Concrete Today

Photo courtesy of the Precast/ Prestressed Concrete Institute

The Quest for Sustainable
Construction Methods

The 470-story Hearst Tower in Charlotte, NC, features nearly 300,000 sq ft of architectural precast concrete panels cladding its exterior, which feature a light-colored, sandblasted finish designed to simulate natural stone. A special window-unit panel was designed to allow the panels to span floor-to-floor, reducing the number of pieces that needed to be cast and erected by several hundred. The project was designed by Smallwood, Reynolds, Stewart, Stewart & Associates Inc.

At the end of March, a news release that missed the attention of the world’s news media contained one of the most important announcements of the year. Dated March 30 out of Geneva from the World Business Council for Sustainable Development (WBCSD), the announcement was about the formation of an alliance of leading global companies to determine how buildings can be constructed so as to need no energy from external power grids, to be carbon neutral and to be built at fair-market costs.

The Las Olas City Centre in Fort Lauderdale, FL, designed by Cooper Carry Inc., features a 23-story office/retail complex and 718-space parking structure. The tower features architectural precast concrete panels on its façade, while the parking structure features an all-precast concrete structure. Repetition and cost-effective detail reduced the piece count and made the exterior skin more affordable. (Photo courtesy of the Precast/Prestressed Concrete Institute, © Ed Zealy Architectural Photography).

The industry effort is led by United Technologies Corp. (NYSE:UTX), the world’s largest supplier of capital goods including elevators, cooling/heating and on-site power systems to the commercial building industry, and Lafarge Group (NYSE: LR , Euronext: LG), the world leader in building materials including cement, concrete, aggregates, gypsum and roofing. The WBCSD and the two leading companies are in discussions with many other global companies that are expected to join the project, to be announced soon.

Today buildings account for 40% of energy consumption in developed countries, according to the OECD. The effort announced for transforming the way buildings are conceived, constructed, operated and dismantled has ambitious targets: By 2050, new buildings are to consume zero net energy from external power supplies and produce zero net carbon dioxide emissions while still being economically viable to construct and operate.

Constructing buildings that use no net energy from power grids will require a combination of onsite power generation and ultra-efficient building materials and equipment.

The initiatives will comprise three phases, each producing reports that will form a roadmap to transform the building industry. The first report will document existing green building successes and setbacks. The second will identify the full range of present and future opportunities. The third will present a unified industry strategy for realizing specific opportunities by 2050 in China, India, Brazil, the United States and the European Union.

Each report will take one year to complete and involve hearings and conferences with building contractors and suppliers, sustainability experts, government representatives, regulators, utility officials and others.

Why now?

Jim Purcell

“Sustainable development makes good economic sense,” says Jim Purcell, vice president, Materials Pacific Region for Lehigh Cement Inc. and executive sponsor of the Lehigh Cement Sustainable Development Committee. “With the growing emphasis on ‘green’ building, more and more companies, builders, architects and municipalities seek solutions to the Green Building Challenge. Under any of the certification systems, concrete is a hands-down winner. Concrete is durable, energy-efficient and made with local and often recycled materials. Its mass cuts down on heating and cooling costs, as well as noise. Time and again, concrete wins the life-cycle cost contest, especially for large structures. Concrete allows creative and flexible design, yielding beautiful and pleasing places to work, live and play. Concrete is the product of choice when it comes to sustainability.”

“Lehigh Cement and its associated companies throughout North America are actively engaged in and committed to sustainable development. In addition to working with customers to meet green building objectives, our production facilities use sustainable manufacturing techniques. We recycle alternative fuels and raw materials and meet stringent permit conditions for air, water, and land emissions to make cement. Our concrete plants reclaim unused product and recycle waste waters. We reclaim quarried land and encourage wildlife protection at our aggregate operations. By making these capital investments, Lehigh provides the building community a sustainable product.”

Contributors to Sustainable Construction

Kevin Cail

Asked to illustrate his company’s role in sustainability, Kevin Cail, director of technical marketing and in charge of sustainable initiatives for Lafarge North America, chose the components. He suggested that responsible environmental practices in the design, manufacture, distribution and application of concrete components minimize the negative impact on human health and the environment, contribute to sustainable construction, and limit the air emissions, water releases and amount of waste generated.

