The “Code for Seismic Design of Buildings” GB50011-2016, sections 5.1.4 and 5.1.5, stipulates the relationship between the seismic impact coefficient, intensity, site category, design earthquake grouping, structural natural vibration period, and damping ratio. I have developed a UI-selectable plotting tool, which may not be aesthetically pleasing but is functional.
The MATLAB plot is as follows:
The MATLAB code is as follows:
classdef SeismicAlphaApp < matlab.apps.AppBase
% Seismic Impact Coefficient Curve Plotting Tool
properties (Access = public)
UIFigure matlab.ui.Figure
ParameterPanel matlab.ui.container.Panel
ResultPanel matlab.ui.container.Panel
IntensityDD matlab.ui.control.DropDown
GroupDD matlab.ui.control.DropDown
SiteDD matlab.ui.control.DropDown
LevelDD matlab.ui.control.DropDown
ZetaEdit matlab.ui.control.NumericEditField
PlotBtn matlab.ui.control.Button
AlphaMaxLabel matlab.ui.control.Label
TgLabel matlab.ui.control.Label
FormulaLabel matlab.ui.control.Label
end
properties (Access = private)
AlphaTbl % α_max Table
TgTable % Characteristic Period Table
end
methods (Access = private)
% ---------- Initialization ----------
function setupAlphaTable(app)
app.AlphaTbl = containers.Map();
app.AlphaTbl('6 degrees_Most Likely Earthquake') = 0.04;
app.AlphaTbl('6 degrees_Design Earthquake') = 0.12;
app.AlphaTbl('6 degrees_Rare Earthquake') = 0.28;
app.AlphaTbl('7 degrees(0.10g)_Most Likely Earthquake') = 0.08;
app.AlphaTbl('7 degrees(0.10g)_Design Earthquake') = 0.23;
app.AlphaTbl('7 degrees(0.10g)_Rare Earthquake') = 0.50;
app.AlphaTbl('7 degrees(0.15g)_Most Likely Earthquake') = 0.12;
app.AlphaTbl('7 degrees(0.15g)_Design Earthquake') = 0.33;
app.AlphaTbl('7 degrees(0.15g)_Rare Earthquake') = 0.72;
app.AlphaTbl('8 degrees(0.20g)_Most Likely Earthquake') = 0.16;
app.AlphaTbl('8 degrees(0.20g)_Design Earthquake') = 0.45;
app.AlphaTbl('8 degrees(0.20g)_Rare Earthquake') = 0.90;
app.AlphaTbl('8 degrees(0.30g)_Most Likely Earthquake') = 0.24;
app.AlphaTbl('8 degrees(0.30g)_Design Earthquake') = 0.68;
app.AlphaTbl('8 degrees(0.30g)_Rare Earthquake') = 1.20;
app.AlphaTbl('9 degrees_Most Likely Earthquake') = 0.32;
app.AlphaTbl('9 degrees_Design Earthquake') = 0.90;
app.AlphaTbl('9 degrees_Rare Earthquake') = 1.40;
end
function setupTgTable(app)
% Rows: Group 1, Group 2, Group 3
% Columns: I₀ I₁ II III IV
app.TgTable = [0.20 0.25 0.35 0.45 0.65;
0.25 0.30 0.40 0.55 0.75;
0.30 0.35 0.45 0.65 0.90];
end
function [alpha_max, T_g] = getParameters(app)
intensity = app.IntensityDD.Value;
group = app.GroupDD.Value;
site = app.SiteDD.Value;
level = app.LevelDD.Value;
key = [intensity '_' level];
alpha_max = app.AlphaTbl(key);
groups = {'Group 1','Group 2','Group 3'};
sites = {'I₀','I₁','II','III','IV'};
