Design of Isolated Footing as per IS 456 2000 is explained in detail in this post. You can interact with the data base and based on that you can get the design of Isolated footing as per IS 456 2000.

body {
font-family: ‘Inter’, sans-serif;
background-color: #f0f4f8;
}
.mono {
font-family: ‘Roboto Mono’, monospace;
}
.result-value {
font-weight: 600;
color: #1d4ed8;
}
.step-card {
background-color: white;
border-radius: 0.75rem;
padding: 1.5rem;
margin-bottom: 1.5rem;
border: 1px solid #e2e8f0;
box-shadow: 0 1px 3px 0 rgba(0,0,0,0.05);
transition: all 0.3s ease-in-out;
}
.input-group label {
display: block;
margin-bottom: 0.5rem;
font-weight: 500;
color: #475569;
}
.input-group input {
width: 100%;
padding: 0.5rem 0.75rem;
border: 1px solid #cbd5e1;
border-radius: 0.375rem;
transition: border-color 0.2s, box-shadow 0.2s;
}
.input-group input:focus {
outline: none;
border-color: #2563eb;
box-shadow: 0 0 0 2px rgba(37, 99, 235, 0.2);
}
.safe { color: #16a34a; }
.unsafe { color: #dc2626; }
.formula {
font-family: ‘Roboto Mono’, monospace;
font-size: 0.8rem;
background-color: #f1f5f9;
padding: 0.75rem;
border-radius: 0.25rem;
color: #334155;
margin-top: 0.75rem;
display: block;
white-space: pre-wrap;
word-wrap: break-word;
border-left: 3px solid #60a5fa;
}
/* Visualization Styles */
.viz-container {
position: relative;
background-color: #f8fafc;
border: 1px dashed #94a3b8;
border-radius: 0.5rem;
padding: 1.5rem 1rem;
margin-top: 1rem;
}
/* Plan View */
#detailing-drawing-plan {
width: 100%;
aspect-ratio: 1/1;
max-width: 300px;
}
#footing-plan {
width: 100%; height: 100%;
background-color: #e2e8f0;
border: 1px solid #94a3b8;
position: relative;
}
#column-plan {
position: absolute;
background-color: #94a3b8;
border: 1px solid #475569;
top: 50%; left: 50%;
transform: translate(-50%, -50%);
}
.rebar-plan {
position: absolute;
background-color: #475569;
}

/* Section View */
#detailing-drawing-section {
width: 100%;
height: 250px;
max-width: 400px;
}
#section-view-container {
width: 100%; height: 100%;
position: relative;
}
#footing-section {
position: absolute;
bottom: 20px;
left: 0;
width: 100%;
background-color: #e2e8f0;
border: 1px solid #94a3b8;
}
#column-section {
position: absolute;
bottom: 20px;
left: 50%;
background-color: #cad3e0;
border-left: 1px solid #94a3b8;
border-right: 1px solid #94a3b8;
border-top: 1px solid #94a3b8;
}
.rebar-section {
position: absolute;
background-color: #475569;
border-radius: 50%;
border: 1px solid #1e293b;
}
.dowel-bar-vert {
position: absolute;
width: 2px;
background-color: #475569;
}
.dowel-bar-foot {
position: absolute;
height: 2px;
background-color: #475569;
}
.rebar-hook {
position: absolute;
width: 2px;
background-color: #475569;
}
.dim-line {
position: absolute;
background-color: #64748b;
}
.dim-line-vert {
width: 1px;
left: -20px;
}
.dim-line-vert::before, .dim-line-vert::after {
content: ”; position: absolute; left: -4px; width: 9px; height: 1px; background-color: #64748b;
}
.dim-line-vert::before { top: 0; }
.dim-line-vert::after { bottom: 0; }
.dim-label {
position: absolute;
font-size: 0.65rem;
font-weight: 500;
color: #475569;
background-color: #f8fafc;
padding: 0 2px;
}
/* BBS Table */
.bbs-table {
width: 100%;
font-size: 0.875rem;
text-align: left;
border-collapse: collapse;
}
.bbs-table th, .bbs-table td {
padding: 0.5rem 0.75rem;
border-bottom: 1px solid #e2e8f0;
}
.bbs-table th {
background-color: #f8fafc;
font-weight: 600;
color: #334155;
}
.shape-drawing {
width: 60px;
height: 30px;
border: 2px solid #475569;
border-top: none;
}
.shape-drawing.dowel {
border-right: none;
border-left: none;
height: 40px;
width: 2px;
margin: 0 auto;
position: relative;
}
.shape-drawing.dowel::after {
content: ”;
position: absolute;
bottom: -2px;
left: -15px;
width: 15px;
height: 2px;
background-color: #475569;
}

