Archive for the 'Concrete' Category

02
Jul
08

AGS Case Study: West Side Skate Park, Albuquerque

Who would have thought such an exquisite degree of planning could go into a skate park? The project undertaken by Morrow Reardon Wilkinson Miller (MRWM) certainly proves that collaboration with the widest possible team can pay off in terms of the wow factor. In the Building Sitework chapter of Architectural Graphic Standards, 11th Edition, Gregg Miller relates every step in the creation of this large-scale in-ground skate park. Here’s the overview:

The majority of the basic elements of the skate park utilize standard construction details and methods. The unique aspect of this project is the modification, application, and combination with these elements that makes them more “skate-able.” …. The arrangement, spacing, and connection of elements was resolved and refined in concert with the grading design. Through this process, the majority of the schematic design remained intact. Modifications were made to establish grades to acceptable slopes and to provide better internal circulation.

Now, what exactly are these elements? They are all standard concrete applications, either flat, sloped, or vertical, but it’s the imaginative way they’re put together that makes this park such a treat. They’re combined into features such as volcanoes, which are transitioned ledges with flat tops, and pyramids, which are multi-banked structures. There’s a thing called a sofa, which is a notch running laterally in a bank, and another called a loveseat, which is a protrusion at a bank’s corner. Since skaters like to jump over things, they have vertical separations and horizontal gaps to jump over.

Everything is grouped into two main areas, a section called the Trenches, mostly made from cast-in-place concrete around a central plaza of brick. This is described as a liner-flow area, replete with walls, banks, ledges, gaps, rails and steps. Separated from the Trenches by a grassy area is the Dogbone, a feature combining three bowls with a ¾ pipe. These bowls are from 8 to 11 feet deep, made to resemble the backyard swimming pools where many skaters learned their trade. The brick area pays homage to the University of New Mexico’s brick plazas, and the Trenches to the city’s system of drainage arroyos. Another part is modeled after a supremely skateable California bridge.

This illustration from Architectural Graphic Standards (from page 726) gives some idea of the meticulous planning that went into this unique recreational facility.

Miller goes into great detail describing the composition and formation of the various parts. The concrete paving, for instance, has to withstand not only skateboards but trucks, in the Trenches area, because they have to get in there for maintenance. So some of the concrete flatwork is six inches thick, reinforced by steel. The four different kinds of joints are enumerated and described: expansion joints, cold joints, cold-keyed joints, and control joints. The concrete retaining walls are of course not just walls, but skateable elements also, and vary from 8″ to 24″ in thickness, while part of the retaining wall is an aggregation of granite boulders with two-thirds of their bulk above ground. Both banks and ledges are composed of numerous variations on a theme, with different heights, widths, lengths, slopes, and connections.

The success of the project is attributed to the expertise of the consultants, namely, professional skateboard maestros who are usually on tour displaying their skills. All their ideas for exciting features were pulled together by an architect into a site plan. MRWM’s implementation of the plan started off with 3-D modeling, and at each step, everything was checked again with the experts who had envisioned the plan. Some changes and improvements were made along the way, but the park essentially came into reality matching the initial dream.

SOURCE: “West Side Skate Park” 2007
photo courtesy of striatic , used under this Creative Commons license

29
May
08

Greener Than Green: Hempcrete

Hennep (hemp)

Texas may not usually be the state that immediately springs to mind when the words “bold innovation” appear in the same sentence, but The Woodlands, Texas, a community near Houston, is the site of America’s first hempcrete building. T. L. Hamilton tells us about it in the Montgomery Courier, while interviewing builder Gail Moran of Old World Exteriors. Moran told the reporter,

We’re cycling back to that traditional look and feel because it works better in some cases than the newer technology…I am so desperately wanting to make a difference in the way we currently build. I would like to see more people use natural products. I think they’re better for us and they look better.

How to build green is a topic on everyone’s mind these days, and hempcrete fulfills the requirements of being made from natural materials, being non-toxic, and providing energy efficiency. Formed into foot-thick walls on a wooden frame, the material eliminates the need for both insulation and sheet rock. Such walls are “breathable” and have a pleasant, natural appearance, as well as the ability to alleviate noise pollution from the outer world.