row = find(strcmp(groups, group));
col = find(strcmp(sites, site));
T_g = app.TgTable(row, col);
end
function updateDisplay(app)
[alpha_max, T_g] = app.getParameters();
zeta = app.ZetaEdit.Value;
app.AlphaMaxLabel.Text = sprintf('α_max = %.3f', alpha_max);
app.TgLabel.Text = sprintf('T_g = %.2f s', T_g);
app.FormulaLabel.Text = sprintf('Seismic Impact Coefficient Curve (ζ = %.2f)', zeta);
end
% ---------- Plotting ----------
function plotCurve(app)
[alpha_max, T_g] = app.getParameters();
zeta = app.ZetaEdit.Value;
% Damping adjustment coefficient
if abs(zeta - 0.05) < 1e-5
gamma = 0.9; eta1 = 0.02; eta2 = 1.0;
else
gamma = 0.9 + (0.05 - zeta) / (0.3 + 6*zeta);
eta1 = 0.02 + (0.05 - zeta) / (4 + 32*zeta);
eta2 = max(1 + (0.05 - zeta) / (0.08 + 1.6*zeta), 0.55);
end
% Calculate α(T)
T = linspace(0, 6, 1000);
alpha = zeros(size(T));
for k = 1:numel(T)
t = T(k);
if t < 0.1
alpha(k) = 0.45*alpha_max + 10*(eta2*alpha_max - 0.45*alpha_max)*t;
elseif t <= T_g
alpha(k) = eta2*alpha_max;
elseif t <= 5*T_g
alpha(k) = (T_g/t)^gamma * eta2*alpha_max;
else
alpha(k) = max(eta2*0.2^gamma*alpha_max - eta1*(t-5*T_g), 0);
end
end
% Create figure
fig = figure('Name', 'Seismic Impact Coefficient Curve', ...
'NumberTitle', 'off', ...
'Position', [200, 200, 900, 700], 'Color', 'w');
ax = axes('Parent', fig);
plot(ax, T, alpha, 'b-', 'LineWidth', 2);
hold(ax, 'on');
grid(ax, 'on');
% ---------- Key Points ----------
% 1) 0.1 s
alpha_01 = 0.45*alpha_max + 10*(eta2*alpha_max - 0.45*alpha_max)*0.1;
% Add 0.1s marker line
plot(ax, [0.1, 0.1], [0, alpha_01], 'k--', 'LineWidth', 1);
plot(ax, 0.1, alpha_01, 'ro', 'MarkerSize', 8, 'MarkerFaceColor', 'r');
text(ax, 0.1, alpha_01 + 0.08*alpha_max, '0.1 s (η2αmax)', ...
'FontSize', 11, 'FontName', 'SimSun', 'Color', 'r');
plot(ax, 0.0, 0.45*alpha_01, 'ro', 'MarkerSize', 8, 'MarkerFaceColor', 'r');
text(ax, 0.1, 0.45*alpha_01, '0.45αmax', ...
'FontSize', 11, 'FontName', 'SimSun', 'Color', 'r');
% 2) T_g
plot(ax, [T_g T_g], [0 eta2*alpha_max], 'k--', 'LineWidth', 1);
% plot(ax, [0 T_g], [eta2*alpha_max eta2*alpha_max], 'k--', 'LineWidth', 1);
plot(ax, T_g, eta2*alpha_max, 'ro', 'MarkerSize', 8, 'MarkerFaceColor', 'r');
% Adjust T_g label position
if T_g < 1.0
text_x = T_g + 0.2;
else
text_x = T_g + 0.1;
end
text(ax, text_x, eta2*alpha_max + 0.01*alpha_max, ...
sprintf('T_g = %.2f s', T_g), ...
'FontSize', 11, 'FontName', 'SimSun', 'Color', 'r');
% 3) 5T_g
if 5*T_g <= 6
a5 = (T_g/(5*T_g))^gamma * eta2*alpha_max;
plot(ax, 5*T_g, a5, 'ro', 'MarkerSize', 8, 'MarkerFaceColor', 'r');
plot(ax, [5*T_g 5*T_g], [0 a5], 'k--', 'LineWidth', 1);
% Determine text label direction based on position
if 5*T_g > 4.5
text(ax, 5*T_g - 0.5, a5 + 0.02*alpha_max, ...
sprintf('5T_g = %.2f s', 5*T_g), ...
