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Why Are More Structural Engineers Choosing Total Precast Concrete Buildings?

It may be because structural engineers report no difficulty in learning to design with total precast concrete systems. But in addition, a full precast concrete system has design flexibility, engineering support, is aesthetically versatile, and can be installed quickly. So what does all of this truly mean during the construction process?

Fairmont Water Treatment Plant

Higher Ground

Jackson Fire & Emergency Services

 

 

 

 

 

 

Design Flexibility: Architectural wall panels have a structural portion that is laterally stiff and designed to resist wind and earthquake forces. These multipurpose panels limit the need to incorporate multiple materials and trades. Designs also include precast columns, beams, double tees, and hollow core, and utilizing precast concrete’s natural fire resistance eliminates messy and expensive fire proofing. Hollow core floors provide a fire rated floor system that can span upwards of 50 feet. Spans of 110 feet can be achieved by using precast double tees often needed for long roof spans.

Engineering Support: A shop drawing will be provided that is a one-stop shop for the entire shell and core design. This allows better coordination among construction trades with less time required for planning. A calculation package can also be provided that is signed and sealed by a professional engineer registered in the state of the construction project.

Aesthetically Versatile: When it comes to precast concrete there are many different shapes, colors, and finishes available. An architectural wall panel not only provides structural support but can replicate brick, stone, or granite at a fraction of the cost. The concrete for these panels can be gray cement to white cement with any array of vibrant colors. As for finishes, there are options from water wash and acid etch, to sandblast and polished.

Installation Speed: Setting the precast concrete components is done quickly due to pre-planned lifting requirements designed by the precast engineer. When compared to cast-in-place concrete the savings in time is critical, a fully enclosed building can be achieved in a matter of days in some cases. Weather is not an issue as the components are produced in a quality controlled factory allowing for consistency year around. This also allows other trades to start and finish the interior sooner, which ultimately meets the owner’s need for occupancy.

Whether you’re an owner, architect, general contractor, or structural engineer there is a benefit to choosing an all precast concrete system.

 

Matt Gregg
Design Engineer


Architectural Precast Samples/Mockups Processes

Architectural Precast aesthetic appearance is virtually unlimited by varying and combining aggregates, sands, color additives, cement color, applied finish textures, cast in stone, granite and clay products, and reveal patterns/sizes. Early conversations with the architects/owners with regards to creating the desired appearance, setting the expectations and developing a schedule process for samples/mockups is critical for the project’s success.

Typically, a precaster will start with a pre-design sample (12”x12”) to establish the general color and texture for the project. The precaster should communicate a level of expectations to the architect/owner with regards to how the samples are made by quality control technicians in their lab, as the concrete is not provided by a production batch plant mixer, but mixed by other methods, and the concrete strength of a sample will not be that of the mockup or project panels, which could affect the applied finish exposure. The architect should allow sufficient time (7-14 days) for the precaster to develop a requested sample. Once approved, the architect should list the mixture proportions in the specifications and have the pre-selected sample available for all bidders. Keep in mind, the sample select represents only the first step in development of the actual production precast element and should not be considered the final decision for appearance.

2814 – Acid Etch | Sandblast | Water Wash

570 – Sandblast | Acid Etch | Water Wash

560B – Acid Etch | Polish

 

 

 

 

 

 

 

 

 

After award of the contract, a mockup for production approval will be produced with the approved concrete mix; the minimum panel size should be 4’x4’ and can be as large as a full-scale project panel. Mockups should encompass all finishes (both interior & exterior), reveal patterns/sizes and cast in stone, granite & clay product units per the project construction documents. The mockup panel will be produced by production in forms similar to those the project’s final panels will be cast in. The production facility’s batch plant mixer will supply the concrete, which could vary the color and/or the consolidation of the mix slightly from the quality control lab concrete (pre-selected sample). The contractor should anticipate delivery of the mockup for approval within three to four weeks from award, or the sample approval date. A mockup approval review meeting (at the project jobsite or precaster plant facility) should be attended by the architect, owner, contractor and precaster for the approval process and to discuss any concerns or issues that may arise with the mockup. PCI Plant Certification Standards require the architect/owner to provide a formal “signing off” documentation designating the acceptance of the mockup. The precaster should provide a mockup drawing and the mix design information to the architect/owner to be incorporated into the formal signed document. The approved mockup shall remain on site or be delivered to the jobsite for maintaining quality of the precast for the duration of the project. Remedial work should also be performed on the approved mockup panel for setting acceptable appearance standards.

