allows to run Clash Detection, identifying any clashes and addressing potential conflicts in the pre-construction stage itself. Below we look at the three types of clash in BIM and also state their importance.

1. Hard Clash:

Hard Clash is a type of conflict which involves geometrical issues. A hard clash occurs when two objects pass through each other or are taking up the same place. It could be intra discipline clash like a duct colliding with a pipe or it could be an inter discipline clash like an air-conditioning duct running through a load-bearing wall. In Architectural BIM Services they can also be due to modeling errors like bad connection between the partition and the wall or placing the toilet too close to the door. A hard clash is easy to spot because of the logical arrangement of elements and their null dynamics.

There is also a rarer kind of hard clash which is concerned with duplicates. During the modelling phase the user might put two same objects in one common place. The modern modeling software will usually highlight the occurrence of the duplicate objects. Undetected this error might lead to significant inaccuracies in the bill of materials. Hard clashes are detected by applying geometrical, semantic and rule-based algorithms on the BIM object with embedded information.

2. Soft Clash:

Soft clashes are defined by clearances and it occurs when any object either encroaches into geometric tolerances set for other objects. Any building object has spatial or geometrical tolerance when that buffer zone is breached a soft clash is detected. For example: insufficient beam or lintel positioning or not providing sufficient headspace in a room etc. MEP components like air conditioning units, heaters, etc. commonly require buffer space for safe and easy maintenance access. It is imperative to catch soft clashes from a safety point of view. Navisworks identifies soft clash as per applicable regulations and standards.

3. Work-Flow Clash:

Work-flow clash or 4D clash involves clashes related to contractor scheduling, equipment and material delivery and general workflow timeline conflicts. Even though these problems are not directly connected with design but they can significantly affect the ongoing work timeline. A workflow clash not only disturbs the project efficiency but also can have a domino effect. Even one major undetected workflow clash can ultimately bring the whole project to a standstill. Navisworks allows to develop a 4D construction sequencing timeline which points out the start and end date of each activity and thus helps to schedule each activity. 4D BIM simulation brings scheduling conflicts between multiple disciplines and trades as well as macro-level construction phasing strategies to the forefront and streamlines the whole construction process.

Conclusion:

Using BIM Coordination Services is the easiest way to detect clashes. Today by using clash detection software, like Revit and Navisworks project managers can easily detect clashes and generate clash reports. A well-coordinated BIM model goes a long way in providing an avenue for collaboration between all the stakeholders involved in the project. It enables them to resolve issues early on making the project design precise and accurate.