'FontSize', 11, 'FontName', 'SimSun', 'Color', 'r', ...
'HorizontalAlignment', 'right');
else
text(ax, 5*T_g + 0.1, a5 + 0.02*alpha_max, ...
sprintf('5T_g = %.2f s', 5*T_g), ...
'FontSize', 11, 'FontName', 'SimSun', 'Color', 'r');
end
end
% ---------- Formula Explanation (Right Side Blank) ----------
xTxt = 4.0;
yTop = 0.9*alpha_max;
dy = 0.08*alpha_max;
% Add text box background
text(ax, xTxt, yTop, 'Rising Segment: α = [0.45+10(T-0)]αmax', ...
'FontSize', 11, 'FontName', 'SimSun', 'BackgroundColor', 'white', ...
'EdgeColor', 'black', 'Margin', 2);
text(ax, xTxt, yTop-dy, 'Platform Segment: α = η2αmax', ...
'FontSize', 11, 'FontName', 'SimSun', 'BackgroundColor', 'white', ...
'EdgeColor', 'black', 'Margin', 2);
text(ax, xTxt, yTop-2*dy, 'Curve Segment: α = (Tg/T)^γ η2αmax', ...
'FontSize', 11, 'FontName', 'SimSun', 'BackgroundColor', 'white', ...
'EdgeColor', 'black', 'Margin', 2);
if 5*T_g < 6
text(ax, xTxt, yTop-3*dy, 'Linear Segment: α = [η2(0.2^γ)-η1(T-5Tg)]αmax', ...
'FontSize', 11, 'FontName', 'SimSun', 'BackgroundColor', 'white', ...
'EdgeColor', 'black', 'Margin', 2);
end
% ---------- Axes and Title ----------
xlabel(ax, 'Period T (s)', 'FontSize', 14, 'FontName', 'SimSun', 'FontWeight', 'bold');
ylabel(ax, 'Seismic Impact Coefficient α', 'FontSize', 14, 'FontName', 'SimSun', 'FontWeight', 'bold');
level = app.LevelDD.Value;
title(ax, sprintf('%s Seismic Impact Coefficient Curve (ζ=%.2f, T_g=%.2f s, α_max=%.3f)', ...
level, zeta, T_g, alpha_max), ...
'FontSize', 14, 'FontName', 'SimSun', 'FontWeight', 'bold');
xlim(ax, [0 6]);
ylim(ax, [0 alpha_max*1.2]);
set(ax, 'FontName', 'SimSun', 'FontSize', 12, 'LineWidth', 1.5);
box(ax, 'on');
hold(ax, 'off');
end
end
% ---------- UI Construction ----------
methods (Access = public)
function app = SeismicAlphaApp
app.UIFigure = uifigure('Name', 'Seismic Impact Coefficient Curve Plotting Tool', ...
'Position', [100, 100, 850, 650]);
app.setupAlphaTable();
app.setupTgTable();
app.createParameterPanel();
app.createResultPanel();
app.setupCallbacks();
app.updateDisplay();
end
function createParameterPanel(app)
app.ParameterPanel = uipanel(app.UIFigure, ...
'Title', 'Parameter Settings', ...
'Position', [20, 350, 810, 280], ...
'FontSize', 12, 'FontWeight', 'bold');
% Seismic Design Intensity
uilabel(app.ParameterPanel, 'Text', 'Seismic Design Intensity:', ...
'Position', [20, 230, 100, 22], 'FontSize', 11);
app.IntensityDD = uidropdown(app.ParameterPanel, ...
'Items', {'6 degrees','7 degrees(0.10g)','7 degrees(0.15g)','8 degrees(0.20g)','8 degrees(0.30g)','9 degrees'}, ...
'Position', [130, 230, 150, 22], 'Value', '7 degrees(0.10g)', 'FontSize', 11);
% Design Earthquake Group
uilabel(app.ParameterPanel, 'Text', 'Design Earthquake Group:', ...
'Position', [20, 190, 100, 22], 'FontSize', 11);
app.GroupDD = uidropdown(app.ParameterPanel, ...
