General Information
Figure 1 shows a pedestrian frame bridge.
![Pedestrian steel frame bridge over an irrigation canal](bridges/frame-bridges/bridge-1/1-frame-bridge.jpg)
Main span: | ≅ 6 m |
Width: | ≅ 0.8 m |
Girder: | Steel frame |
Structural Behavior
Figure 2 shows the bridge.
![Pedestrian steel frame bridge](bridges/frame-bridges/bridge-1/2-frame-bridge.jpg)
The frame is made of U-sections, the deck of L-sections, and the safety barrier of circular hollow sections. The safety barrier has a truss-like geometry and is connected to the frame as shown in figure 3.
![Connection between safety barrier and steel frame](bridges/frame-bridges/bridge-1/3-frame-barrier.jpg)
The safety barrier is connected to the web by transverse members (weld connection). Supposing that the safety barrier does not have transverse members and is connected by welding to the upper flange, as shown in the schematic three-dimensional view in figure 4.
![Three-dimensional view of a pedestrian steel frame bridge](bridges/frame-bridges/bridge-1/4-3d-view.jpg)
Structural Model
Figure 5 shows the bridge.
![Pedestrian steel frame bridge](bridges/frame-bridges/bridge-1/5-frame-bridge.jpg)
The frame is trapezoidal shaped. Figure 6 shows three structural models.
![Structural models of a frame bridge](bridges/frame-bridges/bridge-1/6-structural-model.jpg)
All models have the same constant cross-section, material parameters, span to height (h) ratio, and uniformly distributed load (p). The supports are of type pinned (triangle) and roller (circle).
Which is the model with the greatest normal force?
Consider a steel frame and a RC abutment. What are some possible constructive details of supports B1 and B3?