document.addEventListener(‘DOMContentLoaded’, () => {
const inputs = document.querySelectorAll(‘input’);
inputs.forEach(input => {
input.addEventListener(‘input’, calculateAll);
});

function createResultRow(label, value, unit) {
return `

${label}: ${value} ${unit}

`;
}

function createStatusRow(label, status) {
const statusClass = status === ‘SAFE’ ? ‘safe’ : ‘unsafe’;
return `

${label}: ${status}

`;
}

function calculateAll() {
// — Get Inputs —
const P = parseFloat(document.getElementById(‘columnLoad’).value) || 0;
const sbc = parseFloat(document.getElementById(‘sbc’).value) || 0;
const b = parseFloat(document.getElementById(‘columnWidth’).value) || 0;
const fck = parseFloat(document.getElementById(‘fck’).value) || 0;
const fy = parseFloat(document.getElementById(‘fy’).value) || 0;
const clearCover = parseFloat(document.getElementById(‘clearCover’).value) || 0;
const concreteRate = parseFloat(document.getElementById(‘concreteRate’).value) || 0;
const steelRate = parseFloat(document.getElementById(‘steelRate’).value) || 0;

// — Step 1 —
const W = P * 1.10;
const A_req = (sbc > 0) ? W / sbc : 0;
const L = Math.ceil(Math.sqrt(A_req) * 10) / 10;
const A_prov = L * L;

document.getElementById(‘step1-results’).innerHTML = `
Area = (Column Load + 10% Self-weight) / SBC
${createResultRow(‘Total Service Load’, W.toFixed(2), ‘kN’)}
${createResultRow(‘Required Area’, A_req.toFixed(2), ‘m²’)}
${createResultRow(‘Calculated Side Length’, Math.sqrt(A_req).toFixed(3), ‘m’)}
${createResultRow(‘Provided Footing Size’, `${L.toFixed(2)}m x ${L.toFixed(2)}m`, ”)}`;

// — Step 2 —
const Pu = 1.5 * P;
const qu = (A_prov > 0) ? Pu / A_prov : 0;
document.getElementById(‘step2-results’).innerHTML = `
qu = (1.5 * Column Load) / Provided Area
${createResultRow(‘Factored Column Load (Pu)’, Pu.toFixed(2), ‘kN’)}
${createResultRow(‘Net Upward Pressure (qu)’, qu.toFixed(2), ‘kN/m²’)}`;

// — Step 3 —
const assumed_pt = 0.3;
let tau_c_val = 0.36 + (0.48 – 0.36) * (assumed_pt – 0.25) / (0.5 – 0.25);
if (fck === 20) tau_c_val = 0.36;
if (fck >= 30) tau_c_val = 0.39;

let d = 0;
const B = L * 1000;
const qu_N_mm2 = qu / 1000;
if ((tau_c_val + qu_N_mm2) > 0) {
d = (qu_N_mm2 * (B – b) / 2) / (tau_c_val + qu_N_mm2);
}

let twoWaySafe = false;
while (!twoWaySafe) {
const ks = 1.0;
const tau_c_punch = Math.min(ks * 0.25 * Math.sqrt(fck), 0.25 * Math.sqrt(fck) * 2);
const b0 = 4 * (b + d);
const Vu2_N = qu_N_mm2 * (B * B – Math.pow(b + d, 2));
const Vc2_N = tau_c_punch * b0 * d;
if (Vu2_N <= Vc2_N) {
twoWaySafe = true;
} else {
d += 10;
}
}
d = Math.ceil(d / 10) * 10;