Cail alluded to blended cements, which combine portland cement and other supplementary cementitious materials, such as slag cement, fly ash and silica fume. These 100% recycled materials are by-products from the manufacturing streams of other industries, yet each offers specific product performance advantages. Using these supplementary materials improves performance for concrete and extends the environmental benefits, such as reduced overall greenhouse gas emissions and less waste for disposal.

His model for a good end product was the Sustainable Condo, an EcoSmart project designed by Busby Perkins + Will Architects to address the challenges of urban sustainability. As published at EcoSmart’s www.sustainablecondo.com Website, the Sustainable Condo is an educational, traveling, full-size display that demonstrates how human comfort and environmental responsibility can be achieved by combining smart, innovative design with state-of-the-art green building technologies, materials and products that are available and affordable now from local suppliers and manufacturers.

Portland Cement Association’s new website description

David Shepherd, AIA, director of Sustainable Development for the Portland Cement Association, explains that the ConcreteThinker Website was designed to solve the issue of the sustainable information pool being “a mile wide and an inch deep.”

Visitors to www.concretethinker.com will find an in-depth array of content ranging from introductory information to technical research reports, presented with proven sustainable solutions not normally associated with cement-based materials. Case studies, energy models, technical briefs, and green specifications provide real world examples for immediate application, while links to allied industries, federal agencies and building science laboratories offer additional resources from a range of perspectives.

Canadian Cement Industry Releases First Ever Sustainability Report

On March 29, 2006, the Cement Association of Canada released its 2006 Canadian Cement Industry Sustainability Report. The report outlines the progress that the industry has made toward implementing the priorities outlined in the World Business Council for Sustainable Development’s Cement Sustainability Initiative (WBCSD-CSI).

“The release of this report demonstrates to Canadians the extent to which the cement industry has embraced the principles of sustainable development,” said Alan Kreisberg, chair of the CAC board of directors. “By measuring the performance of Canadian companies against the CSI commitments, we have shown that our interest is not only in making pledges, but also in being held accountable for results.”

The industry has a long-standing commitment to develop innovative technologies and processes to reduce the industry’s environmental footprint. In the 1990s, in response to concerns about smog and acid rain, the cement industry installed new technologies such as low NOx burners and bag houses to reduce emissions of oxides of nitrogen and fine particulate.

Mike Shydlowski

Additives

Mike Shydlowski, president and CEO of Degussa Admixtures Inc., adds another voice: “We believe that the concrete industry can make significant contributions to sustainable development in structures and infrastructure. Our products are designed to make concrete more durable, longer lasting and aesthetically pleasing. We continue to push new innovations, such as pervious concrete and carbon dioxide reduction through cement replacement/clinker reduction, by using alternate binders as part of comprehensive mix optimization programs that provide significant environmental benefits to the building industry.”

Another cement company’s part

Al Innis

“At Holcim, we are committed to sustainable development and our society’s future,” says Al Innis, vice president of quality for Holcom (U.S.) Inc. “The U.S. Green Building Council’s LEED program provides standards and guidelines for construction that continue to drive green building initiatives. LEED is about doing what’s right for our society’s future by making intelligent decisions on construction design and the choice of materials used. We are proud to support these efforts.”

Dust to dust

This statement came from Rich Holston, director safety, health and environment at the American Concrete Pipe Division of Rinker Materials: “With its long life cycle and natural raw materials, concrete pipe meets the needs of the environmentally conscious consumer. The raw stock—sand, rock, cement and water—is readily available from the earth and easily converted into a drainage product. Concrete Pipe lasts for over 100 years under normal conditions and is often either reused or recycled for other beneficial purposes.”

RoundTable

Q: Where is this quest for sustainable structures taking the industry?

David Shepherd, AIA
Director, Sustainable Development, Portland Cement Association

The responsibility for our planet’s future rests on all our shoulders. And the portland cement and allied industries are well equipped to provide sustainable solutions, including those not normally associated with concrete. Site water management, indoor air quality, and thermal performance can be positively affected by cement- based solutions. Manufacturing and material improvements, along with established construction applications, are providing immediate benefits for those designers educated to the benefits.

