The presentation will begin in 30 seconds. Hello, everybody. I'm Jim Schneider, the Executive Director of PCI Mountain States. I'll be your moderator for today's webinar, titled Precast 101 Plus, High-Performance Precast Concrete. This webinar is sponsored by Georgia Carolina's PCI, in conjunction with a broader effort by PCI regions all across the United States to deliver online learning to design and construction professionals. Be sure to contact your local PCI region to learn more about online learn-at-lunch opportunities for your firms. Contact information for your local chapter is available at pci.org slash regions. The evolving construction industry, recent code changes, challenging economy, natural disasters, and sustainable development requirements are just some of the factors increasing demand for high-performance and resilient building design. This webinar will provide an overview of precast and prestressed concrete design and fabrication in the context of high-performance structures. Lifecycle costs and accelerated schedule benefits of prefabrication, modular, and off-site construction will be identified. And case studies will highlight architectural and structural precast, prestressed concrete building systems and their high-performance attributes, including the optimization of versatile, efficient, and resilient precast concrete design solutions. This webinar is registered for one hour of continuing education credit, and you will earn one PDH or one HSWLU with AIA. To receive credit, you must attend the full webinar and provide complete registration information. If an AIA number was provided at the time of registration, your attendance will be reported to AIA. Within one week of completion of the presentation, you will receive an email from RCEP to download your certificate. If there are any groups in attendance, we do have a group attendance form you can download in the handout section. That can be emailed to Ruth Lehman, whose email address is on the form. During the presentation, you may ask questions through the questions function on your screen. You'll have a question and answer session at the end. We'll try to get to as many of your questions as we can. Today's presenter is Peter I. Finson, FPCI, Associate AIA Executive Director and CEO of Georgia-Carolina's PCI, a chapter of the Precast Pre-Stressed Concrete Institute. Peter is responsible for association management with key emphasis on educational, technical, and marketing promotion of solutions to advance the design, manufacture, and use of precast pre-stressed concrete products. He has a Master of Architecture degree from the University of Pennsylvania and a career that spans more than 45 years in the design and construction industry. His early experience includes as a design architect and a PMCM project development services over $6 billion in construction value of educational, correctional, housing, infrastructure, and governmental projects. Peter, we're thrilled to have you here today, and over to you, sir. Thank you, Jim, and please forgive the opening slides there. We had a little technical difficulty at the beginning. Welcome everyone. With the preliminaries complete, let's jump right into our topics for today. I call this Precast 101 Plus with a twist. We'll cover the basics of precast and pre-stressed concrete, but I've positioned this from the angle of discussing high-performance building attributes and why we need them. We'll take a virtual plant tour and discuss the plant manufacturing process, and next we'll briefly discuss quality assurance and the importance of PCI certification. Then we'll explore precast components or the kit of parts with options for structural solutions, and we'll review aesthetic features and how we achieve color, form, and texture. Throughout I'll be showing applications of how designers met their owner's program of requirements via some mini case studies, and we'll wrap up with a case study of a high-performance project and a summary of available design resources. As a forewarning, I'll show a lot of images with a fair amount of detail, and I tend to talk rapidly in order to cover a lot of ground, so you might want to make sure that you're watching in full-screen mode. So let's start, but first let's make sure we're all on the same page and review some definitions. Concrete is one of the oldest and most used building materials. Precast concrete is simply defined as concrete that's cast elsewhere than its final in-service position. So we're focused on plant-manufactured concrete produced in a quality-controlled plant manufacturing environment. Thus we're talking about prefabrication and off-site construction. Now concrete as a material is strong in compression but weak in tension. Thus concrete is usually reinforced with steel, and to improve on this, we pre-stress concrete. Pre-stressing is a method of reinforcement where high-strength steel strand is pulled into tension. We then place our concrete, which bonds extremely well to the steel strand, and after curing and releasing the tensile force, we're able to take full advantage of the concrete's compressive strength. This has several benefits, including increasing load carrying capacity, allowing greater span to depth ratio, and helping to reduce cracks. There are many benefits when we design with precast and pre-stressed concrete, and I'll avoid reading this list to you, but you can see many of the advantages here. Certainly speed of construction and durability are two of the more widely recognized benefits, and safety and security are of ultimate importance. We'll explore most of these attributes momentarily, but why the emphasis on high performance? We've been inundated with this notion of high performance, which defined means performing to a high standard. Just look at any of the current architectural or engineering magazines. We see it everywhere, articles, advertising, et cetera, and it's important we understand where this was generated. It's been something of an evolution, and over the past several decades, we've come to better understand sustainability and sustainable development. Organizations like the USGBC, with the LEED rating system, have been instrumental in helping us to focus on integrated, sustainable building practices, but toward the goals of green building and reduced environmental impact, several elements were missing. What were we missing? Well, for instance, life cycle assessment, the durability of materials, multi-hazard resistance, and functional resilience, which is the structure's ability to maintain its integrity and have its function restored following a natural or a man-made disaster. Toward this notion of performing to a high standard, the federal government was a catalyst in the effort, specifically through the Energy Independence Act of 2007, which has now been morphed into the current federal high performance and sustainable building guiding principles, which requires a federally funded building over 10,000 square feet to be designed as a high performance and sustainable structure. The Act defines this as structures that integrate and optimize on a life cycle basis all the major high performance attributes, and as you can see, sustainability in this definition is now just one of those attributes. Inherent in this definition is that a high performance structure must consider resiliency, and you'll note at the bottom, authorization of the Act includes requirements for funding of numerous building types. So taking direction from these developments, and knowing that precast concrete inherently provides many of these attributes, we at PCI organized the high performance benefits of