Table of Content for Building Information Modeling-
- Uses of Building Information Modeling
- Why implement BIM?
- Dimensions of Building Information Modeling
- General Workflow of Building Information Modeling
- Platforms for Building Information Modeling.
The requirements of the modern world are increasing day by day thus creating a challenge for engineers to keep creating more optimized and efficient designs with no compromise to the quality. The constraint of space and finance adds more to the complexity of the design.
With the said challenges, it becomes difficult to visualize all the aspects in one go which leads to the redesign and rework. The revisions in design at the last moment or the rework cause a loss of capital and time thus increasing the overall cost of the project. Building Information Modelling is such a 3D model-based process that mitigates the above-said problems at the design phase itself.
The work scope and the client requirement defines the aspects to be considered in Building Information Modeling. These aspects can be civil construction, PEB, HVAC, fire-fighting system, mechanical fabrication, operation, and maintenance, etc. with the desired level of detailing and complexity.
ISO 19650:2019 defines Building Information Modeling as-
“Use of a shared digital representation of a built asset to facilitate design, construction and operation processes to form a reliable basis for decisions”
The term Building Information Modeling implies following-
Building- Residential, Commercial, Industrial, Infrastructure.
Information- Spatial (coordinates, dimensions etc.), Quantity, Schedule, Elements (Footings, Beam etc.)
Modelling- Site, Architecture, Structural, MEP, Sustainability.
Why implement BuiIding Information Modeling?
- BIM can get an accurate representation of the project.
- To reduce the construction cost by optimizing the design and construction materials.
- It increases collaboration among stakeholders.
- To simulate the working conditions.
- It controls the cost of the project.
- To track the work progress.
- Clash detection and their mitigation at the design phase.
- To reduce rework.
- It reduces documentation errors.
- To reduce claims/litigation
Fundamentals of Building Information Modeling-
- Level of Development
Levels of Building Information Modeling-
The levels of BIM are also called Maturity Levels. These Levels indicate collaboration among the stakeholders during the process of BIM. The respective levels have a well-defined information-sharing mode across different platforms. Maturity levels are defined below, ranging from zero to three-
Level 0 operates on the 2D CAD drafting by pen-paper or electronic print. It is an obsolete level and is only used for very small-scale projects.
Level 1 may involve 2D or 3D drafting. Data sharing happens electronically. Low or no collaboration between stakeholders.
Level 2 promotes collaboration between stakeholders by sharing the 3D CAD model. It requires a seamless sharing of information between stakeholders through a common file format. IFC (Industry Foundation Class) and CoBie file formats are used for information exchange across the platforms. The industry is using Level 2 at present.
The scope of Level 3 hasn’t been defined yet and is still under research. However, it is said it promotes deeper collaboration among stakeholders with a model stored in a central repository which allows all the stakeholders to work on the model simultaneously. Open Data Standards and a new framework for data sharing are being developed.
Level of Development (LOD)-
The level of Development (LOD) defines the precision of a BIM model. The purpose of the model and quantum of details to be put into the model are defined by it. The cost of implementing BIM relies heavily on LOD. The higher the LOD, the higher is the cost of BIM implementation. The LODs range from LOD-100 to LOD-500. With an increase in LOD value, the precision of BIM increases.
The LOD-100 model may be created by generic representation. Only conceptual model is created in this LOD and the dimensional parameters (length, area, volume, location, orientation etc.) along with information from model are approximate.
This level has elements of the model represented by the generic symbols. Non-graphic information can be attached to the model. The dimensional parameters and any information derived from the model are approximate.
The model elements are graphically represented with exactly defined details like dimensions, spatial information, orientation. Non graphic information can also be attached with the elements. At present, Indian infrastructure industry is using this LOD. The clash detection can be performed in this LOD.
The LOD-350 is similar to LOD-300 except the fact that it has additional details of supports and connections are provided. Thus, it can be said that LOD-350 has element details and its interface with other elements.
LOD-400 has element details along with mechanical fabrication, assembly and installation information. Non-graphic information can be added to the elements.
LOD-500 model represents the actual details of elements, their assembly and installation. This model is based on the field verified information. Non graphic information can be attached to elements. This LOD is used for operation and maintenance. It is very seldom used in the industry.
Dimensions of Building Information Modeling
The Dimensions of BIM represent the quantum of information that has been incorporated into the model. Dimensions can also be called the purpose of BIM. The model can have information related to 3D model, schedule, cost and sustainability. The BIM generally has seven dimensions. However, up to twelve dimensions have been defined by researchers.
Model represented by a point. Used for existing conditions, regulations, weather simulation etc.
Model represented by lines in x-y plane. Used for 2D views, plans etc.
3D- Modelling & Information
Model represented in x-y-z plane. Used in BIM element creation.
4D- Duration & Scheduling
When BIM 3D model is integrated with time schedule, the BIM is said to have 4 dimensions. Hence, critical activities along with critical path can be identified. Activities to be crashed can also be identified. WBS can be easily realised in 4D BIM.
When the cost factor is integrated into model it gives birth to fifth dimension in BIM. The capital expenditure, change in cost, cost tracking, budget allotment can be identified with this model.
6D- Facility Management
The sixth dimension of BIM includes the operation & maintenance part. It tracks asset data such as status, operation/maintenance manuals, warranty information, technical specifications, etc. It helps in improving the services provided by the project.
The seventh dimension in BIM corresponds to the sustainability of the project. It helps in assessing the impact of the project on it’s surrounding during the project life. Thus, it is also called project life cycle information. 6D model helps in facility management, estimating electricity consumption, schedule maintenance, optimum configuration, expected lifespan.
The eight dimension of BIM takes safety into consideration. It helps is defining the accident-prone spots of the project, evacuation plan etc.
General Workflow of Building Information Modeling
The BIM process has been standardised by the authorities of the respective countries. However, no framework has been prescribed in India for the same.
Employer’s Information Requirements (EIR)
It is a pre-tender document setting out the information to be delivered, and the standards & processes to be adopted by the supplier as a part of the project delivery process. It is prepared in accordance with UK PAS 1192-2:2013 & ISO 19650.
BIM Execution Plan (BPU)
To explain how the information modelling aspects of a project will be carried out, BPU is prepared. The BEP Guide can be obtained from http://bim.psu.edu/
Building Information Modeling Platforms
Since Building Information Modelling is a process thus it needs various software for different operations. For example, 3D modeling can be done using Revit or Navisworks, time schedule can be linked by MS Project or Primavera, and the cost incurred and other aspects can be linked to model by Synchro or Vico.
The comparison of Navisworks, Synchro and Vico is as follows-
Get BIM software here-
Get Synchro https://www.synchroltd.com/
Get Navisworks https://www.autodesk.com/products/navisworks/overview