const Vu1_N_final = qu_N_mm2 * B * ((B – b) / 2 – d);
const Vc1_N_final = tau_c_val * B * d;
const onewayStatusText = Vu1_N_final <= Vc1_N_final ? 'SAFE' : 'UNSAFE';

const ks_final = 1.0;
const tau_c_punch_final = Math.min(ks_final * 0.25 * Math.sqrt(fck), 0.25 * Math.sqrt(fck) * 2);
const b0_final = 4 * (b + d);
const Vu2_N_final = qu_N_mm2 * (B*B – Math.pow(b + d, 2));
const Vc2_N_final = tau_c_punch_final * b0_final * d;
const twowayStatusText = Vu2_N_final <= Vc2_N_final ? 'SAFE' : 'UNSAFE';

const mainBarDia = 12;
const D = Math.ceil((d + clearCover + mainBarDia) / 10) * 10;

document.getElementById('step3-results').innerHTML = `

`;

// — Step 4 & 5 —
const Lc = (B – b) / 2;
const Mu_Nmm = qu_N_mm2 * B * Math.pow(Lc, 2) / 2;
const a = (0.87 * fy) / (B * d * fck);
const c = -Mu_Nmm / (0.87 * fy * d);
const Ast = (-1 + Math.sqrt(1 – 4 * a * c)) / (2 * a);

let tau_bd = 1.4;
if (fck === 20) tau_bd = 1.2;
if (fck >= 30) tau_bd = 1.5;
tau_bd *= 1.6;

const Ld_req = (0.87 * fy * mainBarDia) / (4 * tau_bd);
const Ld_avail = Lc – clearCover;
const ldStatusText = Ld_avail >= Ld_req ? ‘SAFE’ : ‘UNSAFE’;

document.getElementById(‘step4-results’).innerHTML = `
Mu = (qu*B*Lc²)/2 (at column face)
${createResultRow(‘Factored Bending Moment (Mu)’, (Mu_Nmm / 1e6).toFixed(2), ‘kNm’)}
Mu=0.87*fy*Ast*d*(1 - Ast*fy/(B*d*fck))
${createResultRow(‘Required Steel Area (Ast)’, Ast.toFixed(2), ‘mm²’)}
Ld = (φ*σs)/(4*τbd) (Cl. 26.2.1)
${createResultRow(‘Required Dev. Length (Ld)’, Ld_req.toFixed(2), ‘mm’)}
${createResultRow(‘Available Dev. Length’, Ld_avail.toFixed(2), ‘mm’)}
${createStatusRow(‘Dev. Length Status’, ldStatusText)}
`;

// — Step 6 —
const permBearingStress_col = 0.45 * fck;
const A1 = B*B;
const A2 = b*b;
let rootA1A2 = Math.sqrt(A1/A2);
if (rootA1A2 > 2) rootA1A2 = 2;
const permBearingStress_foot = permBearingStress_col * rootA1A2;
const actualBearingPressure = (Pu * 1000) / A2;
const bearingStatusText = actualBearingPressure <= permBearingStress_foot ? 'SAFE' : 'UNSAFE';

const Adowel_min = 0.005 * A2;
document.getElementById('step6-results').innerHTML = `
σ_br = 0.45*fck*sqrt(A1/A2) (Cl. 34.4)
${createResultRow(‘Actual Bearing Pressure’, actualBearingPressure.toFixed(2), ‘N/mm²’)}
${createResultRow(‘Permissible Bearing Stress’, permBearingStress_foot.toFixed(2), ‘N/mm²’)}
${createStatusRow(‘Status’, bearingStatusText)}
A_dowel,min = 0.5% * Column Area
${createResultRow(‘Min. Dowel Area’, Adowel_min.toFixed(2), ‘mm²’)}
`;
const dowelBarDia = 20;

// — Final Summary —
const numBars = Math.ceil(Ast / (Math.PI/4 * mainBarDia*mainBarDia));
const spacing = Math.floor((B – 2 * clearCover – mainBarDia) / (numBars -1));
document.getElementById(‘final-summary-text’).innerHTML = `

Footing Size: ${L.toFixed(2)}m x ${L.toFixed(2)}m

Overall Depth (D): ${D} mm

Main Reinforcement: Provide ${numBars} nos. of ${mainBarDia}mm bars @ ${spacing}mm c/c (Both ways)

