Last year I completed a model of the Sydney Harbour Bridge in LEGO. It took over a year, and used almost 9000 bricks. The arch span is 3.5 metres long and just over 1 metre high, and is supported just like the real bridge with hinges at each end.Because I have no sandstone outcrops in my yard, I cheated and used LEGO baseplates to stop the abutments from spreading!

I designed the arch by drawing it on paper, then working out the lengths of each beam required to most closely fit. Because LEGO only comes in discreet lengths, it's not exact, but it's about as close as I could get.
Hope you like it!
My next project is the Story Bridge in Brisbane Australia.
ROSCO