Recently, I took part in a review of the 8th Edition of the PCI Design Handbook. These sessions take place whenever a new edition is released for public use. Generally, these reviews would fall into the “watching paint dry” spectrum on the interesting meter; there will be some fairly minor design changes or possibly a reorganization of chapters but nothing earth shattering. That was not the case this year. For this engineer (who received the 3rd edition on my first day of employment), the most noteworthy of the changes in this 8th edition was the REMOVAL of the double tee wall panel design example.
Prior to today’s unlimited architectural shapes and finishes on flat wall panels, there were raked and broomed finishes on flat wall panels. Prior to that, the double tee wall panel was the bread and butter for precasters in this region. They were used for warehouses, gymnasiums, manufacturing facilities, office buildings, etc. Heck, even the Imax theatre at Valley Fair was constructed using double tee wall panels. They’re lighter, stronger, and much easier to erect than flat wall panels. More cost effective also. I’ll grant you that aesthetically there are more options with a flat wall panel, but from a pure functionality standpoint, nothing beats a DT wall panel and it saddens me that its popularity has fallen so far as to warrant exclusion from the Design Manual.
I shared the news with a couple of retired engineers and one of them sent a message back. It read:
“Just think, in a few years we’ll have a
unique economical product that
architects will gush over.”
Precast concrete provides many areas in which to save for a project. Some of these saving are in accelerated design, construction, and finishing processes, areas that aren’t always considered when doing the initial budgeting.
Repetition in precast panels allows for the design process to move fairly quickly through the shop drawing stage. A lot of the time while precast is being designed, the other phases of a job are still being designed. Repetition in panels helps the design process go more quickly, and it also helps in forming requirements that allow for continuous production without changing the bed.
Precast can be erected very quickly, which can knock off days, weeks, or even months from a project’s schedule. Contractors appreciate this because they can get a roof on faster and start interior work without having to worry about the exterior elements.
Since precast panels are produced in a controlled environment, they can be erected all year long. The nasty winter weather doesn’t have an impact on the production schedule or the quality of the product.
Precast panels provide a finished interior wall which eliminates time and cost of framing, dry-walling and taping/mudding. Electrical conduit and boxes can also be cast into a panel. With this benefit of precast you can produce a wall with one trade instead of a combination of five or six for other materials.
The construction industry as a whole is experiencing an amazing stretch of long backlogs and exciting market forecasts! However, as with most things, there is another side to that coin. The labor shortage is becoming more and more apparent with each passing year and we are not seeing any data that would tell us things are going to improve in the near future. This is true of both labor in the field as well as skilled labor on our manufacturing facilities. Is there a solution?
Builders and contractors are finding ways to continue to put up new structures and doing so with some innovative pre-planning and using as many prefabricated/preassembled building components as they can. We have seen this type of construction really take a strong hold in the prison and hotel markets with modular units being completely constructed offsite and brought in on truck to be stacked (like Legos) onsite. This has significantly reduced the number of laborers needed onsite as well as shortened construction durations. We are starting to see this ideology grow into more and more building types and it does not look like this method of manufacturing and construction is going to fade away.
As a precast/prestressed concrete manufacturer Wells Concrete has gotten on board with this mindset and asked ourselves what we could do to help our clients. As it is, insulated precast wall panels already encompass several components needed in an exterior wall assembly: the load bearing element, the interior finish of the conditioned space, the insulating wythe, vapor and air barrier, as well as the architectural color and finish options for the exterior. Once onsite all it takes is a crane and a few ironworkers to get the panels in place and welded off to the other structural elements of the structure.
The usual next step in the process is bringing in a glazing contractor to install the windows into the precast openings. This is where Wells Concrete saw an opportunity to save some time and labor needs at the jobsite. We have teamed up with Marvin Windows and are now offering preinstalled windows as a part of our finished product. These windows are installed and glazed at our facility so that when the panels are erected at the site the exterior wall assembly is completed in one simple step!! Once the wall panels are in place, the roof can go on and the building can be weather tight in a matter of weeks vs. several months…and with a very small amount of field laborers needed.
