How can I have one unstacked bar in an otherwise stacked bar graph

I have a stacked bar graph with several values and I want a 6th value that is not stacked. In the graph below I want the "shear demand at M_n" bar to be gray for example, and have its own spot in the legend. I can't figure out how to separate it from the other values though. Here is the code to produce the figure below:

estcap=[157.75 34.07; 94.34 84.57; 135.73 72.55; 70.16 13.07; 109.76 31.16; 0 146.15];
actcap=[159.4];
figure('name','A1, a/d = 2.5');
barg=bar(estcap, 'stacked','linewidth',1.5);
hold on
plot(xlim,[actcap actcap], '-k','linewidth',2);
legend('Steel Contribution','Concrete Contribution','Shear Demand at Failure','location','northoutside');
ylabel('Capacity (kips)');
Labels = {'1973-STD','ACI', '2012-SIMP', '2012-GEN', '2004-AASHTO','Shear Demand at M_n'};
set(gca, 'xtick',1:6, 'XTickLabel', Labels,'XTickLabelRotation',45); 
colormap gray
set(gca,'Linewidth',1.5);
hold off

I hope that makes sense, thanks in advance for any help.

Answer 1

[Kelly Kearney]

I would simply call add a second bar object, making sure to specify the x-locations for each bar. I also prefer to pass specific handles to the legend command; it's not always necessary but it gives you more control than assuming legend will grab the right objects in the right order:

estcap=[157.75 34.07; 94.34 84.57; 135.73 72.55; 70.16 13.07; 109.76 31.16; 0 146.15];
actcap = 150;

figure('name','A1, a/d = 2.5');
axes;
hold on;

barg = bar(1:5, estcap(1:end-1,:), 'stacked','linewidth',1.5);
bar2 = bar(6,   estcap(end,2), 'linewidth', 1.5, 'facecolor', ones(1,3)*0.8);
ln = plot(xlim,[actcap actcap], '-k','linewidth',2);

legend([barg bar2 ln], 'black', 'white', 'gray', 'line', 'location','northoutside');

ylabel('Capacity (kips)');
Labels = {'1973-STD','ACI', '2012-SIMP', '2012-GEN', '2004-AASHTO','Shear Demand at M_n'};
set(gca, 'xtick',1:6, 'XTickLabel', Labels,'XTickLabelRotation',45); 
colormap gray
set(gca,'Linewidth',1.5);
hold off

[Cameron Murray]

Okay, this is kind of the same direction I was thinking but I didn't have the right commands. Thank you so much!