Solar Panels Arrays
Innovation and Structural Considerations
With the increased implementation of green-building practices, concepts from the past have been resurrected and are being presented as advancements within the construction industry.
The evolution of solar panels has progressed considerably since the emigrant Californians invaded Oregon in the 1970s with their geodetic domes, "holistic" gardens and Dialing for Dollars with McCormick and his puppet characters, Charley and Humphrey. At that time, solar panels were homegrown - I mean home built - and were used to run the florescent lights, off the grid, nurturing "holistic" gardens in people's garages. They never moved their VWs into the garage - very strange.
Today, solar panels implement a combination of revolutionary materials to drive efficiencies from below 10% to the high teens. SunPower model 215: an individual 32"x62" panel produces 215 watts at 17.3% efficiency.
Current solar panel systems have been refined to "stand off" current roofing material with sufficient attachment to withstand wind uplift loads, while providing adequate ventilation below the panel for maintenance purposes.
Since solar panels are typically installed postconstruction, the additional
2.4 lbs./square foot beyond the existing roofing material weight may warrant evaluation of the current roof structure, reinforced concrete, concrete composite deck, metal pan with foam insulation or wood assembly for its ability to vertically support the added assembly. Also, the added panel weight may increase the seismic lateral loads at the roof level sufficiently enough to exceed the existing shear wall panel capacities and/or wind loads. Solar panels will act as hydrofoils even on flat roofs, creating uplift connection and framing concerns. Thus, within high wind or seismic regions, having a structural review and implementing recommendations by an engineer may be prudent.
COMMERCIAL APPLICATIONS
Solar panel arrays are rapidly appearing within new retail construction as well as existing buildings, which are being structurally evaluated/rehabilitated to accept rooftop-mounted solar panel arrays and associated equipment: control panels/converters.
The electricity produced utilizing the rooftop-mounted arrays are easily powering the interior store lights for thousands of big box stores like Macy's, Lowe's, Target and Walmart; imagine the number of arrays you can put on a 50,000 square-foot box store.
Solar arrays have been recently accepted by commercial building owners without reservation and have been used for green campaigning to customers and tenants. But who wouldn't be bragging about being ecologically friendly, as their rooftop-mounted arrays convert up to 22% of available sunlight into electricity!
TRANSPARENT RESISTORS: NANOTECHNOLOGY
Remember those emigrant-Californians? Apparently, their offspring are now researchers at Oregon State University (excellent school … OK, I'm an OSU '82 grad) and have in the past couple of months collaborated with HP to develop transparent transistor and optoelectronics (thin film), creating a solar energy system that is expected to be twice as efficient and half the cost of traditional solar panels. GO BEAVERS!
Solar energy is present every day (unless you are in Alaska, then you get really long days or really long nights). We have hundreds of millions of accessible square feet of retail rooftops in the USA, which all see the light of the sun. Our task is to effectively and consistently capture this energy resource with rooftop-mounted solar panel arrays while folding it into current designs, architectural and structural, which enable the installation of optional solar equipment.
September 2008 Commercial Edition Issue
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California Historical Building Code - Title 24 Part 8
By Perry A. Tabor, P.E.
The California Historical Building Code (CHBC) provides specific regulations (alternative building codes) for the preservation, restoration, rehabilitation, relocation or reconstruction of qualified historic buildings or properties so as to preserve their original or restored architectural elements and features. At the same time, it provides for the safety of occupants and for the reasonable accommodation of people with disabilities.
While these alternative solutions are intended to protect historic buildings from the adverse impact of certain requirements of the regular building code, they also translate into cost-effective incentives as described by the California Office of Historic Preservation.
A "qualified historical building" is defined as any building, group of buildings, district, site or object that is listed by any level of government as having historic importance. This also includes those resources listed in the state of California's evaluated inventory, and given any level of significance other than "not eligible." Also included are ships and railroad rolling stock of historical significance.
The CHBC recognizes and endorses the need - on a case-by-case basis - to find and adopt reasonable alternative situations where strict compliance with established statutes or regulations would jeopardize the historic building's appearance or rehabilitation of economic viability (i.e., full upgrade of building).
The "triggers" for full upgrading to current standards, with respect to length of vacancy, change of occupancy or percentage of value of the work proposed, and which exist in other codes, are not recognized by the CHBC, which concentrates instead on the preservation-sensitive resolution of genuine safety considerations.