As you can see the Insulated precast wall panel can solve all of your exterior wall assembly needs, be produced/procured offsite and many months in advance of the site being ready. With the addition of pre-installed windows it is pretty clear that precast concrete components are ready and capable of being an innovative partner in the ever changing world of modular and prefabricated construction ideology!
Throughout the past few years Wells Concrete has been perfecting their architectural capabilities and also expanding their product line to stay current with modern architectural demands. The newest product line we are soon to be offering is Graphic Concrete imaging. This will expand the clients’ and architects’ imaginations and provide an opportunity to put a personal stamp on buildings of the future.
What is Graphic Concrete?
Graphic Concrete provides technology for use by architects in the design process, and also for the precast concrete industry to manufacture high-quality patterned concrete surfaces. Builders use these surfaces in industrially-produced façades, floors and walls. Graphic Concrete is a patented technology invented by interior architect Samuli Naamanka, and the technology is a proven concept within the precast concrete industry. An extensive number of completed projects from all over the globe demonstrate the vast range of designs in which architects can use Graphic Concrete, be it public, residential or industrial. When an architect decides to use Graphic Concrete in the design of a concrete surface, the visual quality of the traditional surface is radically altered.
How does Graphic Concrete work?
Graphic Concrete technology is the printing of a surface retarder on a special membrane. Concrete is cast on top of the membrane and the retarder slows the setting (hardening) of the concrete in the selected areas. The unset, softer concrete surface is high pressure washed, revealing the fine aggregate finish. The actual pattern (or image) on the surface of the concrete then results from the contrast between the smooth (or fair-face) finish and the exposed aggregate. Color pigments can be added to the cement and aggregates of different colors can also be used to further enhance a pattern or design. Casting of the concrete elements takes place in a precast plant; the membranes are ordered through a certified vendor and delivered to the precaster specifically chosen for that project by the architect, developer or builder.
Wells Concrete is excited about this new technology and the doors it opens for architects and their creative minds. We hope to be a part of this exciting finish development and will display these finishes once we have a few under our belts. For now, stay tuned!
It is typical and has been for many years to hear the word “cement” used in place of “concrete.” We hear of cement blocks, cement driveways, and cement buildings… It was back in the late 70’s when I was in my Engineering 101 class in college that the instructor, after one of the exams, offered an opportunity for extra credit. He informed us that one could get an extra point for each thing he could list that was made out of cement in the next two minutes. As the entire class rushed to write down as many things that came to mind in two minutes I learned something I will never forget.
Only one person had the correct answer that day: you can make concrete out of cement with the combination of aggregates and water. You see, cement is only an ingredient in concrete – it is a dried powder on its own. In this form, it would make a pretty worthless cement block or cement driveway; the powder would merely blow away in the wind.
So the next time you hear someone talk about cement buildings you have an opportunity to educate them on the differences between cement and concrete.
Control over your jobsite and schedule. With offsite production, pieces are poured and cured in a controlled environment and then stored offsite until they are headed to a particular jobsite. This means you get a high-quality product that requires less onsite labor and has less impact on the construction site. Remember, “Time Is Money.”
Precast building systems can be installed by a relatively small crew in a timely manner. This means fewer trades on site and fewer safety risks. Precast also takes some of the worker-safety liability away from the general contractor thanks to off-site production.
Along with our high quality products, Wells provides a high level of service. With each project Wells designates a specific project manager to see projects through, starting with contract documents all the way until the final checklist has been complete. This results in smooth supplier coordination and logistics, good communication, product knowledge, and product service.
Structural & architectural precast products are typically hoisted from a transport truck by crane and set into final position ready for service, thus eliminating the need for on-site laydown areas, where space is precious.
Precast concrete virtually eliminates weather-related construction delays. Due to our geographic location weather is one of a general contractor’s greatest nemeses. It is uncontrollable and can completely ruin a project schedule. Since a big part of being a GC is managing risk, it makes a lot of sense to eliminate some of the uncertainty.
