Consider the structure shown in Figure. The distributed load, w$,$ is random variable with mean value$=6\mathrm{.}5$ k$/$ft and COV$=0\mathrm{.}25.$ Assume other loads can be neglected. Both members are made of perfectly ductile material. For beam AC$,$ consider only the negative moment at point B $($do not consider the maximum positive moment between A and B$).$ The mean$-$moment carrying capacity at B$,$ RAC, is $95$ k$-$ft and its COV is $15$ percent. Tension member DB is made up of two parallel bars, each with the mean tensile strength of $60$ k and COV$=0\mathrm{.}12.$ Calculate the system reliability index assuming that all members are uncorrelated. beam AB$=10$ft$,$ AC$=15$ft $,$ and tension rod DB $=9$ft and the load distrubuted on member AC