Steel ConnectionsProgram to calculate steel structures connections

according to EC3 and DIN18800

Steel Connections

The theoretic basis of the program covers the following types of joints:

1. Nominally pinned joints2. Rigid joints3. Semi-Rigid joints4. Full strength joints5. Partial strength joints

Theoretic Analysis Overview

The program classifies the beam to column joints by their stiffness in:

1. rigid2. semi rigid and3. nominally pinned joints.

The program Steel Connections calculates and designs connections in steel frames. The analysis and the dimensioning is based upon either EC3 or DIN 18800.

Steel Connections

Analysis TechniquesType of joint model Method of global analysis Classification criterion Used connections

Simple All Stiffness Nominally pinned

Strength Nominally pinned

Continuous Elastic Stiffness Rigid

Nominally pinned

Rigid Plastic Strength Full strength

Nominally pinned

Elastic - Plastic Stiffness Rigid

Nominally pinned

Strength Full strength

Nominally pinned

Semi continuous Elastic Stiffness Semi Rigid

Rigid

Nominally pinned

Rigid Plastic Strength Partial strength

Full strength

Nominally pinned

Elastic Plastic Stiffness Semi Rigid

Rigid

Nominally pinned

Strength Partial strength

Full strength

Nominally pinned

Steel Connections

Connection Classification

By Stiffness

1. Rigid2. Semi-rigid3. Nominally pinned

By Strength

1. Full-Strength2. Partial-Strength3. Nominally pinned

Steel Connections

Rotational Stiffness (Sj)

The rotational stiffness of the joint is being determined from the flexibilities of its basic components each represented by its elastic stiffness coefficient ki.

The results related with rotational stiffness and all the ki coefficients (where ever needed) appear in the output forms of the program.

Ki is the stiffness coefficient for basic joint component i

i ri

reff

k

k

,

, 11

eq

rrreff

eq z

hkk

,

i i

j

k

EzS

1

2

and

A beam-to-column joint may be classified as rigid, nominally pinned or semi-rigid according to its stiffness, by determining it’s initial rotational stiffness Sj,ini

Steel Connections

Classification by Stiffness

Init.Rotat. Stiffness. Sj,ini Braced frames Unbraced frames

Rigid Sj,ini > 8 E I b /Lb Sj,ini > 25 E I b /Lb

Nominally Pinned Sj,ini < 0.5 E I b /LbSj,ini < 0.5 E I b / Lb

Ib/Lb: Ratio of second moment of area of beam to spam of beam

Zone 2: Semi -rigid

M

Boundary 1

Zone 1: Rigid

Zone 3: Nominally pinned

Boundary 2

M-Φ Diagram

Steel Connections

Classification by Strength

A beam-to-column joint may be classified as full-strength, nominally pinned or partial strength by comparing its moment resistance with the moment resistances of the members that it joins.

Full Strength: Mj,Rd> Mpl,Rd,b

Partial Strength: Mj,Rd< Mpl,Rd,b

Nominally Pinned: Mj,Rd < 0.25 Mpl,Rd,b

Steel connection computes Mpl,Rd of beam, and informs the user for the connection classification according to strength.

Steel Connections

Connection Resistance - Basic Components (1)

The strength of the connection is being calculated using the strength of the connections components which are named “Basic Components”.

For the beam to column moment connectionStrength of welded joints

The strength of the connection is being calculated using the following "basic components":

1. The strength of the column web panel in shear (Vwp,Rd)2. The strength of the column web in compression (Fc,wc,Rd)3. The strength of the column web in tension (Ft,wc,Rd)4. The strength of the column flange in bending(Ft,fc,Rd)5. The strength of the beam flange and web in compression (Fc,fb,Rd)6. The strength of the beam web in tension (Ft,wb,Rd)7. The lever arm (z)8. The strength of the welds.

Strength of bolted connections

The strength of the connection is being calculated using the previous plus the following "basic components":

1. The strength of the end plate in bending (Ft,ep,Rd)2. The strength of the bolts in tension, in shear and in bearing3. The lever arm (z).

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Steel Connections

Connection Resistance - Basic Components (3)

For the Beam to Column connection with angle cleats

1. Bolt's resistance in Shear2. Cleat's resistance in Bearing3. Strength of Cleat in Shear4. Strength of Cleat in Rupture5. Strength of Beam in Shear6. Strength of Beam in Moment7. Column's Web in Bearing

For the Foundation Connection

1. Anchor's Resistance in Tension2. Anchors Resistance in Shear3. Resist. of Footing Pl. in Bearing4. Concrete Resistance in Compression5. Column's Resistance in Compression6. Footing Plate Resistance in Tension7. Resistance of The Welds

Steel Connections

Connection Resistance - Basic Components (4)

For the Beam Splice Connection

1. Bolt's Resistance in Shear2. Bolt's Resistance in Bearing3. Strength of Bolts in Shear4. Strength of flange Plate in Tension5. Strength of web Plate in Shear6. Welds Resistance of Flange Plate7. Strength of plate in rupture8. Strength of beam in rupture

For the Tube Splice Connection

1. Effective Length per Bolt2. Resistance in Compression3. Resistance in Tension4. Resist. of Compressioned Bolt in Shear5. Resist. of Tensioned Bolt in Shear6. Resistance of Bolt in Bearing7. Welds Stresses

Steel Connections

Connection Resistance - Basic Components (5)

