Abstract
To ensure the stability of the bottom under the floating bridges according to the worst conditions, our study aims to determine the height and width and bearing the floating bridge to ensure the safety of origin with a high security factor. Our study determines the amount of damage under the floating bridge to be treated by a treatment method. We have used a practical model for a water channel and standard dimensions cut by the floating bridge connecting the two ends of the channel and when studying the erosion under the floating bridges and the possibility of maintaining the floating bridges without damage to the structure and perimeter of the bridge (bridge width, maximum load, bridge height, water depth in the channel with a factor Security This study examines the effect of floating bridges on the bottom by designing a model of a channel with a floating bridge and selecting a variable earth and sand floor. We conducted one hundred and sixty-eight experiments to examine the five variables (water depth in the channel, bridge width, loads on the bridge, soil type) Bottom, flow). We observed the effect of these five variables on topography of the bottom of the floating bridge. Experiments were conducted without a bridge and we observed erosion after laying the bridge, we noticed the erosion and sediment that occurred before and below and after the floating bridge and the effect of the bridge on it. We observed the type of positive and inverse relations between the variables mentioned. We took the loads on the bridge, the width of the bridge, the depth of the water and the drainage with a safety factor, as well as ensuring that the appearance of the channel and maintain the geometry of the channel. We put floating loads on the floating bridge to see a load. We used several models to view the floating bridge and made the water depth in the channel change more than once. We also made three different discharges. Finally, we used two types of soil and we recorded the durability and the worst conditions. The effect discharge, by (100% .64%, 45%) The velocity in the sandy soil changes (100%, 42%,38%) and the velocity in clay soil changes (100%,59%,41%) As well as change the width of the bridge by (100%, 85%,71%)velocity changes by (80%,82%,100%) for sandy soil and the ratio of clay soil to (90%,95%,100%) As well as weight change by (100% ,83%,66%)the rate of velocity in the sandy soil to (100%,78%,61%) also change the velocity in clay soils to (100%,68%,62%) as well as depth change (100%,87%,75%)The speed in the sandy soil changes to (50%,75%,100%) and also changes in clay soils by (71%,78%,100%) Thus, we have a knowledge of the rates of change and the effect of each variable on velocity.
Therefore, we can draw up a plan to address erosion and sedimentation in the watercourse. Moreover, identify the expected challenges of (overload, flooding, deterioration, foot and aging as well as the structural strength of the bridge gradually decreasing with the foot.