Bridge design in SCIA Engineer

 

2012.0

Brief introduction

A bridge design requires specific calculation rules which are only needed for the analysis and design of this type of civil engineering structures. Take for example the input of combinations. A bridge is subjected to specific types of loads like traffic loads, foot travel by pedestrians, conduits used for the movement of goods and materials, and so on. But next to this, also standard loads like wind and snow may be present. The combination rules are described in Eurocode 0. To facilitate the user, bridge combinations are automatically generated and the decomposed combinations are set out for having sufficient transparancy during this process.

These combinations are available for 3 types of bridges: Road bridges, Footbridges and Railway bridges.

Next to this, design rules for prestressed and reinforced concrete bridges are implemented. This includes new concrete grades, several checks (redistributed bending moment, min and max characteristic strength, reinforcement classes for ductility, detailing provisions, decompression check and crack width) and extension of the National Annex library.

Detailed Technical information

Short description

Combinations

The module Bridge Load combinations allows the user to define load combinations for bridges according to EN 1990 and EN 1991-2. Load combinations can be defined for 3 types of bridges:

  • Road bridges
  • Footbridges
  • Railway bridges

With the enhanced combination generator in SCIA Engineer, Decomposed EN combinations are obtained from original combinations and from these, bridge envelope combinations are automatically generated.

To prevent mistakes during the input of the combination, a filter has been added which facilitates the user to create either a combination for buildings or for bridges.

It is known that the bridge combinations are rather complex due to the big range of Psi factors (safety factors) and the numerous combination rules for the specific types of loads. To make this more transparant for the bridge designer, a dialog has been added to SCIA Engineer which shows the decomposed EN combinations.

Click here to watch the short introduction to Bridge combinations in SCIA Engineer

 

Concrete

  • New concrete grades according to EN1992-2 have been added to the material library
  • Time dependent analysis is enabled for concrete grades with strength fck ≥ 55MPa according to EN1992-2, Annex B.
  • The National Annex library has been extended with numerous National Annexes according to EN 1992-2
  • Checks on minimal and maximal characteristic cylinder strength (fck,min and fck,max)
  • Check on allowed reinforcement class for adequate ductility: the allowed class for nonprestressed reinforcement are B and C. If the low ductility class A is used, an error message is given.
  • Formulas for the redistribution of the bending moment according to clause 5.5.4(104) are implemented
  • For a crack check, it's important to know the maximum crack width for each exposure class. These values are integrated in SCIA Engineer.
  • The decompression distance of prestressed concrete is now also checked for bridge design: i.e. the required perpendicular distance from the edge of the prestressing strand or duct to the neutral axis where the concrete has to be in compression.
  • Check of minimal diameter of transversal reinforcement for columns.

Detailed information

Astrid Bastiaens

03/06/2012