Structural/seismic upgrading issues are governed by the CHBC, permitting design based on real values (performance) of archaic materials and solutions based on engineering principles and professional judgment (providing a framework within which unique solutions may be custom tailored to the specific problems related to each unique historic resource), rather than solutions limited to code-based (prescriptive) formulas. This flexibility usually translates into a higher degree of retention of the historic fabric.
You may very well benefit if your building qualifies as a "historical building." Places to research whether your prop- erty "qualifies":
- The Office of Historic Preservation - computer lists of the National Register and California Register
- Local planning office - The planning department is usually the best place to find local lists
- Local heritage or history commissions
- Local neighborhood or preservation organizations - These groups may have access to official lists, but can't create official lists
- Local, state and federal agencies that promulgate projects - CalTrans, Department of Water Resources, Department of General Services/Real Estate Services Division, local water agencies and local public works departments
June 2008 Commercial Edition Issue
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Are You Ready for the New Building Code?
California Makes Way for the International Building Code
By Perry A. Tabor, P.E.
As Builder/Architect's structural engineering expert columnist, we continue to feature our monthly "Structural Design Corner," bringing you interesting and useful information, including viable design innovations and alternatives.
This month we are discussing impending significant building code change. While there is a great deal of information on this topic to cover, our objective is to provide you with a general overview and encourage you to start now, if you haven't already, to familiarize yourself with the changes that will take effect on January 1, 2008.
The International Building Code (IBC)/California Building Code (CBC) will soon be upon us in all its glory. We escaped the 2003 de- cision by the California Building Standards Commission to adopt the National Fire Protection Association's model code NFPA 5000 when Gov. Schwarzenegger's administration rendered a decree that the adoption of the NFPA 5000 by Gov. Davis' administration was nonbinding. We are now being asked to come to the table on January 1, 2008, with the 2006 IBC and 2007 CBC under our arms.
Since we've had an eight-year hiatus from the three-year cycle of code updates, we as a building design community are having difficulty getting out of the big chair. We were quite comfortable in the big chair; the 1997 UBC fits like an old pair of slippers, and frankly, our bones are stiff from not moving around. Well, it is time to get up, down a cup of coffee, get outside (of your comfort zone) and exercise (work the mind).
Design professionals (yeah, you!), on January 1, the governing agency has an obligation to enforce the 2007 CBC, and if they don't, they face the potential of being liable for malice. So they will be coming to the table in a big way. Of course you can still submit your project under the 1997 UBC (if you didn't bother updating your design and specifications to the earlier enacted 2000 CBC), and in turn, get a laundry list of plan check comments, delay project approval, face losing a client and damaging your professional reputation. But I'd suggest avoiding that option.
Instead, if you haven't already, now is the time to begin implementing the code changes into your schematic designs (e.g., side yard setback) or start producing construction documents under the 2007 CBC.
Ensure that your library has the 2007 CBC and then invest the time to read the CBC at least a couple times. You will be amazed at code changes. This column is not big enough to list all of the changes in the code (both structural and nonstructural) from the 1997 UBC. Just within the "Structural World," we are seeing changes in load combinations (the need to consider temperature and rain), seismic vertical effects, revamped wind design methodology, amplified collector loads, etc.
Because the 2007 CBC seismic criteria have moved from "Life Safety" to "Collapse Prevention" design criteria, we have, under the 2007 CBC, yielded a 10% to 40% reduction in seismic lat- eral loads depending upon the project location. However, one upside of the recent new design criteria is that the code updates and building rehabilitations are yielding substantial economies for "seismic prone" projects with the design-level criteria reduction.
Unfortunately, there is no simple way to become current with the 2007 CBC (there are differences between the IBC and CBC). Simply put your nose to the grindstone, study and put your knowledge to work. Also, you may benefit from taking an overview course, such as those provided by CALBO, SEAOC, AIA and ICC.
We hope that this article moves you into taking immediate action. We want to make sure that no one is asleep at the wheel and that our design industry is prepared for the unavoidable code transition.
January 2008 Commercial Edition Issue
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Structural Engineers Can Do More than Just 'Calc'
By Perry A. Tabor, P.E.
For over 20 years, we have been actively collaborating with building industry colleagues, acquiring valuable information that we look forward to sharing in this column. Our goal is to help introduce information in our monthly articles that can have a direct and positive impact on your future projects.
