Kirkuk Journal of Science (Jun 2007)
Dynamic Loadings Of Precastretaining Walls
Abstract
The research aims for the selection of a suitable retaining wall amongst two types of precast concrete walls under dynamic loads (wave pressure). The first wall is of a triangular cross section and has the dimensions (3)m (in height) by (2.2) m (in width) by (0.25-0.3) m (in thickness) and the width of piece (1.44) m. The second wall has dimensions of (6.4)m (in height) , (3.5) m (base width) and thickness (0.18-0.3) m with the width of piece (2) m .Tests were carried out on both to establish the stability characteristics by the factor of displacement for the composite walls of both specimens, and comparing the results with those of the theoretical analysis. The first specimen showed very little displacement under dynamic loads resulted from a load of (125) kg of charge weight at a distance (10) m , and compares reasonably with the analytical calculations which give only (3-5) cm. The second specimen, with steel frame showed a displacement of (5) cm compared to the calculated displacement of (14) cm when tested from a load of (125) kg of charge at distance (15) m. The rotational characteristics and overturning behavior for the walls, in both specimens showed no signs of rotation or overturning .This was predicted by analysis since the subjected loads were well below the required loads which caused rotation or overturning. The subjected loads were a third and half of the required load for (rotation and overturning) for the first and second specimens respectively. The results of the equations for both pressure and displacement are greater than the experimental results. Also it was shown that the presence of retaining precast walls did not prevent negative wave pressures and this is natural as it is less effective than the positive wave pressure and its impact is limited on reinforced concrete structures. The linear acceleration measured by linear acceleration devices showed an acceleration equivalent to five times the earth gravitational acceleration which reflects itself by shaking of the concrete walls. The vertical angle of inclination of (20o) showed clear effect in dissipating wave pressure.
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