I propose an enhancement in STAAD.Pro to simplify and automate the deflection check process for beam-type elements by facilitating the assignment of DFF , DJ1 , and DJ2 parameters, as well as the selection of appropriate load combinations for each deflection verification scenario.
The idea is to introduce a feature that allows the user, upon selecting multiple beam elements, to define in a grouped manner:
- The load combinations to be used for deflection checks.
- The deflection limit ( DFF ) value corresponding to each group of combinations.
- The automatic identification of the start and end nodes of each beam to correctly assign DJ1 and DJ2 , eliminating the need for manual input.
Additionally, it is important to consider that deflection checks are not carried out using a single DFF value, but rather different DFF values are required for different types of load combination groups , based on applicable design codes and project criteria (e.g., L/240 for gravitational loads, L/360 for service loads, L/500 for sensitive finishes, etc.).
This becomes especially critical in complex structural models with a large number of beam elements, where the current methodology—requiring manual definition of parameters for each element— becomes tedious, time-consuming, and error-prone , significantly reducing productivity and increasing the risk of inconsistencies.
Furthermore, an improvement is proposed in the output report generation:
Currently, the deflection check results are presented only as a ratio, without clearly showing the parameters used in the check. It is recommended that the output report explicitly include:
- The effective span length used ( L = DJ2 – DJ1 ),
- The deflection limit applied (based on the specified DFF , such as L/240 , L/360 , etc.),
- The specific load combination used for the deflection check.
This would enhance result traceability and allow easier validation and engineering review.
Key Benefits of the Proposal:
- Significant time savings in parameter assignment for multiple elements.
- Minimization of errors when assigning DJ1 and DJ2 manually.
- Greater flexibility to manage multiple deflection verification criteria.
- Support for checking different DFF values according to load combination types.
- Improved clarity and traceability in result outputs.
- Facilitates the handling of complex structures where the current workflow becomes inefficient and cumbersome.
Suggested Functionalities:
- Wizard or tool to select beam elements, define load combinations, and assign different DFF values by group.
- Automatic DJ1 and DJ2 assignment per element based on node positions.
- Option to save settings as reusable templates across different projects.
- Enhanced output reports detailing element span, applied DFF value, and the corresponding load combination used for each deflection check.
Many thanks for posting this idea. We do have an initiative to streamline the assignment of these parameters for serviceability checks which is currently underway.
Automatic Parameter Calculation
Incorporate a functionality that allows the program to automatically calculate the DFF, DJ1, and DJ2 parameters based on the model characteristics and defined load combinations. This functionality could include:
Automatic Model Analysis: The program could analyze the geometry and properties of the beam elements to automatically determine the optimal values for DJ1 and DJ2.
Intelligent DFF Assignment: Based on the load combinations and specified design criteria, the program could suggest appropriate DFF values for each group of load combinations.
Dynamic Adjustment: Allow the program to dynamically adjust the parameters based on changes in the model or load combinations, ensuring that the most appropriate values are always used.