Last June OSHA launched its inaugural “Safe + Sound Week”. OSHA described the initiative as “…a new nationwide effort that calls on organizations of all sizes in a wide range of industries to raise awareness of the value and importance of workplace safety and health programs.” They have targeted the week of August 13 – 19, 2018, for this year’s “Safe + Sound Week”.
In keeping with OSHA’s “Safe + Sound Week” launch, last June Wells debuted an internal reporting and tracking system designed to raise the awareness of workplace safety. The reporting and tracking system, dubbed S.E.E. for Safety Enhancement Effort, asked first level supervisors to pay special attention to their work environment and work crews to either (1) identify potential safety issues to remedy, or (2) recognize co-workers for demonstrating safe work practices. The system is web-enabled and in cases where potential safety issues are identified, appropriate personnel are automatically notified (e.g., safety / environmental professionals, operations managers, company officers, etc.) and corrective measures are put in motion. The corrective measures may include an immediate shut-down of operations depending on the nature of the potential hazard.
So far, so good. The system has heightened all employees’ level of awareness of their work surroundings. We’ve seen a drop in worker injuries and an increase in preventative activities to make the workplace a safer place.
Are you painting concrete or are you coating concrete? Painting implies a finish thickness of 2 to 4 millimeters, while coating implies a thickness of 10 to 16 millimeters. Coating is also the proper term for products that provide decoration and protection for exterior concrete walls.
Here’s what you should expect from a good coating:
It should be breathable. Water vapor should be able to move from the concrete through the coating to the air at the same time that it repels liquid water.
It should have good resistance to wind-driven moisture.
It should perform well on moderately alkaline surfaces.
It should be UV-resistant and protect concrete from carbonation and chloride penetration.
It must be able to withstand movement resulting from freeze/thaw activity.
It must have enough viscosity to build up the required thickness, close pores, and not run.
It can bridge dynamically-moving cracks.
Both solvent- and water-based coatings are available. Water-based products emit fewer volatile organic compounds (VOCs) than solvent-based products, making them safer to work with while meeting most stringent environmental regulations.
When comparing Concrete with other building materials, concrete has higher levels of both moisture and alkalinity. Coatings must therefore be formulated to be compatible with the pH level and moisture content of concrete.
A successful application starts with the proper preparation of the concrete. Coatings must absorb a little bit into concrete surfaces in order to achieve the proper bond. Here are some recommended steps:
Patch and repair cracks, spall marks, and unsightly surface areas.
Provide a surface free of bond breakers, dirt, and laitance. On walls, contractors frequently use pressure washing.
Perform a water absorption test to ensure that all bond breakers and contaminants are gone.
Perform a pH test. Test frequently. This can be done using a pH pencil. If the reading is too high for the coating being used, allow further curing or apply a primer designed for high pH conditions.
Perform a relative humidity check to measure the moisture content of the concrete. Always check for the manufacturer’s recommended levels.
Temperature is important when coatings are applied. Follow the manufacturers recommendation.
Building codes require that resistance to fire be considered in the design for protection of both life and property. The degree of fire resistance required depends on the type of occupancy, the size of the building, its location, and in some cases, the amount and type of fire detection and extinguishing equipment available in the structure. Precast concrete members are inherently noncombustible and can be designed to meet any degree of fire resistance that may be required by building codes, insurance companies, and other authorities.
Both fire resistance and containment must be considered when building. Building codes commonly assign fire resistance ratings based on results of standard fire tests. In recent years, there has been a trend toward calculating the fire endurance of building components, rather than relying entirely on fire tests. This is where concrete shines.
What Is Fire Endurance?
Fire endurance is defined as the period of time elapsed before a prescribed condition of failure or end point is reached during a standard fire test. The major “end points” used to evaluate performance in a fire test include:
Structural End Point: Collapse of loadbearing specimens (structural end point).
Flame Passage End Point: Formation of holes, cracks, or fissures through which flames or gases hot enough to ignite cotton waste may pass.
Heat Transmission End Point: Temperature increase of the unexposed surface of floors, roofs, or walls reaching an average of 250 °F (122 °C) or a maximum of 325 °F (163 °C) at any one point.