We are proud to serve as the structural engineering experts for Builder/Architect, featuring our monthly "Structural Design Corner."
The topics we will bring to you will include design concepts, innovations and trends, as well as practical considerations that can bring value to a wide variety of projects.
Our first column topic is "Structural Engineers Can Do More than Just Calc." More specifically, we will highlight the importance of having your structural engineer serve as a collaborative partner; actively participating from early conceptual design, into design development and construction documents, continuing through construction administration.
Architects are unquestionably the most visible design professional associated with any building project. Who and what a structural engineer does is much less visible to the public and his/her name is very rarely remembered. The satisfaction of efficiently transforming a concept into a tangible object that serves and shelters its occupants is the engineer's reward.
Builders and architects have welcomed a change from the old industry standard in which the structural engineer only became involved in a project after the architect has completed the fully dimensioned drawings with building elevations and sections, having limited input during the design phase and almost no involvement once actual construction began.
Today, structural engineers continue to be more fully involved as an integral part of the project team. There are certain stages of involvement that are particularly important to consider.
CONCEPTUAL DESIGN PHASE
Collaboration meeting(s) between the architect, owner/developer, structural engineer, geotechnical and other engineering professionals during the conceptual design can translate into substantial construction savings. This is the stage when the structural engineer can help by proactively discussing the most viable foundation and building assembly, as well as by identifying other challenges.
DESIGN DEVELOPMENT PHASE
Continued periodic collaboration between the owner/developer, design team and the general contractor can further refine construction savings. Together, they can help to identify opportunities for practical plan modifications, as well as identify potential challenges (e.g., grading, sound, etc.). For example, in a recent project design meeting, the team agreed to adjust the store front opening by eliminating one window panel, which reduced header member sizes, as well as changed the store front lateral system to a shear wall panel system from an inverted column (steel) system. This simplified construction, reduced coordination of different trades (steel fabricator and erector), avoided potential schedule delays and reduced building costs (reducing footing sizes and reducing man-hours/material costs). This is just one example of how a minor change translated into more efficient and economical construction.
On small projects, a schematic design meeting may be more appropriate than the conceptual and design development phase involvement.
CONSTRUCTION DOCUMENT PHASE
As the design is evolving, periodic meetings should be held at milestone stages with the critical team members. Architects have an invaluable opportunity to enlist the participation of the structural engineer, truss manufacturer, framing contractor, MEP engineer/contractor and sound consultant during superstructure discussions. It is also important to enlist the participation of the geotechnical, structural engineer, concrete contractor and civil engineer during foundation discussions.
Their joint collaboration (value engineering) can help to identify appropriate cost saving assemblies prior to finalizing the building design, as well as create an opportunity to introduce alternative assembly or design considerations much earlier than by value- engineering during the construction process.
On small projects, a preconstruction meeting during which the project team briefly can interface may be more appropriate than the above listed construction documentation phase outlined meetings.
CONSTRUCTION OBSERVATION PHASE
Periodic site observations by the structural engineer during various structural stages of construction are critical and will vary by project type, size and complexity. At a minimum, site observations should be conducted at foundation reinforcement, rough framing and interior/exterior/roof shear, as well as after the HVAC/plumbing/electrical installation.
The engineer can often assist to identify noncompliance structural assembly and offer immediate solutions/directions to rectify the assembly, avoiding potential construction delays and reducing their clients' potential liability.
In addition to fully engaging structural engineers throughout the above described phases, it is also important that the structural engineer be encouraged to present viable design innovations and alternatives. Structural engineers can be forward-thinking in implementing new concepts and communicating new methodologies. Becoming familiar with and evaluating alternative materials can often lead to introducing design options that promote greater flexibility, easier installation, reduced delays and lower construc- tion costs overall.
We've highlighted certain design and construction stages in which to involve your structural engineer. These stages can certainly be further elaborated in future articles as well. Do you currently engage your engineer as a collaborative partner to the fullest extent? If not, we encourage you to join the increasing number of building participants that wholeheartedly embrace this valuable concept of increased involvement. By doing so, you can yield cost savings and greater efficiency while producing structurally sound homes and buildings.
September 2007 Commercial Edition Issue
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Structural Engineers Can Do More than Just 'Calc'
By Perry A. Tabor, P.E.