Ed Sauter
Director, Tilt-Up Concrete Association

The increased emphasis on sustainability as a consideration in building system determination should lead designers and owners to options that can deliver efficient, durable, and cost-effective solutions. The longevity, inherent energy performance, and efficiency of concrete systems positions them to take a strong role in the sustainability effort.

James G. Toscas
President, Precast/Prestressed Concrete Institute

Our quest is not just for sustainable structures, but for a sustainable way of life—one that does not irreversibly deplete natural resources and thereby limit options available to our descendants. Of course, the way we design and build structures is part of this, but the useful lifetime of those structures, and their performance in terms of maintenance and energy required over that lifetime, is probably even more important. I see a trend toward durable, energy-efficient structures designed with concrete. Moreover, I see more sophisticated and complex designs that incorporate functional as well as structural features. The precision and quality control required to build such complex and integrally-functional designs will require a greater reliance on manufactured structural elements—in short, precast concrete.

Gerald F. Voight, P.E.
President & CEO,
American Concrete Pavement Association

The concrete pavement industry is moving forward with sustainability efforts through participation in the U.S. Environmental Protection Agency’s (Region II and III pilot program), “Green Highways Partnership,” while also monitoring activities and staying abreast of emerging trends.

Conceived in 2004, the Green Highways Partnership has elected to target water quality, air quality, and conservation as key initiatives, with emphasis on low-impact development practices, sustainable development, and voluntary participation for improving environmental stewardship. ACPA has supported and participated in this program almost since its inception.

The program is aimed at balancing the needs and expectations of virtually everyone involved in highway design and construction, as well as those of highway users.

Also on our radar screen is Leadership in Energy and Environmental Design (LEED), developed by the U.S. Green Building Council and representing all segments of the building industry. What will LEED hold for pavements? Time will tell.

ACPA also continues to watch other emerging sustainability programs, including GREENGLOBES.com, a virtual resource that provides an online environmental assessment and rating system.

Ultimately, the concrete pavement industry will align with programs that best serve our members in terms of balancing construction needs with economic, environmental, and societal considerations. It’s important to note that these words represent more than just philosophies, but a way of life for a growing number of states, cities, counties, and towns.

The Evolution of Formwork

With over 20 years of experience in the industry, Tom Ameel, CEO of PERI Formworks Systems Inc., has seen formwork undergo many changes. Traditional lumber formworks still seen on many sites today, though functional, are not labor efficient. That, and the continued shortage of skilled craft labor, makes traditional forming uneconomical in today’s construction market. This increased labor liability is in addition to the purchase price of the lumber which gets minimal reuse on site.

How it used to be done. A newer way.

We see more and more contractors turning to modern formwork systems to reduce these costs. These systems must also provide safety, efficiency and versatility in constantly changing site conditions. PERI, the world’s largest manufacturer and distributor of formwork, has engineered its formwork systems to these ends.

The company’s SKYDECK is a modular, high-strength, aluminum-panel slab system designed for fast erection and stripping. It includes many additional features such as easy cleaning and maintenance, increased shore spacing, and lightweight, manageable system components. No individual component weighs over 35 lb, thus freeing up valuable crane time and minimizing worker fatigue.

The drophead allows easy stripping, and in many cases after just one day. The early stripping allows for reduced inventory on site and improved equipment cycling. Ameel says that production rates of 50+ sq ft/hr with SKYDECK are not uncommon.

With engineering, logistical, and on-site service, the company aims to provide formwork support services to clients, and not just formwork equipment users.

Release improvements

Hand stripping of forming panels.

Steven R. Maimon, president and CEO of Maxam Industries Inc., added another evolutionary note: “As construction labor costs and the number of environmentally and architecturally sensitive projects increase, so do the requirements for forming products that can provide quick, clean release from cured concrete for multiple pours without any type of form oil or other release agent. They also minimize seams and surface defects in the cured concrete that need finishing, and can be recycled. We see the new generation of environmentally-acceptable polymer-composite forming products providing the desired performance and cost-competitive solution to these requirements.”

