Results – BuildSoft Support

How are moment, shear and normal force combined?

Dorothee — Wed, 24 Jan 2024 10:00:30 +0000

In the PowerConnect results, you see clearly see the interaction between moment and normal force.

But what about interaction with the shear force? The shear resistance is by default reduced by the maximum resisting moment . See ‘Analysis > Analysis options’, although you can choose to use the applied moment .

The formula used to calculate the resisting shear capacity of the bolts is (according to Eurocode 3-1-8 table 3.4)

takes both moment ( or ) and applied normal force into account.

How to understand a bolt row with 0 moment

Dorothee — Fri, 21 Apr 2023 12:45:07 +0000

In some cases, there are bolt rows with 0kNm resisting moment. This can be seen in the detailed result. What does this mean and how should you deal with this?

First, we need to point out the role of the the bottom bolt row. This bolt row is in the compression zone for a positive bending moment, and will always be at 0kNm. It is good practice to keep this bolt row in place, even with 0kNm. In combinations with a negative bending moment, this bolt row will be in the tension zone and become active.

Other, higher positioned, bolt rows can sometimes be at 00

How to get detailed results

Dorothee — Thu, 20 Apr 2023 12:21:40 +0000

When you click the calculator button, PowerConnect will default present the summary results. But there is is more to see. Click ‘results pref’ at the bottom right corner of your window to open the result options. Per load combination you can ask to see only the headers – short report, the components – containing more details, or the complete detailed intermediate calculation results.

If you want to compare your hand calculations with PowerConnect, the advice is to look at the detailed results. The summery results provide the best overview of the most important results so that you can judge if the current connection configuration is ok or not.

When to use Sj or Sj,ini in global analysis

Dorothee — Mon, 12 Jun 2017 14:03:51 +0000

In case of a semi-rigid joint, the effects of the behaviour of the joints on the distribution of internal forces and moments within a structure, (and on the overall deformations), should be taken into account. When these effects are sufficiently small they may be neglected, this is the case when you have a pinned or rigid joint.

Whether a joint is pinned, semi-rigid or rigid can be determined by comparing its initial rotational stiffness S_j,ini with the classification boundaries given in Eurocode 1993-1-8 §5.2.2.5.

The effect of the joint behaviour can be represented in a moment-rotation diagram or by a rotational stiffness value.

Possibilities to model the joint’s stiffness

Moment rotation diagram

Eurocode 1993-1-8 §5.1.1 (4) allows you to use any appropriate curve, including a linearised approximation, such as a bi-linear or tri-linear diagram. This last one is used in PowerConnect. If you are working with the Diamonds <> PowerConnect link, this tri-linear diagram is transferred to Diamonds automatically, ready to be used in the global analysis.

Example of the tri-linear moment-rotation diagram in PowerConnect

Rotational stiffness value Sj or Sj,ini

From Eurocode 1993-1-8 §5.1.2 (3) and (4) we learn that

(3) In the case of a semi rigid joint, the rotational stiffness S_j corresponding to the bending moment M_j,Ed should generally be used in the analysis. If M_j,Ed does not exceed 2/3 M_j,Rd, the initial rotational stiffness S_j,ini may be taken in the global analysis.

(4) As a simplification to (3), the rotational stiffness may be taken as S_j,ini/η for the analysis for all values of M_j,Ed, where η is the stiffness modification coefficient.

This means for the rotational stiffness:

you should always use S_j
but if M_{j_Ed} < 2/3M_j,Rd, you may use S_j,ini