Thursday, September 23, 2010

"The House my Father Built"

EFFICIENT (aka Sustainable) Design
A Changed Paradigm

Sustainable, Green, LEED and especially Global Climate Change are FIGHTING WORDS.  They tend to raise the ire of people’s political sensitivities.  Liberals tend to believe that we are destroying our planet through “Global Climate Change” and Conservatives tend to believe that “Global Warming” is a lie meant to cost us money.  The arguments for and against raise the same level of anger as the Anti-Abortion/Pro-Choice “discussion”.   An honest discussion cannot occur as long as we are not even using the same language to discuss our positions.

I believe that People will believe what they want to believe. 

So, convincing someone as to the efficacy of either side is a waste of time and brain cells.

Over the last 30 years, we have been warned by list of Republican and Democratic Presidents, starting with Nixon (who created the Environmental Protection Agency), Carter (who installed solar collectors on the roof of the White House), Bush Senior, Clinton and Obama that our dependence on foreign oil was a National Security Issue.  But nobody cared, except when the cost of fuel was expensive (like under Bush Junior) or inconvenient to get (like under the gas lines of Carter).

As Architects, over the years, we were taught about the importance to design Sustainably, but then very few of us ever took that education to heart and actually did it.  

Everyone believed it would cost more. When an Architect did embrace “Sustainable” design, like Paulo Soleri’s city in the desert “Arcosanti”, that Architect was generally berated as being a little off in the head.  I met Mr. Soleri and found him to be a visionary, well ahead of his time.

What is needed is a changed Paradigm that everyone can benefit from - EFFICIENT DESIGN. 

In 1952, my father designed and built his own house in the San Fernando Valley of Los Angeles County.  This house, if constructed today, would qualify as LEED Platinum or Build it Green by every current measure.  However, in the 1950’s energy was cheap and plentiful.  Words like Sustainable, GREEN, LEED did not exist as we know them today.  The word that WE used to describe my father’s house was EFFICIENT.  This was the most Efficient House I have ever seen.  And it cost no more than a smaller typical Track Home built in the same area.

My father’s house had concrete block exterior walls (thermal mass that warmed the house at night and cooled it during the day), a white rock shingle roof (that reflected the suns rays away while also acting as a thermal mass), built under the shade of three desciduous mature walnut trees (shading the house in the summer and letting the light in during the winter), heated by a hot water radiant heating system that was regionally controlled by three separate thermostats (the most efficient and The Most Comfortable Heating System around) and was cooled by a 1 hp fan in the attic that was controlled by a thermostat (such that it came on automatically once the temperature rose and cooled not just the attic but the complete house).  We never had air conditioning and in the 115 deg summers of Los Angeles, we almost never felt a need for it.  This is just a partial list of the Efficiences of this house. And it cost no more to build than the houses my friends lived in.

To be honest, very few buildings built today are Efficient in their design, and that includes buildings that carry the Build it GREEN or LEED certifications.  We are pros at designing code compliant, yet in-efficient, buildings (Architecturally, Structurally, Mechanically, etc.).

As a group of professions, the building industry is struggling to know exactly what is Sustainable Design.  Buildings constructed of Steel (probably the most non-sustainable building material), which were designed without the thought of Efficient Design, carry LEED Platinum labels, because the mechanical and lighting systems are energy efficient.  Mediocrity in Efficient Design is being rewarded to simply encourage people to design “Sustainably”.  This is fine – this is great, but a truly Efficiently designed building (designed efficiently across the spectrum) improves the performance of the building and reduces costs.

I believe that designing Efficiently is designing Sustainably.  I believe that designing Efficiently Reduces the Construction Cost at the same time.

What is necessary is a Holistic and Organic approach to the Efficient design of the Complete building – a whole new sensitivity to how to design. 

At POSTEN Engineering Systems, with our programs POSTEN Multistory, TiltUP and TaperSTEEL, we have shown how to design Efficiently in Concrete and Steel in such a way that not only is the building Sustainable, but costs less to build without a loss in building performance, while at the same time also reduces the Design Costs.

At Reilly & Company, we have shown how construction costs can be reduced by up to 30% through Efficient design Light Gauge Metal Framing Systems.

Efficient Design breeds more efficiency.  When you design Efficiently, you open up more design opportunities.  If, as a Structural Engineer, I can reduce the thickness of a concrete slab by 1” per floor, that creates the additional benefits of less weight, lower building height or higher ceilings, and lower construction cost.  Everyone wins.

Across the board, every Design and Construction discipline needs to be engaged with the emphasis being Efficient Design and lower construction costs will follow (and with the additional benefit of being Sustainable). 

