March 22, 2018

Utilizing RISA-3D for Seismic Design of Concrete Walls

By: RISA

In RISA-3D we now have the ability to design concrete shear walls for seismic forces.

There are 3 main aspects to concrete shear wall design. We will explain them here.

Pier Design: ACI 318-14 Section 18.10.8 defines the wall pier design parameters.

Coupling Beam Design: ACI 318-14 Section 18.10.7 defines the coupling beam design parameters.

Boundary Zone Design: ACI 318-14 Section 18.10.6 defines the boundary zone design parameters. Currently RISA-3D determines whether a boundary zone is required or not per Section 18.10.6.3.

These results are then condensed into a single code spreadsheet view complete with code checks.

For details on the calculations and the additional reinforcement checks, search Concrete Walls – Seismic Design topic in the RISA-3D help file.

RISA Help File

Additionally, check out the video below for more information concerning concrete wall design for seismic forces.

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

February 19, 2018 | RISA-3D, New, Masonry

Masonry Cover Flexibility in RISA-3D

In RISA-3D we now have the ability to: Define a cover other than the minimum from the ACI 530 code provisions Define a single reinforcing bar that is non-centered in a grouted masonry cell From the Wall Design Rules in RISA-3D: We can see here that a new option is available in the Bar Placement column called Non-Center that allows you to place a single non-centered bar in a cell. The Cover then allows you to specify the distance from the exterior of the masonry block to the extreme fiber of the reinforcement. The default cover value is defined as Min. The Min input will use whichever governs between these two sections of the specification (ACI 530-13): Section 6.1.3.5 states a minimum distance between the inside of the face shell and the reinforcement is required. RISA is conservative and always assumes this to be 1/2″. Thus, the cover calculated in this fashion = t_faceshell + 1/2″ Section 6.1.4 requires a cover dimension = 1-1/2″ or 2″ depending on bar size and whether the masonry is exposed to weather. In the program this is always assumed to be 1-1/2″. Thus, the Min term will create a cover equal to the maximum…

February 15, 2022 | Seismic, RISA-3D, Walls, New, Masonry

Seismic Design of Masonry Walls (TMS 402-16) in RISA-3D

RISA-3D is expanding its industry leading support for the analysis and design of various materials with the implementation of Seismic Design of Masonry Wall Panels according to the provisions of TMS 402-16 (as well as ACI 530-13). When creating a model in RISA-3D, users now have the ability to easily define a "seismic design rule" for masonry walls with one of three options: Ordinary Intermediate Special When the seismic design rule is established, various provisions from TMS 402-16 are evaluated including checks for: Boundary Zone Reinforcement Minimum Spacing of Horizontal Reinforcement (Out-of-Plane) Maximum In-Plane Shear Reinforcement Mortar Type When the analysis is complete, users can evaluate the design either in spreadsheet results or using the detailed reports similar to what has previously been available for concrete shear walls. For additional details on the calculations, visit the Masonry Walls – Seismic Design topic found in the RISA-3D Online Help file: RISA Help File For additional information, check out the video below:…

September 3, 2020 | ADAPT-Builder, ADAPT, Slab, New

Precompression in Two-Way Post-Tensioned Slabs

Introduction In the design of two-way post-tensioned slabs, whether it be by use of unbonded or bonded tendons, precompression or “average minimum precompression,” is a critical serviceability requirement in ACI318. It is used to serve as a means for selecting a prestressing force and/or quantity of tendons and also directly addresses the serviceability of column-supported floor systems and the need for minimum reinforcement for shrinkage and temperature. The intent of minimum precompression is satisfied through use of crack control or total reinforcement for other major design codes, hence, a minimum limit for precompression is not required. These other design codes meet a similar need by stipulation for minimum reinforcement versus use of minimum precompression. In theory, a combination of non-prestressed reinforcement and prestressed reinforcement can satisfy code minimum requirements. It is the entirety of prestressed and non-prestressed reinforcement and proper distribution that guarantees satisfactory service-level performance of a two-way post-tensioned slab. For designs conforming to ACI318, where precompression delivered to the slab through prestressed reinforcement meets the minimum requirement of 100psi (0.69MPa), this is deemed acceptable in lieu of non-prestressed reinforcement. Other requirements related to spacing are also necessary to be met. If they are not, a combination of prestressing…