In addition to these processes, there are other determining factors for a successful precast project in terms of appearances, such as which concrete mixes work better for the different applied finishes (acid etched, retard water-washed, sandblasted & polished) or having repetitive reveal patterns/sizes to complement the panel size/layouts.

Rick Ostgard
Sales


If You Want High-End Architectural Concrete, Use White Cement.

In most cases, concrete made from standard gray portland cement will do the job nicely. However, if you’re dealing with high-end architecture and projects where colors need to be the same from one batch to the next, then you’re going to want to turn to white-cement concrete as part of the solution. When gray cement is manufactured, it’s carefully controlled for performance characteristics, but color is NOT and can vary significantly. On the other hand, when white cement is made the color is also carefully monitored. White and gray cement have essentially the same properties, except for when it comes to color – the color comes from the raw materials and the manufacturing process. Metal oxides, primarily iron and manganese, influence the whiteness and undertone of the material, and to eliminate the gray color, manufacturers select raw materials that are naturally low in iron and manganese.

People choose white cement because every color option becomes available and it provides consistent, high-quality results. The colors are more vibrant and bold with a white base, and contribute to a sharper contrast among the variations of colors and tones. People will even utilize white cement to make a gray product. They could make that product with gray cement, but they won’t get the flexibility and/or consistency of matching a specific shade.

The main disadvantage of white cement is that it’s more expensive than gray. In our region of the world, the cost of white cement itself is basically double that of gray, which equates roughly to an extra $45 per yard of concrete. The extra care that is required, such as storing it in a separate silo or always having clean equipment, can also be viewed as a disadvantage, but the premium results one achieves cannot be denied.

Dave Eilertson
Sales


Qualified Producer

Seems when the economy booms businesses get busy with lead times getting longer and longer. The economic boom also spawns new start -up companies or established companies trying new systems to get into the game in hopes to get their share of the pie. So how does one select a qualified producer?

Get references, do your homework on the makeup of each system (i.e: how is the product made (prestessed vs precast), uniform insulation thickness, use of solid zones (thermal transfer), do they deliver consistent schedules, do they deliver consistent quality).

There is more concern about the environment today than ever in previous years, meaning do producers have an environmentally friendly way of producing and finishing panels? How is the air and ground water protected?  It is up to you to ask questions and get educated on the differences of each system. Don’t assume everyone is equal! Once you commit to a specification make sure it is followed.

Spencer Kubat
Vice President – Sales/Marketing


How Many Points Can You Score in Precast Concrete Jeopardy!

You know how it works, the clue is given and you need to answer it in the form of a question.  No cheating, see how many points you can get.  Write down your answers and compare them to the answers listed below. Let’s begin…

Jeopardy!

  • Concrete for 100 – a laboratory test for compressive strength of a sample of concrete.
  • Concrete for 200 – a highly flowable, non-segregating concrete that spreads into place, fills formwork, and encapsulates even the most congested reinforcement, all without mechanical vibration.
  • Hollowcore for 100 – prestressed high-strength steel wires wound helically around a center wire.

Double Jeopardy!

  • Wall Panels for 300 – the structural connection to a footing or foundation wall.
  • Wall Panels for 400 (Daily Double) – the exterior portion of concrete with an architectural finish, usually 3” thick.
  • Wall Panels for 600 – the removal of the cementitious surface to expose the sand and matrix creating a fine sandy textured appearance.
  • Double Tees for 300 – the connection used to fasten the sides of doubles tees together on a roof, floor, or parking ramp.
  • Double Tees for 500 – the process of notching the end of a stem to create a bearing point higher than the lowest part of the product.

Final Jeopardy! (remember make your own final wager of points)

  • Precast Engineering – the shear stress on a transverse cross section resulting from a twisting action.

Scoring:

Novice:                0-500 points
Intermediate:      500-1500 points
Expert:               1500-2500 points

Congratulations – let us know how you scored!  Hope you had fun scoring some points and learning a little more about precast concrete.  If you have any questions or would like to discuss anything, please feel free to call me!

 

Mat Boie
Sales – Twin Cities

 

References:


Answers:

Concrete 100 – what is a cylinder test?
Concrete 200 – what is self-consolidating concrete?
Hollow Core 100 – what is strand?
Wall Panels 300 – what is a base connection?
Wall Panel 400 – what is an exterior wythe/architectural wythe?
Wall Panel 600 – what is acid etching?
Double Tees 300 – what is a flange connector?
Double Tees 300 – what is a dapped end?
Precast Engineering – what is torsional stress?


Why do designers use Precast in Detention Centers?

