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Spread Footing Foundation

Jim Houlette — Mon, 12 Dec 2011 23:46:24 +0000

This has to be the most typical foundation type with basement or crawlspace construction. The spread footing design is simple; provide sufficient footing area to distribute the weight of the structure onto the soil. Typically, a 16” wide x 8” concrete footing is used.

The width of the footing distributes the dead and live load of the structure on the soil allowing a typical 8” wide concrete wall to be placed on the footing in lieu of a wide 12” to 16” concrete wall. In addition, the poured footing helps to provide a level surface for the concrete foundation walls. The thickness of the footing will vary due to unlevel soil conditions. The designer should also keep in mind that even if a 12” wide footing satisfies soil bearing, the foundation crew may need at least 16” to allow enough area to set the wall forms on the footings and allow for dimension errors to be adjusted.

A typical spread footing foundation is also referred to as a ‘T wall’.

PROS
Cost effective
Common Construction
Low Tech

CONS
Fails with Swelling Soil

Learn more about different types of foundations

Originally posted 2009-09-13 02:09:33.

Building Season in Colorado, What About Winter?

Sean O'Hara — Mon, 12 Dec 2011 23:46:23 +0000

We frequently have projects and clients who are concerned with the idea of building during a Colorado winter. Snow, ice, cold temperatures and frozen ground can all make building more difficult. With that being said, in the Front Range cities, like the Denver metro, we can generally build year round without many weather delays. As you get into the mountains the delays become more frequent and if you have the luxury of picking your time for building it certainly makes sense to work around the winter.

There are techniques for doing work with frozen ground and cold temperatures, you can tent, you can change your concrete mixtures, you can use blankets to thaw frozen ground, but they do have cost premiums. At the same time, the price of waiting for the spring can also add cost to a project.

Of course the other thing that we all know about the weather in Colorado is that its always changing and hard to predict. You can have a December where the snow doesn't melt, or a March with no snow or a May where it rains almost every day. In any schedule you should plan for weather delays but you shouldn't let the winter be the deciding factor in when you build in Colorado.

Originally posted 2011-05-29 00:27:29.

Separation of Top of Foundation Wall and Adjacent Exterior Grade

Adam Denton — Fri, 09 Dec 2011 23:50:08 +0000

One of the most commonly asked questions to the structural department involved the required distance between the top of a foundation wall and the adjacent exterior grade. The 2009 International Residential Code requires a minimum of 6 inches of separation where brick veneer is not present. The idea here is to provide a buffer zone to help prevent moisture wicking into the timber framing typically framed above residential foundations. Where brick veneer is present this requirement drops down to 4 inches.

The code text reads:

R404.1.6 Height above finished grade. Concrete and masonry foundation walls shall extend above the finished grade adjacent to the foundation at all points a minimum of 4 inches (102 mm) where masonry veneer is used and a minimum of 6 inches (152 mm) elsewhere.

An example of where minimum separation is close, but not met.

Originally posted 2011-04-03 00:01:32.

Landscape Architecture available from EVstudio in Colorado

evstudio — Fri, 09 Dec 2011 23:50:05 +0000

Landscape Architecture is a necessary component for land development plan approval and building permit approval for many jurisdictions. EV Studio provides landscape architecture along with all other related disciplines to assure quality control for your project.

We work with a broad range of private and public clients on project types including detached and attached single family housing, multi-family housing, schools, offices, medical, and retail spaces. Our services include streetscapes, parks and recreation, land entitlements, design guidelines and even HOA retrofits. We practice sustainability with all of our landscapes selecting appropriate plant material for the context and working closely with our civil engineers to manage and utilize storm water effectively. We offer full service landscape architecture including necessary construction documentation and specifications.

Our Director of Landscape Architecture is John Olson, RLA, LEED-AP, CNU-A. John has over eight years of landscape architecture experience and has worked on projects in a variety of climates across the country. John will be your landscape architecture point person on your project. Some of his recent work includes landscape architecture improvements at Medinah Country Club (home of the 2012 Ryder Cup), the Pueblo Justice Center in downtown Pueblo and planning and entitlements work for The Mountain Preserve, a luxurious sustainable development south of the Broadmoor Hotel of Colorado Springs, owned by famous folk singer Pat Boone.

Originally posted 2010-05-07 00:01:22.

