A structural design and representation library. Documentation can be viewed here.

Overview

limitstates is a python library that can represent and design structural elements according to code and material standards from various countries. Limit states has two main components: a set of classes that representations structural objects, e.g. A Ibeam that is 6m long made or steel; and design libraries that can act on elements and determine capacities, e.g. Canada's CSA s16 2024 steel material standard. Limitstates is currently incomplete and in public beta testing. Expect breaking changes before the first version release.

A simple script is shown below where a structural object is created and used.

import limitstates as ls
import limitstates.design.csa.s16.c24 as s16

L = 6
Fy = 350
sectionName = 'W310X118'

# Define the material, in this case a code specific steel with Fy = 350 MPa
mat = s16.MaterialSteelCsa24(Fy, sUnit='MPa')

# Define a steel section from a database, in this case a cisc 12 w section.
steelSections   = ls.getSteelSections(mat, 'csa', 'cisc_12', 'w')
section         = ls.getByName(steelSections, sectionName)

# make a member, in this case a simplely supported beam 6m long beam.
member = ls.initSimplySupportedMember(L, 'm')

# Make a element, which the design library can act on.
beam = s16.BeamColumnSteelCsa24(member, section)

# Check capacity assuming it's laterally supported using CSA's s16 standard.
Mr = s16.checkBeamMrSupported(beam) / 1000

# Make a Plot of the Section.
fig, ax = ls.plotElementSection(beam)

Installation

pip install limitstates

Documentation

https://limitstates.readthedocs.io/en/latest/

Library Organization

There are four main parts of the limitstates library: units, objects, design, analysis.

The units library is a light-weight module for unit conversions. All structural objects in the limitstates libary are dependant on the unit library for conversions. See units api reference for more detail.

The objects library contains generic classes that represent and manipulate structural elements. Members of the object library are not specific to any code, for example a W530x150 cross section has the same geometry for American and Canadian codes. See the objects api reference for more detail.

The design library contains specialized objects for a particular design code, and functions that act on them. For example, "BeamColumnSteelCsa24" is a code specific implementations of the generic "BeamColumn" class, and the function "checkBeamMrSupported", acts on it to determine a sections unsupported moment. Design libraries are divided by country and material standard. Currently, content only exists for Canadian design codes. See design api reference for more detail.

The Analysis library will contain functions that act on structural objects to analyze them. The analysis Library is a work in progress.

Development Roadmap

Version one of limitstates will release when the library can design most major elements in canadian design codes, and the core objects can handle American/EU design codes. The specific items required for version 1 are below:

Object Library

• Create a section element for reinforced concrete
• Improve section and material database documentation
• Support plotting for concrete elements / sections
• Support plotting for CLT elements / sections
• Add section summary to section plotting
• Add an generic design example showing how database can be used.

Design

CSA o86

• Add Examples.
• Add beam shear checks.

CSA S16

• Develop multi-span beam checks.
• Add beam shear checks.

CSA A23.3

• Complete code checks for basic concrete beams in moment/shear.
• Add section solvers for concrete that can determine steel required based on input capacities.
• Complete code checks for basic concrete columns in compression / bending.
• Complete code checks for basic concrete columns in compression / bending with slenderness effects.
• Add examples for basic concrete checks
• Add examples for concrete in compression

US/EU Standards

• Ensure all basic design objects are compatible with US codes and units.