August 8, 2015

How do you add Shear Caps to columns?

Per the ACI, you can add a Shear Cap to your column to increase the shear strength of the slab. In RISAFloor ES two-way slabs, adding a shear cap will thicken the plates around the column automatically. The Shear Cap will affect the Punching Shear and the One-Way shear calculations.

As you draw the columns in RISAFloorES, there is an option to include a Shear Cap. The thickness is measured from below the bottom of the slab. The Depth and Width are based on the column definition and local axis.

It is common to model without Shear Caps and only add Shear Caps as they are needed. You can add Shear Caps to the columns at any time from the Windows menu- Modify – Columns. This allows you to create a Shear Cap on an existing model and shift the Shear Cap eccentrically.

You can also modify the Shear Cap in information is stored in the Columns spreadsheet. The eccentricity is defined based on the column local axis. The picture below shows a Shear Cap that is shifted eccentrically by 12 inches in the ey and ez directions.

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Tags: RISAFloor ES, Concrete, New

September 22, 2020 | ADAPT-Builder, ADAPT, New, Meshing

Troubleshooting Mesh Failures Using Component Representatives within…

ADAPT-Builder is a three-dimensional free-form finite element software for structural concrete modeling and analysis. Structural components in ADAPT-Modeler do not have to be input along grid lines or at connective, adjoining node locations as is the case in most other structural engineering software on the market today. ADAPT-Builder's free-form modeling allows the user to model and represent the true physical structure, as compared to an analytical representation. To facilitate this flexible modeling, the ADAPT-Mesher will consolidate nodes of considered components using its "Node Consolidation" feature. This feature allows the user to set a maximum distance for node consolidation and the software will consolidate nodes within the define proximity. The Node Consolidation (Node Shift) feature is described in more detail in the ADAPT-Floor Pro 2019 Basic Manual (linked below). When node shifting, the program accounts for the eccentricity between the modeled location of the element and the analytical location of the element. In most cases this feature is effective, and the program will consolidate nodes and produce a mesh. However, as the program allows the modeling of very complex geometries, there are times where the mesher fails to produce a mesh. When the mesher fails, the user is prompted with an…

October 21, 2014 | RISAFloor ES, Concrete, New

How are Cantilevered Slabs designed?

Concrete buildings often have large cantilevers. In RISAFloor ES, the Support lines can be drawn to support points but also they can be drawn as cantilevers (shown below). The reinforcement design for the cantilevered section assumes that there will be a positive moment along the distance of the cantilever. This assumption forces the top rebar to be continuous for the entire cantilever span. Deflection Another big consideration for cantilevered slabs is the deflection. The deflection can be checked a few different ways. The easiest way to interpret the deflection is the Contours shown on the slab. This will help you easily visualize the deflection at the edges. Just click on the Contours display icon and select Displacement. If you don’t have this icon showing, click on the following link for instructions on how to add it to your toolbar. Viewing the Deflected shape of the slab is also a quick and easy way to visualize the behavior of the slab. These methods above are showing the overall deflection, however the codes references deflection based on the type of loading and span or distance from support. So it’s important to review the deflection results based on the Design Strips which can…

January 1, 2021 | ADAPT-Builder, ADAPT, New, Punching Shear

Consideration of Openings for Punching Shear of Two-Way Slabs in…

Punching shear of two-way reinforced concrete and post-tensioned slabs is a critical design consideration. The presence of openings near a support can complicate the calculation of shear capacity at the location. ADAPT-Builder v20 now includes enhancements in how openings are treated near columns and walls that are checked for punching shear in the software. In previous versions of ADAPT-Builder, an opening in the vicinity of a column was treated the same as slab edge regardless of its size. For example, when a small opening is close to a column, the whole side of a column is disregarded from the punching shear check, which is conservative in many cases. For ADAPT-Builder 2020 the check for punching shear has been improved in the detection and handling of openings as per ACI code requirements. This new method for handling of openings is enabled when an ACI code version is selected. Two new input parameters are shown in the Punching Shear input dialogue. These include: Radius of detection – This setting is used to determine at what distance from the face of support will openings be detected and deducted from the critical sections that fall within the opening. The input is based on a…