Skipping over to NaturalEnvironment.com, we learn that sustainable housing and hemp products go together like sunshine and picnics. It’s being used for fiberboard, mortar, stucco, insulation, fencing, pipe, and other housing-related applications, all over the world. Hemcrete, Isochanvre, Canobiote, and Canosmose are some of the trade names under which these products are marketed.

Hempcrete, which can be used in the same way as concrete, is made by mixing hemp, lime, sand, plaster and cement. It is mixed on site and sprayed onto the frame. Aside from doing away with the need for insulation, the material is waterproof, fireproof, and resistant to weather, rodents, and rot. It is said to be seven times stronger than concrete, as well as being more elastic, thus less prone to crack, and half the weight of concrete. Rather then emitting carbon dioxide, the construction of a hempcrete building can remove carbon dioxide from the air and trap it.

From another eco-friendly source, we learn that the growing of hemp yields four times as much material as the equivalent amount of land planted in trees, and can be harvested yearly rather than every 20 years. It grows well in many different climates, and its deep root system helps to prevent soil erosion. There is no need for herbicides, and very little call for pesticides in its growing; and since the ever-shedding leaves add to the soil, the land is left in better shape than before the crop was planted, and can be immediately used again the following year without needing to rest.

So, Gail Moran has achieved the distinction, with her small pottery studio/chapel, of being the first builder in the United States to use a material that humankind has depended on for centuries. Unfortunately for America’s farmers, builders, and environmentally-concerned citizens, hemp may not be grown in the United States and must be imported from more advanced countries.

SOURCE: ” Building green: Local company using hemp concrete ” 05/24/08
photo courtesy of psd, used under this Creative Commons license

28
Apr
08

Did Pyramid Builders Use Cast-in-Place Concrete?

In a Boston Globe article titled “A New Angle on Pyramids,” Colin Nickerson describes the research conducted at the Massachusetts Institute of Technology by Linn W. Hobbs and his students. The professor of materials science suggests that the ancient Egyptians might have invented concrete. This would mean the technology was developed a couple of thousand years earlier than was previously thought. As Nickerson explains:

That’s a notion that would dramatically change engineering history. It’s long been believed that the Romans were the first to employ structural concrete in a big way, although the technology may have come from the Greeks. A handful of determined materials scientists are carrying out experiments with crushed limestone and natural binding chemicals – stuff that would have been readily available to ancient Egyptians – designed to show that blocks on the upper reaches of the pyramids may have been cast in place from a slurry poured into wooden molds.

If indeed the Nile denizens invented concrete, they would have made it from a mixture of crushed limestone, kaolinite clay, natron, and silica. Hobbs is one of a small circle of scientists trying to solve this inquiry into the origin of the most common building material used by humans. The concept of Egyptian invention is not new, but goes back to the theories of Joseph Davidovits, a chemical engineer, who posited sacks of wet cement being carried aloft by slaves in a kind of bucket brigade.

Another scientist believes that as many as 20 percent of the pyramids’ blocks may have been cast in place. In Philadelphia, Michel W. Barsoum announced in 2006 that the Khufu Pyramid had yielded stone samples that differ from limestone on a microstructural level. However, critics point out that although apparent concrete may have been found, it has been incorrectly interpreted, and will eventually prove to date not from the building of the pyramids, but from more recent repair work.

In “Concrete Pyramids“, Isabel R. Harris and Matthew W. A. Bruder V say the concrete pyramid theory has been around since the 18th century. They point to the process the ancient artisans used for making alabaster vases with plywood molds. Although wood for molds was very scarce in Egypt, it could, like many other commodities, be imported. There’s a whole lot of technical discussion about the precision cutting — or was it casting? — of the pyramids’ stone blocks, and the question of scrap is raised — where did it go? They do the math, and tell how many workers would have been needed, and how much time, to build pyramids of concrete.

