Construction Deviation Field Test and Geometry Analysis of Continuous Beam Assembled by Short-line Match Casting Segments
Short-line match casting is a method of producing segmental pre-cast concrete bridges,but its construction deviation is almost inevitable,derived from segments manufacturing size,weight,assembling timing,temperature,seam width,prestress,etc.This destroyed assembling geometry and deviated from the target.Setting seam shims could effectively rectify the deviation of assembling geometry,but also caused incomplete seam,water seepage,prestress loss,weakening of the overall stiffness.All the same,there was no other effective way to rectify deviations.The construction deviation and its influence on the assembling geometry were investigated in this paper.It carried out field test on a continuous beam assembled by short-line match masting segments.Three-dimensional point cloud data was collected for virtual assembly and geometric control of segments.Segments weight,temperature,and seam width were monitored to obtain its construction deviation characteristics.To analyze its influence law,the characteristics was imported into the finite element model on the continuous beam bridge.The strategy and method of geometric control were also discussed.The results of field test and finite element analysis show that the deviation of segments weight is between-6％and 6％,while the total weight deviation of the segments on the same side is about 4.5 tons,which is only 1/10 of a single segment weight.It also provides other construction deviations from field test.Compared with the maximum deformation caused by dead load of continuous beam,these deform bending deflection about 259.2％,108.9％,81.8％,20.5％,9.0％,and 7.5％,respectively correspond to segments manufacturing size,temperature,seam width,assembling timing,weight,and prestress.Segments manufacturing size is the most important factor of all the construction deviation,which indirectly affecting segment weight and seam width.The first segment assembled by short-line match casting plays a key role on geometric control.A maximum vertical displacement deviation of 83 mm could be generated by segments manufacturing size.The segment inverse prefabricated method and'two-level deviation rectify'method were put out to control geometry accurately.
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