simdesign.rcmrf.bdim.baselib.stairs

This module provides the base class for representing stairs in the BDIM layer.

class simdesign.rcmrf.bdim.baselib.stairs.StairsBase(rectangle, thickness=None)[source]

Bases: ABC

Abstract base class for stair slab elements.

It provides geometry definition, self-weight calculation, load transfer, and load assignment behaviour. It must be inherited by design-class- specific stair implementations.

Variables:

rectangle (Rectangle) – Geometric mesh representation of the stairs (tag, points, lines).
gamma_rc (float) – Unit weight of reinforced concrete [kN/m^3].
pg (float) – Total permanent load per unit area of stairs slab [kN/m^2]. Set via set_loads.
pq (float) – Variable (live) load per unit area of stairs slab [kN/m^2]. Set via set_loads.
roof (bool) – Whether the stairs slab is located at roof level.
_thickness (float) – Default stairs slab thickness [m], used as fallback when no thickness is provided at instantiation. Default is 0.15.

Parameters:

rectangle (Rectangle)
thickness (float)

Notes

Plan view of mesh objects (rectangle) representing stairs:

y
|__x
              l2(p2,p3)
 p2(x2,y2,z2) o------>o p3(x3,y3,z3)
              ^       ^
    l1(p1,p2) |       | l3(p4,p3)
              |       |
 p1(x1,y1,z1) o------>o p4(x4,y4,z4)
              l4(p1,p4)

pi is the i-th Point representing a corner point.

li is the i-th surrounding Line.

xi, yi, and zi are the coordinates of the i-th Point.

gamma_rc: float

pg: float

pq: float

roof: bool

rectangle: Rectangle

property t: float

Stairs slab thickness (depth).

Returns:: Stairs slab thickness (depth) [m].
Return type:: float

property lx: float

Stairs slab length along the global X-axis.

This corresponds to the length of rectangle.lines[1].

Returns:: Stairs slab length along the global X-axis [m].
Return type:: float

property ly: float

Stairs slab length along the global Y-axis.

This corresponds to the length of rectangle.lines[0].

Returns:: Stairs slab length along the global Y-axis [m].
Return type:: float

property area: float

Plan area of the stairs slab.

This corresponds to rectangle.area.

Returns:: Stairs slab area [m^2].
Return type:: float

property pself: float

Self-weight of the stairs slab per unit plan area.

Returns:: Self-weight per unit area [kN/m^2].
Return type:: float

property beam_influence_areas: float

Tributary area assigned to each of the two supporting beams.

Both beams run along the X-direction: one at mid-storey level and one at floor level. Each beam is assigned half the total slab area.

Returns:: Tributary area per supporting beam [m^2].
Return type:: float

set_loads(permanent_loads, variable_loads)[source]

Assign permanent and variable loads to the stairs slab.

Sets gamma_rc, pg (self-weight plus superimposed dead load), and pq (variable load) from the provided load objects.

Parameters:

permanent_loads (PermanentBase) – Permanent load data, including unit weight of reinforced concrete [kN/m^3] and superimposed staircase dead load.
variable_loads (VariableBase) – Variable load data, including staircase live load [kN/m^2].

Return type:

None