×
The submission system is temporarily under maintenance. Please send your manuscripts to
Go to Editorial ManagerThis study addresses of contraction scour affect in Tigris River on Al-Nuhairat Bridge on the Basrah Governorate. It includes an analysis of key hydraulic variables and their interaction with the geological nature of the river and structural behavior of the concrete bridge, influencing the development of erosion. The data were entered and analyzed into the Federal Highway Administration (FHWA) hydraulic toolbox. The data were collected through a field survey of the bridge site and information obtained from the Directorate Irrigation of Basrah, some tests was also conducted at the Soil Laboratory of the University of Basrah. Two computational methods were used to determine the scour depth, erosion through clear-water and live -bed scour and cohesive soil erosion. The results of the study showed that the depth of scour in the live-bed and clear water flow method increases by 25% approximately with each increase in the depth of flow and the amount of discharge. However, in the cohesive soil method, it depends on the effect of the shear force resulting from the velocity and depth of flow, which is much less, as its effect is 1% approximately with each increase in these parameters. The results of each method were discussed in detail, and the necessary recommendations were made to mitigate the effects resulting from the occurrence of such a type of scour and its impact on the Al-Nuhairat bridge.
The finite element method is used to simulate the soil vibration behavior due to the Basrah-Baghdad passenger train and its effect on a targeted building in the Al-Ma'qal quarter, Basrah governorate. Three-dimensional dynamic elastic analyses are performed to calculate the particle velocities for a train speed of 120 km/hr. The effectiveness of screening using active (10 m long) open trench barriers with variable depth (2 m - 5 m) and width (0.4 m - 0.8 m), is being studied. For a given trench width (0.4 m), the results of the parametric study revealed a considerable effect of trench depth where the screening capability near the trench is increased by (10.4 %, 26.1 %, 36.3 %) due to a (50 %, 100 %, 150 %) increase in depth. The results are less sensitive to the variation in trench width. The screening capability of a double open (0.4 m × 10 m × 2 m) trench system was also investigated, where a mitigation improvement of (36.4 %) was achieved. The vibration mitigation using single and double trench systems, filled with (40 %) rubber content mixture, was also analyzed. It is concluded that using the additional passive trench increases the mitigation of the single system by around 19.1 %. An important finding is that the (40 % rubber + 60 % native cohesive soil) mixture proved to be a good filling material, since the infilled-trench systems produced comparable screening ratios to the open systems, where (97.7 %) and (85.4 %) were accomplished for the single and double systems, respectively.