Vlad Clima - Module 9 - Part 1

Journal Entry For
Module 9 - Make Your Pitch
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Vlad Clima

Reinforced Concrete Optimization

Intended users

Structural Engineers, Architects

Need you’re trying to provide a solution or support for

This script is intended to be used for early decision-making regarding beam sizes in a reinforced concrete building. Typically, a designer would approximate the span and spacing of columns in a building, followed by approximate dimensions of the rectangular beam. This leads to several iterations of work as these decisions heavily influence the resisted loads, weight, clearance, area of reinforcing steel, and amount of embodied carbon. The tool allows for a better optimization of this process.

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Inputs

For the purpose of this script, the spacing of columns will be equal and will depend on the input u and v divisions. This script will focus on the typical joists only (no girders/columns - FUTURE WORK). For simplification this will be a two-story building but can be easily modified if necessary.

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  • Building Length (y-direction) – variable
  • Building Width (x-direction) – variable
  • Column Spacing (x-direction) – by v_divisions
  • Column Spacing (y-direction) – by u_divisions
  • Floor-to-Floor Height – variable
  • Column Size – constant
  • Girder Size - constant
  • Beam Dimensions – variable
  • Number of joists/beams in a bay - variable
  • Minimum bar size for negative moment regions - constant
  • Material Properties – constant (e.g., concrete strength, rebar yield)

Underlying logic of the model you’ll implement

All calculations will be performed for one interior beam (all have equal loadings and require more reinforcement than exterior joists) - critical case.

  • Generate a one-story building based on the input length and width.
  • Generate columns based on a constant dimension with calculated spacings in y and input dimensions for x.
  • Use ACI 318 coefficients to determine the moment demands at critical locations (at column and mid-span) based on constant loadings. The Live loads are based of ASCE 7 while the dead loads depend on the self-weight of the structure (assumed slab thickness and input beam dimensions).
  • Calculate required steel reinforcement area for each of the locations.
  • Select a bar size and the number of bars based on:
    • minimum 2 bars
    • minimum and maximum spacing between bars
    • capacity>demand
  • Calculate the efficiency of the beam, cost, embodied carbon, weight, and overhead space.
    • For optimization:
      • Minimize cost
      • Minimize embodied carbon
      • Minimize weight
      • Maximize beam efficiency (demand/capacity - closer to 1 ⇒ more efficient)

Outputs

  • Revit model showing the structure
  • Table of weight, cost, efficiency, embodied carbon, overhead space