precast around three higher level concepts, versatility, referring to the aesthetic and structural versatility in design as well as in building use and operation, efficiency in design, construction, and throughout the operational phases of the building, and resiliency in providing long-term durability, multi-hazard protection, and the required life safety and health issues, i.e. the codes. High performance materials must provide all three of these. Let's start with life safety issues. Over the past decade, we've been confronted with an increasing number of natural disasters. Designing for Disruption was an editorial by the 2018 AIA president, Karl Oliphante. This map exhibits natural disasters in the U.S. just in the calendar year 2017. The concept of designing for these disruptions has become a catalyst for AIA's vision for the future of design and construction. And you see, tornado activity affects a major portion of the U.S., so resilient design is important for storm resistance, and both FEMA and the ICC have published guidelines and standards for the design and construction of safe rooms and storm shelters. Design wind speeds of 130 to 250 miles per hour are required to meet the specific flying debris or missile impact criteria. And hurricane activity has also been more frequent. Hurricane Katrina in 2005 was particularly devastating, and this is Katrina taken from a satellite image, and I could have picked any of our more recent hurricanes as well. The way we test for simulated tornado and hurricane flying debris is with a wind cannon. Here we test four differently constructed wall panels. Each wall is impacted with a two-by-four, fired at approximately 150 miles per hour from the wind cannon. Each of the first three panels is insulated and with a sheetrock interior layer. The first, vinyl siding and wood studs. Then we have brick and wood studs. Ouch. This one's similar to my house. Next brick and steel studs, similar to light commercial. And finally, a picture's worth a thousand words. This is a precast insulated sandwich wall panel with embedded thin brick. This demonstrates the strength and safety of precast concrete and gives you a visual image of a resilient structure. The hurricane force winds during Hurricane Katrina left two parochial elementary schools completely destroyed along the Mississippi Gulf Coast. The owner of these schools decided to merge the two as the St. Vincent de Paul Catholic School and per the owner's directive as a resilient total precast structure. This time-lapse video documents the erection process. Note the clean construction site. While the site was cleared and foundations were laid, the precast manufacturer was fabricating and storing the precast components offsite. Components were then transported to the site via flatbed trucks and are lifted by crane into position. You might note that the crane backed itself out from the footprint of the school and typically we can limit site disturbance in this manner. The school facilities include 21 classrooms, science labs, music and art rooms, a library, computer lab, a full-size gymnasium and a cafeteria. The assembly areas are on the left and you can see buff colored or pigmented precast where it will be left exposed and gray concrete where it will be covered up or painted. No additional site storage or lay down area is required and the only time panels are laid on the ground is when they're delivered on a Friday waiting for Monday erection and safe brazing. Some of the classrooms are on the right with clear story windows for daylighting and the exterior has thin brick embedded in the precast panels. You'll note that erection occurs even in some rainy and windy weather. The only constraint being when it's too windy or unsafe for our crane operator. With the accelerated construction of the prefabricated elements, the building has dried in much quicker than with traditional construction and it's now going to be in much better condition for all of the other trades, for instance, HVAC, plumbing, electrical, sheetrock, etc. To more efficiently complete their work in a more controlled environment. Now the precast on this project paid for the Oxblue site camera that took these images and took it with them upon completion of their trade. That day coming up in just a moment. So that's the day we left the site. And again, this was the school under construction where you might notice the panelized construction with insulated sandwich wall panels on the exterior and solid wall panels on the interior, pigmented where it will be left exposed or gray concrete where it's going to be covered up in one fashion or another. This is the front entry of the school upon completion. Everything you see other than the window and door components is precast concrete. Resilient, thermally efficient, precast insulated sandwich wall panels with embedded thin brick or a sandblast finish. And this is the classroom wing where you can notice the panelized facade. Everything you see on the panels except the glazing is transported and erected as a modular element. And you might note the return on the corner panel on the right. This is cast in sequential castings and allows for a better aesthetic for the thin brick and importantly allows for continuous insulation on these insulated sandwich wall panels. We'll explore how we fabricate these a bit later. Again, everything you see other than the window glazing and the metal roofing is high performance resilient precast concrete. Now to better understand these precast components, let's explore how we manufacture precast. We're talking about precast prefabrication and a plant manufacturing process. Because precast is fabricated in a quality controlled manufacturing plant environment, we can better control the critical variables such as mixed design, consolidation, tolerances and finishes. And weather becomes less of a scheduling variable than occurs with onsite construction as with cast in place or tilt up concrete options. And while our precast plants vary based on the products they manufacture and the sites that they're on, there are many similarities. For instance, each plant has some form of manufacturing facility such as this long line plant under roof. Precasters mix their own concrete so they have a batch plant located convenient to the product forms and to raw material storage. And precast is a just in time delivery product. So every one of our plants has very large storage areas, which is another advantage since we don't need onsite storage or valuable lay down area on the construction site. Here's one of our modern precast batch plants. You see several cement silos used to store the different cements we might use. Type three for structural products, white cement for architectural mixes. In this plant, raw materials such as aggregates and sand are stored underground where we can better control moisture and temperature to allow for more precise mix specifications. These are electronically measured and brought up conveyor belts to the concrete mixers and mixed along with the cement and chemical add mixtures that are used to create high early strength concrete, low water cement ratios, self-consolidating concrete, et cetera. We typically batch our concrete mixtures to greater than five or 6,000 PSI, often higher than might be specified in a design to be able to gain high early strength and allow us to turn beds or forms on a daily basis, providing for greater productivity and profitability of the plants. This also contributes to additional benefits like higher strength, greater durability and less moisture permeability. Also like the rest of the construction industry, precast