ABAQUS model of local stress of bottom plate and web under the action of steel box girder jacking

1. Calculation basis

1.  Code for design of steel structures （GB50017-2003）

2. Model building

The steel box girder of the project is orthotropic plate , The roof is thick 16～24mm、 The bottom plate is... Thick 14～24mm, Most of the longitudinal ribs of the roof are made of T Shaped rib ,T Specification of V-ribbed panel 12×100mm、 Web size 10×150mm, The top plate at the cantilever arm adopts flat plate ribs locally , Stiffener plate specification 16×180mm、16×160mm、12×120mm; The longitudinal rib of the bottom plate also adopts T Shaped rib ,T Specification of V-ribbed panel 12×100mm、 Web size 10×150mm; Steel box girder is set with 3 A vertical web , Plate thickness 14～24mm, Inside 、 Outer web 3 A flat stiffener , The middle web adopts 6 Flat stiffeners , Stiffener plate specification 14×150m; The layout spacing of the standard section of the diaphragm is 2m, The diaphragm is... Thick 12mm; The thickness of diaphragm plate at the fulcrum shall be strengthened to 24mm. The steel plate is made of Q345qD.

The specific structure is shown in the figure below .

In order to eliminate the influence of boundary conditions on the calculation results , This report is based on the general finite element software abaqus and midas establish 15 rice ,11 Refined model of m-long standard section girder , The unit type is shell,midasz The medium element type is plate element , The elastic modulus of steel is 2.0e11, Poisson's ratio 0.3, density 7800kg/m^3.

The boundary conditions of the model are as follows ：

1.   The end of the main beam is restrained at one end 6 Degrees of freedom in two directions , Equivalent to consolidation , The other end of the main beam develops longitudinal displacement along the bridge , Constrain vertical and lateral displacement .

3. Content of stress analysis

The figure shows the displacement and deformation of a section of steel box girder during jacking , The maximum deformation at the midspan is 16mm

The picture shows the stress of steel box girder during jacking , It can be found that the maximum stress at the web is 47mpa, The bottom plate stress does not exceed 345mpa, The steel plate is in elastic state , The structure is relatively safe .

The above calculation results show that , The local stress near the midsection and bottom plate in contact with the bottom surface is large , At the same time, construction errors should be considered , And the uncertainty of the distribution proportion of the side slide , Therefore, the slide area of the original structure shall be reinforced .