Reading up on the subject in the cast-in-place concrete section of Architectural Graphic Standards, 11th Edition, we find that, in addition to portland cement, water and aggregates, concrete admixtures are of many types. An admixture might entrain air, reduce water, or control hydration. It might accelerate, retard, or superplasticize. Then there are “miscellaneous admixtures that aid workability, bonding, dampproffing, gas-forming, grouting (nonshrink), coloring, and admixtures that reduce permeability and inhibit corrosion.”

Given the evidence of their other accomplishments, is there any reason to believe the ancient Egyptians couldn’t have figured out concrete?

SOURCE: ” A new angle on pyramids” 04/22/08
photo courtesy of Ahmed Rabea , used under this Creative Commons license

23
Apr
08

First LEED-Certified Parking Structure, Santa Monica, California

Santa Monica Civic Center parking structure

Count on California to implement pioneering technologies, especially those related to cars. In Santa Monica, the city’s Green Building Program offers an interesting case study – the first certifiably green parking garage. This article is more oriented toward the technical details, but fortunately, another website, Inhabitat, offers spectacular pictures of the building’s exterior.

As for what the City of Santa Monica itself has to say about it, here is the Project Overview, as presented on their website:

The City of Santa Monica has made an aggressive commitment to becoming more sustainable. The new Civic Center Parking Structure embodies that commitment while at the same time establishing a new aesthetic monument in the City. This parking structure promises to be the first building of its type in the country to receive a LEED-Certified rating through the U.S. Green Building Council. The building features design strategies, materials, products, and construction practices that preserve natural resources, conserve water and energy, and reduce waste.

The page includes photos of many of the details that went into the sustainable design, like the photovoltaic panels on the roof which also provide shade for the top parking level. On the other levels, white ceilings augment the available light which is also bolstered by fluorescent lamps. A solar power inverter takes the energy harvested by the photovoltaic panels, and changes it to alternating current for the building’s needs. Stormwater is filtered and used for landscaping and toilet-flushing. Recycled steel and glass are used, in addition to recycled flyash in the concrete, and the building has outlets for 14 electric vehicles for public use. Alternative transportation is encouraged by the provision of bicycle storage lockers, and signs help the public understand the advantages of the building’s green components.

The building’s creators, Moore Ruble Yudell Architects & Planners, also contribute some remarks:

Pre-cast white, ribbed concrete panels are set in a rhythmic, variegated pattern on all facades. These panels, in shifting locations along the facades, lend a surprising quality that screens the presence of parked cars. On the Fourth Street façade, a series of bays made of channeled colored glass breaks down the scale of the structure, and are set at varying sizes and angles to provide a light, luminous, and ever-changing quality to the viewer.

The considerations related to vehicles and parking are much more complicated than would be apparent to the uneducated eye. Architectural Graphic Standards, 11th Edition devotes several pages of its Building Sitework section to these questions, and then goes into the matter of accessible parking in even greater detail in its Inclusive Design section, including all the specifications for various scenarios. Its introduction on design considerations says:

Creating vital places is the job of those who design, build, finance, and plan the built environment. Unfortunately, too often as acres of asphalt attest, engineering standards are applied cavalierly; they are not used properly to help design the place. Even “just a parking lot” can be made into a place of delight.

We might also want to consider what Bobby Grace asks, at Media & the Environment:

I hope you realize the contradiction of terms here; this is an earth saving structure dedicated to the machine that has arguably accelerated the destruction of the earth…Is this making a joke of LEED certification?

SOURCE: “Santa Monica Civic Center Parking Structure”
photo courtesy of Omar Omar , used under this Creative Commons license

18
Apr
08

Rainwater Harvesting at the University of Georgia, Athens

Water Drop

From OnlineAthens comes a report about the University of Georgia’s latest water conservation project, a $600,000 cistern adjacent to the Tate Student Center. This is not the first cistern to grace the UGA grounds. The old ROTC building and the Paul D. Coverdell Building already had smaller cisterns. Several months ago, the university’s Ad-Hoc Task Force on Water Resources issued a report which describes the many measures the campus had been taking even before this current project began. Lee Shearer describes the latest addition to the campus:

The box is a giant cistern designed to collect rain and condensation from the building’s air conditioning system, and a real example of the kind of water-saving features UGA planners are including in new UGA buildings these days…The cistern is expected to save nearly a million gallons of water a year, which can be used to flush toilets in the Tate addition and irrigate landscaping beside the building.

