CT model experimental research on cable saddle zone of extradosed bridge

Most of cable saddle test and theoretical study about extradosed bridge consider that the normal force on arc wall of embedded pipe is evenly distributed. The approximate load simulation will affect the accuracy of analytical results. Referring to the typical cable saddle structure of extradosed bridge, a polyurethane model was produced for this paper. Through a series of CT scan experiment, we obtained contact interface images under two loading conditions. Interface analysis based on image processing technology can provided displacement values of key points on the contact interface. Then the displacement values were applied as loads on the corresponding ANSYS finite element model. Results show that: 1) the contact normal pressure is nearly cosine distribution instead of uniform distribution; 2) There exist stress mutations around the junction of straight line and arc if the embedded pipe adopts "straight-arc-straight" design form. 3) Construction deviation may make excessive extrusion called "end effect" between cable and the exit of embedded pipe, causing the concrete near pipe edge appear stress concentration.