Energy Efficiency and Precast Concrete
Through its numerous design benefits, precast can be the go to solution for clients looking to meet sustainability goals and reduce their impact on the environment.
Environmental discussions are becoming more and more important and precast has become apart of those discussions with its ability to act as an energy efficient construction solution. Through its numerous design benefits, precast can be the go to solution for clients looking to meet sustainability goals and reduce their impact on the environment.
Because concrete has a higher density, it has the capacity to absorb and store larger quantities of heat than other materials such as wood. Concrete reacts very slowly to changes in temperature which reduces heating and cooling loads. During the day, the concrete slowly heats up using the heat from the outside environment and then slowly releases this heat during the night using natural ventilation. The result is flatter swings in temperature and energy savings of up to 25%. Thermal mass is an important element to precast’s ability to provide more energy efficient to a structure.
Using precast concrete structural wall panels with architectural finishes reduces the redundancy that comes with traditional cavity wall systems. Precast concrete is an all-in-one construction material that provides a moisture barrier, fire resistance, noise cancellation, and insulation wall without the need for additional materials. It also is able to maximize its thermal properties by delaying heating/cooling requirements which can reduce strain on HVAC equipment over the life of the structure.
When a building is erected using precast concrete, the building is enclosed which limits moisture and mold during construction. Also, precast concrete is an efficient construction material from its construction stage throughout the operation of the building. Hard finished surfaces are easy to maintain and precast is the perfect material for an organized, time and labor saving, cost-effective building system.
The resources below discuss more about the efficiency of precast concrete
New Orleans BioInnovation Center
The BioInnovation Center was the first laboratory building in Louisiana to achieve LEED Gold certification as a result of various sustainable and efficiency features.
FIU Student Academic Center
The design team of the precast FIU Student Academic Center was able to balance nature light with temperature, limiting the native heat and keeping temperatures cool.
Precast Plant Safety
Regardless of the design or product being produced, all precast building materials get their start in a manufacturing facility at the hands of highly skilled producers. The “day-in-day-out” production process is shrouded in a blanket of safety protocols intended to minimize or eliminate worker injury.
Beautiful precast structures wow and amaze us. The versatility and unique adaptability of precast concrete allows for high impact designs, as well as straightforward brute strength building components. Regardless of the design or product being produced, all precast building materials get their start in a manufacturing facility at the hands of highly skilled producers. The “day-in-day-out” production process is shrouded in a blanket of safety protocols intended to minimize or eliminate worker injury.
SAFETY IS EVERYONE'S RESPONSIBILITY
*Management’s Role: Supervisors and managers bear the enormous responsibility of ensuring that crews are safe at all times. Oftentimes, a company Safety Manager will head the training, both initial and on-going” for safety issues in precast plants. They will oversee that all mandates are being followed and provide company-specific training. Many companies kick-off their day with a “toolbox talk” which serves as a brief meeting to highlight areas of concerns and provide daily reminders about safety rules.
*Employee’s Role: Employees often “police” themselves and remind fellow workers when they observe safety protocols not being followed. Some companies provide different colored hardhats to new employees so they are easy to spot and special attention can be paid to them as they become acclimated to the plant environment. It is the employees responsibility to familiarize themselves with the employee handbook and the safety plans for the plant.
AREAS OF CONCERN IN A PRECAST PLANT
The Plant
Is PPE being worn? Gloves, steel toed boots, ear protection, specially fitted sandblasting suits etc. are all items designed to protect workers from chemical exposure and silica exposure as they perform their duties.
Is the machinery being properly maintained? Machine maintenance not only ensures a breakdown doesn’t inhibit the production process but it also ensures that workers are not injured while machines are in use. Items such as back-up alarms as well as using “lock-out-tag-out” systems are in place to provide an additional layer of safety at the plant.
Is the plant neat and orderly? Slips and falls are easily avoided when the plant is free from spilled liquids and items left laying around.
The Yard
Do yard employees have situational awareness? As cranes and trucks move about the storage yard, workers are at increased risk of injury if they are not keenly aware of their surroundings.
Are lifts being used at proper capacity? Exceeding capacity of machines, whether in the plant or in the yard, can result in dangerous situations. It is the responsibility of both management and workers to ensure that unsafe practices are not happening with the goal of saving time.
The Erection Crew
Is the crew on the jobsite practicing safety? Because precast producers are often subcontractors for a general contractor, many times a safety plan will be requested by the general contractor addressing how the precast products will be handled and erected safelyon the jobsite.
