Now available: Allplan Bridge 2021

Allplan Bridge
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Allplan Bridge is the professional BIM solution for modeling, analysis, design, and detailing. Engineers work with a single solution from parametric model creation with high level of detail including pre-stressing to integration of the construction process, structural analysis, and reinforcement design and detailing.

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Allplan Bridge 2021

Earthquake Load

Allplan Bridge uses the multi-mode Response Spectrum Method for evaluating the effects of seismic loading. The solution consists of 2 separate tasks in the calculation procedure, firstly the determination of the relevant natural modes of the structural system and secondly the evaluation of the response spectrum prescribed in the design code.

Calculation of Eigen Modes

The natural modes of the structure are calculated on the undamped system by determining the roots of the homogeneous equation system [K]*u - Ω2*[M]*u = 0. A subspace iteration scheme is used to find the eigenvalues of this equation system and thus the natural frequencies Ω and relevant displacement directions for computing the mode shapes. Further also the mass matrix is required, representing the vibrating masses of the structure, as governing parameter of the Eigen value calculation. In the program, the self-weights and superimposed dead loads as defined for the static load-case calculation and any further user defined mases are considered for calculating a consistent mass matrix.

Response Spectrum Analysis

In case of an earthquake, the actual extent of excitation of the different natural modes is dependent on the direction of the seismic waves (ground accelerations), the corresponding mass participation and on the damping behavior of the structure. The analytic solutions for typical structures and unit impacts are provided in the design codes as relevant response spectra, specifying the relevant proportionality factors for the individual eigenmodes dependent on the natural frequency. The calculated amplitudes related to the individual natural modes are superimposed using different methods described in literature. The program offers the ABS-method, the SRSS method, and the Complete Quadratic Combination (CQC). Three separate calculations are provided to consider different possible earthquake directions, transverse, longitudinal and vertical directions. These different cases are combined to get finally the envelope of extreme values.


The table definition and visualization of the combination scheme allows for highest usability and perfect overview. The table form gives the user an overview not only of the defined load factors but also of different types of combinations. The combination type becomes an important attribute when the code-based design is performed. It allows specific design procedures for automatically using the corresponding combinations.

Allplan Bridge 2021

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solution for Bridge Engineers



Creep, Shrinkage and Relaxation according to JTG and Korean Standard

Particularly important for the construction stage analysis of prestressed and reinforced concrete structures is the correct consideration of the time-dependent effects. In Allplan Bridge the calculation of creep and shrinkage of concrete and relaxation of prestressing steel is code-compliant and now also available for Chinese and Korean Standard.

Code-Based Design

Once the global effects are calculated and the relevant envelopes have been created the user can perform code dependent design tasks to determine the required reinforcement content. After the reinforcement area has been calculated or manually specified, ULS and SLS checks can be performed according to EN code, and ULS flexural capacity checks also according to AASHTO LRFD.

Further New Features

There are many further features and improvements included in this version. An important new functionality is the possibility to interactively moving a station or a section. Furthermore, it is possible to interactively displaying the cross-section at any point along the structure. This gives the user a better control of the parametrically defined geometry. Some new features are available also for tendon modeling. For example, it is possible to use a longitudinal eccentricity for the tendon point definition. This minimizes the necessary definition of stations. A further new functionality is a sophisticated tendon report, which generates an Excel sheet containing not only geometrical data but also certain analytical data, e.g. the initial forces in the tendon. What is more, the construction sequence calculation is extended with a detailed computation of camber values, which are exported to an Excel sheet.

Technical support from bridge experts

ALLPLAN’s bridge design experts have over 30 years’ experience supporting engineers worldwide. ALLPLAN’s clients can benefit from our technical experts providing comprehensive consultancy, training and support.

ALLPLAN Infrastructure GmbH
Andreas-Hofer-Platz 17/4, 8010 Graz, Austria
Telephone: +43 316 269786