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.
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.
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.
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.
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…
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.
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.
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!
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?
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.
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.