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Examination of fracture bridge across the river Gums

Organization of the Russian Environmental Fund "TEHEKO" was created in order to implement programs of environmental, financial and economic, industrial and technological security of enterprises and organizations.

By order of the organization "TEHEKO" was performed strength analysis of the pillars of the bridge across the Desna River.

  Construction of models and the full range of calculations were carried out using 64-bit version of the design module APM Structure3D.

 

 Concept of the problem:

 

In the process of reconstruction of the bridge at a certain stage of dismantling the old span beams, was its destruction. The main objective was to review and analyze the behavior of how the individual supports and the whole of the bridge as a whole, in various stages of disassembly of superstructures on the right side of the bridge, in accordance with the implementation schedule.

 

 Calculation of bridge construction:

 

Within the framework of a given problem, we consider the calculation of the fourth support, as well as the calculation of the bridge, beginning with the fourth bearing and finishing ninth.

 

Modeling support №4

 
Total estimated №4 support scheme is executed in module APM Structure3D. Reliance №4 to dismantle
 
Total estimated №4 support scheme is executed in module APM Structure3D. Reliance №4 after the dismantling of the beams on the right side of the bridge

When building the model there are two types of finite element (FE) modeling for finite element solid concrete core and FE modeling for reinforcement.

 Consistency operation is ensured by a complete coincidence of nodes and rods solids. To obtain a reliable picture of the best way to approach the distribution map of the principal stresses S1. Positive values ​​of the principal stresses will characterize the stretching zone.

 
Map of the distribution of the main stresses for the calculation №4 support model to disassembly
 
Map of distribution of principal stresses for the calculation model supports №4 as after dismantling
 
The distribution map of normal axial stress for the design bearing model №4do dismantling
 
The distribution map of normal axial stresses for the calculation model №4 after the dismantling of support.

As seen from the results in the card edge docking location and support body has a splash tensile stresses. However, this spike is, only the result of error modeling docking space, characterized by the transition from 8 to 4 ex-nodal finite element. The actual level of effective stresses must be evaluated at 2-4 and a layer of finite elements will be slightly lower value by about 10-15%.

The figures below show the consistent interface disclosure in support of manufacturing defect area due to significant tensile stresses.

Card distribution of principal stresses on the support №4 after dismantling

 
The first step of changing the calculation model
 
The second step of changing the calculation model
 
The third step of changing the calculation model
 
Fourth step of changing the calculation model

imulation supports №4-9:

 

Now consider a model of three pillars of the bridge as a unified design scheme in the last stage of dismantling the old span beams right side of the bridge.

To simulate the compatibility with adjacent elements bridge spans the right end beams (length which is exactly half the real beam length) fixed by preventing movement along the beam axis, thereby providing accounting and the presence of adjacent support beams span

 
Calculated bridge circuit with dismantled right beams untrapped
 
Map of distribution of principal stresses in the final stage of dismantling the old span beams right side of the bridge supports for №4-9
 
Map of distribution of principal stresses in the final stage of dismantling the old span beams right side of the bridge supports for №4-9

Modification of the bridge at the last stage of dismantling the old span beams right side of the bridge are shown in the figures below.

 

Card distribution of principal stresses on the supports №4-6 after the dismantling of the old span beams right side of the bridge.

 
1st stage
 
2nd step
 
3rd step
 
Photo from the site of the destroyed bridge

Conclusions: 

 

The work was performed in its entirety. The results obtained are reliable and confirmed by the real picture of the destruction of the bridge. 

The calculations are performed Shanin Dmitry

 
 
 
 
 
 
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