Foundation Design

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Footing Design: How to Check the Shear Capacity per ACI 318

By: Javier Encinas, PE | August 14, 2017 The foundation is that part of the structure that transfers the loads to the supporting soil in such a way that the resulting bearing pressures are kept under acceptable limits. If the underlying soil is satisfactory, then a spread footing is usually the recommended solution by the soils engineer. In addition to the stability checks and the design for flexure, a spread footing needs to be designed for shear. This blog post discusses the shear checks required by ACI 318. Our software ASDIP FOUNDATION will be used to support our discussion. What [...]

By | August 14th, 2017|Categories: Foundation Design|Tags: , |0 Comments

How to Design Spread Footings Using ASDIP FOUNDATION

By: Javier Encinas, PE | July 12, 2017 ASDIP FOUNDATION is a structural engineering software for design of concrete footings. It includes the design of spread footings based on the latest ACI provisions. Following is a graphical overview of the required design steps, with annotated screenshots of the software. Click To Enlarge Enter the footing dimensions in plan and elevation view. Specify the soil cover and the water table depth. Click on the Column tab and specify the column dimensions. The column can be offset in both directions. If column is a short pedestal, loads [...]

By | July 12th, 2017|Categories: Foundation Design|Tags: , |4 Comments

Combined Footings: How to Calculate the Bearing Pressures

By: Javier Encinas, PE | June 27, 2017 ASDIP FOUNDATION includes the design of concrete combined footings. This structural engineering software is based on the latest ACI 318 provisions. This post explains the calculation of the soil bearing pressures in a typical combined footing. A combined footing usually supports two columns. The use of a combined footing may be justifiable under conditions where the distance between columns is short, so a large excavation is not required. There are two common scenarios in practice: A property line exists at or near the edge of an exterior column, so a normal isolated footing [...]

By | June 27th, 2017|Categories: Foundation Design|Tags: , |0 Comments

Anchor Rods: How to Calculate the Tension Breakout Capacity

By: Javier Encinas, PE | June 14, 2017 Anchor rods are elements designed to resist mostly tension forces, sometimes in combination with shear. Out of all the tension limit states required by ACI 318, concrete breakout is particularly important because a concrete failure would be non-ductile, and therefore it should be avoided. This blog post discusses how to calculate the breakout capacity of anchor rods. I will use our software ASDIP STEEL to support the discussion. Concrete breakout assumes a failure forming a concrete cone based on a prism angle of 35 degrees. This method predicts the strength [...]

How to Use the Pre-combined Load Feature in ASDIP Software

By: Javier Encinas, PE | May 16, 2017 ASDIP is a structural engineering software for the design of structural members based on the ASCE 7 load combinations. But what about if you don't want your loads to be internally combined? This blog post discusses this important feature in ASDIP software. Structural engineering is all about calculations with loads, which are classified in different types, called Load Cases, such as Dead, Live, Snow, Wind, Seismic, etc. Typically the calculation results are generated and stored individually per each load case. These load case results are then affected by load factors in order [...]

How to Design a Fence Wall Using ASDIP RETAIN

By: Javier Encinas, PE | May 2, 2017 ASDIP RETAIN is a structural engineering software to design retaining walls. However, the software is so flexible that it can also be used to design a masonry fence wall exposed to wind. This article shows the steps required to design a fence wall using ASDIP RETAIN. Click To Enlarge As an example, let's design a typical fence 7'-0" high exposed to a wind load of 20 psf. The first obvious step in the software is to set the backfill height to match the soil cover at [...]

By | May 2nd, 2017|Categories: Foundation Design, Retaining Wall Design|0 Comments

Can Anchor Rods Resist High Shear Loads?

By: Javier Encinas, PE | April 26, 2017 During a recent technical support session a customer asked how effective the anchor rods are, as compared to shear lugs, to resist high shear loads. The obvious answer was that shear lugs are by far more effective. Rather than arguing with theories, I decided to quantify the answer by testing, using our software ASDIP STEEL. This document reports my findings. For this experiment, I selected a 18"x 18" base plate supported on a 24"x 24" pedestal, which are very common sizes. The column will transfer the factored loads shown below [...]

By | April 26th, 2017|Categories: Foundation Design, Structural Steel Design|2 Comments

Strap Footings: How to Calculate the Bearing Pressures

By: Javier Encinas, PE | April 16, 2017 ASDIP FOUNDATION includes the design of concrete strap footings. This structural engineering software is based on the latest ACI 318 provisions. This post explains the calculation of the soil bearing pressures in a typical strap footing. A strap footing usually supports two columns, so it's a special type of combined footing. If a property line exists at or near the edge of an exterior column, a normal isolated footing would be placed eccentrically under this column and it would tend to tilt. This problem may be prevented by connecting this footing with [...]

By | April 17th, 2017|Categories: Foundation Design|Tags: , |0 Comments

Shear Lug Design: Overview of the ACI Provisions

By: Javier Encinas, PE | April 4, 2017 Shear lugs are steel elements welded to the underside of base plates to resist shear loads. The design of shear lugs is covered by the ACI 349 anchorage provisions. This post is an overview of the structural design process. Our software ASDIP STEEL will be used to support our discussion. How do you calculate the shear force in a shear lug? The lateral forces acting on a structure will produce a horizontal reaction at the foundation level. For steel frames supported on base plates, a small horizontal force can be resisted by the [...]

By | April 4th, 2017|Categories: Foundation Design, Structural Steel Design|0 Comments

Strap Footings: A Very Useful Structural System

By: Javier Encinas, PE | May 8, 2016 ASDIP FOUNDATION includes the design of concrete strap footings. This structural engineering software is based on the latest ACI 318 provisions. This post covers the steps in the design of strap footings when subjected to a combination of vertical loads, horizontal loads, and bending moments. A strap footing usually supports two columns, so it's a special type of combined footing. If a property line exists at or near the edge of an exterior column, a normal isolated footing would be placed eccentrically under this column and it would tend to tilt. This [...]

By | May 8th, 2016|Categories: Foundation Design|Tags: |4 Comments