Time—a critical factor

“Changing dynamics within the construction industry vis-à-vis decreased availability of experienced field personnel, increased commitment to safety, and an ongoing demand for faster cycle times have influenced the evolution of modern formwork systems,” according to Stephen Tisdall, president, Aluma Systems Concrete Construction. “Here at Aluma, we have developed solutions for forming suspended slabs with large-area, crane-handled units (tables). Two such systems are the Aluma Truss and the Aluma Hi-Flyer, which allow the contractor to build large contact-area units of up to 3,000 sq ft. Compared with conventional knock-down systems, their use dramatically reduces labor demand and increases safety, as access platforms, handrails, etc. are built in. Cycle times are also reduced because of savings associated with moving large, complete, self-supporting units in a fraction of the time it takes to move more conventional strip and re-erect systems.”

An alternative to plywood

3,000 ft2 (300 m2) Aluma Hi-Flyer panel put in position.

Scott Fisk, the manager of Meva Formwork Systems, enumerated the limitations of older forming systems, which basically boil down to high labor costs for assembly, the expense and delicacy of plywood, and the frequent need for walers that involve yet more labor. His company’s solution has been to reduce working components by up to 90%, by substituting efficient clamping systems, and by introducing Alkus. Alkus is a synthetic substitute for plywood that does not rot, is water-resistant, and can be nailed but then re-used after nail holes are refilled with no evidence of the repair.

Column forms
Using FRP Column Forms for Stanford Stadium’s Fast-Paced Renovation

A $90 million renovation project, representing the single most significant capital project in the history of Stanford University Athletics, was to prepare the 80+ year-old stadium for the future.

With a nine-month completion schedule, General Contractor Vance Brown Builders (Palo Alto, CA) enlisted Peck and Hiller Co. (East Palo Alto, CA) as the structural concrete formwork subcontractor to construct approximately 400 round columns that would adorn the entire perimeter of the stadium and support the steel field bleachers.

In seeking the optimal RCF solution, Peck and Hiller’s construction supply company (Level Construction Supply, San Francisco, CA) analyzed traditional disposable paper RCFs which can be cost-efficient. However, given Northern California’s inclement weather, the possibility of the forms (tubes) getting wet became a factor because if the tubes were to get wet they could lose their structural properties, jeopardizing the form. Additionally, if using a light wall tube at 5.4 lb of paper per linear ft of tube; they would have had to dispose of 23,328 lb of paper when the job was complete.

Level contacted MFG Construction Products who manufactures a complete range of standard and custom one-piece fiber-glass-reinforced plastic (FRP) column forms whose composite properties made them corrosion-resistant and reusable. They also have the ability to nest/stack, which reduces storage and shipping space costs, and also produces a smooth, clean finish (leaving no spiral rebar seams or bug holes) to the columns. According to Mike Baker, owner of Level Construction Supply, “MFG’s composite forms essentially took weather, storage, and landfill out of the equation.”

Given the project’s short deadline, MFG Construction Products responded quickly in providing 30 cut-to-length (12 ft x 24 in. dia.) forms so construction could begin two weeks ahead of schedule (January 2005). Approximately 30 concrete pours were completed every three days until completion in February 2006.

Five hundred tons of number nine concrete reinforcing bar were used for the drilled pier and columns combined. The single-seam, flex-open spiral rebar cage came out of drilled piers set 30 ft below ground. Thirty columns were set, poured and reversed every three days, complete with the bleacher anchor bolt assembly.

More columns

In the late 1800s and early 1900s concrete was primarily cast in wooden board forms which resulted in a rough surface and required finishing with a finish coat. By the mid-1930s, concrete was cast in plywood forms, and burnished and spot patched with cement grout. According to Pete Gioldasis, market segment manager, Construction Products, in 1954 Sonoco patented the first fiber-concrete form, marketed under the Sonotube® brand, and fiber forms quickly became the preferred forming method for round concrete columns. Sonoco again changed concrete column forming in 2005 with the introduction of Sonotube® with RainGuard™ technology, which resulted in a water-resistant fiber form to let contractors achieve the lower labor and material costs associated with single-use fiber forms, and to make weather much less of a factor in the scheduling of concrete pours. Other concrete forming innovations from Sonoco include Sonotube® Square forms, a single use concrete form designed to achieve square columns with pre-chamfered corners, and Sonotube® FinishFree, a fiber concrete form with a special inside coating that yields a smooth column that does not require any hand finishing.