manufacturing is becoming greener. PCI operates a sustainable plants program, encouraging lean construction practices, material recycling, and in the case of this plant, water reclamation, where all the water used is then recycled through an efficient filtering system and none goes into the ground or into the adjacent stream bed. The second element that goes into our structural products is a seven-wire steel strand. The strand is delivered to our plants in rolls like this. It is then placed in a racking system to allow it to be pulled more easily into our forms. This is a steel double T form. All of our forms are cleaned after each use, and here you can see reflection from the form release agent, which is applied to help reduce friction when the product is lifted from form after it reaches its specified high early design strength. This is a long line form. It's over 400 feet long, and the pre-stressed strand racks are at the far end where strand is threaded through an abutment and locked with pre-stressed chucks at what we call the dead end. These workers are now pulling strand and threading it through headers, which are spaced based on the dimensions of the final product. For instance, a typical length of a double T for a parking structure might be 60 feet, an efficient dimension allowing for parked cars on either side and two-way traffic. And for economy and efficiency in the manufacturing process, we're pre-tensioning this 400 plus foot bed and making multiple components at once. We'll pull the strand through the abutment shown near us at the live end, and then pre-tension it using a hydraulic jack to the specified force defined by the structural engineer and our pre-stressed plant engineers. PCI requires the plant to measure strand tension via a gauge and also measure elongation of the strand as an added quality control measure. Once our high-strength concrete is placed, it bonds extremely well along the entire length of the seven-wire strand. This combination of durable, high-strength concrete and high-strength steel results in a lasting strength that ensures retention of the component's durability throughout its lifetime. In this diagram, if the green is our precast bed or form, and the black is our seven-wire pre-stressing strand that has now been stretched or pre-tensioned and is now locked down at the abutments at both ends, a lot else happens prior to actually placing our concrete, such as placing mild steel reinforcement, various embeds, lifting loops, et cetera. Once the concrete is placed, it bonds extremely well along the entire length of the strand. You might note that the strand in the double T in the right photo is only in the lower portion of the stems of the double T and is placed asymmetrically toward the lower portion, as in the diagram. Once the concrete is cured, typically overnight, in approximately 8 to 12 hours, we go about cutting down the form. The first thing we do is the detensioning process. We cut, or actually we use an acetylene torch to slowly heat and break strand. This releases a great amount of tension and the strand wants to return to its original shape or length. For beams, double Ts, et cetera, that are designed to resist a horizontal load, we typically place the strand asymmetrically toward the lower portion of the beam. And when the tension is released, the result is camber. This camber can be predicted and controlled to a certain degree. If we don't want camber, for instance, in our vertical products like walls and pylon, we can place our strand more symmetrically, as shown in the bottom right for a wall panel. All of this is designed to best resist the dead and live loads for your design requirements. Now, this is a hollow core plant. You can see three pretensioned long line beds in the photo at the top left. Most hollow core is manufactured in an extrusion process. The batch plant in this facility is behind the wall in top center. We place no slump concrete, which is concrete mixed with very little water, in the bucket which is shuttled via the overhead crane to the bed. The no slump concrete is dropped into the hopper at the top of the extrusion machine, is then tamped down to dimension with a steel plate, and then the six stainless steel augers at the bottom of the machine rotate, three in one direction and three in the other, to advance the machine down the length of the bed. This no slump concrete is quite dense, and this worker can stand on it right after being placed without leaving a footprint. Not possible with ready-mixed concrete with its higher water content. The next morning, after reaching its highly strength, planks are cut to dimension for such uses as flooring in hotels, motels, dormitories, condos, or schools. The planks are then brought out to the plant storage yard, waiting for just-in-time delivery to the construction site. I'm showing here a unique arched single T-beam, shown to exhibit some of the other processes used at every plant. Most precast products use a lot of reinforcing steel. So each plant has a steel shop to cut, bend, and tie reinforcing cages like the one in the top left photo. The reinforcing cage is then placed in form after a quality control check, which is done at each step along the process and is required as part of PCI certification. The worker in the middle left photo is pulling the prestressing strand through this congested reinforcement and through the header at the end of the beam. Additional reinforcement, lifting loops, etc. will be positioned prior to placing concrete, which in this case is placed with a hydraulic pumping truck, used to pump a large volume of concrete in a short period of time to avoid cold joints. Once the concrete is placed, the process of hydration or curing begins. Many of our forms have either steam or electric heating elements under the bed to elevate the heat of the concrete and accelerate the curing process. We make test cylinders of every product, and in this case, cylinders will probably be placed on the side rail of the form under a tarp cover to be at the same environmental conditions of the product. Our quality control technicians show up very early at 4 or 5 a.m. and take the test cylinders to the quality control lab, where they place them in a compression machine and test to determine if it has reached the specified high early design strength. If it has, the process of cutting down the form begins, first with a detensioning process done by releasing the great amount of tension by heating the strand with an acetylene torch and slowly breaking strand to avoid cracking the beam ends. The side forms are then pulled back and the product is lifted and placed on dunnage in our storage area. It is also inspected for any imperfections to assure that all dimensions are as specified. These arched single T-beams were designed for a pedestrian bridge above and a multimodal transit facility below, adjacent to the two new sports stadiums along the Cincinnati riverfront shown in the top right photo. Now architectural components are produced somewhat similarly. We use steel forms for typical fairly two-dimensional walls. The side rails of the form can move in or out and we can produce up to 12 or 15 foot wide and 45 to 50 foot tall panels. We are constrained by transportation restrictions based on width, height, and weight of loads over the road. Each of our producers is versed in DOT requirements and I suggest early communications with your local precast fabricator to better understand efficient panel design. Making forms in the third dimension requires more labor and is thus more costly. So we have tricks of the trade to be more economical. The wall panel on the left