The United States has such a large GDP because 1/3 of it is the private healthcare industry. Another massive chunk is the government throwing tax dollars at a shell company of a shell company of a shell company that moves a government contract for construction around to each other 4 times, all subsequently increasing GDP.
I will grant them that it is very dangerous for them to build in Gaza due to the high probability of friendly fire from their allies indiscriminate bombing.
The bridge collapsing suggests that it may be affiliated with hamas.
Hamas had tunnel complex under the bridge