BRIDGE DESIGNER II (BD2)
is a versatile Bridge Design software package, which addresses the varied requirements of Pre-stressed Concrete Bridge Analysis and Design.

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BD2 uses basic matrix structural analysis formulation combined with time-dependent material properties, to carry out a Time Simulation of Bridge Designs under construction. During this process, all stress conditions are checked at every construction step as well as in service.

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Displacement Method The current release includes a standard plane-frame, two-dimensional displacement method. The field of unknowns is the vertical plane (coordinates x and y, and rotation r). Various stiffness components may be inserted in the global stiffness matrix, such as support stiffness and restraint stiffness (boundary conditions).

Specific Concrete Segmental Bridge Design Features:

• Unlimited number of components (nodes, segments, post-tensioning tendons, spans, construction phases, etc…)
• Time Dependent Material Properties (Concrete Creep, Shrinkage and Steel Relaxation)
• 3D Post-Tensioning Geometry with automatic initial and long term PT losses (Tendon stress, de-stress and grout)
• Non-Linear Cable-Stay Analysis (Stay stress, de-stress, re-stress)
• User defined boundary conditions and Construction Phases
• Time Dependent Stress redistribution
• Service Loads – AASHTO Stress Combinations
• Microstation-compatible (DGN) file export

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Time Simulation of Construction Sequence The construction of a structure may be simulated in great details. Concrete segments may be poured in-place or pre-cast and assembled. Tendons and stays may be stressed or de-stressed. External loads (concentrated or distributed) may be applied at any time, anywhere on the structure, moved on various sections, or removed. The construction time steps account for the correct concrete age throughout the construction, as well as proper evaluation of time-dependent strains.

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The analysis performed by Bridge Designer is a two-dimensional displacement method based on the assumption of linear elasticity and the condition of static equilibrium. Under any loading condition, a structure may be broken down into elementary pieces that behave in accordance with the Theory of Elasticity. In addition in the range of small displacements and assuming that the material remains elastic, this behavior is linear, and the Principle of Superposition of the deformations and stresses applies

Long Term Redistributions
Time dependent effects are evaluated during and after construction. Creep is handled as an internal load-case to simulate the effect of restrained long term strains. Shrinkage is also applied as an internal load, although it is independent of the stress level in the material

Service 2000
The new Bridge Designer Service 2000 Module was developed to check bridge structures under different service codes. It provides a flexible user defined live load generator, as well as a service code definition language (macro instructions). This user-driven environment lets you use the US AASHTO code as well as redefine service codes as complex as the British Standards 5400 or the up and coming LRFD code for the United States.