is being set up with a box out or void for fenestration, be it a window or a door, and will be a load bearing panel approximately three stories tall with the footing away from us. The corbels or haunches will hold a load at the first floor level. They're produced in a separate steel form with reinforcing steel protruding and then steel from the bed will be bent up and tied such that when the two-dimensional portion is poured, it will become an integral structural element. Each of our plants has a form shop to build the custom forms that might be required. And in the right photo, we see three custom forms. Concrete is being placed in the furthest form. The closer form is still being set up and we can see the beginning of a box out for fenestration. We typically pour with architectural surface down in form. And so the wood lathing you see will produce reveals in the exterior surface of this panel. This form also has a self-leveling white epoxy paint applied to assure a consistent smooth finish. Now precast walls are typically made in either of three primary types. Solid walls, which consist of one solid concrete wife and are usually somewhere in the range of four to eight inches thick or thin shell, which consists of one exterior wife, typically one and a half to three inches thick, supported by a frame system often made of steel. They can also incorporate insulation. And another example of thin shell system is GFRC or glass fiber reinforced concrete. It uses glass fibers for reinforcement instead of steel. And a key advantage of thin shell is it reduces thickness and weight of the panel. Now what we're seeing designed a lot more of these days are insulated sandwich wall panels shown on the right. They consist of exterior and exterior wifes of concrete sandwiching a layer of rigid insulation. Now these insulated sandwich wall panels can be either load bearing or non-load bearing. They're aesthetically versatile and can be formed in limitless shapes and finishes. And importantly, they are a barrier wall system and provide a thermal rain, air and vapor barrier in one trade versus a rain screen. Let's spend a moment talking about building enclosure systems. Codes such as ASHRAE 90.1 require continuous insulation in most of our climate zones. Precast sandwich wall panel systems can easily provide continuous edge to edge insulation meeting this requirement. And precast wall systems are easily scalable to allow variable insulation thicknesses as required by code or building function. For a building envelope to be thermally efficient, it must provide many things starting with protect protection from bulk moisture intrusion. Precast concrete is a face sealed barrier system. The low water to cement ratio, low permeability and high strength concrete easily resists bulk rainwater and moisture ingress. This provides several advantages as compared to cavity wall systems. For instance, they're typically more cost effective. They eliminate the need for a cavity where moisture problems include mold and build may go undetected. Building enclosure systems must also manage heat, air and moisture vapor. Thermal mass is another great attribute of precast. The ability of concrete to store energy and dampen the effect of temperature change on heating and cooling systems is known as the thermal mass effect. Concrete has a high specific heat capacity, which means it absorbs and slowly releases heat. This thermal lag delays the onset of peak demands and it also reduces the magnitude of these peaks. Hence, less overall energy is used to heat and cool a structure. Accounting for thermal mass and design can result in an increased effective R-value and the thermal mass effect helps reduce fluctuations in temperature, improving occupant comfort. This example of a precast insulated sandwich wall panel building enclosures for a project in California. The material R-value of the sandwich wall system was calculated to be 11.3. However, due to the thermal mass of the wall system and no thermal bridging, the effect of R-value is much higher at an R-26. This is the R-value the mechanical engineer was able to consider when sizing the HVAC components. And in this example, it resulted in a tonnage reduction of 37%. This not only helps reduce first cost, but also ongoing operating costs and thus total lifecycle cost. To manufacture thermally efficient insulated wall panels, we first pour the exterior wife or a layer of concrete with architectural surface down in form. We then place our layer of rigid insulation with the thickness being scalable based on the thermal requirements of the building. After placing the required reinforcement embeds, et cetera, we'll then pour the interior wife of concrete. Now, we need some method to connect these two wives to avoid delamination. And we have several systems used by our producers made of non-conductive materials, which reduce thermal bridging. There are several proprietary connection systems available to our precast fabricators. I always recommend that designers specify based on the required thermal performance, since different producers may use different suppliers for these connector tie systems. The connector ties used have limited or virtually no thermal conductivity, thus eliminating the thermal bridging. The ties shown above can be designed for either composite or non-composite wall systems. Another example of a composite insulated wall panel system uses a fiberglass truss bar. This bar material has low thermal conductivity, low modulus of elasticity, and nearly twice the strength of steel rebar. These are all favorable conditions, and they allow for a 3-4-3 or 10-inch wall assembly to easily span 40 feet between floor and roof. Another connector solution is using GFRP, where carbon fiber grids are cut as trusses and inserted in the two wives of concrete, providing a shear connection between the two panels and producing a composite connection. The thickness of the concrete wives and the amount of insulation can vary depending on your design requirements. Walls can be designed to work as a composite system, where the two wives work together to resist loads and provide a full shear transfer between the layers, thus reducing wall thickness. Or they can be designed as a non-composite, where the two wives work independently to resist loads, and the interior typically being the thicker structural wife. Your structural engineer and your precast producer can help evaluate what makes the most sense for your specific project. This brief video summarizes the precast fabrication processing we just viewed, and gives me a moment to catch my breath and catch a drink of water. Now we're placing our rigid insulation and our connectors, tie these two whites together. In this case, the carbon fiber grids, pouring our top layer or exterior layer, interior layer, excuse me, of our wall system. The next morning we're breaking down, you can see the rigid insulation going from edge to edge. In this case, we had a form liner on this product, and you can see we're doing a light sandblasting to the exterior face. We'll store this material until it's needed for onsite just-in-time delivery, and travel by flatbed truck to the construction site for the final erection and installation. Now the wall panels you just saw were plant-produced and shipped about 30 miles to Clemson University for the erection of the Douthit Hill Student Housing Complex. This development is one of the largest university student housing projects, and it includes seven new residences halls and a student commons along the primary gateway to Clemson's campus. The project stretches nearly a quarter of a mile, with 980 