Abhishek Vijayan - Module 9 - Part 1

Journal Entry For
Module 9 - Make Your Pitch
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Abhishek Vijayan

Precast Bridge Girder Configurator

A Dynamo + Revit Tool for Rapid Bridge Girder Design and Visualization

Intended Users

  • Bridge and structural engineers (consultants, agencies)
  • Civil engineering students
  • Contractors and precast suppliers interested in early-stage design or bid preparation

Need You’re Trying to Provide a Solution or Support For

Bridge girder selection and preliminary design is an iterative, time-consuming process that must balance structural performance, code compliance, constructability, and transport constraints. Traditional methods often require manual calculations and repeated modeling to evaluate different girder types, spans, and configurations. There is a need for a parametric tool that enables engineers to rapidly configure, visualize, and assess multiple precast girder options directly within a BIM workflow, leading to more efficient, optimized, and constructible bridge solutions.

Inputs

  • Span length (m)
  • Bridge width (m)
  • Girder spacing (center-to-center)
  • Deck thickness
  • Column heiht
  • column radius
  • Girder Deoth assumed to be 1.5m and girder width 0.4m for this project whiach are fixed inputs

Underlying Logic of the Model You’ll Implement

  • Parametric Geometry Generation:

    • Dynamo scripts generate all bridge components (deck, precast girders, and columns) as true 3D solids based on user inputs, ensuring real-time updating and geometric consistency.

  • Preliminary Structural Checks:

      • Performs simplified, code-based checks:

    1. Flexural capacity (Mn vs Mu, using user’s f<sub>ck</sub> and span/load assumptions)
    2. Span-to-depth ratio (flags designs outside code recommendations, e.g., 18–25)
    3. Shear capacity and/or estimated deflection (optional, further enhancement)
    4. Outputs clear “OK” or “Exceeds code” warnings
  • Constructability & Transport Feasibility:

    • Calculates total girder length and weight per unit for realistic transport assessment, flagging options that may exceed practical or regulatory limits.

  • Sustainability Calculations:

    • Calculates total concrete volume, self-weight, and embodied carbon using an assigned emission factor (kg CO₂e/m³).

  • Instant Visualization:

    • Models are placed directly in Revit (via DirectShape), supporting plan, elevation, section, and 3D views for instant visual feedback and easy documentation.

  • Schedules and Takeoffs:

    • Outputs quantities and estimated material takeoff data for cost and environmental evaluation.

Outputs

  • Structural check summary for each girder configuration (flexure, span/depth, transportability; “OK” or warning for each)
  • Material quantities (volumes of girders, deck, columns)
  • Total self-weight and estimated dead load
  • Embodied carbon estimate for full bridge (kg CO₂e)
  • Visual 3D bridge model in Revit (including all main elements)
  • Exportable schedules for materials, weight, and carbon (for reporting or further analysis)
  • Automated warnings or guidance if any design or code limits are exceeded

This tool streamlines the early stages of precast bridge design, supports rapid iteration, and improves communication among project stakeholders by leveraging BIM and automation for more efficient and constructible bridge solutions.