Links from EVstudio.info to Your Website

Sean O'Hara — Sun, 04 Dec 2011 22:02:53 +0000

With the increasing number of link requests that we get from Consultants, Clients, Engineers, Contractors and Builders, I thought it would be useful to explain how to get EVstudio.info to link to your website.

First, an important distinction, generally speaking our evstudio.us domain does not provide links unless we have an interest in the company. Most of our linking comes through evstudio.info which actually has higher page rank anyway.

What we have devised as the most fair way to distribute links is that we provide links within posts where describe projects. That way if we're only working on one project with a certain company we are providing less links that if we are working on five projects with another company. Just let us know that you'd like to be mentioned in conjunction with projects and we'll make sure that we do. The blog currently has a page rank of 5, so we can really help out.

The other way is we provide links to organizations and blogs that our readers may find interesting, just email me and I'll look over your site.

We always appreciate any reciprocal links as it helps more people find us and the information that we have generated to let them know more about architecture and the architectural process.

Originally posted 2009-04-16 00:46:42.

Steel Screw Pile Foundation

Jim Houlette — Mon, 21 Nov 2011 08:02:27 +0000

A deep foundation system that is gaining popularity in areas with difficult soil, contaminated soil and due to its speed of construction is steel screw piles.

At first glance screw piles look like the typical helical pier. However, there are significant differences that make a dramatic change in capacity. First, the screw piles are installed as a single continuous piece in lieu of sections bolted together. Second, the machinery used to install screw piles is larger and capable of producing a higher torque.

The components of a screw pile are simple; a steel shaft, steel helix at bottom of shaft, and a connection plate at the top of the shaft. Screw piles can vary in size to accommodate different design loads. The steel shaft size is a function of axial load, torsion during installation and thickness due to corrosion. The helix is a plate that is shaped just like the threads of a wood screw and engages the soil to distribute the axial load and it locks into place to provide tensile loads as well.

One of the first questions people have is, “How long will it last until failure from corrosion?” There are several factors that go into corrosion of steel; oxygen, moisture, dissolved salts and other corrosive chemicals. Since there is very little oxygen in the soil, corrosion is limited and can be controlled by using thicker material to allow for expected corrosion. The life of steel screw piles can be 50 years to an indefinite period depending on the type of structure and life span needed.

I designed foundations in Stapleton where the site was located over the old terminal and contaminated soil was discovered. If typical straight shaft drilled piers were used the spoils from drilling the hole would have had to been bagged and disposed of properly. To avoid bringing contaminated soil up to the surface steel screw piles were used.

I list a lot of PROS below and for good reason. I have been very impressed with screw piles and the wide range of uses of them. EVstudio was recently visited by Alpine Site Services for a lunch and learn. Mike Oliveira discussed how screw piles are installed and the many advantages to their system over other typical foundation types. What really impressed me was the speed of placement of screw piles. Alpine can place 30 to 50 screw piles in one day!

Another great advantage to screw piles is that they can be placed at an angle to provide bracing and tension resistance that is aligned with the force of the tension. An example is a typical counterfort that braces a foundation wall. You can see the angled screw pile above.

PROS
Fast Installation
Can be Proof Tested
Negligible Uplift Pressure from Swelling Soil
High Capacity up to 500kips
High Tensile Resistance
Made from a reusable material (LEED point)

CONS
Specialized System
Large Equipment
Concerns with Corrosion

Learn more about different foundation types.

Originally posted 2009-10-10 00:21:43.

Foundation Settlement: The Push Pier Alternative

Adam Denton — Mon, 21 Nov 2011 08:02:26 +0000

EVstudio is asked quite frequently to perform structural evaluations of cracked foundation walls. These cracks are often due to settlement. Modern design philosophy (and most geotechnical reports) calls for the original structural engineer to design foundation walls to clear span ten to fifteen feet to account for soft patches of bearing soil or soils that may be become saturated and hydro-consolidate (shrink in volume when wet). Older homes are more susceptible to damage because they were typically not designed with this in mind. This is not to say they were designed poorly, there were just different design philosophies and industry standards at the time they were constructed.

There are many different ways to approach the problem of foundation settlement. One way is the foundation push pier.

Steel push pier with hydraulic ram installed.