'Items', {'Group 1','Group 2','Group 3'}, ...
'Position', [130, 190, 150, 22], 'Value', 'Group 1', 'FontSize', 11);
% Site Category
uilabel(app.ParameterPanel, 'Text', 'Site Category:', ...
'Position', [20, 150, 100, 22], 'FontSize', 11);
app.SiteDD = uidropdown(app.ParameterPanel, ...
'Items', {'I₀','I₁','II','III','IV'}, ...
'Position', [130, 150, 150, 22], 'Value', 'II', 'FontSize', 11);
% Earthquake Level
uilabel(app.ParameterPanel, 'Text', 'Earthquake Level:', ...
'Position', [300, 230, 100, 22], 'FontSize', 11);
app.LevelDD = uidropdown(app.ParameterPanel, ...
'Items', {'Most Likely Earthquake','Design Earthquake','Rare Earthquake'}, ...
'Position', [400, 230, 150, 22], 'Value', 'Most Likely Earthquake', 'FontSize', 11);
% Damping Ratio
uilabel(app.ParameterPanel, 'Text', 'Damping Ratio ζ:', ...
'Position', [300, 190, 100, 22], 'FontSize', 11);
app.ZetaEdit = uieditfield(app.ParameterPanel, 'numeric', ...
'Value', 0.05, 'Limits', [0.02, 0.2], ...
'Position', [400, 190, 150, 22], 'FontSize', 11);
% Plot Button
app.PlotBtn = uibutton(app.ParameterPanel, 'push', ...
'Text', 'Plot Curve', ...
'Position', [300, 150, 150, 30], ...
'FontSize', 12, 'FontWeight', 'bold');
end
function createResultPanel(app)
app.ResultPanel = uipanel(app.UIFigure, ...
'Title', 'Parameter Results', ...
'Position', [20, 20, 810, 310], ...
'FontSize', 12, 'FontWeight', 'bold');
uilabel(app.ResultPanel, 'Text', 'Maximum Seismic Impact Coefficient:', ...
'Position', [20, 250, 120, 22], 'FontSize', 11);
app.AlphaMaxLabel = uilabel(app.ResultPanel, ...
'Text', '', 'Position', [150, 250, 200, 22], ...
'FontSize', 11, 'FontWeight', 'bold');
uilabel(app.ResultPanel, 'Text', 'Characteristic Period:', ...
'Position', [20, 210, 120, 22], 'FontSize', 11);
app.TgLabel = uilabel(app.ResultPanel, ...
'Text', '', 'Position', [150, 210, 200, 22], ...
'FontSize', 11, 'FontWeight', 'bold');
uilabel(app.ResultPanel, 'Text', 'Current Curve:', ...
'Position', [20, 170, 120, 22], 'FontSize', 11);
app.FormulaLabel = uilabel(app.ResultPanel, ...
'Text', '', 'Position', [150, 170, 400, 22], ...
'FontSize', 11, 'FontWeight', 'bold');
% Instruction Text
infoText = ['Usage Instructions:\n' ...
'1. Select seismic design intensity, design earthquake group, site category, and earthquake level\n' ...
'2. Set damping ratio (default 0.05)\n' ...
'3. Click the "Plot Curve" button to generate the seismic impact coefficient curve\n' ...
'4. Key points and formulas are annotated in the figure, complying with specification requirements'];
uilabel(app.ResultPanel, 'Text', sprintf(infoText), ...
'Position', [400, 200, 380, 90], ...
'VerticalAlignment', 'top', 'FontSize', 10);
end
function setupCallbacks(app)
app.IntensityDD.ValueChangedFcn = @(~,~) app.updateDisplay();
app.GroupDD.ValueChangedFcn = @(~,~) app.updateDisplay();
app.SiteDD.ValueChangedFcn = @(~,~) app.updateDisplay();
app.LevelDD.ValueChangedFcn = @(~,~) app.updateDisplay();
app.ZetaEdit.ValueChangedFcn = @(~,~) app.updateDisplay();
app.PlotBtn.ButtonPushedFcn = @(~,~) app.plotCurve();
end
end
end