Usage¶

Installation¶

To use PondPy, first install it using pip:

pip install pondpy

Example Implementation¶

The PondPyModel class is designed to work with several purpose-built classes that help the user organize their input into a form that are readily utilized to build and analyze the model. These are the PrimaryFraming, SecondaryFraming, and Loading classes. In addition, the package is designed to work with the steelpy and joistpy packages, though any object containing the requiring information attribures (i.e. moment of inertia, cross-sectional area, elastic modulus, etc.) could be used in lieu of either package.

To create and analyze a roof bay model, first import the required dependencies and classes:

from joistpy import sji
from steelpy import aisc

from pondpy.analysis.fem_analysis import (
    SteelBeamSize,
    SteelJoistSize,
)

from pondpy.analysis.pond_analysis import (
    PrimaryMember,
    PrimaryFraming,
    SecondaryMember,
    SecondaryFraming,
    Loading
)

from pondpy.pondpy import PondPyModel

Next, define the steel shapes and joist designations in your model.

w12x16 = SteelBeamSize('W12X16', aisc.W_shapes.W12X16)
w16x26 = SteelBeamSize('W16X26', aisc.W_shapes.W16X26)
k_14k1 = SteelJoistSize('14K1', sji.K_Series.K_14K1)

Next, define the primary and secondary framing in the roof bay framing system. Note that all inputs should be in kips and inches.

p_length = 20*12 # length of primary members in inches
s_length = 20*12 # length of secondary members in inches

# Support types are designated by tuples representing (Tx, Ty, Rz).
# A 0 indicates the degree of freedom is unrestrained while a 1 indicates a
# restrained degree of freedom.
p_support = [[0, (1, 1, 0)], [p_length, (1, 1, 0)]]
s_support = [[0, (1, 1, 0)], [s_length, (1, 1, 0)]]

p_girder1 = PrimaryMember(p_length, w16x26, p_support)
p_girder2 = PrimaryMember(p_length, w16x26, p_support)
s_beam1 = SecondaryMember(s_length, w12x16, s_support)
s_beam2 = SecondaryMember(s_length, w12x16, s_support)
s_joist1 = SecondaryMember(s_length, k_14k1, s_support)
s_joist2 = SecondaryMember(s_length, k_14k1, s_support)
s_joist3 = SecondaryMember(s_length, k_14k1, s_support)

p_framing = PrimaryFraming([p_girder1, p_girder2])
s_framing = SecondaryFraming([s_beam1, s_joist1, s_joist2, s_joist3, s_beam2])

Note that each member should be individually defined as shown above. Otherwise, the loadings will not be applied correctly to the members.

The roof slope can optionally be set in the SecondaryFraming object by using the keyword slope and entering the roof slope in inches/foot. The default value is 0.25.

Next, define the loading in the roof bay.

p_framing = PrimaryFraming([p_girder1, p_girder2])
s_framing = SecondaryFraming([s_beam1, s_joist1, s_joist2, s_joist3, s_beam2])

q_dl = 20/1000/144 # Surface dead load in ksi
q_rl = 22.4/1000/144 # Surface rain load at secondary drainage inlet in ksi

loading = Loading(q_dl, q_rl)

The input rain load should include the static head and the hydraulic head, but no ponding head.

Finally, define the PondPyModel object and analyze the model.

pondpy_model = PondPyModel(p_framing, s_framing, loading)

pondpy_model.perform_analysis()

Optional arguments for the PondPyModel include:

mirrored_left: bool indicating whether the roof bay is mirrored on the left side; default is False
mirrored_right : bool indicating whether the roof bay is mirrored on the right side; default is False
stop_criterion : float indicating the error in total impounded water weight at which the iterative analysis should be terminated; default is 0.0001
max_iter : int indicating the maximum number of iterations that should be performed; default is 50
show_results : bool indicating whether the iteration results should be printed to the terminal upon completion of the analysis; default is True

Analysis Results¶

Each primary and secondary member is represented within the PondPyModel object by a BeamModel object. As such a great deal of analysis results can be obtained fairly easily once the analysis is complete.

To access the deflected shape, shear force diagram, or bending moment diagram of a particular member, use the following calls:
```
member = pondpy_model.roof_bay_model.secondary_members[0]
bmd = member.plot_bmd()
bmd.show()
```
The shear force diagram and deflected shape can be accessed in a similar fashion.

The support reactions can be obtained as follows:

support_nodes = member.support_nodes
support_reactions = [member.support_reactions[node] for node in support_nodes]

Several other attributes of the BeamModel object can be accessed in a similar fashion.

Note that only the final analysis results can currently be accessed.