The Trucking
Is the movement of the product from plant to jobsite safe? From loading of the trucks to tie down of products, safety begins before the precast components leave the yard. Once loaded, products must be trucked on public roadways and unloaded safely on the site. Sometimes special permits are required for the trucking of extra large components.
Safety is everyone’s concern. It is imperative that time and energy are devoted to processes and protocols that keep workers safe and injury free. The Optimum Safety Group offers beneficial safety guidelines to PCI members and can be found at www.pci.org. OSHA also has a wealth of information regarding silica and other pertinent topics.
Precast Automation
Labor shortages are wreaking havoc across the nation. The precast manufacturing industry, along with other industries, is actively taking steps to address the issue while consistently maintaining a reputation for high quality. A solution has been found with the adoption of automation.
Labor shortages are wreaking havoc across the nation. The precast manufacturing industry, along with other industries, is actively taking steps to address the issue while consistently maintaining a reputation for high quality. A solution has been found with the adoption of automation. Automation in precast plants ensures a steady and uninterrupted flow of product will be delivered in an efficient and controlled manner.
Precast automation boosts several benefits including offering high quality products, improved efficiency, increased safety, and reduced manpower. These benefits offer improved work conditions for employees and keep products rolling out the door in a timely manner.
Greater Consistency/High Quality
Human error is impossible to avoid. People make mistakes and those mistakes can be anything from something small with little impact to something large scale mistakes that affects budgets and schedules. Automated machines and computer programs don’t make mistakes which equates into less budget busting errors.
Increased Efficiency/Less Time Consuming
Automated machines and processes can be tweaked to achieve the highest efficiency possible and then that efficiency can be maintained day in and day out. Precast automation allows for accelerated production schedules thus maximizing the manufacturing potential of the plant.
Safer for Workers
Manufacturing precast can be a difficult job even for the most experienced worker. Health risks associated with silica dust, noise pollution, and muscle strains/sprains are risks that precasters work to avoid on a daily basis. Automation helps cut down on risks posed to workers and improves the overall safety of the environment.
Reduced Labor Intensity for Workers
Automated precast processes means less workers are needed to manufacture precast products. Processes that traditionally required 10 workers could potentially only take 3 using automation. The reduction in workforce provides a cost saving to precast manufacturers that is passed on through more competitive market prices for precast products. It is important to note that although automation reduces the number of overall workers, there will always be need for personnel to program and run the machines. Precast automation is an opportunity for precasters to employ a higher caliber of laborer at a higher wages who uses more brain power and less brute force.
The automated production of precast concrete is a riveting process to witness. Vollert Precast recorded the automated production of double walls and floor slabs showing how automation can be used in conjunction with workers to create precast components.
As with any new innovation, automation has both positives and negatives to consider. The downside of precast automation includes the significant upfront costs associated with either building a new production plant dedicated for the automation or upgrading an existing facility. However, the long-term benefit of precast automation lies in money saved through a reduced workforce and accelerated production potential.
Precast Double Tees
As one of the most widely used precast components in North America, the double tee is a versatile and cost-effective precast product that can be used for a variety of projects. But what is the double tee and what makes this precast component so popular?
As one of the most widely used precast components in North America, the double tee is a versatile and cost-effective precast product that can be used for a variety of projects. But what is the double tee and what makes this precast component so popular?
What is a precast double tee?
Double tee precast components tend to be used for larger structures such as parking garages or large buildings, but they can be used for other projects including shorter bridges and highway structures. The design allows them to offer wide uninterrupted spans while supporting higher loads.
The shape of the double tee resembles its name and looks like two capital “T”s put side by side. Double tees are prestressed prior to casting with prestressing tendons which consist of high tensile strength cables. They can be used as both horizontal and vertical load-bearing members.
What are the benefits of Double Tees?
Precast double tees benefit from the same attributes as other precast components including resistance to extreme weather, minimal required maintenance, and cost-effectiveness in comparison to other construction materials. In addition, double tees also have their own specific benefit which is the ability to provide long, clear spans while still supporting high loads.
Precast double tees can be designed for spans reaching up to 100 feet. This is an important benefit for structures such as bridges which span over wide areas or buildings created with open-concept designs.
NPCA tested the strength of a precast double tee beam against multiple 4,400 lb barriers placed on top. What happened? Watch the video to find out!
Camp Shelby Training Center
The Camp Shelby Operational Readiness Training Center is an all precast facility whose construction included the use of 163 double tees. Precast was used to create the facility to meet occupant load requirements.
The Park at South Market
The Park at South Market is an excellent example of the most common use of double tee precast beams. The project included 286 12’ double tee beams integral to the construction of parking garage located in New Orleans, LA.
