Arrangement of pressure detection p

Arrangement of pressure detection points:Pier top cast-in-site segment center, continuous beam cantilever root, L/8, L/4,3L/8, L/2(among which, L is the main span of the bridge)sections and the end of side span are control sections.Besides all of the above, the support reaction should also be detected.According to the result of detection, the stress state of box beam in the construction can be acquired which ensures construction safety.Meanwhile, the stress of each point on completed bridge also can be measured to verify the design bearing capacity of the bridge.Description of Balance Cantilever Construction Process(32+48+32)MNo.0#Section ConstructionConstruction of Side-Span Closure SectionFrame Abutment/Portal AbutmentScaffold adopts bowl-shaped all-round scaffold with Φ 48 mm and wall thickness of 3.5 mm.Spacing of scaffold poling:spacing along the bridge direction under end cross beam and middle cross beam and spacing along poling in all directions shall be arranged according to calculated data.Adjustable strong collets shall be installed under each poling, which facilitates load bearing of foundation, and through adjusting height of collet to make cross-bar bear stress in horizontal direction.Adjustable jacking shall be installed in top of backing deal to facilitate construction of subsequent procedures, such as elevation adjustment and falling.The step of cross bars are 120 m, expect for two in the top most is 60 cm. For increasing rigidity and stability of scaffold, Φ 50 steel pipe will be used in transverse and longitudinal direction, rods will be set every five rows, and one row of diagonal bridging will be arranged in scaffold respectively along overall height of scaffold.Included angle between diagonal rod of diagonal bridging and ground shall be controlled within 45° ~60° and diagonal rod must be connected with poling firmly by fastening; along longitudinal axis direction of bridge, square timber of 15 cm X 15 cm shall be arranged in jacking of scaffold, and then horizontal square timber of 6 cm X 10 cm shall be arranged on the square timber to serve as stressed framework of box beam bottom formwork.Spacing of vertical square timber and spacing of scaffold horizontal bridge direction shall be arranged according to the calculating data; and spacing of horizontal square timber under beam and spacing of other horizontal square timbers shall be arranged according to calculating data.All square timbers can be used after thickness treatment and processing; two stress surfaces of square timber must be flat and with uniform thickness.Cross point of transverse and longitudinal square timber shall be connected by iron nails and cramps to form whole stressed point, and plywood(plywood is connected with framework of square timber by iron nails)with thickness of 18 mm shall be put on whole stressed point as bottom formwork.Scaffold prepressingFormwork processingInternal formworkPrestress initial tensioninyReinforcing steel bar of bottom slab formwork Reinforce steel barBottom and formwork concreteInternal formwork reinforcing steel barTop slab concrete pouringScafford and external formwork removingMud jacking and seal anchorPrepressed final tensioningInternal lateral formwork removingDiagram of Frame Abutment Cross Beam Construction ProcessConstruction method of all-round scaffoldScaffold foundationErection of all-round scaffold adopts bowl-shaped scaffold.When construction, scaffold foundation must have sufficient bearing capacity, non-uniform settlement shall not be occurred.Its foundation type, area and thickness shall be determined according to scaffold structure type, stress condition and foundation bearing capacity, and C20 concrete with thickness of 25 cm shall be used, meanwhile, drainage treatment of ground must be done and drainage ditch shall be set.Two layers of crossties are paved in the processed ground foundation according to design distance, so as to reduce stress of foundation, and the tray under the bowl-type scaffold shall be in the upper crosstie directly.Adjustable screw shall be set in scaffold top of steel pipe to adjust elevation of bottom formwork Channel steel distributive beam is set in adjustable screw, vertical square timber is put into the distributive beam, and then bottom formwork and lateral formwork shall be laid in square timber.Steel pipe shall ensure that horizontal and vertical are in straight line.All above mentioned constructions shall be laid according to design horizontal and vertical distance strictly.Setting for camber of constructionEqual-load prepressing of scaffoldAfter scaffold of box beam is erected and bottom formwork of box beam is paved, prepressing shall be loaded to scaffold according to 1.2 times of dead load of beam, non-elastic deformation of scaffold and to act as basis of reserved camber of construction.During prepressing, settlement value shall be measured by stages,