The use of precast components, in detention centers are gaining more and more popularity due to the following benefits and advantages precast can offer:

  • Durability – Precast Concrete is resilient and requires little to no maintenance to preserve the original look.  Detention Centers are subject to everyday wear and tear, and this is where the use of precast concrete really makes sense.  Its hard tough surface is extremely resistant to everyday dents and dings.  Precast components are poured with high cement content and low water-cement ratios which prove to increase resistance to rain penetration, flood damage and wind-blown debris.  It can also withstand many winters of freeze-thaw cycles unlike other materials, which can deteriorate quickly with such regular exposure to expansion and contraction. 

    Mountrail County [Stanley, ND]

  • Aesthetics – Precast Concrete can be poured from many different aggregates and pigments that can be incorporated into the exterior building façade, depending on what is required. Visual interest can be enhanced with the use of ribs, reveals, finishing processes and various types of formliners.
  • Construction Year Round – Precast Concrete offers a structural and architectural system that can constructed year round – even in the harsh upper Midwest winter months. Precast installation is quick which allows other trades to begin their work sooner – often saving weeks on the construction schedule.  Precast also requires less storage onsite as the components are produced in a manufacturing plant and shipped to the jobsite.
  • Structurally Efficient / Easy to Extend – Precast Concrete can be designed with a high span-to-depth ration – thus reducing the need for additional columns and supports. Precast Concrete can also be dismantled to add extensions or new wings to detention centers.  Simply remove the end panels and continue building – the end panels can be reinstalled upon completion.

    Wabasha County Justice Center

  • Protects Against Fire – Precast Concrete is non-combustible with inherent fire-resistant capability. It protects against the spread of fire between rooms or properties.  It cannot catch fire, burn or drip molten particles – which helps protect personnel, equipment and the building itself.
  • Thermally / Energy Efficient – Precast Concrete wall panels incorporate the insulation into a “sandwich” type wall panel. Cost associated with heating and cooling can be greatly reduced through concrete’s thermal mass benefits – thus saving energy year round-round by reducing large daily temperature swings.

Mike Mortensen
Regional Sales Manager – North Dakota


Industrial Structures: Designing Industrial Structures with Precast/Prestressed Concrete

No matter what sector the building may be for, whether it’s manufacturing, food processing, distribution, or any other industrial application, utilizing precast as the primary building material lends itself nicely. By essentially becoming another piece of equipment whose function is to provide the platform for a smooth process flow, this option not only leads to a quick return on investment but also helps maximize operational efficiency.

Using precast can result in a quicker return on investment by first and foremost shortening the overall lead time on the building. It’s no secret that precast has very beneficial aspects in regards to construction schedule, but those are only enhanced when a total precast building system is used, as is often the case for industrial markets. Precast production can begin shortly after shop drawings are approved, generally around the same time that site work begins, so as soon as portions of the site are ready, precast components can start to be delivered and installed. The total precast aspect means that as the precast is installed, the building enclosure is essentially ready to have specialty equipment installed, often at the same time as the precast to utilize the same installation equipment. Going with interior finish options on the precast that are adequate for a finished wall product eliminates the need for any additional materials to be installed after the precast, minimizing trades that need to be on site during construction and the coordination beforehand. Even for buildings that include windows, Wells can literally provide a wall enclosure system from in-to-out in a single piece as soon as it arrives on site. The windows can be installed at the plant, which is also where stringent finishes often required by USDA specifications are achieved, so work required at site is minimal.

A total precast system has the flexibility to either be designed around specific equipment or to provide an open layout to be used in whatever manner is needed at that time. The layout of the building can also be used to seamlessly incorporate elements such as shipping and receiving loading docks, planned future expansions utilizing current elements of the building, and interior walls that double as fire, sound, or thermal barriers. Concrete performs excellently as a fire barrier and as a sound barrier, making it ideal to enclose rooms that have a fire hazard associated with them or contain loud equipment. This can reduce noise in the facility, and enclosing the building in architectural precast not only aids in reducing the overall noise effect of the facility on the surrounding area but can help what otherwise might be large, intimidating structures blend in. Interior walls can also be insulated to separate rooms with different thermal requirements, whether it be for sensitive equipment or food storage or production. All of this is inherent while still being a low maintenance, durable material that can withstand the sometimes necessary harsh environments present. Along with this, special steel materials and sealants are provided in these cases, typically dictated in the specifications, to match the durability of the concrete.

Using the precaster as a resource early on in the building framing process is highly recommended for these types of buildings. Not only does this allow us to get a handle on the specifics as they are being nailed down, but we may be able to find more economical situations to achieve the same end result and we can start sizing members to bring attention to any conflicts and work around clearance requirements. Building with precast in industrial applications allows for the needed structure to be provided quickly, and perform with superior attributes in both the short-term and long-term. This lets the owner get to work and gives them peace of mind that they’ll be able to stay focused on handling day-to-day business. For more information on the specifics for precast of each industrial market follow the link below, otherwise feel free to contact Wells Concrete with any questions.

