Step $1$: Idealized Structure

We will represent the bridge geometry using a plane Howe truss. The final structure and the

applied external load are given below:

L

Figure $2$: Idealized Iruss Geometry

The member spacing is $L=30ft.$ The cross section of each truss member is constant and shown

in Figure $2$ above. Each truss member is made of A$992$ steel, which has $E=29,000$ksi.

Step $2$: Structural Analysis Using the Principle of Virtual Work

Question $2$: Calculate the mid$-$span deflection in vertical direction using the principle of virtual

work. Use A $=29\mathrm{.}41i{n}^2.$ Ignore the self$-$weight of the members and consider only the loading

shown in Figure $2.(15$pts$)$