Problem $\backslash$#$5$:

A simply supported beam spans $10$ meters.

a$)$ Draw the IL for the bending moment at midspan.

b$)$ Calculate the maximum bending moment at MIDSPAN due to the load shown below.

c$)$ Using the absolute maximum moment method, calculate the maximum moment that is caused by AASHTO's HL$93$ truck load traversing the beam. Compare the results with those from part b$)$

d$)$ Repeat parts b$)$ and c$)$ if the span was $80$ meters

e$)$ Based on the above results for $\backslash (\backslash$mathrm$\{$L$\}=10\backslash$mathrm$\{$~m$\}\backslash )$ and $\backslash (\backslash$mathrm$\{$L$\}=80\backslash$mathrm$\{$~m$\}\backslash ),$ do you think designers have to always use the absolute moment method, or is calculating the maximum moment at midspan is close enough to the absolute maximum moment.