File size: 2,571 Bytes
a8ced59 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 | % Name: Rembrant Oyangoren Albeos
% Singly Reinforced Rectangular Beam Calculator
% Inputs
fc = input('Compressive strength of concrete, fc (ksi): ');
fy = input('Yield strength of steel, fy (ksi): ');
b = input('Width of the beam, b (in): ');
d = input('Effective depth to centroid, d (in): ');
dt = input('Depth to extreme tension layer, dt (in): ');
As_choice = input('Input steel area: [1] Area [2] Bar Size: ');
if As_choice == 1
As = input('Steel area, As (in^2): ');
else
Asq = input('Number of bars: ');
Asd = input('Bar size: ');
As = Asq * (pi * (Asd/8)^2) / 4;
fprintf('As: %.3f in^2\n', As);
end
Es = input('Modulus of Elasticity, Es (ksi): ');
Ecu = 0.003;
% Tension Force
T = As * fy;
fprintf('T: %.2f kips\n', T);
% Beta 1
if fc <= 4
beta1 = 0.85;
elseif fc > 4 && fc <= 8
beta1 = 0.85 - 0.05 * (fc - 4);
else
beta1 = 0.65;
end
% Depth of compression block
a = T / (0.85 * fc * b);
c = a / beta1;
fprintf('a: %.3f in\n', a);
fprintf('c: %.3f in\n', c);
% Steel Strain
Strain_y = fy / Es;
Strain_s = Ecu * (d - c) / c;
fprintf('Ey: %.5f\n', Strain_y);
fprintf('Es: %.5f\n', Strain_s);
% Check yielding
if Strain_s >= Strain_y
fprintf('Steel yielded. Assumption OK.\n');
Mn = T * (d - a/2);
else
fprintf('Steel did NOT yield. Recalculating c...\n');
A_quad = 0.85 * fc * b * beta1;
B_quad = As * Es * Ecu;
C_quad = -As * Es * Ecu * d;
c = (-B_quad + sqrt(B_quad^2 - 4 * A_quad * C_quad)) / (2 * A_quad);
a = beta1 * c;
Strain_s = Ecu * (d - c) / c;
T = As * (Es * Strain_s);
Mn = T * (d - a/2);
fprintf('Exact c: %.3f in\n', c);
fprintf('Exact T: %.2f kips\n', T);
end
% Nominal Moment
Mn_ft = Mn / 12;
fprintf('Mn: %.2f kip-in\n', Mn);
fprintf('Mn: %.2f kip-ft\n', Mn_ft);
% Minimum Steel Area
fc_psi = fc * 1000;
fy_psi = fy * 1000;
limit_check = 3 * sqrt(fc_psi);
if limit_check < 200
As_min = (200 / fy_psi) * b * d;
else
As_min = (limit_check / fy_psi) * b * d;
end
fprintf('As_min: %.3f in^2\n', As_min);
if As >= As_min
fprintf('As >= As_min. OK.\n');
else
fprintf('As < As_min. FAILED.\n');
end
% Strength Reduction Factor
Strain_t = Ecu * (dt - c) / c;
fprintf('Et: %.5f\n', Strain_t);
if Strain_t >= 0.005
phi = 0.90;
elseif Strain_t < 0.002
phi = 0.65;
else
phi = 0.65 + (Strain_t - 0.002) * (250 / 3);
end
fprintf('phi: %.2f\n', phi);
% Design Strength
phi_Mn = phi * Mn_ft;
fprintf('M: %.2f kip-ft\n', phi_Mn);
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