Residential Precast
Residential projects can make use of precast to meet their high-performance goals. From single-family homes to large-scale condos, precast is the right choice for constructing residential facilities.
Residential projects use of precast to meet high-performance goals. From single-family homes to large-scale condos, precast is the right choice for constructing residential facilities.
Credit: Jack Jennings & Sons
Single and Multi-Family
Precast is definitely not the first construction material people think of when it comes to single and multi-family homes, but the benefits it provides to homeowners makes it a valuable option. Precast offers several security benefits to homeowners including resistance to extreme weather events and inherent fire and storm protection. Precast is also cost-effective over time because of its energy efficiency and lower maintenance costs. Homeowners can also take advantage of the aesthetic versatility of precast to design a home that matches their specific design taste. Accelerated building schedules allow precast to be erected faster than homes designed with traditional building materials . Multi-family homes benefit from the noise-canceling qualities precast offers. In the end, precast is a great alternative to stick-built construction for homeowners who are looking for a more resilient, durable solution that saves money over the life of the home.
Credit: Kloudvue Koncepts
Student Housing
Student housing facilities face many demands during their lifetimes. Decades of students moving in and out translates into a lot of wear and tear on a structure. Durable construction materials that meet the challenges of student populations are key, along with safe and comfortable environments that allow for flexibility. Precast meets these demands because it is an inherently durable, resilient material that provides protection from storms, fires, and other threats. Precast offers the reduction in noise pollution that can occur in crowded residential spaces. Lower life cycle maintenance costs provides value to the university in the long run. Additionally, schools are often challenged with accelerated schedules to complete construction projects while students are away and precast is able to meet these accelerated schedules without issue.
Commercial Hotels and Condos
Hotels and condos take a lot of abuse from guests and demand durable options for construction. Precast provides building owners with numerous aesthetic and structural options to meet their project goals for beautiful and functional high residency structures. Precast offers sound insulation, resiliency, and protection of guests from extreme events such as weather and fires. Precast hotels and condos work well in all geographic areas and serve residents with the comfort and safety they expect.
Credit: Scott Shigley
Senior Living
Senior Living centers are designed with the priority of creating comfortable environments for occupants in a budget-friendly manner. Precast is able to help senior living facilities optimize their buildings with aesthetic and structural versatility. High-performance precast is great for both low and high-rise structures and is a durable, resilient material that can be constructed quickly without sacrificing quality.
Case Study
The One South First mixed-use building projects from Gate Precast showcases just how versatile precast can be for residential projects. Using precast, designers reused a 22-story commercial structure and transformed it into a contemporary residential building. Precast was used for the facade to pay homage to the original use of the building as a Domino Sugar factory.
Ultra-High Performance Concrete
Ultra-High Performance Concrete or UHPC is a type of concrete that has steadily grown in popularity due to its increased durability and strength over traditional concrete. The US Army Corps of Engineers first used UHPC in the 1980’s, but it wasn’t until 2000 that it became commercially available in the US.
Ultra-High Performance Concrete or UHPC is a type of concrete that has steadily grown in popularity due to its increased durability and strength over traditional concrete. The US Army Corps of Engineers first used UHPC in the 1980’s, but it wasn’t until 2000 that it became commercially available in the US. Since then, more professionals, including PCI precast producers, have been using UHPC in projects ranging from bridges to buildings.
What is UHPC?
UHPC is characterized by several things including ultra-high compressive strength, high pre-cracking, and post-cracking tensile strength, and enhanced durability due to high density and discontinuous port structure. While there are numerous advantages that UHPC brings to projects that will be covered later in this article, the overall benefit of UHPC is the elimination of reinforcing steel and the material’s ability to self-compact.
UHPC is made by combining portland cement, supplementary cementitious materials, reactive powers, limestone/quartz, fine sand, water reducers, and water. Fibers are included in the mix to help provide the strength and durability that UHPC is known for. Fibers can range from brass-coated thin wire to glass fibers mainly used for architectural applications.
UHPC can come in a prepackaged mixture or as local material-based mixtures. Prepackaged UHPC mixtures have several benefits including more selective raw materials, assured batching consistency, and reduced batching times. UHPC made from local materials has slightly different benefits such as lower cost and the ability to be tailored to project needs, but it requires local expertise and verification testing.
PCI has a pre-recorded UHPC webinar free to view which gives a more in-depth description of UHPC at the link below.
What are the benefits?
UHPC’s durability has been extensively tested and it has been found to respond exceedingly well to extreme conditions that standard concrete struggles with. UHPC’s testing has been completed in three main areas and includes:
Freeze/thaw resistance: Testing has shown UHPC retained 100% of its material properties after 600 thaw/freeze cycles.