For over 20 years, we have been actively collaborating with building industry colleagues, acquiring valuable information that we look forward to sharing in this column. Our goal is to help introduce information in our monthly articles that can have a direct and positive impact on your future projects.
We are proud to serve as the structural engineering experts for Builder/Architect, featuring our monthly "Structural Design Corner."
The topics we will bring to you will include design concepts, innovations and trends, as well as practical considerations that can bring value to a wide variety of projects.
Our first column topic is "Structural Engineers Can Do More than Just Calc." More specifically, we will highlight the importance of having your structural engineer serve as a collaborative partner; actively participating from early conceptual design, into design development and construction documents, continuing through construction administration.
Architects are unquestionably the most visible design professional associated with any building project. Who and what a structural engineer does is much less visible to the public and his/her name is very rarely remembered. The satisfaction of efficiently transforming a concept into a tangible object that serves and shelters its occupants is the engineer's reward.
Builders and architects have welcomed a change from the old industry standard in which the structural engineer only became involved in a project after the architect has completed the fully dimensioned drawings with building elevations and sections, having limited input during the design phase and almost no involvement once actual construction began.
Today, structural engineers continue to be more fully involved as an integral part of the project team. There are certain stages of involvement that are particularly important to consider.
CONCEPTUAL DESIGN PHASE
Collaboration meeting(s) between the architect, owner/developer, structural engineer, geotechnical and other engineering professionals during the conceptual design can translate into substantial construction savings. This is the stage when the structural engineer can help by proactively discussing the most viable foundation and building assembly, as well as by identifying other challenges.
DESIGN DEVELOPMENT PHASE
Continued periodic collaboration between the owner/developer, design team and the general contractor can further refine construction savings. Together, they can help to identify opportunities for practical plan modifications, as well as identify potential challenges (e.g., grading, sound, etc.). For example, in a recent project design meeting, the team agreed to adjust the store front opening by eliminating one window panel, which reduced header member sizes, as well as changed the store front lateral system to a shear wall panel system from an inverted column (steel) system. This simplified construction, reduced coordination of different trades (steel fabricator and erector), avoided potential schedule delays and reduced building costs (reducing footing sizes and reducing man-hours/material costs). This is just one example of how a minor change translated into more efficient and economical construction.
On small projects, a schematic design meeting may be more appropriate than the conceptual and design development phase involvement.
CONSTRUCTION DOCUMENT PHASE
As the design is evolving, periodic meetings should be held at milestone stages with the critical team members. Architects have an invaluable opportunity to enlist the participation of the structural engineer, truss manufacturer, framing contractor, MEP engineer/contractor and sound consultant during superstructure discussions. It is also important to enlist the participation of the geotechnical, structural engineer, concrete contractor and civil engineer during foundation discussions.
Their joint collaboration (value engineering) can help to identify appropriate cost saving assemblies prior to finalizing the building design, as well as create an opportunity to introduce alternative assembly or design considerations much earlier than by value- engineering during the construction process.
On small projects, a preconstruction meeting during which the project team briefly can interface may be more appropriate than the above listed construction documentation phase outlined meetings.
CONSTRUCTION OBSERVATION PHASE
Periodic site observations by the structural engineer during various structural stages of construction are critical and will vary by project type, size and complexity. At a minimum, site observations should be conducted at foundation reinforcement, rough framing and interior/exterior/roof shear, as well as after the HVAC/plumbing/electrical installation.
The engineer can often assist to identify noncompliance structural assembly and offer immediate solutions/directions to rectify the assembly, avoiding potential construction delays and reducing their clients' potential liability.
In addition to fully engaging structural engineers throughout the above described phases, it is also important that the structural engineer be encouraged to present viable design innovations and alternatives. Structural engineers can be forward-thinking in implementing new concepts and communicating new methodologies. Becoming familiar with and evaluating alternative materials can often lead to introducing design options that promote greater flexibility, easier installation, reduced delays and lower construc- tion costs overall.
We've highlighted certain design and construction stages in which to involve your structural engineer. These stages can certainly be further elaborated in future articles as well. Do you currently engage your engineer as a collaborative partner to the fullest extent? If not, we encourage you to join the increasing number of building participants that wholeheartedly embrace this valuable concept of increased involvement. By doing so, you can yield cost savings and greater efficiency while producing structurally sound homes and buildings.
September 2007 Commercial Edition Issue
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