For the Truss joint connection with Plate

1. Bolt's resistance in Shear2. Member's Resistance in Bearing3. Member's Resistance in Rupture4. Member's Resistance in Axial5. Plate's Resistance in Bearing6. Plate's Resistance in Moment7. Plate's Resistance in Axial8. Plate's Resistance in Shear9. Weld's Resistance in Moment10.Weld's Resistance in Axial11.Weld's Resistance in Shear

For the K or N type joint

1. Resistance in Chord Face Failure2. Resistance in Brace Failure3. Resistance of Chord in Shear4. Resistance in Punching Shear5. Resistance in Chord's Web Stability6. Resistance of Chord in Shear NoRd

Steel Connections

Equivalent T-stub – Bolted joints

In bolted joints the flange of an equivalent T-stub may be used to model the resistance of the following basic components:

1. column flange in bending2. end-plate in bending3. flange cleat in bending

Steel Connections

Failure modes of actual componentsand equivalent T-stub flanges

The “Actual component” the “Equivalent T-stub” the “Force diagram” and the “Moment diagram” are presented for three different failure modes.

Note:

It is important to state that this program cannot be used to check the strength of the members of a steel frame.

The program only checks the member’s components very near to the connection and it assumes that a member’s check is already been done.

Steel Connections

Steel Connections

The Program

Steel Connections

Main Menu

Command Menu

Main window

Warning MessagesCurrent state messages

Steel Connections

Support programs

Steel Connections

Section

Database

Graphic section’s representation

Sections list

Required Data

Ser – ManagerManipulate all program’s section properties

(change values or add-create user defined sections)

Steel Connections

DXF output

Simple step generation of dxf filesfor every connection.

Scales database

The program can be used undependably from Steel Connections

Steel Connections

Pre-solved connections library (DIN 18800)

Multiple search criteria

Results presentation

Graphic connection representation

Is a very useful feature for searching for a connection that satisfies specific criteria

Steel Connections

Reading Nodes from a SOFiSTiK Database

Select analysis nodes, from a SOFiSTiK database, to import in Steel Connections.The selected nodes will be regarded as connections in the program.The selection is made graphically.

Steel Connections

Translate Nodes to Connections

If the user wishes to manually change or declare the members that take part in the connection he must simply right click on the desired member and select it from the popup menu.

The Program tries to automatically define the members that take part in the connection for each node selected.

Steel Connections

Reading Loads from a SOFiSTiK Database

Import loads from SOFiSTiK database

Steel Connections

Optimization(Automatic optimum calculation for the“Beam to column moment connection”)

Compute maximumor optional strength

Input loads fromSOFiSTiK databases

Manipulation of possible allowed reinforcements

Design restrictions regarding bolts (number of rows, type or quality)

Results representation. Both list and graphical

Steel Connections

Connection selection

Graphic view

Button selection and details

Steel Connections

Analysis

Steel Connections

Foundation connectionwith or without shear elements

K or N type joints

Beam to column bolted connection.Flush or extended end plate configuration

Apex connection by flush or extended end plate

Truss joint with plate

Beam to columnwelded connection

Beam to column connection with angle cleats

Beam splice connection

Beam to beam connection by angle cleats

Tube spliceconnection

Supported Connection Types

Steel Connections

Data Input

InteractivePreview Window

Graphic representationof all geometric data

Simplified “Input Data” forms

Steel Connections

Bolts calculations

Independentdata manipulation

Fully user customizedbolt distances

Automatic boltlayout generation

Steel Connections

Graphic Results Layout

Representation of most common used results, according to connection’s elements checks

Graphic representations where ever needed

Ability to handle multiple analysis results, at the same time, for comparison

Steel Connections

Connection ClassificationAccording to Stiffness

Design Moment-RotationCharacteristic

Zone 1 Boundary

Zone 3 BoundaryM-Φ diagram

Initial rotational stiffness of the joint

Steel Connections

Full Results Printout

Ability to produce fullycustomizable result files.

The files can be stored for use in later time, or either modified with a simple text editor.

The user have access to all the program’s strength results.According to the design code used for the analysis (EC3 or DIN18800) the connection’s "basic components“ strength is presented as well as all the calculations needed by the design code.

Steel Connections

Example(Beam to column moment connection)

Dimensioning of the basic components that form the connections on top left corner of the structure.

The structure was already solved by SOFiSTiK programs.

There is no restriction regarding the analysis type (eg: elastic, elastoplastic, serviceability, ultimate strength)

Steel Connections

1. Select connection type

2. Add nodes from SOFiSTiK database

Steel Connections

3. Check selected nodes

Steel Connections

4. Add SOFiSTiK loadcases

Presentation of nodes/loadcases

Every kind of loads can be applied to Steel Connections.There is no restriction regarding analysis type (e.g. serviceability, ultimate strength, elastic, elastoplastic)

Steel Connections

5. Bolt layout

Steel Connections

6. Results overview

Errors regarding strength of basic component's strength.The designed connection is not sufficient.

dbl click for more info

Steel Connections

7. Results evaluation for every node-loadcase

Steel Connections

8. Automatic correction of connection - Optimization

Steel Connections

9. Optimization results overview

1

1

1

2

1. Optimization results2. Transfer selected result to

Steel Connections for further processing

Steel Connections

10. Optimized connection’s results overview

No error ratios.Optimum design –> Ratios close to 1