By John Pelicone
Like a persistent mosquito, one question has plagued precast concrete producers for years: “How can I eliminate bug holes?” In the past, this question was much harder to answer, because concrete was placed at a stiffer consistency that required excessive vibration. And excessive vibration sometimes caused more bug holes. After the introduction of self-consolidating concrete (SCC), bug holes(ii) became a less common occurrence. Yet, as a recent online industry discussion revealed, this perturbing problem is still with us.
Recent innovations in energy efficiencies and assembly techniques for precast concrete building envelopes open the door to unimagined architectural and sustainable designs.
By Matt Roper, M.Arch., LEED AP BD+C
The influence of concrete on the modern world cannot be understated. It has formed, shaped and progressed our built environment. Its solidity, strength and durability have advanced its prevalence in the building sector.
Precast concrete in particular has advanced modern civil, structural and architectural design. It has been used in some of the world’s most iconic structures, borne of advancements and refinements in material properties and assembly techniques.
A staff engineer reports on pre-assessment audits for the NPCA Plant Certification Program.
Quality has everything to do with high expectations, whether in the precast concrete industry or in the world of sports. Before British miler Roger Bannister ran a 4-minute mile in 1954, the world’s best runners believed that it was impossible for a human to run that fast. But once athletes believed it was attainable, they also began running the mile under 4 minutes.
What changed? Read More »
This month we are pleased to feature Wilbert Precast, Inc. as part of our Meet a Precaster blog series. The following answers have been provided by Dan Houk, President and CEO and current NPCA Chairman.
Q: Where are you located?
A: Our headquarters is in Spokane, Wash. We also have branch plants in Yakima Wash. and Lewiston, Idaho.
Q: How long have you been a member of NPCA?
A: We became members in 1977.
Q: Why did you join NPCA and what are the best benefits?
A: We needed to diversify and felt that joining NPCA would help us to make the right decisions when buying forms, trucks and other equipment. Obtaining the best forms and equipment with the latest technology and efficiencies certainly ranks at the top. What makes it best for our customers is good for everybody.
Q: What products do you produce?
A: It is probably quickest to describe the things we don’t make. Since 1977, we have been on a tear to diversify. We have added products continually ever since. The main product categories we now make are wastewater, stormwater, utility, stairs, Wilbert burial vaults, Redi-Rock retaining wall blocks, raised garden planters, window wells, MSE walls (mostly RECo), some light pre-stressing, wall panels, light pole bases, forest service toilets, utility buildings and a multitude of custom products.
Q: Have you introduced any new products lately?
A: Forest service toilets, utility buildings, raised garden planters and the stair systems are the ones we have introduced in the last 12 months.
Q: What are the top attributes of precast concrete?
A: It is moldable in any shape. The use of SCC and rubber form liners makes spectacularly beautiful products. In addition, superior quality control systems, less on-site time, and faster production time to meet strict construction timetables.
Q: What has your company done to fight off the recession?
A: We have diversified in three new areas, reduced our office staff somewhat and really have not purchased much in the way of new equipment. We will be there when it is all over, it is just not very much fun right now.
Q: What have you see in your area as far as recovery?
A: Not much yet. I’m afraid there will not be much next year either. We need confidence in Washington D.C. That will not happen until the next election cycle and I just hope it turns out well. There is some government spending, but that is not what sustains an economy in the long run.
Q: What are your plans for the future?
A: We plan to market ourselves to architects, the engineering community and general contractors in our region to increase the products we can precast that are currently being poured in place. Another location within 200 miles may be a long-range goal, but for the short term increasing our current product line sales will have to be the objective.
Please check out our past Meet a Precaster blog posts and if you’re an NPCA producer member and would like to be featured in a future Meet a Precaster post, please send an email to NPCA’s assistant director of communication, Kirk Stelsel.
By Sue McCraven
Editor’s Note: Work in the precast industry inevitably involves a requirement or specification established by one of many associations with acronyms such as ASTM, ACI and CSA. This series introduces you to these associations and their histories and a perspective on why they matter to precasters. This article takes a close look at the American Concrete Institute.
For the past 70 years, before the development of precast or prestressed concrete, the vast majority of structures made with cement, stone and water were cast-in-place concrete. Concrete was poured on site into wooden forms to build bridges and other structures. America’s first concrete roadways were tamped (pounded) laboriously by hand. Masons troweled mortar, made with cement, to erect brick and concrete blocks into homes and buildings. With a lot of manual labor and sweat, reinforced concrete played a major role in building our infrastructure. It was understandable, therefore, that the prevailing building codes were written only for cast-in-place construction.
When the Walnut Lane Memorial Bridge (the first major precast/prestressed concrete bridge made in the United States) was built in Philadelphia in the 1950s, there were no applicable U.S. codes for precast concrete. The design, technology and specifications for this bridge were imported from Europe. The successful completion of the Walnut Lane Bridge was the inspiration for more than 200 precast concrete plants being established in North America during the ’50s and ’60s. Read More »
By Gustavo A. Gonzalez
Forms, or molds, are one of the most common pieces of equipment in a precast plant. They come in various shapes and sizes. They may be as small as 18 inches by 18 inches or as big as 15 feet by 30 feet or even bigger. They are flat, round, rectangular and octagonal. But one thing they all have in common is the potential hazard for injury to the employee.