September 22, 2015

Why Did the Wood Design Values Drop?

You may notice discrepancies in the wood design values when comparing RISA with the NDS 2012 and older versions of the code. The American Wood Council updated the wood design values in the Addendum, which supersede the values used in the NDS 2012 and previous versions of the Design Values for Wood Construction. The design values for all grades of visually-graded Southern Pine and Mixed Southern Pine lumber 2-4″ thick have changed. The Addendum can be found on the AWC website using the link below.

AWC - Addendum to 2012 NDS

The updated wood design values from the Addendum have been implemented in the Shape Database in RISA programs for all wood codes. These values can be found in the Shape Database under the Wood tab once a specific a material and size are selected.

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Tags: RISA-3D, RISAFloor, New, Wood

February 9, 2024 | Featured, Structural Engineering

Black History Month

Black History Month is a month-long celebration in the United States that takes place annually from February 1 to March 1. This month-long celebration is dedicated to honoring and celebrating the contributions and influence of Black and African Americans to the history, culture, and achievements of the United States. As we enter February, we embark on a journey of celebration and reflection of Black History Month—a time to revel in the richness of Black culture, honor trailblazers, and amplify voices that echo through history. Join us in this joy-filled exploration as we dive into stories of triumph, courage, and unyielding determination. From iconic figures to modern inspirations, let's dance through the pages of history with enthusiasm, curiosity, and profound respect for the diverse contributions that have shaped our world of Structural Engineering. 1. African Burial Ground National Monument, NY The African Burial Ground National Monument in New York City is a poignant testament to resilience and remembrance. Crafted by the skilled hands of African American architect Rodney Leon, this monument stands as a solemn tribute to the burial ground of enslaved and free Africans during colonial times. Leon's architectural vision breathes life into the narratives of those laid to rest…

December 8, 2017 | RISAFoundation, New, Piles

Pile Design now Available

Hot rolled steel, wood, and concrete piles are now available in RISAFoundation v10.0. The Pile Definition Editor lets the user input the pile’s properties including the pile’s shape, material, and length. For concrete piles the user has the ability to apply a custom shear and flexural rebar layout or have the program optimize the reinforcement design. RISAFoundation automatically calculates the compressive and tensile capacities and stiffnesses using the pile’s properties and material design code selected in the Model Settings. The pile’s stiffness is then used to compute the load the pile receives during the analysis to determine the pile’s unity check. With the addition of Soil Depth Properties, the static pile capacity is calculated to compute the pile’s soil unity check. After the model is solved, the results are available in the Pile Results spreadsheet and in a Pile Detail Report. Pile Detail Reports can be accessed to view the pile’s geometry, material, code, analysis and the design results used to calculate the code checks. The Axial Capacity Diagram at the bottom of the detail report shows the demand force in blue versus the static pile capacity line in red. This diagram can be helpful in understanding the pile’s load…

February 24, 2016 | Time History, Dynamics, RISA-3D, New

What are the Ramp Up/Coast Down Functions in Time History?

Ramp Up Function RISA allows you to define “Ramp Up Functions” to control how the force and frequency vary during this initial startup time. Typically cyclic equipment loading is applied as a reduced force or frequency when it is initially starting up. It would be overly conservative if it were assumed that the equipment instantaneously reaches its operating force and frequency. You can enter the duration of time it takes for the equipment to reach it steady state force and frequency, and whether the frequency is constant versus a linear or quadratic function during this time. See the image below for a quadratic variation in the frequency of a sine function: You may also vary the magnitude of the function during this start up time. It can be constant (as shown in the image above) or it may vary linearly, quadratically, or automatically calculated by the program as a function of the operating frequency. When the AutoCalc option is chosen, the magnitude will vary with the square of the frequency. See the image below for the AutoCalc option for a linearly varying frequency change: Coast Down Function The same concepts apply in reverse when the equipment is turned off. The…