Flying form production for medium and low-rise buildings

Contractors who build high-rise structures over 20 floors have always had the option to use large flying forms or tables to achieve high productivity. However, these systems require a great deal of time, space and labor for assembly and disassembly. These startup and takedown costs made large tables impractical for medium- or low-rise structures.

The new Dokamatic table system from Doka offers a high-production alternative, developed specifically for this market, with reduced startup and takedown costs. The Dokamatic table system consists of lightweight pre-assembled tables delivered to the site with quick connections used to install the Eurex props, and moving equipment that allows one worker to set, strip, and move the individual tables, thereby greatly reducing costs. The tables arrive on site, are taken off the truck, with props installed and set in place the same day.

The tables are available in four typical sizes, 9 x 18 ft, 9 x 12 ft, 7 x 18 ft and 7 x 12 ft to accommodate most any floor plan. Insertion beams that slide between tables are used for fill-in work. Non-typical mezzanine or mechanical high floors can be accommodated up to 23 ft, 6 in. high. Changes back to typical floor heights are done with a quick switch of props that takes only a few minutes. Built-in perimeter working platforms make work at the slab edge safe and quick. Accessories are available to support slab edge forms or form down-turned spandrel beams as well.

Special lifting “C” caddies called transport forks are provided to move the tables by crane. Battery-operated hydraulic shifting and drive units allow one worker to raise, lower, and move the individual tables around on the floor slab.

The Dokamatic table system exists to systemize slab shoring for low- and mid-rise buildings.

Insulating Forms

Since the increases in price and decline in quality of North American lumber in the early 1990s, the use of ICFs in the U.S. housing market has skyrocketed. In fact, according to data collected by the Portland Cement Association, it has become the fastest growing alternative to wood frame for above-grade perimeter wall construction. The number of single-family homes built from footing to eaves with ICFs has been increasing approximately 25% each year. In 2004, about 60,000 above-grade ICF homes were built in the U.S. About one-third of all ICFs sold are used in above-grade residential construction. ICFs are basically forms for poured concrete walls that stay in place as a permanent part of the wall assembly.

The forms, made of foam insulation, are either pre-formed interlocking blocks or separate panels connected with plastic ties. The left-in-place forms not only provide a continuous insulation and sound barrier, but also a backing for drywall on the inside, and stucco, lap siding, or brick on the outside.

Joseph E. Lyman

According to Joseph E. Lyman, executive director, Insulating Concrete Form Association, Glenview, IL, “Since receiving its first patent in 1966, the insulating concrete form (ICF) building system has grown from sparse use as a residential foundation material to one that is now used in every segment of the residential and commercial construction market. As energy prices increase and the construction industry continues to search for building materials that can be installed quickly and efficiently, ICFs will continue to make significant gains in market share.”

An example of ICFs

The PolyPro Form is American Polysteel’s newest ICF product. It is a 2 ft x 4 ft knock-down Flat Wall Form that has an extender allowing for wall widths of 4 to 24 in. and beyond.

Eliminating protruding dowel bars in segmental pours

Dowel bars, the reinforcing steel that protrudes through formwork, have long been the traditional method for joining bars in segmental pours. In recent years, many contractors and construction product suppliers have discovered that dowel bar substitutes can improve their schedules and the bottom line by helping to eliminate costly form repairs, bending and rebending rebar and reducing protruding dowel hazards. LENTON® FORM SAVER is a new product for eliminating protruding dowel bars in segmental pour applications and temporary openings. It is designed with the LENTON® tapered thread, factory-installed thread protector, and a mounting plate for easy attachment to the form.

