1. Bridges

2. History of Bridges How many of you notice bridges? Essential to modern travel –People –Goods –Services

3. Early Bridges Incidental bridges –Fallen logs –Not realiable Primitive Bridges –Single rope –People not goods Rope Bridges –Suspension bridge with sophisticated design –Allows for light loads

4. Modern Bridges Stone Arch Bridge –Among strongest and most durable –Compression –Expensive Steel Arch Bridge –Steel arch is compressed and the cables holding up the roadbed are in tension

5. Modern Bridges Suspension Bridges Has the longest span Efficient materials Use steel cable under tension to hold up roadbed –Individual strands hold 1000’s of lbs

6. Modern Bridges Truss designed bridge –based on the geometric rigidity of the triangle and composed of straight members subject only to longitudinal compression Cantilever Bridges –Truss bridge –Built toward center from each bank then joined by center section

7. Modern Bridges Steel Truss Bridge –Not able to span great distances –Easy and quick to assemble –Mostly used for railroad bridges