Workflow is of great importance in managing road and railway infrastructure design in BIM.

Efficient workflow and efficient coordination activities improve design quality, contain design and modeling costs, and reduce errors during construction.

Work in BIM

Maximum efficiency is achieved by integrating design, geometric-informative modeling, information exchange and analysis and verification activities in a single activity. The use of software tools that integrate these different activities in a single platform is the main tool for obtaining an efficient workflow.

The main work

In the design of the workflow the first and most important element that must be considered is which is the main work and which are the ancillary works. The main work defines the choice of software that manages it both in design and in management and which must be able to manage models of ancillary works. The main work determines whether we are in horizontal or vertical BIM.

Horizontal BIM and Vertical BIM

Horizontal BIM (Infrastructure) is very different from Vertical BIM (Buildings) and requires very different workflows and tools. Among the most important differences between the two types of BIM we find:

INFRASTRUCTURES / HORIZONTAL BIM	BUILDINGS / VERTICAL BIM
Design using axes, profiles and cross sections	Design using objects and parametric elements
Model based on parametric extrusions and little on objects	Model based mainly on objects (object libraries)
Use of the terrain as a fundamental element for design	Use of terrain as a marginal element in design
Large extension of the model	Medium-small extension of the model
Interchange formats specific to infrastructures	Interchange formats specific to buildings

Interchange formats

The exchange of information for infrastructures requires the transfer of specific information of the infrastructures world. The formats that can be used are:

• IFC
• LandXML

Workflows

Two workflows are most commonly used:

• Modeling-based BIM workflow

  Workflow widely used in pilot projects.
  Design and modeling are separate and architectural or neutral software is used for modeling.
  It is a workflow with many criticalities that can only be used in the 'Pilot Project' phase as it involves the re-entry of information and the creation of the information model on a non-infrastructural software.

  PROS

  • The architectural and infrastructure modeling software is the same.

  CONS

  • Possible inconsistency between information documents produced by the infrastructure design software and the models produced by the information geometric modeling software
  • Cumbersome and expensive flow in terms of resources and time
• Design-based BIM Workflow

  Optimised flow for design activities in BIM.
  Workflow where modeling occurs concurrently with design. Infrastructure design software simultaneously performs information geometric modeling.

  PROS

  • Information documents consistent with geometric information models.
  • Optimized workflow with BIM related cost containment.

  CONS

  • Requires infrastructure design software with included geometric information modeler

Take part in the SierraSoft Workshops on BIM Workflow

SierraSoft periodically organizes free online workshops entitled “Work in BIM: Design, workflow and coordination for road infrastructures”. The workshops are constantly being reviewed to provide the state of the art on the subject. For more information about these workshops send an email to info@sierrasoft.com.