Hose Stream Test: Collapse of walls and partitions during a hose -stream test or inability to support twice the super-imposed load following the hose stream test.
Fire Resistance Rating
In IBC 2012, there are two ways to define the required fire-resistance rating. The first is based on type of construction, the second on separation distance, with the more restrictive of the two applying to the job being rated. Performance is defined by the authorities (regulatory and insurance) as the time for which each component would reach its controlling end point if it were subjected to a standard test.
Designing for Fire Safety
A key goal for the design team and the client of any given project is to protect the building from the many risks and potential losses that can be caused by fire. A common misconception is that fire destroys by flames, which can be suppressed by sprinklers. In practice, this oversimplification can leave both property and human life vulnerable during a fire.
Among the goals that must be achieved when designing for fire safety are the following:
Contain high heat, which can melt or ignite materials or kill in one breath.
Contain smoke that can blind, choke, and ruin building components and contents. Smoke is often generated by the sprinkler suppression process, and it is unavoidable.
Contain toxic gas, which is given off when plastics, synthetics, and chemicals burn. They can be deadly at any temperature.
Confine the fire event to its place of origin and prevent it from spreading.
Reduce the fuel content of the building by using non-combustible building materials whenever possible.
Avoid the potential for structural collapse during the fire by protecting all structural framing elements that support the building.
Create a passive fire-protection strategy for the building that will enable it to survive should arson, low water pressure, or a delayed fire-department response occur.
Divide the building into several noncombustible compartments that will help achieve solutions for all the aforementioned hazards. This is the most important aspect of all.
Recognize that building codes provide the minimum protection allowable and may not be enough to achieve the fire protection the building and its occupants will need. Each risk exposure requires a defense.
Using precast concrete in your building solves many of these problems.
Using Precast for Fire Safety
As previously stated, precast concrete is naturally noncombustible, and can help contain a fire within minimal boundaries. As a separation wall, precast concrete helps to prevent a fire from spreading throughout a building or jumping between structures. During wildfires, precast concrete walls help provide protection to human life and the occupant’s possessions. As an exterior wall, concrete that endures a fire can often be recycled and reused when the building is retrofitted.
Noncombustible compartmentalization, combined with an inherently fire-resistant/tolerant structural frame, provide the best combination of economics and protection that owners and users seek. When this passive design combines with other safety measures, including sprinklers and early-warning detection systems, a balanced design approach is achieved.
A variety of precast concrete components can be used in creating a complete passive-design system for a building:
Hollowcore planks, which can serve as a combined floor/ceiling system and can also be used as wall panels in either vertical or horizontal configurations.
Wall panels, which offer high fire ratings and work with other components to create a noncombustible envelope. Insulated sandwich wall panels can also be used.
Double tees, which can be used similar to hollow-core planks for roofs, ceilings, floors, or wall panels.
Columns and beams, which create a framework that will resist intense heat and will not add fuel to a fire.
As you can see, a total-precast concrete system provides an effective design for minimizing fire damage and containing the effects within the smallest space possible for the longest time. It is the most economical way to ensure your next project meets all of the fire resistance requirements of building codes, insurance companies, and all other authorities.
In this blog, I hope to discuss ways we can improve our “team.” We all belong to a team. Whether it is a corporate office team, sales team, sports team, or ministry team we all play an important role in the success of the organization.
If you have ever participated in team rowing you can appreciate the importance of everyone working together with the same goal of moving forward to arrive at a desired destination. In rowing, there are no star players. However, this does not mean each person does not have a vital role to play. The coach sits in seat number one in the rear of the boat. The coach steers the boat, while also giving motivation and reassurance to the crew. Each oarsman uniquely provides power to the boat: setting the pace, translating the rhythm, determining stoke, injecting power, relaying power, backing up the stroke, and keeping balance. Every position on the boat is important, and all are dependent on each other for success.
