May 17, 2012

Detailed Look at Lintel Analysis for Concrete Walls in RISA

RISA-3D now has the ability to design concrete walls with openings for both in-plane and out of plane loading. For lintels we provide analysis results based on the finite element results of the region above the opening.

At solution, the program creates a finite element mesh for the wall to compute the stiffness. From this mesh the program can also calculate the stresses and forces in the individual plates. In the area that defines the region above the opening, the program uses a summation tool to calculate the forces for the region. This summation is done many times over the horizontal distance of the region and the results are then used to create axial, shear and moment diagrams for the lintel.

These diagrams (both In-Plane and Out of Plane) are presented in the opening detail report and can be used to perform concrete design for the lintel.

Tags: RISA-3D, Walls, Concrete, New

November 20, 2013 | RISA-3D, New, Torsion

Why Is My Beam Failing in Shear?

When solving a RISA-3D model you may find you have a Shear UC (unity check) much higher than expected from bending shear alone. If you open the detail report and compare the shear demand to the shear capacity you may see that the demand/capacity is less than the Max Shear Check reported. What is likely occurring is that the member has torsion in it. In RISA-3D both the bending and shear demands are affected by torsion, though it is shear that usually causes the most problems. If you look at the detail report and in the Member Torsion spreadsheet results you can see this torsion. Warping Member (Wide Flange, Channel, etc): Non-Warping Member (Tube, Pipe, etc): Generally speaking wide flanges and channels work very poorly in torsion, while tube sections are much more efficient. Eliminating torsion or using a more efficient section are common ways to eliminate this problem. Note that this torsion problem can happen for all material types…

December 20, 2018 | RISA-3D, RISAFoundation, New, Rebar

How to Create and Apply A Custom Rebar Layout

Applying a Custom Rebar Layout in RISA-3D: To begin creating a custom rebar layout, simply click the Custom Rebar Layout button located in the Advanced tab of the ribbon toolbar. In RISA-3D, within the rebar layout dialog you can create a custom rebar layout for concrete beams, concrete columns and even create a custom shear rebar layout. Using the rebar layout editor is very easy and the following example will demonstrate creating a custom rebar layout for a rectangular concrete column. Click “New” to create a new rebar layout and create a label for the layout. Select whether the rebar layout is for a rectangular column or circular column. You can also choose the rebar standard and yield stress for your custom rebar configuration. To create the reinforcement layout, input the parameters into the spreadsheet to configure each row of rebar. Each parameter is explained below: 1. Placement: This is the direction that will determine where the reinforcement will be measured from (based on the reference graphic). Top or Bottom: The row of reinforcement will be measured from the top or bottom of the concrete member and will distributed the number of rebar horizontally and evenly between the concrete cover…

August 11, 2015 | Seismic, RISA-3D, RISAFloor, New, Wind

What Loads Transfer from RISAFloor to RISA-3D?

RIAFloor designs the gravity system and then integrates with RISA-3D to design the lateral system. Only the lateral members are taken from RISAFloor over to RISA-3D. The loading is automated in this integration so one of the most common questions is: what loads are transferred when switching from RISAFloor to RISA-3D? Below is the brief explanation to answer this question. Gravity Loads: The lateral members that become part of the RISA-3D model bring over their gravity loads. This also includes the beam reactions from the gravity only members that were not transferred in to RISAFloor. The load categories in RISAFloor are automatically converted into Basic Load Cases in RISA-3D. The exception to this are the Load Categories that deal specifically with construction loads (DL Const and LL Const), which are not converted. Wind Loads: The wind loads are automatically calculated as the RISAFloor model gets integrated into RISA-3D. The wind load parameters are located in the Wind tab of the Global Parameters in RISAFloor. However, these settings may also be changed when the wind load dialog pops up when transferring to RISA-3D: The option to generate roof wind loads are only present in RISA-3D models that are integrated with RISAFloor…