apartment-style beds for upper-class students and 782 beds for first-year students. The complex is anchored by a commons known as the Hub that serves as a vibrant center of a campus life with dining, recreation, a bookstore, and offices. The project achieved LEED Silver certification, creating a more sustainable, more resilient, and higher-performing environment for the Clemson students. Let's transition a bit and spend a couple of minutes sharing information about our quality assurance and the PCI certification program. Now, quality assurance is necessary in every manufactured product, and certification is a program to ensure the QA program is present and functioning properly. PCI has a robust certification program that has three major elements to it. Plant certification, where every certified producer plant undergoes two annual, random, two-day inspections. Each plant must have a quality systems manual, and aspects of this QSM are inspected, including materials, forms, products, QA paperwork, et cetera. Plant quality personnel certification includes three different levels. And to ensure there are no broken links in the entire fabrication and erection chain, we also have a certified erectors program. Now, based on this robust program, PCI is an approved quality assurance agency by several code agencies. And PCI is the ANSI-accredited standards developed for the entire precast industry. Now, PCI certifies plants in four categories. A is for architectural certifications. And I should note that the PCI architectural certification category is undergoing a major overhaul. You'll be seeing lots of communications shortly regarding increased level of quality in the coming months. And we're increasing from two levels to four levels for that architectural certification. B is for our heavy structural or bridge. C is for commercial, for structural and structural with architectural finishes. And G is for GFRC, or glass fiber reinforced concrete. At the top, I highlighted MNL, or manual 117 for architectural, and manual 116 for commercial. These manuals dictate quality assurance requirements for production and provide details for design specification. I always recommend designers consult with your local precast fabricator early in the design process to better understand which spec might be best used for your product. Let me briefly talk about the environmental impact of precast. Without going into detail, PCI conducted a comprehensive life cycle assessment, or LCA. It was a cradle to grave LCA, meaning that it considered all facets from harvesting of raw materials, production, transportation, and even disposal after its effective life. The LCA was conducted by a third party in accordance with ISO requirements. And key finding is indicated that you could utilize all the high performance benefits of precast concrete without any additional environmental burden. And PCI has published the results of these industry-wide cradle to gate EPDs. As an industry, PCI conducted this in coordination with the Canadian Precast Pre-Stressed Concrete Institute and the National Precast Concrete Association. As shown, these were published with three different product categories, structural precast, architectural and insulated wall panels, and underground or utility precast. Now let's take a closer look at how precast structures are put together. We start with some of the basic precast components or building blocks, our kit of parts. These are all custom components and can be manufactured in many shapes and sizes. They consist of architectural and structural components. All of these are custom design and manufactured products. They are not commodities to be ordered by size out of a catalog. Only our hollow core and double Ts have more standardized shapes and sizes to be more economical. These components can be combined to create what we call total precast concrete structures. And to be efficient with our time today, let's explore solutions which integrate architectural and structural components to create the building's structural frame and panelized enclosure, often in the same components. Using precast concrete components together as a complete structural system creates a design in which the whole is greater than the sum of the parts. While I'm sharing three basic types of systems, rigid frame, exterior shear wall, or interior shear wall, there are unlimited options to design efficient, cost-effective structural systems. The PCI Design Handbook is the major resource in the industry Bible for exploring structural solutions. In a moment-resisting frame system, all lateral forces from the floor diaphragms are transferred to a moment-resisting frame that ties beams and columns together with appropriate connection. The need for shear walls may be eliminated. On the right, you see some of the forms we might use in manufacturing and the components produced from these forms. Or we can design interior shear wall systems with the lateral load transformed to a structural core. Or exterior shear wall systems. These tend to be more flexible, eliminating the need for a structural core and often more economical, combining the load-bearing function with the lateral force resistance. And we can integrate these load-bearing elements in a single trade with our building enclosure requirements. For instance, insulated sandwich wall panels encompassing the thermal, air, moisture, and vapor barriers with the aesthetic architectural features. We can span any of these systems with our horizontal products, like double Ts, offering long spans and flexible floor layouts by eliminating interior columns and increased fire resistance and durability. Or we can use hollow core plank, which also helps accelerate construction, allowing other trades to begin their work sooner. Now, contractors tend to like these systems as it allows them to more easily meet their OSHA safety requirements. And if you incorporate precast stairs, they tend to be erected early in the process, accommodating crane sequencing and allowing contractors now to walk up stairs rather than up ladders all day. Now, the design of these structural solutions is limitless with custom design components. They can accommodate open space, long spans, and based on your design requirements, provide for things like optimal daylighting and energy efficient building enclosures with high thermal mass. This is an example of a spec office building with a load bearing precast punched window panel, building enclosure, and economical reveals to help with visual scaling. And here you see the precast components that might be used to create this structure with clear spans to allow the designer meet the owner's interior program of requirements. The Bookends Condo Project in Greenville, South Carolina. This is adjacent to an eight-story pre-stressed parking structure shown on the right. The owner designed a masonry building due to limited site constraints with no lay down area for brick and sand and limited area for scaffolding, et cetera. The project was designed as a total precast structure with embedded thin brick for all the right reasons. Given seismic design requirements, the load bearing insulated sandwich wall panels on the back wall are four inches away to isolate it from the adjacent parking structure. The owner, a developer who has built several masonry projects was impressed that the construction started at one end with the crane backing out of the footprint of the building. The structural integrity of the precast allows for this versus masonry must be constructed one floor at a time. You can see the lay down area is just a flatbed truck backed up to the construction site. The building is