Shear Wall ========== The `ShearWall` class models a reinforced-concrete structural wall for **in-plane shear analysis and design** per ACI 318-19 Chapter 11. - Concrete shear capacity follows ACI 318-19 §11.5.4.6 with the aspect-ratio factor ``α_c``, instead of a longitudinal-reinforcement term. - Reinforcement is **distributed mesh** in two orthogonal directions (``ρt`` horizontal, ``ρl`` vertical), placed on **both faces** of the wall (E.F. — each face), not stirrups. - The minimum horizontal ratio is ``ρt,min = 0.0025`` (§11.6.1). The minimum vertical ratio follows the §11.6.2 interpolation ``ρl,min = max(0.0025, 0.0025 + 0.5·(2.5 − hw/lw)·(ρt,req − 0.0025))``, with ``hw/lw`` clamped to ``[0.5, 2.5]``. The same shear provisions serve both **ACI 318-19** and **CIRSOC 201-25**; CIRSOC differs only in the reinforcing-bar catalogue used for design (it allows Ø6 mm for the transverse mesh and Ø10 mm minimum for the vertical mesh). .. note:: The module covers **shear check and design only**. Flexure design for shear walls is not implemented yet. Inherited flexure methods from ``RectangularBeam`` are not validated for wall geometry and should not be used. Key Concepts ------------ - **Geometry**: - ``thickness`` (*t*) — out-of-plane dimension - ``length`` (*lw*) — in-plane length, resists in-plane shear - ``height`` (*hw*) — story / overall wall height, used for the ``hw / lw`` aspect ratio - **Material Properties**: requires a ``Concrete`` object (currently ``Concrete_ACI_318_19`` or ``Concrete_CIRSOC_201_25``) and a ``SteelBar`` object. - **Reinforcement**: distributed bars defined by **bar diameter + spacing** in each direction. - **Forces**: a list of ``Forces`` objects passed to ``check_shear()`` or ``design_shear()`` — either directly on the wall or through a ``Node``. ``V_z`` is the in-plane lateral shear demand at the section. Usage ----- Below is a step-by-step guide on how to use the ``ShearWall`` class. 1. Creating a Shear Wall Object ******************************* Specify the geometry, materials, and clear cover using the wall-friendly constructor parameters ``thickness``, ``length``, and ``height``. .. code-block:: python from mento import ShearWall, Concrete_ACI_318_19, SteelBar from mento import MPa, cm, mm, m concrete = Concrete_ACI_318_19(name="H25", f_c=25 * MPa) steel = SteelBar(name="ADN 420", f_y=420 * MPa) wall = ShearWall( label="W1", concrete=concrete, steel_bar=steel, thickness=25 * cm, # t length=4.0 * m, # lw (in-plane length) height=3.5 * m, # hw (story height; hw/lw = 0.875) c_c=20 * mm, ) After construction, the dimensions are accessible as ``wall.thickness``, ``wall.length``, and ``wall.height``. 2. Setting the Distributed Reinforcement **************************************** Use ``set_horizontal_rebar(d_b, s)`` for the horizontal (transverse) mesh that resists in-plane shear, and ``set_vertical_rebar(d_b, s)`` for the vertical (longitudinal) mesh. The mesh is placed on **both faces** of the wall (E.F. — each face), so the reinforcement ratio counts both curtains: ``ρ = 2 · Ab / (t × s)``. .. code-block:: python # Ø12 @ 150 mm in both directions wall.set_horizontal_rebar(d_b=12 * mm, s=150 * mm) wall.set_vertical_rebar(d_b=12 * mm, s=150 * mm) 3. Performing the Shear Check ***************************** Call ``check_shear()`` with a list of ``Forces`` — either directly on the wall or through a ``Node``. The returned DataFrame has one header row (units) followed by one row per combination. .. code-block:: python from mento import Forces, Node, kN f1 = Forces(label="1.2D+1.0E", V_z=800 * kN) f2 = Forces(label="0.9D+1.0E", V_z=1200 * kN) # Directly on the wall ... wall.check_shear([f1, f2]) # ... or via a Node (recommended — enables results / detailed reports) node = Node(section=wall, forces=[f1, f2]) node.check() node.results Returned columns: +--------------+-----------------------------------------------------+ | Column | Meaning | +==============+=====================================================+ | ``ρt,min`` | Minimum horizontal reinforcement ratio (0.0025) | +--------------+-----------------------------------------------------+ | ``ρt,req`` | Required horizontal reinforcement ratio | +--------------+-----------------------------------------------------+ | ``ρt`` | Provided horizontal reinforcement ratio | +--------------+-----------------------------------------------------+ | ``ρl,min`` | Minimum vertical reinforcement ratio | +--------------+-----------------------------------------------------+ | ``ρl`` | Provided vertical reinforcement ratio | +--------------+-----------------------------------------------------+ | ``Vu`` | Demand shear | +--------------+-----------------------------------------------------+ | ``ØVc`` | Concrete shear strength (factored) | +--------------+-----------------------------------------------------+ | ``ØVs`` | Steel shear strength (factored) | +--------------+-----------------------------------------------------+ | ``ØVn`` | Total nominal shear strength (factored) | +--------------+-----------------------------------------------------+ | ``ØVn,max`` | Section-crushing limit (factored) | +--------------+-----------------------------------------------------+ | ``DCR`` | Demand-to-capacity ratio | +--------------+-----------------------------------------------------+ 4. Designing the Shear Reinforcement ************************************ ``design()`` is fully automatic: it sizes **both** meshes against the worst-case force combination, applies them to the wall, and returns the re-evaluated check DataFrame. .. code-block:: python result = wall.design([f1, f2]) # The wall now carries a designed mesh: print(wall._d_b_h, wall._s_h) # horizontal (shear) bar + spacing print(wall._d_b_v, wall._s_v) # vertical (minimum) bar + spacing What it does: 1. Runs the check for every force and tracks the worst-case ``ρt,req``. 2. Derives the worst-case ``ρl,min`` from §11.6.2. 3. Selects a bar diameter and spacing for the **horizontal mesh** (against ``ρt,req``) and the **vertical mesh** (against ``ρl,min``). 4. Applies both via ``set_horizontal_rebar`` / ``set_vertical_rebar`` and re-runs the check. **Vertical mesh.** Because for now *mento* does not check flexure, the vertical mesh is always sized to the §11.6.2 *minimum* — it is reported and plotted as "Minimum vertical rebar". .. note:: For **CIRSOC 201-25**, ``design`` automatically uses the CIRSOC bar catalogue (Ø6 mm minimum transverse, Ø10 mm minimum vertical). No extra configuration is needed — the design code is read from the ``Concrete`` object. 5. Inspecting Intermediate Quantities ************************************* After running a check, the relevant ACI 318-19 quantities are available as attributes on the wall: +----------------------+----------------------------------------------+ | Attribute | Meaning | +======================+==============================================+ | ``_hw_lw`` | Aspect ratio ``hw / lw`` | +----------------------+----------------------------------------------+ | ``_alpha_c`` | ``α_c`` factor (0.25 → 0.17 metric) | +----------------------+----------------------------------------------+ | ``_Acv`` | Gross shear area ``lw × t`` | +----------------------+----------------------------------------------+ | ``_V_c_wall`` | Nominal concrete shear strength | +----------------------+----------------------------------------------+ | ``_V_s_wall`` | Nominal steel shear strength | +----------------------+----------------------------------------------+ | ``_phi_V_n_wall`` | Factored total shear strength | +----------------------+----------------------------------------------+ | ``_phi_V_n_max_wall``| Factored crushing-limit shear strength | +----------------------+----------------------------------------------+ | ``_DCRv_wall`` | Demand-to-capacity ratio for shear | +----------------------+----------------------------------------------+ | ``_rho_t_req`` | Required horizontal reinforcement ratio | +----------------------+----------------------------------------------+ | ``_rho_l_min`` | Minimum vertical reinforcement ratio | +----------------------+----------------------------------------------+ | ``_s_h_max`` | §11.7.3 horizontal spacing limit | +----------------------+----------------------------------------------+ | ``_s_v_max`` | §11.7.3 vertical spacing limit | +----------------------+----------------------------------------------+ | ``_d_b_h`` / ``_s_h``| Designed horizontal bar diameter / spacing | +----------------------+----------------------------------------------+ | ``_d_b_v`` / ``_s_v``| Designed vertical bar diameter / spacing | +----------------------+----------------------------------------------+ All reinforcement ratios (``ρt``, ``ρl``) account for the mesh on **both faces** — ``ρ = 2 · Ab / (t · s)``. A worked example with full output is available in the :doc:`Shear Wall ACI 318-19 example `.