These exclusive dowel bar assemblies from ERICO® provide continuity and structural integrity to reinforced concrete construction. The taper-threaded design, like the complete family of LENTON couplers, provides load path continuity in tension, compression, and stress reversal applications.
The LENTON FORM SAVER mechanical splices are said to provide superior performance well beyond the yield strength of the reinforcing bar. They exceed the requirements for Type 1 and Type 2 and are recognized under ICC Report ER-3967. The splices are also recognized by or meet the standards of ACI®, UBC®, IBC®, AASHTO®, U.S. Army Corps of Engineers and numerous State Departments of Transportation.

Stay-Form panels being installed.

The splices can outperform dowel bars because of their ability to develop strength requirements independent of concrete cover. Their ease of installation, consistent performance, and durability add value and integrity to segmental pour applications.

A stay-in place concrete form

Contractors have been using Stay-Form to form pile caps, grade beams, bulkheads and blindside walls for over 25 years. The primary reason is due to the significant labor savings they realize because they do not have to strip the formwork. The use of rebar, strongbacks, walers, kickers, etc., (location, size and spacing) is similar to that for conventional forming methods. The lightweight sheets (11.9 lb) are easy to cut, bend and install to form keyways with or without waterstop. Rebar and conduit penetrations can be made with tin snips, a grinder, or by pushing a pointed rebar trough Stay-Form herringbone mesh. Another benefit is the ability to visually inspect the concrete pour during consolidation. This cannot be done with modular or plywood forms.

The Precast Advantage

Click image to enlarge 840 North Lake Shore Drive, Chicago.

Paraphrasing the Portland Cement Association’s explanation of precast, the speed and ease with which precast structures can be built has helped make precast a popular building material. Precast concrete allows efficient, economical construction in all weather conditions and provides the long, clear spans and open spaces needed in parking structures. For stadiums and arenas, seating units and concrete steps can be mass produced according to specifications, providing fast installation and long-lasting service. In addition, pedestrian ramps, concession stands, and dressing room areas can all be framed and constructed with precast concrete.

The smooth surfaces produced with precast concrete and the ability of precast, prestressed concrete to span long distances makes precast suitable for use in manufacturing and storage structures. Additional applications for precast concrete include piles and deck for railroad and highway bridges, railway crossties, burial vaults, educational institutions, commercial buildings such as shopping malls, and public buildings including hospitals, libraries, and airport terminals.

A benefit of precast concrete is that the product is created in ideal manufacturing conditions. Although some products are cast outdoors, especially in temperate climates, many precast plants operate indoors where the climate can be fully controlled.

Precast concrete helps fit high-rise into neighborhood

In a city renowned for its architectural heritage, the distinctive 26-story high-rise condominium rising at 840 North Lake Shore Drive in Chicago makes a welcome addition to the skyline. The façade pays homage to the city’s long history of limestone buildings while providing contemporary touches. Architectural precast concrete cladding played a key role in achieving this goal, emulating the natural French limestone used at the base.

Designers specified architectural precast concrete panels in a typical size of about 23 ft wide, 11 ft tall and 7 in. thick. The cladding creates the building’s stone pattern while keeping the project economically viable.

The building’s deep-punched windows, jointing and cornice line were achieved with precast concrete’s flexibility and low cost. The designers also took advantage of precast’s fluidity in producing an elegantly curved rotunda transition at the building’s most prominent corner. A warm buff color and light sandblast were used to simulate natural stone. Close attention to panel configurations and discreet locations of panel joints also helped the cladding remain aesthetically pleasing and cost-effective.

The use of precast panels minimized both construction time and the staging area required for installation, key factors in this urban environment. The precaster scheduled timely deliveries that could be unloaded and transported via tower crane to their erection location without stockpiling any pieces at the site. The use of precast also allowed the window units to be anchored easily into the precast, eliminating the need for a metal strongback system that would have been required to attach them to stone.

The project was named the Best High-Rise Multifamily Housing project in the 2005 Design Awards competition sponsored by the Precast/Prestressed Concrete Institute. The judges called it “an extremely good example of emulated limestone, demonstrating precast’s elasticity and ability to be molded to nearly any shape.”