Chloride permeability: Testing has shown UHPC has extremely low chloride migration, less than 10% of normal concrete.
Abrasion resistance: Testing has shown UHPC has 2x the abrasion resistance of normal concrete.
Aside from its durability benefits, UHPC brings a host of other advantages to projects. UHPC can be produced using local materials which reduce its cost. Overall, UHPC is also a lighter material per foot which results in less expensive shipping and spans can be designed for longer lengths. UHPC isn’t restricted to structural precast components; it can be designed for architectural cladding as well. Best of all, because of UHPC’s durability, it has about double the lifespan of standard concrete which makes it a better choice for the environment in the long run.
Cor-Tuf, a PCI Associate member of FPCA, has created and tested their own UHPC mixture and provides precast components to the Florida region. Below is a video they created that shows multiple tests of their UHPC piling and demonstrates just how durable and strong UHPC components can be.
PCI Foundation Studios
One of the missions of the PCI Foundation is to help support and fund precast studios at universities across the country. Studios are important tools to help future engineers and architects learn what precast is and the benefits it can bring to projects they will design in the future.
One of the missions of the PCI Foundation is to help support and fund precast studios at universities across the country. Studios are important tools to help future engineers and architects learn what precast is and the benefits it can bring to projects they will design in the future.
About the PCI Foundation
The PCI Foundation has been providing curriculum development grants to universities of architecture, engineering, and construction management for 20 years. This funding gives professors the ability to partner with local precast producers, engineers, and architects to create unique precast content. These partnerships foster relationships between the precast industry, university professors and future industry leaders.
PCI Studios
Since 2007, the PCI Foundation began sponsoring learning studios at universities with majors in engineering, construction management, bridges, and architecture. The PCI Foundation assists with funding programs for several years before universities are asked to begin supporting the projects on their own. To date, research has shown a high ROI on program continuation after PCI has passed the program off to universities.
So far more than 4,000 students have participated in a PCI Studio at 31 universities.
How to Apply for a PCI Studio
For schools interested in starting a PCI Studio, there is a simple process to follow to apply for a grant. After reviewing the Proposal Guidelines and Getting Started guidelines to fully understand the application requirements, schools can reach out to the PCI Foundation to discuss the next steps and begin their proposal process. An advisory committee is put in place for applications to help them stay on track during the process. Professors work with a precast partner during the writing of their proposal.
PCI Gulf South Studios
PCI Gulf South has partnered with several studios in the Gulf South region to help provide precast knowledge to future engineers and architects.
Under the direction of Charles Jones, RA at Tulane School of Architecture, future designers enrolled in the university use the studio to tackle environmental issues using precast concrete products.
As a recipient of a newly awarded PCI Foundation studio grant, Assistant Professor Alexis Gregory has begun to immerse her students in the vast opportunities precast offers to the design community.
In August of 2020, the University of Alabama was awarded a studio grant for a 4-year studio focused on precast and prestressed concrete education.
McNeese State University was recently awarded a PCI Foundation Studio. The studio program, which is composed of industry partners and academia, will focus on precast products and their use in the petrochemical industry.
Precast Concrete and Thermal Mass
Because concrete has a higher density, it has the capacity to absorb and store larger quantities of heat than other materials such as wood and gives structures increased thermal mass.
What is Thermal Mass?
Thermal mass is described as the inherent property of a material to absorb heat. A material with a high thermal mass is able to moderate temperatures inside a facility throughout the day.
Because concrete has a higher density, it has the capacity to absorb and store larger quantities of heat than other materials such as wood. Concrete reacts very slowly to changes in temperature which reduces heating and cooling loads. During the day, the concrete slowly heats up using the heat from the outside environment and then slowly releases this heat during the night using natural ventilation. The result is flatter swings in temperature and energy savings of up to 25%.
Benefits of Precast
Energy Saving Benefits
Thermal mass is affected by temperature both inside, from things such as indoor lighting or heat transferring through windows, and outside, from the climate. When a building’s envelope is constructed from precast with the interior concrete exposed and not covered by insulation or drywall, the concrete is able to absorb the heat from inside and reduce cooling costs.
Reduce Urban Heat-Island Effect with Lighter Colors
Lighter-colored concrete will have a higher amount of solar radiation reflected off its surface and reduce the amount of urban heat-island effect. Depending on the needs of the facility, lower amounts of reflection might actually be needed in order to absorb more heat from the outside of the structure. Designs can include different colored surfaces for walls facing different directions to achieve the best energy conserving arrangement.