The “box,” made of steel-reinforced concrete, is basically a 12-foot by 12-foot tank with a length of 70 feet. When fully operational, the massive collection system will claim an astonishing 95% of rainwater from the roof of the Tate Center and a nearby building. That adds up to a hefty 880,000 gallons per year, according to Holder Construction, which is also in charge of the overall student center expansion project.

At any given time, the cistern will be able to hold as much as 50,000 gallons of water, which will supply about half the building’s toilet-flushing needs, and also keep some of the landscaping green. This is especially important because in recent years, the University, long known for its picturesque beauty, has increasingly sacrificed aesthetics to the demands of necessity. Nobody likes to see brown lawns, so it is hoped that the latest effort to collect water will alleviate further need to under-hydrate the foliage. UGA feels strongly about its obligation to not only conserve water for its own sake, but as a publicly-supported learning institution, to set a good example and save the taxpayers’ money.

The other interesting part of this report concerns a new organization, a local chapter of Emerging Green Builders, which comprises not only students, but area professionals. A spinoff of the U.S. Green Building Council, the organization enables youth to become involved in green building in their own local environments, utilize the resources of the USGBC, and set up local events. To this end, Emerging Green builders sponsors an annual design competition and helps match up students and graduates to jobs.

In Architectural Graphic Standards, 11th Edition, the chapter on Plumbing includes a helpful chart of cistern types, categorized according to material, features, and cautions. Many factors need to be taken into consideration when designing a cistern, and this outline covers them all. AGS also lists on page 416 the reasons for the current interest in rain water collection:

  • Escalating environmental and economic costs of providing water by centralized water systems or by well drilling.
  • The relatively pure, soft, low-sodium water source that rain water harvesting offers.
  • Health concerns over the source and treatment of polluted waters.
  • A perception that there are cost efficiencies associated with reliance on rain water.

The last point is worthy of discussion. How is this working out? Is rain water harvesting cost efficient, or not?

SOURCE: ” Tate Center site showcases new water-saving cistern ” 04/16/08
photo courtesy of venkane , used under this Creative Commons license

17
Apr
08

AGS Case Study: The Genzyme Center, Cambridge, Massachusetts

Genzyme Center

Genzyme Corporation’s corporate HQ, part of the Kendall Square Redevelopment Project, was chosen as a case study presented in Architectural Graphic Standards, 11th Edition because of the health and environmental challenges overcome by the RETEC Group, a Massachusetts environmental engineering firm. Immediately following the Introduction to Architectural Graphic Standards, Nancy B. Solomon explains the nature of those challenges as met by the building’s creators on behalf of their client, a biotechnology firm:

The fact that the property (once home to a coal-gasification plant) was contaminated was considered an appropriate challenge: Genzyme’s participation in the transformation of an abandoned lot into a vibrant asset was seen as consistent with its corporate mission of improving individual lives through the proper application of technology.

Solomon goes into more detail about this aspect:

An impermeable vapor barrier consisting of a nonwoven geotextile placed over the treated soil, a 12-inch layer of gravel resting on the fabric, and a spray-applied membrane between the gravel layer and concrete floor slab prevents uncontrolled gas seepage into the building. High-density polyethylene piping (running through the gravel and slab penetrations to vertical risers) safely removes any vapors from below grade. When activated, pressure sensors in various parts of the building and under the slab trigger a blower to draw fumes from this internal piping system to treatment equipment on the roof.

One of the building’s innovations, which earned it recognition as a top ten green project from the American Institute of Architects, is the filigree wideslab construction system, which serves multiple purposes in fulfilling U. S Green Building Council standards. In this method, pre-cast, pre-stressed slabs of concrete are placed on pillars, then a reinforcing bar is added, with polystyrene filling in the spaces. Along with lessening the amount of concrete, this method allowed for nearly 400 fewer tons of reinforcing steel, with a resulting reduction of total building weight of 25%. The thermal mass of the structural frame also helps stabilize the building’s temperature, which adds to energy efficiency.

