February 24, 2021

Video: Applying Tapered Area Loads in RISAFloor

RISAFloor enables you to consider the loads imposed on your structure due to the drifting effects of snow. Tapered area loads in RISAFloor are ideal for modeling this surcharge load due to snow drifting since the loading is approximated by a triangle.

Tags: RISAFloor, New, Area Load, Snow Load

October 10, 2012 | RISAFloor, New

Using Virtual Joist Girders in RISAFloor

The Steel Joist Institute (SJI) has recently put together a Virtual Joist Girder table which converts common joist sizes into equivalent wide flange beams. This topic describes how to use these Virtual Joist Girders within the RISAFloor program. When to Use Virtual Joist Girders: The engineer should use these Virtual Joist Girders in their analysis model whenever their joist girders are part of a lateral frame. They should not be used for simply supported joist girders which only resist gravity loads. When Will I Be Able to Use Virtual Joist Girders in my Version of RISAFloor?: Virtual Joist Girders are included in version 7.0 of RISAFloor released December 2012. How to Use Virtual Joist Girders in RISAFloor: A Virtual Joist Girder database will be listed as one of the database options on the Hot Rolled tab of the Shape Selection dialog as shown below. A Virtual Joist Girder option will appear as one of the Shape Group / Design List options shown in the Draw Beams Dialog below. Note: This only appears when the Material is set to Hot Rolled Steel. Tips on Using Virtual Joist Girders: Depth Restrictions: The RISA optimization is done based on cross sectional area. So,…

October 28, 2015 | RISAFloor, New, Joists

Tolerance Between SP Joists vs. Normal Joists

Have you been in RISAFloor performing a steel product design and noticed an (SP) extension to a joist designation? The following will discuss when the program designs for these special loading conditions. Steel products are designed to resist a uniform dead load (UDL), a uniform live load (ULL), and a uniform total load (UTL). The allowable loads for steel joist are based on the standard load and span tables for K, LH, DHL, and SLH Steel Joists. However, if a concentrated point load (even one with a small magnitude) is detected on a standard joist, the joist will be flagged as a Special (SP) Joist. Similarly, the distributed load on the joist cannot vary by more than 5% along the length of the joist. If it does then the joist will also be flagged as a SP Joist. The exception to this is some additional load variation is allowed within 10% of the end of the joist. A KCS joist can be designated for these special loading conditions. These joists do not have the “SP” label but are considered a special loading joist. KCS joists are checked versus the constant shear and moment capacity. RISAFloor also ensures the largest applied…

October 4, 2012 | RISA-3D, New, Joists

Using Virtual Joist Girders in RISA-3D

The Steel Joist Institute (SJI) has developed a Virtual Joist Girder table which converts common joist sizes into equivalent wide flange beams for use in RISA-3D. Link: SJI: Virtual Joist Girders Table When to Use Virtual Joist Girders The engineer should use these Virtual Joist Girders in their analysis model whenever the girders are part of a lateral frame. This should result in analysis assumptions for the strength and stiffness of the member that are closer to what the joist provider can realistically provide. This will lead to better communication between the EOR and the joist manufacturer, resulting in a quicker, more efficient design process. Can I Use Virtual Joist Girders in my Version of RISA-3D? Virtual Joist Girders are included as of RISA-3D v11 released December 2012. How to Use Virtual Joist Girders in RISA-3D The Virtual Joist Girder database will be listed as one of the database options on the Hot Rolled tab of the Shape Selection dialog as shown to the left. There is a new design list used referencing all the shapes in the SJI Virtual Joist Girder table. This design list is used as part of the RISA-3D optimization or redesign routines. A Virtual Joist…