Torsion Effect Analysis Of Cliff-structures On Cross Slope

Compared with ordinary structure, structures on the slope has significantdifferences due to different ways of grounding, one of which is that the torsion effect ofstructures on the slope is more significant because different heights of structures on theslopes cause the mismatching of the center of stiffness and mass. However, there is littleresearch on structures on the slope and no design specifications to follow, so it is anurgent need to provide a theoretical analysis for engineering design as a reference. Littleresearch has been taken on the torsion effect of structures on the slope under anearthquake. But in this paper the author makes an analysis of the torsion effect ofstructures on cross slopeunder an earthquake, focusing on the effectiveness of torsiondisplacement ratio control in the cliff-structure.In this paper, after establishing a numerical example model by SAP2000andPERFORM3D, the author makes dynamic elastic and elastic-plastic analysis ofcliff-structure, investigates the effect of static eccentricity and strength eccentricity oncliff-structure, compares the difference of torsion effect of normal structure and cliffstructure, and initially proposes a series of structural strengthening methods applicableto anti-torsion and plans applicable to anti-torsion.The main conclusions are achieved as follows:①The torsion of cliff-structure under cross slope force is inevitable and the torsiondisplacement ratio is beyond our general code limit, from which we can conclude thatconventional torsional displacement ratio is not acceptable to cliff-structure;②Under the effect of earthquake ground motions, torsion effect of cliff-structureno longer a linear relationship with the growth of static eccentricity and strengtheneccentricity’s effect on torsion effect ofcliff-structure is not significant. Cliff-structureunder earthquake action does not appear a "strong column weak beam" damage modesince beams, columns of off layer part suffer a lighter damage while the damage ofground columns of upper layer is quite serious, The structure cannot have satisfied totheseismicfortificationtargetof No Collapsing in the StrongEarthquake, which needs tomore attention;③The plastic rotation and component continuation of the ground columns ofcliff-structure, the side column in particular, is significant under the effect of earthquake.So we can multiply an increased coefficient from greater than1when calculating the reinforcement of the side column ground pole to improve the level of anti-seismic of theupper layer ground column;④Cliff-structure which whose off the layers and spans are very large cannotcontrol the torsion of thestructure by adjusting the structure;If we add partial shear wallin the off layer part, the torsion effect of structures supported by foundations withdifferent locations can be reduced. If the off layer is a frame shear wall structure and ifthe upper layer is a frame structure, the upper layer can be regarded as a transformationlayer.