The 12-story Genzyme Center features a central atrium which functions both as light shaft and return air duct. The interior light-enhancement system is meticulously described in Solomon’s article, with explicit diagrams. The exterior features a curtainwall glazing system with operable windows. The evaporative cooling towers and landscaped roof make use of stormwater, and water conservation is aided by automatic faucets, dual-flush toilets and waterless urinals. The lobby contains a water feature, and there are 18 indoor gardens and outdoor terraces. The U.S. Green Building Council presents several very interesting pages on the project, described by one admirer as the “poster child of green building.”

One important mission was not mandated by green standards, but considered imperative by the client in terms of by human needs. Rule 1 was that the building’s form would follow the function of providing openness and togetherness. Everybody working inside would have ample opportunities to see, communicate with, and interact with colleagues.

Conference rooms and open-office areas adjacent to the atrium are separated from the central zone by full-height glass, providing acoustic privacy while maintaining visual continuity. The conference rooms are fitted with darkening drapes that can be employed when needed. The walls of private offices along this inner circle are sheathed with highly reflective anodized aluminum panels below and a combination of fixed panes of glass and operable casement windows above. The windows can be opened and closed manually by occupants, but will shut automatically in case of fire.

An interplay of clients, designers, and builder reinforced Behnisch, Behnisch & Partner’s highly integrated design process, thereby, resulting in a building whose various elements resonate so well together.

If anyone reading this works in the Genzyme Center, it would be interesting to hear how you experience it from the inside.

Photo courtesy of GregPC, used according to its Creative Commons license

15
Apr
08

Building Information Modeling applied to three projects

One Market Street

In his thorough rundown of three current projects, Jeff Yoders of Building Design + Construction gives a clear picture of what BIM is all about. All three projects, he says, “are achieving a high degree of integrated project delivery through the use of building information modeling and other software tools.”

The historic 11-story Landmark at One Market Street has occupied San Francisco’s financial district since 1916. Without affecting the outside of the building, a team assembled by Autodesk is revamping the first floor into a customer briefing center replete with interactive exhibits. Yoder quotes Phil Bernstein, an Autodesk VP, who says, “If I’m running around the world saying BIM makes vast improvements in process possible, how can we not do this on our own building?”

The other players are Anderson Anderson Architecture , HOK, and DPR Construction. Autodesk, of course, is the creator of the Revit BIM platform, so it’s only natural that DPR is utilizes their products.

DPR is using Autodesk NavisWorks to merge the individual Revit models created by Anderson Anderson and HOK. The general contractor is also using a point-cloud laser scan of the existing floor into a final design. The laser scan even took into account the structural integrity of the building’s existing slabs and brick columns.

In New Jersey, the Giants-Jets Stadium benefits from BIM technology in the form of Revit Structure and Tekla software, wielded by design-build contractor Skanska.

In addition to using the programs to find interferences in the design stage, Skanska is also tracking 3,200 pieces of precast concrete from fabrication to installation using radio frequency identification (RFID) tags. Field construction software provider Vela Systems of Burlington, Mass., updated its RFID-based Materials Tracking module to interface with the Tekla BIM model, color coding each section of precast concrete in the model…Vela calls this interface “Field BIM,” as it elevates the model from design management to construction management by incorporating live field information.

The splendid aspect of this is that the BIM models can be done in sections so work can proceed without having to wait for the entire project to be visualized. When finished, the stadium will seat nearly 83,000 and include four restaurants and two club lounges.

In Las Vegas, the Convention Center takes shape through the efforts of Turner Construction Company’s Jan Reinhardt, who is their program manager of virtual design, and HNTB’s Patrick Davis, who is their CADD/BIM expert. In this case, the working team was set up before the project was chosen. Each discipline, architecture, engineering, and construction, contributes its own model, then the BIM process analyzes and integrates the information from all of them into a single model.

SOURCE: “”Integrated Project Delivery builds a brave, new BIM world”” 04/01/08
photo courtesy of Traviscrawford, used under this Creative Commons license