Self-weight load case SWT is automatically generated as a uniform vertical load q_SWT = density × thickness. Set density to 0 to disable.

Use this as a panel boundary table. Each closed boundary references a row in Slab Properties, so thickness, density and stiffness come from that property reference.

Example: 0,0; 4,0; 4,3; 0,3; 0,0. Rectangular/orthogonal panel boundaries insert their X/Y ordinates into one shared mesh, so adjacent panels merge continuously where they meet.

Priority: lower number wins when panels overlap. Property ref 0 defines an opening / void and always overrides slab panels. Repeated closing points are accepted and stripped internally. Shared edges use a small tolerance so adjacent panels do not leave sliver gaps. Elements inside openings are omitted and unused nodes are pruned before analysis. Areas not inside a panel use the first slab property row as the default property reference.

Use this table for persistent setting-out points: boundary corners, panel/opening corners, RC column centres, beam endpoints, line-support endpoints and load points.

These points are used by the canvas pick tools for snapping. They are not generated FEM mesh nodes. Leave Use blank/on to include a point in snapping; type off to keep the row but ignore it.

Temporary supports are compression-only vertical supports placed at mandatory mesh nodes. Enter k in kN/m if a spring stiffness is known, or leave k blank for a pinned/rigid temporary support. Use + Add temp support by canvas to place a support graphically, then edit X, Y and k in the table.

Back-span stiffness calculator. Computes the rotational stiffness per metre of edge contributed by a continuous slab strip extending out beyond the model boundary, with the far end pinned (3EI/L, default) or fixed (4EI/L) at the next column line. The cracked factor reduces gross EI to a representative cracked value — use 0.5 for typical podium slabs, 1.0 if the model is uncracked. Read the result and type it into the k_rot column below.

Each line support is defined by a line segment (x1,y1) → (x2,y2). Mesh nodes lying on the segment receive lumped stiffness based on tributary length along the line.

k_vert: vertical line support stiffness (kN/m per metre of support). Use this for wall lines, bearings or elastic vertical support.

k_rot: rotational stiffness per metre about the line tangent axis. Use this where the model boundary represents continuity into an adjacent slab bay. The previous k_rot,n column has been removed because normal/twist restraint is rarely needed for this workflow and was more likely to confuse the support definition.

Beam lines can be placed anywhere in the slab by coordinates. They are post-processing only and do not yet stiffen the slab or attract load through coupled beam/shell elements. The reported beam actions are a simple simply-supported check for the selected result case: SWT / blanket UDL is converted using tributary width, and point loads falling on the beam line are projected along the span. Blank tributary width uses half the current mesh size.

Automatic SWT is always generated from slab density × thickness. Add extra whole-slab load cases here, for example DL1 with q = -5 kN/m². Use negative values for downward loads.

Point loads are axial/vertical only. FEMCalc inserts a generated mesh node at each point load/support/temporary prop where the point lies inside the slab.

Patch loads are rectangular temporary blanket loads. The patch load is applied to elements whose centroid falls inside the rectangle.

Define result combinations by case name. Use SWT for automatic self-weight, plus any blanket-load or point-load case name, for example 1.35*SWT + 1.5*DL1. Combination rows are solved and added to the Result drop-down after Run Analysis.

Method. For each point load and each temporary prop the scanner draws a rectangular perimeter at 1.5d offset (BS 8110 critical perimeter), walks the perimeter sampling the FE transverse shear Qx, Qy from the active result case, and computes the local shear stress v(s) = |q_n| / d versus the BS 8110 v_c from your reinforcement input. The peak utilisation around the perimeter is reported with a v(s) profile plot.

Defaults. Point loads → 100 × 100 mm contact patch (prop/scaffold leg). MEWP wheel rows (load type mewp or wheel in note) → 150 × 150 mm. Temporary props → 150 × 150 mm head bearing area. Override the patch size per scan in v2.

Equilibrium. The integral ∮ q_n ds around a closed perimeter should equal the net vertical load enclosed (point-load magnitude, or prop reaction). A large Δeq % means the mesh is too coarse near a singularity — refine and re-run.

Face selection (v1). Point-load scans use the bottom mat (slab sagging under the load). Prop scans use the top mat (slab hogging over the prop head). Manual override and auto-from-moment-sign come in v2.

v_c caps and floors (BS 8110 cl 3.4.5.4). 100·As/(b·d) is held within [0.15, 3.0]. (400/d)^(1/4) is held ≥ 1.0 for slabs without effective shear reinforcement. f_cu is capped at 40 in (f_cu/25)^(1/3).

Select two analysed load cases or combinations. DIFF defaults to absolute comparison, so hogging/sagging sign does not reverse the colour meaning. Elements are shown green where Case 1 is numerically higher, and red where Case 2 is numerically higher. Use the result selector for Mxx, Myy, Mxy, Qx or Qy.