constructed of insulated, load bearing sandwich wall panels and double T floors. And notice the corbels highlighted by the red circle that I showed earlier in the casting bed. These support the stems of the double T floors. The drop down ceiling would be just below these corbels so they will not be exposed on the interior. And here's the completed project with four different thin brick finishes and sandblasted precast with reveals and some stone form liner finishes at the commercial street level. Now I haven't mentioned the acoustic benefits of precast. The developer moved into one of the penthouse condos from his former home outside the city. His wife was quite concerned with the potential of noise from the nearby restaurants and bars and trash trucks in the early hours of the morning. She was amazed by the acoustical properties. Precast typically having an STC rating of 55 or above, especially for insulated wall panels. On a project tour, she mentioned to me that this was the quietest home she has ever lived in. And of course the classic total precast structure is a parking deck. This one is in the historic district of Augusta, Georgia that had to meet strict architectural design requirements. Now PCI has a manual for the recommended practice for the design and construction of parking structures. It includes typical recommendations for functional design, circulation, structural framing systems, construction and maintenance, and goes beyond to highlight durability, sustainability, aesthetics, and issues such as safety and security, lighting and wayfinding. PCI has sponsored several seismic design research projects. Two of these have had the greatest impact on design and the codification of precast for seismic design. The PRESS or Precast Seismic Structural Systems Research was a multi-phase program conducted by PCI in conjunction with the National Science Foundation and the University of California at San Diego. Through the research, they developed unbonded, post-tensioned, precast shear walls and non-emulative hybrid moment frames. The hybrid moment frames were both pre-tensioned and post-tensioned, and they ended up testing several scale structures over the 10 years research program. Several of the research engineers also became engineers of record on the Paramount Building in downtown San Francisco, which holds the title as the tallest precast concrete building in the highest seismic zone in the United States. Now the second major program, DSDM, or the Diaphragm Seismic Design Methodology, tested several horizontal precast structural systems. They were tested at the University of California at San Diego on the largest shake table in the country, and were tested to the limits of the highest seismic event in the US, which was the Northridge earthquake, which occurred just outside of Los Angeles. These two research programs helped codify precast for seismic design. This is just a quick little snippet from about a 10-minute video on this research. Now PCI also completed research for blast requirements. They performed this research in conjunction with the Air Force Research Laboratory at Tyndall Air Force Base. Now blast, of course, is all about standoff resistance. Here you see two three-story wall panels. The one on the left is a solid wall panel. The one on the right is an insulated sandwich wall panel. You can see the enormous amount of deflection from the blast. Both wall panels performed well with minor cracking and keeping their structural integrity intact. And the wall panel and the sandwich wall panel performed best since the interior insulation allowed the panel to deform and then return to its original shape. And you can see here the great amount of deflection. Now, based on this type of research, we now see precast use for a lot of building design requiring blast resistance, such as for federal courthouses. Let's move on and explore color, form, and texture and the aesthetic versatility of precast. PCI has several resources and much of the following information comes from either the architectural manual or the color and texture selection guide. In understanding how to design different aesthetic options, we first need to understand material characteristics. Concrete is a composite material made of cement, aggregates, fines, and other materials that are used to make concrete. Water, admixtures, and pigment, if required. And we have various methods to affect color. Color can be affected by the type of cement we use, the aggregates, the pigments, or we can use applied coatings or stains after the fact. And color can be cement dominant or it can be aggregate dominant, which we might want, for instance, if we are going to sandblast the finish to bring out the aggregate color. And it's important to understand how we can bring out the aggregate color. And as mentioned, we can add pigments, which are applied to the concrete mix via powders or liquid mix systems to obtain colors which cannot typically be obtained through a combination of cement and aggregate alone. And fairly economically, we can use applied coatings to paint color onto the panels after erection as in these examples. Or we can use stains to dramatically enhance concrete facades. And stains can be used to accentuate architectural details with color that won't chip, peel, or fade. Now, concrete is a plastic flowable material and shape is affected by the physical forms we cast it into. We use various steel forms for components with standardized shapes and dimensions. These forms can withstand hundreds of uses over numerous years. And because creative designers rarely design the same thing twice, we make a lot of custom forms to create unique shapes of your unique designs. Precast manufacturers have numerous tools and tricks of the trade to construct custom forms. For instance, while you may desire clean, crisp, 90 degree angles for a project's reveals, we need drafts in those reveals to be able to remove the product from form and not chip the edges and be able to reuse the form. We can still get the crisp lines and shattering desired. And as you can see in the SCAD Museum of Art in Savannah, Georgia. In these load bearing, thermally efficient, insulated sandwich wall panels. We can make forms called molds in a variety of shapes. However, the more complex, the more labor intensive and thus possibly an added expense. For custom wood forms, we suggest 25 to 30 pours to best amortize the cost of building the form. After that many uses, we probably need more labor to refurbish the form. We can include unique architectural features such as arches with a keystone, reveals, window sills and headers for these school wall panels. This panel will also be an insulated sandwich wall panel and repetitive use helps amortize the cost of this custom form. Here, these panels are being erected and temporarily braced. Each panel is actually slightly different, which introduces the master form concept, which we'll explore a little bit later. Now the entire building enclosure of the Centralia High School consists of thermally efficient, precast insulated sandwich wall panels with architectural features. And some as you see with embedded thin brick. Using thermography, we can see the thermal efficiency of these panels with their non-conductive connectors and edge to edge continuous insulation, showing very little heat loss on a cold Southern Illinois winter evening. And as an added architectural feature, these panels used custom letter form liners inserted in the master form to create the effect of the engraved school name in the facade. We can create unique architectural elements in this case by crafting wood and fiberglass form. This