How a push pier works is quite simple. First, a steel bracket is fastened to your foundation, typically at the footing. Then a hydraulic ram is installed on the bracket which pushes a steel pier into the ground. Using the hydraulic forces in combination with the weight of the structure above, the steel pier is driven down through the softer soils (which are causing the settlement problem) until bedrock or suitably firm soils are reached. Once the pier reaches competent bearing, the foundation is stabilized and in some instances can even be raised back into a level position.

EVstudio works closely with foundation repair contractors such as Pinnacle Structural Services in the evaluation of foundation repairs utilizing the push piers as one of many considered solutions.

Originally posted 2010-06-26 00:01:29.

Proper Bearing of I-Joist Rafters

Adam Denton — Mon, 21 Nov 2011 08:02:24 +0000

As today’s architectural design trends toward more open floor plans with vaulted ceilings there is a need for economical rafters that will span long distances while maintaining a shallow profile. In many situations pre-manufactured I-joist rafters fit that need.
As a structural engineer I have inspected many roofs framed with I-joist rafters, but very few that have not needed a correction due to the I-joist bearing. While typically not a problem when the roof is flat and the I-joists bear perpendicularly on the top plate, when the rafters are sloped proper bearing becomes an issue. The simplest way to properly bear the I-joists is to attach a full length beveled block to the top plate. As a structural designer I have not gotten a lot of positive feedback from framers when I specify this method. Beveling the end of the I-joist seems to be preferred over beveled blocking. The problem comes with the compromised stiffness of the I-joist’s web once the bottom flange is beveled.

As shown in the above detail, the web of the I-joist rafter should be reinforced with plywood to increase it’s stiffness at the bearing edge. As always, blocking should be provided between rafters as well as a mechanical clip (such as the Simpson H2.5) to counteract uplift forces.

Originally posted 2010-10-25 00:01:45.

Denver Colorado Architect

evstudio — Thu, 17 Nov 2011 08:11:44 +0000

EVstudio started in the mountains of Colorado just west of Denver and has become known for doing work all over the state. While our Evergreen office is still busier than ever, our Denver office has been in full swing for over a year now. As a result, EVstudio has developed a fine reputation with the City and County of Denver on multiple projects that range from urban residential additions, new single family homes, multifamily projects, commercial office and retail design, restaurants and even schools.

Headed up by Sean O'Hara, the managing principal for EVstudio Denver, we have navigated the many challenges that a wide variety of projects face with various regulations and have had tremendous success with our construction documents during the permitting process. Just recently, we walked the Denver International School (formerly Montclair Academy) project through the building department without a hitch. Kudos to the EVstudio Denver staff and if you have a project in the Denver Metro area and are looking for a great local Denver Architect, there is only one place to call 303-670-7242.

Originally posted 2009-02-12 22:54:22.

How Can a Supplier Play a Larger Role in Design?

Dean Dalvit — Thu, 10 Nov 2011 07:39:07 +0000

I had a great lunch today with Tom Glossa and Denny Rogstad with the Breckenridge Building Center and we discussed the importance of an integrated team approach to design, which would involve a wide variety of team members. The traditional approach to design is for the Architect to design the plans and elevations, then for the engineer to engineer the structure, then for the contractor to price it out, select subcontractors and suppliers, permit the project and then build.

Because we have always provided engineering in-house, we have always been doing it differently (architecture and engineering happening concurrently), however, we are finding more and more that an integrated team earlier in the process results in a more successful and efficient design and construction process. This means that even suppliers can, and should play a role as early on as schematic design to help validate initial estimates of construction cost. The best part is that in most cases, this valuable information is offered for free by the suppliers.

Also, with the advent (at least in Colorado) of the additional permit submittal requirements, namely truss shop drawings, Manual J, Manual D and Rescheck energy analysis tools, contractors can no longer wait until construction has begun to specify many of the building's requirements. These things have to be identified at permitting, which, as a result is changing the base set of construction documents. We are even working with suppliers often times before a contractor has been selected. While this may seem to put the cart before the horse compared to the traditional approach, it is in direct response to the permitting requirements that are changing the landscape of the design scope.

So, in an integrated team approach, we like to have discussions with folks from the lumber and truss suppliers, window suppliers, mechanical contractors, etc. early on in order to value engineer the project and get the very best design solution that is not only elegant, but that can also be sourced economically and locally.

Originally posted 2009-09-08 15:12:10.