Reduced Uncontrolled Air Infiltration
An important part of thermal mass is the air infiltration of a building, as well as its energy-saving benefits. The connection between panels is important for reducing uncontrolled air infiltration and helps minimize heating and cooling costs. Larger precast panels have minimal joints further reducing this issue.
Looking for more information about thermal mass? Check out some of our free resources below!
Case Studies
Statue of Liberty Museum
New York, NY
High Concrete Group
The high thermal mass of the concrete panels helps maintain interior temperatures and minimizes the effects of outdoor temperature swings. Additionally, special connection details minimize thermal bridging between interior and exterior building components.
New Orleans BioInnovation Center
New Orleans, LA
Jackson Precast
Slenderwall precast provides a consistent and controlled building envelope through the use of closed-cell foam insulation which acts as a vapor barrier and contributes to the air/water tightness of the panels.
Schools Tackle Storm Resistance
Because of its resiliency, precast is often used in FEMA shelters and when used in schools, can create a dual purpose for the facility by enabling it to act as a storm shelter for the community.
Precast concrete is an inherently resilient building material and has the proven ability to provide protection against extreme weather events such as tornadoes, hurricanes and earthquakes. Because of its resiliency, precast is often used in FEMA shelters and when used in schools, can create a dual purpose for the facility by enabling it to act as a storm shelter for the community. Many districts apply for FEMA funding grants to assist with the cost of new construction and the new construction must adhere to the types of requirements that precast concrete naturally addresses (i.e. IBC wind rating to 250 mph).
This cutaway BIM drawing shows a gymnasium with a total-precast concrete structural system designed as a FEMA safe room for the Marquand Zion School District in Mar-quand, Mo. The 1,400-square-foot, two-story addition on the side of the 8,000-square foot gym qualifies as part of the safe room but contains restrooms below and mechanical systems above that feed into the gym. Photo: Toth and Associates
Using Precast For School Storm Shelters
Through the use of precast, designers are able to develop hardened areas and safe zones within schools that students and faculty members can use when extreme weather events occur. Total precast solutions are the best solution for resistance to tornadoes, hurricanes, and extreme thunderstorms. The idea of safe rooms tends to be overlooked when designing school facilities because of budget constraints along with the assumption that these structures will have a “bunker” appearance. However, there have been a number of successfully constructed facilities, such as gyms, classrooms, and performing art centers, that meet the needs of safe rooms while avoiding the traditional look of a bunker.
Tornadoes
In the past, most people have associated the Midwest with Tornado Alley. However, in recent years Tornado Alley has shifted further east and encompasses a number of other states in the danger zone including the Gulf South region. These “Dixie Alley” tornados are more dangerous because they occur in greater populated areas and tend to be more costly in property damage. Precast can act as a solution to this problem by helping schools in these danger prone areas develop wind resistant facilities that can withstand tornados. Precast has been impact tested and proven to provide resistance to flying debris associated with tornados.
Twisters occur around the world, but the United States is a major hotspot, with about a thousand tornadoes every year. Research has shown that Dixie Alley is now a more frequent destination of these violent storms. Photo: Federal Emergency Management Agency.
Source: The Weather Channel
Hurricanes
Hurricanes tend to be more complex than tornadoes and therefore require specific design specifications to withstand the variety of forces they can produce. Hurricanes produce not only high winds, and occasionally tornados, but also high impact waves and tremendous amounts of rain and surge. Structures have to be built to withstand these events and protect the people inside. The Gulf South region has dealt with several major hurricanes over the last decade.
Several school facilities within the region, such as St. Vincent’s in Long Beach, MS, decided to adopt a precast solution after losing their facilities to hurricanes.
Precast provides protection from high winds, storm surge, and scour. In the aftermath of a hurricane, precast also prevents mold from developing on its surface and fire resistance making it easier to rebuild quicker and cheaper once the storm has passed.
The Robert J Curry Public Safety Center in Gulfport, MS replaced the original Gulfport Police Station destroyed by Hurricane Katrina. The new facility has an architectural precast exterior wall system that meets FEMA 361 design and construction guidelines and can withstand 200 MPH winds.
After being destroyed by Hurricane Katrina, St. Thomas and St. Paul Elementary Schools decided to merge and rebuild using a total precast system solution. Precast was chosen because of its resiliency.
Unfortunately, extreme weather has become the new normal is many areas of the country. Schools are turning to building materials that provide the durability and resiliency necessary to protect students and the community. Precast building materials protect during the storm and expedite recovery after the storm by creating structures that survive intact.