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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 | % Simple RC-SRP Script Calculator
clear; clc;
disp('--- Simple RC-SRP Calculator ---');
disp('Follow the steps to enter the given variables.');
% Get inputs from the user through the command window
fc = input('Enter concrete compressive strength f_c'' (psi): ');
fy = input('Enter steel yield strength f_y (psi): ');
b = input('Enter beam width b (in): ');
h = input('Enter beam height h (in): ');
cover = input('Enter cover distance to extreme tension layer (in): ');
n_bars = input('Enter total number of bars: ');
a_bar = input('Enter area per bar (in^2): ');
% Ask if there's a second layer
double_layer_ans = input('Is this a double layer reinforcement? (yes/no): ', 's');
if strcmpi(double_layer_ans, 'yes')
layer_type = 'Double Layer Singly Reinforced';
n_bars1 = input('Enter number of bars in layer 1 (bottom): ');
n_bars2 = input('Enter number of bars in layer 2 (top): ');
spacing = input('Enter spacing between layers (in): ');
else
layer_type = 'Single Layer Singly Reinforced';
end
% Ask user if they want to calculate and show output
show_output = input('Ready to calculate and show the output? (yes/no): ', 's');
if strcmpi(show_output, 'yes')
disp(' ');
disp('--- CALCULATION OUTPUT ---');
% Identify the type of calculated section
disp(['Type of section: ', layer_type]);
disp(' ');
% Basic constants
fc_ksi = fc / 1000;
fy_ksi = fy / 1000;
Es_ksi = 29000;
E_cu = 0.003;
% Calculate beta1 factor
beta1 = 0.85;
if fc > 4000
beta1 = 0.85 - 0.05 * ((fc - 4000) / 1000);
end
beta1 = max(beta1, 0.65);
% Minimum steel factor
limit_val = 3 * sqrt(fc);
As_min_factor = max(limit_val, 200);
if strcmpi(double_layer_ans, 'no')
% --- SINGLE LAYER CALCULATION ---
d = h - cover;
As = n_bars * a_bar;
disp(['1. Effective depth (d): ', num2str(d), ' in']);
disp(['2. Area of steel (A_s): ', num2str(As), ' in^2']);
% Force and depth of compression block
T = As * fy_ksi;
disp(['3. Tension force (T, assuming yield): ', num2str(T), ' kips']);
a = T / (0.85 * fc_ksi * b);
c = a / beta1;
disp(['4. Compression block depth (a): ', num2str(a), ' in']);
disp([' Neutral axis depth (c): ', num2str(c), ' in']);
% Check if steel actually yields
eps_y = fy_ksi / Es_ksi;
eps_s = ((d - c) / c) * E_cu;
disp(['5. Yield strain (eps_y): ', num2str(eps_y)]);
disp([' Steel strain (eps_s): ', num2str(eps_s)]);
if eps_s >= eps_y
disp(' Status: Steel yielded. Assumption OK.');
else
disp(' Status: Steel did NOT yield. Assumption failed.');
end
% Calculate Nominal Moment
Mn = T * (d - a/2) / 12;
disp(['6. Nominal Moment (M_n): ', num2str(Mn), ' kip-ft']);
% Check minimum code requirement for steel
As_min = (As_min_factor / fy) * b * d;
disp(['7. Minimum steel (A_s,min): ', num2str(As_min), ' in^2']);
if As >= As_min
disp(' Status: A_s >= A_s,min. OK.');
end
% Compute reduction factor
eps_t = eps_s;
if eps_t >= 0.005
phi = 0.90;
elseif eps_t <= 0.002
phi = 0.65;
else
phi = 0.65 + (eps_t - 0.002) * (250/3);
end
phi_Mn = phi * Mn;
disp(['8. Reduction factor (phi): ', num2str(phi)]);
disp(['9. Design Moment (phi*M_n): ', num2str(phi_Mn), ' kip-ft']);
else
% --- DOUBLE LAYER CALCULATION ---
As1 = n_bars1 * a_bar;
As2 = n_bars2 * a_bar;
As = As1 + As2;
dist1 = cover;
dist2 = cover + spacing;
% Calculate centroid of steel
g = (As1 * dist1 + As2 * dist2) / As;
d = h - g;
d_t = h - cover;
disp(['1. Centroid distance (g): ', num2str(g), ' in']);
disp(['2. Effective depth (d): ', num2str(d), ' in']);
disp([' Area of steel (A_s): ', num2str(As), ' in^2']);
% Force and depth of compression block
T = As * fy_ksi;
a = T / (0.85 * fc_ksi * b);
c = a / beta1;
disp(['3. Tension force (T, assuming yield): ', num2str(T), ' kips']);
disp(['4. Compression block depth (a): ', num2str(a), ' in']);
disp([' Neutral axis depth (c): ', num2str(c), ' in']);
% Check if steel yields
eps_y = fy_ksi / Es_ksi;
eps_s = ((d - c) / c) * E_cu;
disp(['5. Yield strain (eps_y): ', num2str(eps_y)]);
disp([' Steel strain (eps_s): ', num2str(eps_s)]);
if eps_s < eps_y
disp(' Status: Over-reinforced section. Assumption Failed.');
disp(' Solving exact c using quadratic method...');
% Use quadratic for exact answer if not yielded
A_quad = 0.85 * fc_ksi * b * beta1;
B_quad = As * Es_ksi * E_cu;
C_quad = -1 * As * Es_ksi * E_cu * d;
roots_c = roots([A_quad, B_quad, C_quad]);
c = max(roots_c(roots_c > 0));
a = beta1 * c;
disp([' Exact Neutral axis (c): ', num2str(c), ' in']);
disp([' Exact Compression block (a): ', num2str(a), ' in']);
T = As * Es_ksi * ((d - c)/c) * E_cu;
disp([' Exact Tension force (T): ', num2str(T), ' kips']);
else
disp(' Status: Steel yielded. Assumption OK.');
end
% Calculate Nominal Moment
Mn = T * (d - a/2) / 12;
disp(['6. Nominal Moment (M_n): ', num2str(Mn), ' kip-ft']);
% Check minimum code requirement for steel
As_min = (As_min_factor / fy) * b * d;
disp(['7. Minimum steel (A_s,min): ', num2str(As_min), ' in^2']);
if As >= As_min
disp(' Status: A_s >= A_s,min. OK.');
end
% Compute reduction factor using extreme tension layer
eps_t = ((d_t - c) / c) * E_cu;
if eps_t >= 0.005
phi = 0.90;
elseif eps_t <= 0.002
phi = 0.65;
else
phi = 0.65 + (eps_t - 0.002) * (250/3);
end
phi_Mn = phi * Mn;
disp(['8. Extreme tension strain (eps_t): ', num2str(eps_t)]);
disp([' Reduction factor (phi): ', num2str(phi)]);
disp(['9. Design Moment (phi*M_n): ', num2str(phi_Mn), ' kip-ft']);
end
else
disp('Calculation stopped. Have a great day!');
end
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