July 27, 2016

Using Eccentric Chevron Brace Workpoints

RISAConnection now offers the ability to enter an eccentric work point for the braces on a Vertical Brace Chevron Connection.

Entering the Eccentricity

The eccentricity may be horizontal, vertical, or both. These entries are in reference to the origin which lies at the intersection of the beam centerline and the gusset centerline.

Work point offsets may be positive or negative, depending on which direction (from the origin) you want to move the work point.

Quadrant 1: Positive Horizontal Eccentricity, Positive Vertical Eccentricity
Quadrant 2: Positive Horizontal Eccentricity, Negative Vertical Eccentricity
Quadrant 3: Negative Horizontal Eccentricity, Negative Vertical Eccentricity
Quadrant 4: Negative Horizontal Eccentricity, Positive Vertical Eccentricity

Results

While the limit state checks will be the same, the calculated loads at the gusset will be different since they now will include the effect of the work point offset.

Tags: Seismic, New, RISAConnection, Brace Connection

June 28, 2016 | Seismic, New, RISAConnection, News, Brace Connection, Integration

Seismic Brace Connection Integration with RISA-3D

RISAConnection version 6.0 has introduced the ability to design vertical brace connections per the seismic design provisions of the AISC 341-10 Seismic Design Manual. Now you can export Vertical Diagonal Brace Connections and Vertical Chevron Brace Connections from RISA-3D into RISAConnection as either Ordinary Concentric Braced Frames (OCBF) or Special Concentric Braced Frames (SCBF). See post for information on How to Model a Seismic Vertical Brace Connection in the stand alone version of RISAConnection. Link: Seismic Brace Connections now Available RISA-3D Input and Design: 1. First, you must create and apply a Seismic vertical brace Connection Rule to your member in RISA-3D. The application rules are the same as for non-seismic vertical braces. 2. You must also create and apply an appropriate Seismic Design Rule. For OCBF, select a “Minimal” Frame Ductility. For SCBF, select “High” Frame Ductility. 3. Solve the RISA-3D model. Note that you must solve for RISA-3D Seismic Detailing results. If your solution does not include Seismic Detailing results, you will not be able to export the correct brace axial forces into RISAConnection. 4. Solve the Connections within RISA-3D to see a summary of the connection design. 5. For details on the connection design, use the Director…

March 15, 2017 | New, RISAConnection, Brace Connection

Added Knee Brace Connections

RISAConnection v7 recently added a new Knee Brace (Kicker Brace) connection type. This connection can be designed at the brace to column or brace to beam. The connection design is very similar to that of a Chevron Brace: the resultant forces at the connection are calculated using simple statics. The appropriate limit states are then checked in the results report. Integration with RISA-3D Knee Braces may also be assigned to the brace members directly in RISA-3D and then exported to RISAConnection for design. Assign the “Knee Brace” Connection Rule to the brace member (it does not need to be applied to the supporting beam or column), then solve and use the Director tool to export to RISAConnection. Connection details may be adjusted in RISAConnection to achieve a passing design…

March 31, 2016 | Seismic, New, RISAConnection, Brace Connection

OCBF & SCBF Seismic Brace Connections now Available

RISAConnection v6 has introduced the ability to design vertical brace connections per the seismic design provisions of the AISC 341-10 Seismic Design Manual. Now you can designate Vertical Diagonal Brace Connections and Vertical Chevron Brace Connections as either Ordinary Concentric Braced Frames (OCBF) or Special Concentric Braced Frames (SCBF). To create the model: 1. First, select the type of vertical brace connection that you want to use. 2. On the General tab of Connection Properties, select your type of Seismic System. 3. Enter in the other applicable variables for seismic design. OCBF: Brace Length, Brace Length Effective Length Factor, K, and the Ca Beam Ratio which is used to calculate the beam width to thickness ratio per AISC 341-10 Table D1.1. SCBF: Gusset Plate Clearance method, Brace Length Effective Length Factor, K, and the Ca Beam Ratio which is used to calculate the beam width to thickness ratio per AISC 341-10 Table D1.1. 4. Once you have designated the connection as seismic, you will also see that you have inputs for Brace Tensile Axial force and Brace Compressive Axial RISAConnection will design braces for both tension and compression forces at the same time. 5. The results report will reflect the…