Dennis Reilly, Architect/Structural Engineer, was commissioned to present his work on Sustainable Design of Post-tensioned Structures at the Post-tensioning Institute’s National Conference in Fort Worth, Texas.  This presentation demonstrated how, using POSTEN Multistory, an engineer could Automatically design the most Efficient Design Possible, which increased Design Options for the Architect, reduced construction costs and reduced design costs.

Sunday, August 22, 2010

Light Gauge Metal Stud Bearing Walls in Type II FR Construction - Benefits and Challenges

Over the last few years, we have seen a significant increase of the construction of new buildings constructed with light gauge metal stud bearing walls.  Typically this form of construction has been limited to single family homes and low rise condominiums & apartment buildings (i.e. 3 to 4 story).  Note that this type of construction is typically limited to Residential Occupancies, where long spans do not exist and the interior walls are unlikely to move (as in an office building).

Originally these building employed plywood shear wall sheathing and plywood floor sheathing (i.e. Modified Type 3 Construction).  In 3 or 4 story condominiums, steel braced and moment frames have been more recently been used, in a variety of forms, to provide the lateral force resistance for the building, but still with plywood floor and roof diaphragms.

Reilly & Company has taken this technology to it's next level of Innovation, 5 stories of light gauge metal stud bearing walls in a 6 story Type II FR building (i.e. concrete over metal deck floors instead of plywood and totally non-combustible).  Compared to the Concrete and Conventional Steel normal options, this provided the Sustainable - Efficient - Cost Effective solution.

The advantages of this type of construction are as follows:
1.    The Building is typically lighter than a wood framed building;
2.    The metal studs stand straighter than wood studs;The metal studs install faster than wood studs and joists;
3.    Metal stud framers (typically dry wall installers) cost less than wood framers;
4.    The building is more fire resistant and less prone to mildew (or dryrot) as compared to wood framed buildings;
5.    With the use of open web light gauge metal joists, the installation of plumbing, electrical wiring and mechanical ducting is easy; and
6.    If compared to concrete or conventional steel frame construction (Type I or II),  light gauge metal studs with concrete/metal deck construction can be approx. 30% less in cost for the structure.

The dis-advantages of this type of construction are as follows:
A.    Attention to detail is paramount in the proper construction of light gauge metal stud bearing wall construction, because of the inherent weaknesses of the material:
a.   The open web light gauge metal joists need to be aligned so that the preset holes in the webs align;
b.   All floor joists must be placed directly above each bearing stud, since the top track has essentially no strength to support the weight of the joists;
c.   In addition to the blocking between the joists above the studs, it is advisable to install a vertical section of stud (squash block) above the top track screwed to the side of each joist, due to the potential of the joists to buckle at the stud support;
d.   The studs must firmly bear on the curved bend of the top and bottom tracks (i.e. the studs must be completed seated into the top and bottom tracks) so that the screws connecting the studs to the tracks do not fail under the vertical load and so the flanges of the tracks do not buckle under the load; and
e.   Plumbing, conduits or mechanical ducting should not be permitted within any stud bay (let alone cutting through a stud or top or bottom track).  This means that all plumbing, conduits and mechanical ducting should be installed in shafts located outside of the bearing walls.

B.   Unlike wood, Metal is highly conductive of heat and cold.  As such,  light gauge metal studs require a much higher level of insulation on the exterior walls, including the requirement for rigid insulation on the exterior of the wall.  In addition, due to this high conductivity, it is advised, even in mild climates to install a vapor barrier (in addition to the waterproofing on the exterior side) on the warm side of the exterior studs to prevent condensation from occurring in the stud bay.

C.    Sustainability – in Modified Type 3 construction is not a reality.  Steel has a significantly higher negative impact on our environment than either concrete or wood, due to the high level of energy needed in fabrication.  Even though steel can be recycled, recycling is not without significant environmental cost.  Energy use from Deconstruction, Transportation and Re-forging is not insignificant.  Add to that the fact that steel cannot be re-forged back into steel without the addition of virgin steel (around 7% to 10%).  At least, recycled steel does not end up in a land fill.  However, if compared to conventional steel frame construction, light gauge metal stud bearing wall construction is certainly the Sustainable solution due to the partitions serving also at the supporting steel frame.

D.   Sound Transmission:  In an Apartment project of this type that we designed, the client wanted the concrete floors to be exposed stained concrete.  This added to the challenge to conform to the IIC50 and STC50 sound transmission requirements.  Partially since this type of construction is new there are presently no tested fire assemblies for these ratings. After an International search, scouring the world for sound assemblies, we found a sound assembly that would comply with these requirements with field testing.  Just in case we had problems with compliance, we were prepared to include wood flooring over insulation.

