The study of fourth order differential equations has recently intensified in the context of studying the behavior of traveling waves for nonlinear suspension bridges. I will present a blow-up result for the equation
\[
u^{(4)}+ku''+f(u)=0
\]
where $f$ is super linear with $f(u)u>0$ and when $k>0$. Previous work by Gazzola and his collaborators solved the case $k\leq 0$. The case $k>0$ is physically significant as it corresponds to $k=c^2$ with $c$ being the speed of propagation of the traveling wave.