A precast reinforcing alternative

Heldrich Plaza is considered an exciting project by High Concrete Structures, Inc. It involves the company’s CarbonCast carbon-fiber-reinforced precast concrete, which allows for much lighter panels. Here are a few facts about the project.

• The precast concrete panels weigh less than 30 lb/sq ft.
  
• The precast concrete panels are 10+ in. thick with a face thickness of 1-1/2 in., which is 75% lighter than conventional architectural precast.
  
• The precast concrete panels are lightweight and insulated.
  
• The extra thickness of the panels allowed the architect plenty of opportunities for deep reveals and window recesses without negatively impacting panel and shipping cost, or adding weight. The weight of the structure was actually reduced.
  
• CarbonCast speeds erection through the use of fewer larger (but lighter) panels.

The CarbonCast components reinforced with C-GRID are thinner and up to 66% lighter, thus reducing foundation, structure, and seismic connection loads, and lowering shipping and erection costs. CarbonCast is said to be stronger and more durable, with up to five times the tensile strength of steel reinforcing. It’s more corrosion-resistant—C-GRID won’t rust, corrode, or cause staining or spalling. And it minimizes shrinkage cracks up to 50% better than steel mesh.

Project Sportlights

Protecting a Giant Malaysian Pour

The triple tower development designed as a new headquarters building for Maybank involved diaphragm wall construction incorporating a nine-level underground car park. The basement slab required approximately 24,000 m of Xypex Admix dosed masscrete. The initial pour of approximately 13,200 m was conducted over a 60-hour period. It was then and remains today the third largest continuous pour conducted in the world, and the largest in SE Asia. With a minimum thickness of 2.5 m, the slab is up to 6.89 m thick in areas and averages in excess of 5.0 m. Xypex Admix C-2000 NF (dosed at 3kg/m), was selected for the project to assist with control of the heat of hydration, to reduce shrinkage cracking, to give the slab enduring “self-healing” capacity, and to waterproof the concrete as well as increase its strength and durability. (Peak temperature for the first mass pour was approximately 69Þ C and differentials approximately 12Þ C.)

Back to 1918

After inventing the column clamp for more productive forming, the Symons Corp. began advertising it in Engineering News-Record in 1918.

In 1946, Symons began manufacturing Wood-Ply, the first modular and reusable forming system. It comprised a 2x4 lumber frame and crossmembers with a 1 in. lumber face and steel hardware. Symons maintains that the Wood-Ply system proved that prefabricated forms were an economical alternative to job-built forms.

Symons’ innovations have been recognized and rewarded with patents over the years. A.H. Symons earned his first for the Eversquare Column Clamp for Wood-Ply, then again for Steel-Ply. Over the years, Symons engineers have been responsible for hundreds of product enhancements, new formulations for construction chemicals, and whole new forming systems such as Flex-Form. Symons contends that the recent clamp-style systems for heavy construction and the DesignFast software for creating “down to the last wedge bolt” layouts for Steel-Ply are indicative of 10 decades of determination to provide concrete contractors with the very latest in industry innovation.

Notable California Project

The Irvine Ranch Water District (IRWD) serves six different cities in Orange County, CA. A recent IRWD water project involved the construction of a booster-pump station and two prestressed concrete tanks--one 3.5 MG partially-buried tank (see photo) and one 0.6 MG above-ground tank.

This project recently received two prestigious awards from local associations: the Southern California Chapter of the American Public Works Association selected it for its “Project of the Year” award, and the Orange County Branch of the American Society of Civil Engineers awarded it its “Project Achievement” award.

Both awards were established to promote excellence in public-works projects by recognizing the partnership between the agency (Irvine Ranch Water District), engineer (Van Dell & Associates, Inc.), contractor, (Schuler Engineering), and tank prestressor, (DYK Inc.), who all worked together to complete this award-winning public-works project.

New Forming System Speeds Renovation of Ford’s Ohio Assembly Plant

Ford is renovating its entire 3,700,000 sq ft assembly plant in Avon Lake, OH, in order to build the entire Econoline van series under one roof. This includes a production line with more than 16 new pit areas for the assembly.