With this background, we were the first Engineering Firm to design a 6 story building with 5 stories of  light gauge metal stud bearing wall in a Type II structure (i.e. concrete/metal deck floors).  In a tight urban setting, being willing to be Innovative was crucial.  Our options were conventional concrete (which is no longer an economic solution), post-tensioned concrete (not a viable solution within our tight urban setting, surrounded by buildings), conventional steel frame construction (which, along with the concrete solutions, was too expensive), or try something completely different.

Considering that in an apartment or condominium, the light gauge bearing walls could easily serve double duty as bearing walls as well as partition walls and resulted in a significant savings in the cost of the structure.  The gauge of the studs ranged from 18 gauge at the top floor to 12 gauge at the lowest floor.  If you are in a high seismic zone (i.e. California), you will find that the economical solution is to use steel braced or moment frames to resist the high seismic forces.

Reilly & Company is proud of the Innovative Designs and Procedures that we have advanced over the years that produce the most Efficient/Sustainable designs that save construction cost.  Dennis Reilly was recently commissioned to present his Innovative work on Sustainable Design of Post-tensioned Structures at the Post-tensioning Institute (PTI) National Conference.

Sustainable Design should not cost more to build.  Viewing a building Holistically and Organically is the key to designing Sustainable, more Efficient, Lower Cost buildings.

Tuesday, June 15, 2010

Dennis Reilly presents at the Post-tensioning Institute National Conference


The Post-tensioning Institute recently commissioned Dennis Reilly, Arch/SE to present his innovative work in Sustainable Design at their National Conference in Fort Worth, Texas.

At POSTEN Engineering Systems, Dennis Reilly developed procedures whereby the Post-tensioning Software, POSTEN Multistory, automatically determines the thinnest section of concrete & the least amount of steel to create the most efficient design possible, completes the design and then automatically produces documentation required for LEED certification.

In Sustainable Concrete Design, the conversation usually starts with Fly Ash or Building Durability and then goes quiet.

In Sustainable Steel Design, the conversation usually starts with the use of Recycled Steel and then, again, goes quiet.

The use of Fly Ash and Recycled Steel is not new, and with the increasing costs of Cement and Steel, their use will expand whether or not Sustainable Design is important or not. In many cases, Fly Ash improves the performance of the concrete from installation to long term durability. With the exception of Specifying the use of Recycled Steel, the use and acquisition of Recycled Steel is mostly outside the control of the Design Structural Engineer. In any regard, Dennis believes that using materials that you would use anyway is not truly Sustainable Design.

In Structural Engineering, Dennis believes that Sustainable Design demands more - Efficient Design. Even though Post-tensioned Structures use significantly less steel & concrete than Conventionally Reinforced Concrete structures, they still tend to be extremely in-efficiently designed, since they are often designed using inefficient & time consuming Trial and Error Methods.

Dennis demonstrated Automated procedures that could save an inch of concrete thickness and 9% in steel in a typical post-tensioned slab, while improving the performance of the structure & documenting the savings for LEED.

Dennis then presented the concept of Post-tensioned Moment Frame Design (only capable on POSTEN Multistory), which further Expands Sustainable Design by removing the need for shear walls (opening up the building).

Dennis believes that , just as Energy Efficient Radiant Heat also provides the most comfortable heating system, Efficient Sustainable Post-tension design should and can expand the volume of the building or reduce the building height, reduce the building weight and enable the Architect’s creativity, while also REDUCING the cost of construction.

Tuesday, April 6, 2010

PTI Conference - Sustainability Technical Session

As requested by the Post-tensioning Institute,  Dennis Reilly will be presenting a talk on the "Sustainability Advantages of Post-tensioning in Buildings" on May 3, 2010 at the PTI Conference in Fort Worth, Texas.
See you there.

Saturday, April 3, 2010

See! This our father did for us.

“When we build, let us think that we build forever. Let it not be for present delight nor for present use alone. Let it be such work as our descendents will thank us for; and let us think, as we lay stone on stone, that a time is to come when those stones will be held sacred because our hands have touched them, and that men will say, as they look upon the labor and wrought substance of them, “See! This our father did for us.”” – John Ruskin

As Design Professionals, we have a unique responsibility, not just to our current clients, but to future generations that the words of John Ruskin are part of our Goals, Ambitions and Everyday Activities.

In future blogs, I will be discussing issues that are dear to me as a practicing Architect and Structural Engineer, ranging from Sustainable Building Design, Historic Preservation, Innovative New Building Materials and Innovative New Building Systems – some of which were developed at Reilly & Company.