was the former Jefferson Pilot Headquarters Building in Greensboro, North Carolina. The original building facade shown on the right was clad in limestone and terracotta, but leaked like a sieve. In addition with one and a half, no, excuse me. In addition with one and a half times the square footage of the original building was designed and the owner wanted to replicate some of the original architectural features. This was about 20 years ago and the cost of the original materials were prohibitive. So it was designed to precast concrete. This is the panel that was cast from this form now sandblasted and loaded on a flatbed truck for delivery to the construction site. And this is about one of 24 of these panels now erected along with numerous other precast elements. This designer understood how to amortize the cost of a fairly expensive form. So while we can create unique custom elements, the key to economy is repetition. We can cast an unlimited array of shapes like bull noses and arises or cornices and eyebrows. And we can cast reveals to help with scale or create a movement and almost unlimited variety of patterns, shapes, and surface textures can be achieved with the use of either standard pattern or custom form liners. These form liners are placed in our wall panel forms and multiple liners can be placed within a single wall panel. We can emulate stone patterns and we can provide a face mix of different colors within single panels. We can create unique custom artistic form liners like these art deco panels on the Hearst Tower in Charlotte. In the Cole Center basketball arena, images of basketball players were created by placing a CNC crafted pattern in the mold. While each of these panels appear unique, the process is economical via the master mold concept. And by just moving the top and bottom rails of the mold for each pour, so using one mold and consistently adjusting to create numerous unique panels economically. The process of photo engraving uses a photo image to create a CNC model, which is then converted into a textured form liner. This creates a relief like surface texture in the facade, giving the impression that the image has been chiseled out of concrete. And during the day, the changing sunlight patterns creates a range of effects. This type of design exploration was taken to a higher level with parametric modeling for the Perot Museum of Nature and Science in Dallas. The building has three major elements and the facade concept was to replicate the striations in the earth's layers. A comprehensive BIM model was maintained throughout the design and construction process. The model was used for visualization and validation as well as for trade coordination, virtual prototyping, quantity takeoffs and cost estimating, 4D construction sequencing and precast fabrication. The parametric model assisted in making of local patterns. The small precast wave modules located inside the larger precast concrete panels are organized into three families of modules types. Each precast concrete panel contains a series of waves from these three wave families. And the overall parametric organization of the project's precast concrete facade is a non-linear process. To emulate the natural rock striation, the precast fabricator had to create a modular system. 1400 rubber molds were made to be used in the production of the panels. After the form up was built, the rubber molds were installed into the form according to panel tickets. And as you see here, the parametric model was followed precisely and resulted in an award-winning precast facade. The plastic nature of concrete also allows us to achieve a great variety of textures and surface finishes. Here's some of the finishes possible, and I'll explain just a few of them to you. Smooth as-cast precast panels are straight out of the form and have a smooth film or hardened cement matrix. The finish color is determined primarily by the color of the cement. We can economically achieve different colors and textures by varying the finish treatment after casting. This sample has a single mix of concrete and is finished in three different methods, acid etching, sandblasting, and exposed aggregate, or what we call a retarder finish. Each of these finishes can be done to lighter or deeper exposures. And when we acid watch, we spray an acid which lightly removes the matrix of cement that is hardened on the exterior surface, and it pretty much replicates a limestone-type finish. Now, sand or abrasive blasting removes the cement matrix on the exterior surface of the panel, and it tends to expose and round the selected aggregates and may mute the color. And we can paint a chemical retarder on our forms prior to casting. This prevents the matrix of cement from setting up and exposes the aggregates, resulting in more angular aggregate and typically darker color. Similar to our exposed aggregate or retarder finish, graphic concrete uses a membrane with a chemical retarder printed on it. The single-use membrane is inserted in the precast form, and concrete is then placed on top of it. Once cured, the panel is removed from the form, and the membrane was removed, revealing aggregates in the concrete. The image results from the contrast between the concrete matrix and the exposed aggregate surface. Thin brick is yet another aesthetic option for precast facades, and offers several advantages over traditional masonry. Thin brick is embedded in our precast components and our quality-controlled precast plants. We can manufacture year-round with no weather delays. We require no scaffolding or site storage for materials, further reducing general conditions costs. Thin brick requires no anchors, no flashing, and no weeps, all items that cause water intrusion or thermal bridging problems. And thin brick requires no repointing. It is more durable with little or no maintenance required. Precasters have different methods to achieve a high-performance masonry facade. Masonry, of course, and brick in particular, is a good material for creating scale. Thin brick is real masonry. It is fired at higher temperatures and has a lower water absorption rate. Thin brick bonds well with our high-strength concrete and exceeds the bond strengths of conventionally-laid masonry with mortar. Thin brick is intricately cast in our 5,000-plus PSI concrete. It is impervious to moisture penetration, so we don't require an air cavity or methods to extract moisture. And panels are erected in a great reduced time. We can erect approximately 10 times the wall area that masons can lay in a day. When embedded in precast concrete panels, thin brick offers increased durability, low maintenance, such as no repointing, since there is no mortar, and no efflorescence. A cast-in, thin brick, precast, insulated sandwich wall panel becomes a superior rain barrier versus a rain screen system. And within a panel, when we leave the brick out, we can create other architectural features. The sills, lintels, and jams in these windows are integral precast concrete versus a composite wall system of differing materials, providing greater resistance to expansion and contraction, and thus to water intrusion. Additionally, since all dimensions stay consistent based on the forming method, windows can be preordered versus openings having to be site measured, which has yet another benefits toward accelerating construction. For this project in New York, a BIM model and 3D modeling were done to create a unique three-dimensional facade. Thin brick and three-dimensional form liners were used, and the design economically limited the number of unique forms required. The Medical University of South Carolina is in the