PCI Designing with Precast

Chase Radue, EIT
Design Engineer


Five Important Customer Service Skills

  1. The ability to really listen to customers is crucial for providing great service.

Not only is it important to pay attention to customer interactions, but it is also important to be mindful and attentive to the feedback that you receive.

  1. Having knowledge of the product you are selling.

Without knowing all the aspects of your product, you won’t be able to help your customer choose which product is right for their intended use.

  1. Spending time with your customers.

It is proven that spending more time with your customer is beneficial to both parties.

There is a limit. You need to be mindful with getting customers what they need in an efficient manner. They have busy schedules also.

  1. A great work ethic and a willingness to do what needs to be done is a key skill when providing the kind of service that customers remember and will tell others about.

Remembering that your customers are people too, and knowing that putting in the extra effort will come back to you ten-fold, should be your motivation to never take shortcuts, no matter how busy you might be at the time.

  1. If you come across as authentic, if you’re relatable, if you make a product your customers want/need, and if you take the time to show them you appreciate them and connect with them on a real level, the results can be impressive.

“The goal as a company is to have customer service that is not just the best, but LEGENDARY.” – Sam Walton

Rick Hodek
Sales – North Dakota


A World of Precast

The precast concrete industry offers an incredibly diverse range of building and infrastructure products to architects, engineers, DOTs, contractors and homeowners. From structural frameworks and architectural flourishes to septic tanks and bridges, no other building material is as dynamic as precast concrete. You can find precast in many projects all over the world, some of them truly stunning works of art.

Kita Kindergarten – Göttingen, Germany

Located in the town of Göttingen, Germany, the Kita Kindergarten serves as a case study for the proactive approach to self-sufficiency and sustainability through careful attention to energy efficiency standards. The team at Despang Architekten developed multiple strategies to address the various elements that enveloped the site, ranging from thermal performance to daylighting and optimal building orientation.

In terms of space planning, the programming was tightly integrated early on into the design decision to utilize a sloping roof. The rear northern portions of the building with low height ceilings house the mechanical and restrooms. Primary circulation comprises the midway section of the fan shaped floor plan that is designed with built-in furniture and interior glazing between the main activity spaces. Effective daylighting by means of skylights in the ceilings of the hallways ensures more than adequate diffuse light during the day.  Located within the southernmost section of the building are multifunctional rooms, sleeping rooms, and staff and kitchen areas bordering the eastern elevation.

When it comes to designing for highly active uses such as kindergartens, longevity of construction and materiality play a major factor.  When it came to deciding on the material palette, Despang Architekten employed a limited number of materials – precast concrete, spruce wood, and linoleum all untreated and left raw. Utilizing factory produced precast elements in the form of insulated sandwich panels for the exterior walls and thinner slabs for interior bearing elements ensured rapid assembly and better quality control. A limited amount of joints also aided in the rapid assembly – with only a few minor interior demising walls requiring infill construction components.  As the concrete walls radiate from the centroid of the conical floor plan, their non-parallel orientation in combination with ceiling mounted wood diffusers lends itself to enhanced acoustical properties typically not associated with predominantly concrete construction.

Throughout the years the building continues to outperform the Passive House standard of 15kwh/m2 annually. The Kita Kindergarten at the Göttingen University campus stands as testament that energy efficient buildings need not be bland or stale, and through a holistic approach and attention to detail, the aesthetic, performative and humanistic qualities can cross contribute to a create better, healthier overall space to inhabit.

 

General Contractor: Dawe Göttingen
Architect:
 Despang Architekten
Architects In Charge: Günther Despang/Martin Despang
Project Architects: Philip Hogrebe/Jörg Steveker
Client: University of Göttingen
Structural and Bioclimatic Engineering (PassivHaus): Drewes and Speth Hannover
Accoustical Engineering: Reichert Hannover
Prefab Concrete: Universalbeton Heringen GmbH
Area: 512 sqm
Year: 2010
Photographs: Jochen Stüber, Olaf Baumann


Why are more and more designers using precast hollowcore plank?

The Hollowcore product was first introduced to our region in the 1950’s and quickly became the concrete floor system of choice for many designers. Structural floor systems must carry their own weight in addition to all applied loads. While a conventional 8″ cast-in-place concrete slab weights 150 pounds per square foot, the same 8-inch section of Wells Concrete Ultraspan Hollowcore Plank weights only 63 pounds per square foot. The lighter self-weight and use of high strength prestress strand allows for much longer spans with the ability to carry higher applied loads.