Ford selected Rudolph Libbe Inc. as the contractor to build the new pit areas and Libbe chose the Doka Frami forming system because of its unique lightweight clamp-form design that allows for a handset or ganged application. This clamp design eliminates the need for a crane, therefore allowing all work to be completed under an existing roof. Contractor Libbe considered this to be a major advantage during the construction process.

Another advantage of the Frami clamp system is its wide variety of panel widths and heights. The job needed 20,000 sq ft of formwork with heights varying from 2 ft to 10 ft. The average pour was 200 ft long and approximately 60 cu yds of concrete. The contractor had an aggressive schedule and assembled multiple crews, each consisting of three carpenters, one foreman, one laborer, and one telescopic forklift operator. Each crew worked 12-hour shifts, seven days a week, to deliver the concrete package two weeks ahead of schedule. “We were very satisfied with the speed with which the Doka system allowed us to set, pour, strip and cycle every day,” said the contractor. “Three lightweight clamps for connecting the panels compared to 16 wedge bolts, and no horizontal walers, are examples of why this was possible with the Frami system.”

Hospital Goes Up Under Challenges

The William Osler Hospital recently completed in Brampton, Canada, had to overcome a few challenges. In the first place, the contractor had to contend with the cold Canadian winter, which dropped to as low as -35° C. Second, it was a 3 P (private-public partnership) government project the general contractor had to start and progress in a timely fashion in order to assure funding.

The contractor decided to use the Aluma Hi-Flyer forming system, which led to some significant benefits. Most notably, there was no slab on grade under what was to be the ground floor, so a conventional forming system would not have worked (because it would have required full shoring and ground support). Although this system was new to the market and there were safety concerns with large panel sizes, Aluma provided site-specific training and on-site safety supervisor to ensure proper use, movement and “flying” the panels in position.

Another advantage of the Aluma Hi-Flyer® system is that it doesn’t require any re-shoring, thus saves labor and allows other trades to start earlier.

Each floor was 150,000 sq ft, and the Aluma system allowed 50,000 sq ft of panels on each floor, two floors at a time. So it took only three pour cycles to complete one floor. Also, concrete could be poured on two floors at the same time—without waiting for the concrete on the floor below to fully cure—because the system allows the load to be transferred to the columns, not to the floor below.
It’s estimated that there was a 33% labor saving, as the Hi-Flyer system requires no re-shoring—a large labor task. There was also a 50% productivity gain.

—Contributed by Aluma

Tool of the Trade

Make Paving-Width Changes Fast

A new dual-mold system that is hydraulically adjustable for paving at different widths makes width changes fast and simple and will even make on-the-go width changes for tapered slabs. It’s named the V2 Mold from Gomaco.

The configuration of the front and rear molds dictates the minimum and maximum paving widths and the amount of total width variation. It features separate mold control for the left and right side. The molds also have dual power transition adjusters (PTAs), the same PTAs used on GOMACO mainline pavers, for crown-height adjustments. It is also available with a curb profile on one or both sides for municipal paving.

The V2 mold system includes a spreader plow with hydraulic vertical movement to control the head of concrete in front of the mold. The plow framework telescopes to quickly and easily accommodate the width change. Proximity switches on the plow framework set the length of travel, and these switches can be easily moved to change the plow’s settings. The horizontal and vertical movement of the plow can be operated manually or set on automatic. The V2 mold was developed to adapt to virtually any paver operating in the field today.

www.gomaco.com

Portable Mix Plant

This photo shows one of MacLeod Construction’s batch plants on location at Duke Power in North Carolina. In this case, it’s the new SuperMobyMix portable plant bought from SIMEM America.

The maker says that this plant sets up in 480 minutes. Once operating it can produce 222 cu yds per hour of roller-compacted concrete, paving mixes, self-compacted concrete, shotcrete, or grouts.

Bob MacLeod, the contractor on site here, says he chose it for its consistent product. According to the manufacturer, no foundations are necessary: the built-in wiring comes ready for use with automatic controls. Access for a mixer truck or dump truck can be from either of three sides underneath the mixer. The ramp wall and supports are integrated into the aggregates bins and can be used from either side. The hopper unit can be arranged up to 90Þ toward the mixing platform.