historic district of Charleston. It's a hot, humid climate, and their traditional masonry campus has had moisture, mold, and mildew problems, obviously not good for a healthcare campus. Their new buildings are being designed as thin brick insulated sandwich wall panels to complement the historic masonry campus, but now as high-performance, durable, low-maintenance structures. We can also embed other clay products like ceramic tile in our precast panels, such as on the vibrant School of Architecture at the Florida International University. All five buildings in this complex are total precast structures, with the additional inventive use of double Ts extending from the structure and integrated for use for the elevated walkways. We can also embed dimensionally cut stone, avoiding the need for experienced stonemasons and costly on-site scaffolding. The darker color here is embedded limestone, and the lighter color is exposed sandblast precast, all erected more economically as larger integrated panels. Now, we can mix and match color form and texture within a single building, and we can insulate these panels to create an aesthetic high-performance facade. And when we change finishes versus changing materials, we have less chance that expansion and contraction will create failures, including moisture problems that require costly maintenance. And finally, panels can be produced with multiple color form and texture within an individual panel. Do you recognize the panel on the right from the time-lapse video that I showed earlier of the St. Vincent de Paul Catholic School? Let me emphasize, when you change the aesthetics in a precast structure, you gain durability, lower maintenance, and improved performance. The PCI Foundation has provided multi-year curriculum grants and sponsored precast design studios at over 30 universities across the US, including five in my geographic region. And architecture and engineering students have gained knowledge of precast and prestressed concrete systems through an experiential learning process. Once you specify a finish, the precast fabricator will make range samples for review and approval. They can make mock-ups and production samples for the more complex shapes and finishes, and full-scale mock-ups, which can be brought to the construction site, where the general contractor can use it to educate other trades for installation of connections and windows, for instance. I'll finish with a quick case study of Eastern Guilford High School. Now, Eastern Guilford was designed as a prototype from the Northern Guilford High School, designed as an energy-efficient, total precast, sustainable structure. Northern Guilford was nearing construction completion when the original Eastern Guilford High School suffered a fire casualty. Ruled as arson, the school was declared a total loss. Now, I haven't talked much about the benefits of precast concrete as a natural fire inhibitor. Concrete is non-combustible, it doesn't burn, it's inherently fire-resistant, it helps prevent the spread of toxin and minimizes fire development, and it absorbs heat. The thermal mass makes it easier for occupants to escape with their life safety, and it has structural integrity, even when exposed to extreme heat, allowing for functional resilience. So requiring a new facility, the Guilford County School District decided to use the Northern Guilford design as a prototype, which required some site adaptation and they desired numerous aesthetic changes as well. Now, Eastern Guilford was designed for 1,600 students in a design, fabricate, build approach to get students in the new school in an accelerated process. During the design adaptation, they demolished the old structure, cleared the site, and used one of the athletic fields to place students in trailers over the course of one academic year. While clearing the site and starting foundations, the precast manufacturer started fabricating precast components, i.e. off-site construction, and shortly after was delivering components to the site. Despite some exterior aesthetic changes to the prototype design, the floor plan remained similar and the precaster was able to rapidly start fabricating panels for the interior portions. You can see some of the precast elements for this total precast structure here, including columns, beams, insulated and solid wall panels, and double Ts. Construction continued at a rapid pace with three cranes working on separate sides of the site, and you can see the buildings taking shape from the kit of parts. The typical classroom section shows the efficient double-loaded classroom wing. In this version of the prototype, daylighting design was improved, and you can see the different sized window openings on the south with light shelves and enlarged openings on the north side. Insulated sandwich wall panels are used on the exterior walls. Solid wall panels on the interior with double Ts spanning the classrooms and flat slabs spanning the corridor spaces. And due to limited budget based on the insurance proceeds, thin brick was used sparingly with reveal patterns added. The prototype design fabricate build process provided for a new school within an 18-month total design and construction duration, about half the typical schedule for a project of this size. And Guilford County Schools ended up with a well-designed, energy-efficient, sustainable, resilient, and high-performance learning facility. As we've talked about today, precast concrete inherently provides many attributes and related benefits. I've tried to cover many of these three higher level concepts of versatility, efficiency, and resiliency, and true high-performance building materials would provide all three. In closing, PCI and its regional chapters offer ongoing industry support. And PCI now offers most of its publications as free online downloads, or you can purchase hard copies through the PCI online bookstore. Included as part of the body of knowledge are design manuals, recommended practices, and guide specs. And PCI publishes three periodicals. Of specific interest for design architects is the quarterly Ascent Magazine, which offers a free subscription accessible via the PCI website. With that, we conclude the learning portion of our webinar. So back to you, Jim. Thank you very much, Peter. I really appreciate your time today. That's really great, lots of information in that webinar, and thank you for sharing that with us today. I'm afraid we are at time, so we're not going to have time for questions this afternoon, but I do want to thank everyone who took the time to attend. And once again, Peter, for taking the time to share your expertise with us. Just a reminder to attendees, you'll be receiving an email from RCEP to download your certificate. Also be sure to complete the one minute survey at the conclusion of this webinar. It provides an opportunity for you to ask additional questions or request follow-up. And do mark your calendars. Our next webinar is Ultra High Performance Concrete, a game changer in the precast concrete industry. And that's coming up on Thursday, February 18th at one o'clock Eastern time. Presenters on that one are Mar Tadros, PhD, PE, founding principal of E-Construct USA, and John Lawler, PhD, principal at Wisjani Elster Associates. We hope you can join us. Until then, everyone out there, please take care and be well. Have a great day.

Precast 101 Plus

High-Performance Precast Concrete

Peter Finson

FPCI

Georgia-Carolina's Precast Pre-Stressed Concrete Institute

precast concrete design

efficiency in design and construction

resilience to natural disasters

versatility of precast concrete

PCI certification program