Ultraspan Hollowcore Plank is produced indoors on a 4′-0″ wide 500′ long steel casting bed. Concrete is extruded from the Ultraspan machine as it moves down the length of the casting bed; the extruder uses multiple mechanical augers to create the cores and high frequency vibration to aid compaction. A zero slump concrete mix is used to reduce curing time to as little as six hours.  This process also uses 25% less cement than other similar systems.

This product comes in 8″, 10″ and 12″ depths with spans up to 54′-0″ and can be used for virtually any floor or roof system. It is also used as a structural slab on grade where poor soil conditions exist.

Installers can set as much as 8,000 square feet per day and, unlike other concrete decks, can be installed in cold weather areas at the same speed.

The speed of installation alone is a big reason why we are seeing an increase in demand, that coupled with sound transmission (STC) rate of 50 plus and fire ratings up to 3 hours without the need to use applied fireproofing make the value of Ultra Span Hollowcore a designer’s first choice.

Gary Pooley
Regional Sales Manager


BIM – Rekindle the Excitement

Wells Concrete’s experience with BIM (Building Information Modeling) is not an uncommon one in the precast industry. Wells’ first experience with 3D modeling was around the year 2000, and my own first involvement was a decade ago in 2007. Most expectations at the time were that the drafting efficiency using modeling would match existing 2D drafting in a year- or two year-long development phase. After the drafting in 3D was perfected, we’d be able to reap all the additional rewards that BIM has to offer: great coordination in design-build projects and software tools assisting with clash detection, material quantities, scheduling, estimating, and design.

The frustrating result was that we did not quickly achieve efficiency with the basic modeling portion of BIM that is essential for all the extra bells and whistles of BIM.

Now in 2017, a few software packages later, it looks like there is reason to believe we’ve made 3D modeling work. Drafting efficiency in modeling projects is nearing the efficiency of traditional 2D drafting, with some of our best modelers exceeding traditional drafting efficiency. At this point, a lot of elements – including training, software, work process, product and detail libraries – and drawing formats are by no means perfect, but good enough for 3D modeling to function competitively. With so much room for improvement in 3D modeling, there is a lot of potential to out-perform 2D drafting.

While there are many success stories of BIM use by various firms, projects, and individuals at the leading edge of technology, there has also been many who have been discouraged by the difficulties of implementing the technology. With 3D modeling becoming practical and nearing preferred status, the use of information contained in the model can become a greater reality for the masses. That is where we should get excited about BIM again. BIM is no longer just for the tech-savvy fore-runners of technology. It’s at a point that it can assist nearly everyone with items like project planning, estimating, scheduling, material inventories, VR manufacturing, design coordination, and design analysis.

Tim Edland
Director of R&D


Health Savings Accounts (HSAs) for Retirement

 Most individuals think of IRAs and 401ks when the topic of retirement savings comes up.  More and more Americans are looking to an additional option to aid in their retirement goals.  One such savings vehicle that is gaining traction is a health savings account (HSA).

HSAs are designed for to be used to pay for qualifying healthcare expenses. You can contribute pre-tax money and use it towards medical costs whenever you want. There are no “use-it-or-lose-it” rules and any unused funds will roll over year to year.  Also, some providers allow participants to move a portion of their savings into an investment account in efforts to achieve a better return on the money held within the account.  The part of these vehicles that makes them very appealing is what is referred to as “a triple tax benefit”.   As you put money into the account, it is tax deductible, as it grows, the earnings are tax-deferred and you can take it out tax free, if used for qualified medical expenses.

Should you need to access these funds, withdraw money from the account, for non-healthcare expense before the age of 65, you’ll pay a 20 percent penalty.  After age 65 you can withdraw your HSA funds for non-qualified expenses at any time although they are subject to regular income tax.   That’s why HSAs can be an appealing retirement-savings tool.

You can only contribute money to an HSA if you have a high-deductible health care plan (HDHP), one that offers a lower monthly health insurance premium and a high deductible. If an HDHP makes sense for you and you decide to open an HSA, the contribution limit for 2017 is $3,400 per year if you’re single and $6,750 per year if you have a family. If you’re 55 or older, you can make an additional $1,000 “catch up” contribution.  Some employers will make a contribution into this account for its employees, only further driving the benefit of such an account.

HDHP’s are not well suited for someone on medications, have a chronic illness, or you might be going to the doctor frequently over the course of a year.

Ryan Stroschein
Chief Financial Officer