Just as teamwork is critical to rowing, it is the key that drives successful organizations. Never forget you are a valued member of the team, no matter what role you play. Whether you are at the top of the organizational chart or at the bottom, it is critical to work together and support the people around you. Successful teams work together.
Undoubtedly, on every team, there will be conflict. Differences of opinion, personality clashes, competitiveness, power struggles, egos, or someone just having a bad day. Fredrick Douglas, a social reformer once said, “Without conflict, there is no progress.” However, I believe it is how the individuals handle conflict that determines whether there is progress.
Below are six steps to help become a better team player by Khadija Fetuga:
Accept that conflict is normal and can occur within groups. Believe it or not, disagreements can help shape the group’s norms and identity. Conflict will be easier to deal with if each group member understands that disagreements play a normal and fundamental role in group formation.
Be willing to acknowledge good ideas even in the face of competition. In the face of competition, a team player is willing to admit when a fellow group member has a better or more practical idea than his or her own. Praising each other has a positive effect on the group by improving the probability of the project’s success. Remember—when the group looks good, it makes you look good too.
Avoid backbiting and complaining about fellow team members. One of the quickest ways to hurt your own reputation and to disturb group relations is to talk negatively about another group member, particularly behind his or her back. Should a problem develop do your best to solve it with that group member, addressing the issue directly and tactfully, or, if absolutely necessary, consult your supervisor.
Use your resources. When a group is put together for the purpose of completing a particular project, the members may not have all of the expertise needed to perform their tasks sufficiently. Do not be afraid to ask questions and seek advice from those within your organization who can provide the information needed to increase the group’s knowledge and effectiveness.
Delegate according to your strengths. It would be a waste to ask the most talented researcher to do the organizing and the most talented organizer to do the researching. By first assessing the strengths and weaknesses of each group member, you are able to delegate tasks to the members with the strongest skills in that area. Giving assignments according to the interests and strong points of your teammates will increase your chances of success and efficiency.
Go the extra mile. Whether that means staying in the office after 5 p.m., or taking on more responsibility, your team relies on you doing your part and doing it well. Sometimes that means taking on more than you initially expected. Going the extra mile is not only one way to ensure the success of your project, but also an effective way to gain the respect of fellow co-workers.
I hope this blog contributes to the success of your team!
As a construction worker, I like working outdoors when the weather is perfect – 60 degrees and dry. We all know as Minnesotans, North Dakotans, Canadians and Mid-westerners that you may only get a few dozen days a year with those particular outdoor working conditions.
Fresh concreteneeds those perfect weather conditions, but cured concrete is resilient to all types of weather conditions. Outdoor construction sites have no control over the weather while pouring fresh concrete, bringing with it a host of difficulties.
Difficulties with pouring fresh concrete outdoors:
Wet, muddy, frozen or snowy site conditions make it difficult for people and equipment to move around a construction site.
Rain is bad for fresh concrete. Rain can ruin the screed finish and prevent the face of the concrete from getting hard, causing low durability.
Wind and sun are bad for fresh concrete. Wind and sun can cause accelerated drying of the concrete surface which can lead to drying shrinkage, cracking, and low durability of the concrete surface because the water evaporates before the cement can use the water for curing.
Cold is bad for fresh concrete. Curing concrete is based on time and temperature. Higher temperatures equal faster curing. Fresh concrete will not cure in freezing conditions.
How does Wells Concrete manage these changing weather conditions and pour concrete year round? By pouring concrete indoors. All four Wells Concrete production facilities pour concrete indoors, unaffected by the changing weather and seasons.
Benefits of pouring concrete indoors:
A temperature controlled indoor environment gives us “t-shirt weather” year-round for pouring concrete.
Heated rock, sand and water for mixing fresh concrete; no matter how cold it gets outside our fresh concrete is toasty warm.
Accelerated curing using form heaters. During curing, the form heaters raise the temperature of the concrete to between 90 and 140 degrees to ensure high early strength.
No wind, rain, sun, cold or snow to interrupt pouring fresh concrete.
What is the perfect construction site? Indoors!
Ben Dalsing P.E.
Wells Concrete – Albany, MN
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
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.