orthotropic bridge deck FEA simulation (improved)

Abbreviations and explanations

• OBD = Orthotropic Bridge Deck
• HGV = Heavy-Goods-Vehicle

Introduction

This is taking my 6th June 2016 initial orthotropic bridge deck simulation , then

• all geomtric features remain identical
• the boundary movement constraints are changed to better represent an OBD
• the load is changed to 50000N (5tonnes-force) spread over a 0.1m-square area (approximately representing a HGV's tyre-contact-patch)
• the mesh is refined and the the elements are changed from corner-nodes (only) to (with) midside-nodes ie "quad4" to "quad8"

Obvious imminent improvements to apply

A single HGV would have more tyres (tires) landing on this OBD section, at the axle-spacing - which the model would benefit from being included in the load-condition.

Would the "external" constraint conditions for an OBD-section be better represented by applying no-movement/no-rotations to the ends of alternate T-bars?
(Are the plane-of-symmetry conditions in this model reasonably realistic?)

Number of elements and nodes

• Elements : 19392
• Nodes : 57757

The model

Geometry and meshing

Upside-down view, showing ribs and T-bars

End-view, upside-down, showing meshing of T-bar web

Deck surface, as would be seen in a "fly-by" of the bridge

Local view showing mesh details and constraints

Details of geometry and matching of mesh where ribs and T-bars join is one aspect shown here

Movement constraints and load-application of the model

These images are very cluttered.
The constraints (shown in red) and loads (shown in green) are:

• the "z-ends" cannot move in the x-, y- and z-directions (load passes to some unseen support here), nor can they twist in the x-direction (it's a plane-of-symmetry, with this OBD section connected to its mirror-image identical in geometry, restraint and load)
• the "x-edges" cannot twist in the z-direction (is another plane-of-symmetry)
• The applied load lands over a small area at the mid-width, midway between two of the "T-bars"

The computed structural behaviour

Deflection under applied load in the vertical ("y") direction

Deviatoric (tendency-to-deformation) stresses caused by the loading

(R. Smith, 02Oct2016, 04Oct2016)