Dowel Bars: Provide 4 nos. of ${dowelBarDia}mm bars

`;

// — Quantity & Cost —
const concreteVol = A_prov * (D / 1000);
const mainBarCutLength = B – 2 * clearCover;
const mainBarTotalNo = numBars * 2;
const mainBarTotalLength = mainBarTotalNo * (mainBarCutLength / 1000);
const mainBarUnitWeight = (mainBarDia * mainBarDia) / 162.2;
const mainBarTotalWeight = mainBarTotalLength * mainBarUnitWeight;

const dowelLd = (0.87 * fy * dowelBarDia) / (4 * tau_bd);
const dowelLapLength = 49 * dowelBarDia;
const dowelCutLength = (D – clearCover) + dowelLapLength + (12 * dowelBarDia);
const dowelTotalLength = 4 * (dowelCutLength / 1000);
const dowelUnitWeight = (dowelBarDia * dowelBarDia) / 162.2;
const dowelTotalWeight = dowelTotalLength * dowelUnitWeight;

const totalSteelWeight = mainBarTotalWeight + dowelTotalWeight;

const concreteCost = concreteVol * concreteRate;
const steelCost = totalSteelWeight * steelRate;
const totalCost = concreteCost + steelCost;
const formatter = new Intl.NumberFormat(‘en-IN’, { style: ‘currency’, currency: ‘INR’, minimumFractionDigits: 0 });

document.getElementById(‘bbs-body’).innerHTML = `

01 Main Mesh ${mainBarDia} ${mainBarCutLength} ${mainBarTotalNo} ${mainBarTotalLength.toFixed(2)} 02 Dowel Bars ${dowelBarDia} ${Math.round(dowelCutLength)} 4 ${dowelTotalLength.toFixed(2)}

`;
document.getElementById(‘cost-summary’).innerHTML = `

`;

// — Update Visualizations —
renderPlanView(b, B, clearCover, numBars, mainBarDia);
renderSectionView(b, B, D, clearCover, mainBarDia, dowelBarDia);
}

function renderPlanView(b, B, clearCover, numBars, barDia) {
const footingPlan = document.getElementById(‘footing-plan’);
let rebarContainer = document.getElementById(‘rebar-container-plan’);
if(rebarContainer) rebarContainer.remove();

rebarContainer = document.createElement(‘div’);
rebarContainer.id = ‘rebar-container-plan’;
footingPlan.appendChild(rebarContainer);

const colPlan = document.getElementById(‘column-plan’);
colPlan.style.width = `${(b / B) * 100}%`;
colPlan.style.height = `${(b / B) * 100}%`;

const spacing = (B – 2 * clearCover – barDia) / (numBars – 1);
const barThickness = Math.max(1, (barDia / B) * 100);

for(let i=0; i {
const dowelVert = document.createElement(‘div’);
dowelVert.className = ‘dowel-bar-vert’;
dowelVert.style.left = pos;
dowelVert.style.bottom = `${20 + clearCover*scale + barVisual}`;
dowelVert.style.height = `${footingHeight + 50}px`;
container.appendChild(dowelVert);

const dowelFoot = document.createElement(‘div’);
dowelFoot.className = ‘dowel-bar-foot’;
dowelFoot.style.bottom = `${20 + clearCover*scale + barVisual – dowelVisualDia/2}px`;
dowelFoot.style.width = `${dowelFootLength}px`;
if (index === 0) {
dowelFoot.style.left = `calc(${pos} – ${dowelFootLength}px + ${dowelVisualDia}px)`;
} else {
dowelFoot.style.left = pos;
}
container.appendChild(dowelFoot);
});

const dimLine = document.createElement(‘div’);
dimLine.className = ‘dim-line dim-line-vert’;
dimLine.style.height = `${footingHeight}px`;
dimLine.style.bottom = ’20px’;
container.appendChild(dimLine);

const dimLabel = document.createElement(‘div’);
dimLabel.className = ‘dim-label’;
dimLabel.textContent = `${D}mm`;
dimLabel.style.left = ‘-45px’;
dimLabel.style.top = `${footingHeight/2 – 10}px`;
container.appendChild(dimLabel);
}

calculateAll();
});