Updates regarding the new road geometry and bridge configuration were modeled in Synchro to demonstrate it efficiency. Incorporating a traffic circle where the existing island is located will allow for vehicles to redirect themselves if a wrong turn was made. Having a green arrow allowing cars to turn left prior to the light turning green would reduce traffic queues and alleviate congestion. Trying to widen the roads entering the intersection on all sides was an ideal option to reduce traffic queues, but since there’s limited space to do such, changing the duration of the existing traffic signals was the next best option. Roughly 750 vehicles are traveling through this area in the morning and evening each day. The peak AM travel time on Route 29 is roughly 8 AM and vice versa in the evening. Changing the timing of the traffic signals is one of biggest alterations possible to increase efficiency of flow.
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The maximum water elevation under the proposed bridge is 61.66 feet leaving a space of 2 feet to the lower cord of 64 feet, concluding that the proposed bridge design is in accordance with the design manual for bridges & structures published by the NJDOT requiring at least two feet of clearance above the freeboard of a 100-year flood.Īs mentioned earlier, the intersection of River Road and Route 29 does not have a lot of room to alter the existing road geometry. Lastly, the design of the proposed bridge is shown in figure 7 under the conditions of a 100-year flood event. The proposed levee system was deemed as unrealistic as the owners of the properties adjacent to the Delaware River would not accept levees that would obstruct their view of the Delaware River lowering their property value. The high flow method was set to be pressure calculating the backup water building up pressure in combination with the weir flow. The result of the model was set to the highest energy answer utilizing the method resulting in the greatest energy losses in order to achieve a conservative design.
The pier shape constant utilized in the modeling approach was 0.9. The modeling approach used for the proposed bridge for the low flow methods were set to compute the energy in standard step and the momentum with a drag discharge coefficient of 1.33 based on the shape of the pier. Proposed Bridge Design Under Conditions of 100-year Flood Event The dimensions of the proposed bridge are shown in the figure below. The width of the piers is 12 feet and the piers have a total height of 47.03 feet starting at elevation 17.97 feet up to the lower cord of 64 feet. A total of five piers at a center to center spacing of 250 feet starting at the center line station 200 up to the station 1200 were assigned to the proposed bridge. If this ratio is exceeded energy-based calculations are utilized instead of pressure and weir flow. The maximum submergence was set to be 0.98 restricting the allowable submergence ratio that can occur during the weir flow calculations over the bridge deck.
The weir coefficient used for the weir flow over the bridge deck in the standard weir equation was set to be 2.6 as the bridge is designed with a broad crested shape. The total width of the bridge deck along the stream is 28 feet, while the width of the roadway with two twelve feet lanes is 24 feet.
The dimensions of the proposed bridge are 6 feet of structural space between the low and high cord of the bridge.