Precast Concrete Structures
"@context":" ","@type":"BlogPosting","@id":" -concrete/#article","about": "@type": "DefinedTerm","name": "Precast Concrete","description": "Precast concrete is a construction product produced by casting concrete in a reusable mold which is then cured in a controlled environment, transported to the construction site and maneuvered into place.","url": " ","sameas":" _concrete"}
Precast Concrete Structures
Precast concrete is a construction material created by pouring concrete into a preshaped mold. The concrete is then left to cure in an appropriate environment. Once cured, the mold is removed and reused.
The precast concrete product is then taken to the job site and used for the project. For instance, if designed to be walls, the precast concrete walls are typically lifted into position by a crane on site.
While the method was used in ancient times, the credit for its modern use goes to John Alexander Brodie. He was a City Engineer in Liverpool, England. He designed buildings with precast concrete panels in the city.
The most important benefit of using precast concrete is that it considerably speeds up the construction process for any project. Ordinarily, builders used to pour concrete on the job site and wait for it to cure, which could take several days or weeks.
With precast concrete, they can simply order ready-made precast products as per their requirement and fit them in place. There is no waiting period involved at all. Reputable brands like Premier Precast always have precast concrete structures in their inventory.
Precast concrete brands like Premier Precast include carefully chosen materials in their mixes, which you saw in the list above. Adding these elements results in characteristics like high strength, waterproofing, etc.
When curing concrete on the site, many of these materials are difficult to procure and may be forgotten or overlooked. Therefore, precast concrete has a significantly higher strength than an ordinary concrete surface.
Precast concrete is manufactured in facilities where the curing happens in a carefully controlled environment. However, when curing concrete at the construction site, nobody can control the environmental factors such as rain, humidity, heat, etc.
However, on sites with large-scale projects, there is so much work going on that no one can monitor the quality control of cast-in-place concrete at all times. This can lead to low quality and inconsistent construction. For more information, read our in-depth comparison of precast and cast-in-place concrete.
For construction projects, speed is of the essence. Every day lost can add costs in labor and resource waste. By speeding up the process using precast concrete, builders can save a lot of money on the cost of labor and other things.
There are options for builders to order precast concrete structures with complex decorative elements. These elements cannot be created on the construction site with cast-in-place concrete due to the significantly high costs of designing and creating specialized molds.
The benefits of precast concrete are applicable if you are using good-quality precast concrete. Otherwise, your money might be wasted, and the time you save amounts to nothing since it will lead to repair requirements in the future.
The final product has a high consistency when precast concrete is created using high-quality materials and a controlled environment. If your precast concrete structures are inconsistent, you may be using precast concrete of inferior quality.
Good precast concrete does not contain any VOC. VOC in concrete leads to mold and foul odor, common in residential buildings. Therefore, use good precast concrete, and the buildings will be resilient to molds and unhealthy indoor environments.
Precast concrete panels and walls can be used to create both residential and commercial buildings and complexes. These walls come in different sizes and can be designed according to the needs of any project.
Precast concrete slabs are multipurpose and can be used to create elements such as stairs and ceilings. The slab dimensions (including thickness) can vary based on the requirement of the project manager or builder.
The precast concrete industry even offers columns you can order with a single click instead of making them on-site. Using precast columns is better than using fresh concrete for your elevation requirement.
Yes, you read it right. You can buy ready-made elements for use in utility buildings like precast concrete stairways and even individual steps instead of making them on-site. These stairs are used in various structures such as homes, malls, office buildings, etc.
The National Precast Concrete Association has set requirements that precast concrete should meet. Only an APA-certified or NPCA-certified plant can meet these requirements for production practices and quality.
Then there are manufacturers like Premier Precast, constantly evolving and setting the bar higher and higher. As an award-winning business, Premier Precast provides diverse concrete solutions, including an extensive product line in precast concrete.
CXT Incorporated is a wholly owned subsidiary of L.B. Foster Company. We are a leading manufacturer of precast concrete buildings, storm shelters, bridge beams, box culverts, agricultural products such as freezeproof waterers and feed bunks, along with other pre-stressed and precast concrete products.
Precast concrete structures are conventionally designed using manual methods and simplified numerical tools, e.g. linear finite element analysis,hence, structures are often far too conservative thus wasting con- crete and reinforcement. Moreover, the quality of the design is to a large degreereliant on the skill and engineering intuition of the structural engineer. Finite element limit analysis provides a framework for efficient analysisusing mathematical programming. Plane stress elements for modelling precast panels are reviewed and a composite model for reinforced concreteis presented. A four storey shear wall is analyzed using the commercial software Optum Concrete Solution: The model includes mesh reinforcement,column- and beam reinforcement, stringers and joints, and the limit load is calculated in a matter of seconds. The example displays that the useof finite element limit analysis has the potential to greatly optimise precast structures, hence, making our structures more sustainable as well ascheaper.
Precast concrete has many advantages over conventional insitucast concrete. It is cast and cured in a controlled environmentwhich allows for increased quality control and, therefore, makesit possible to decrease many tolerances. The precasting enablesparallel production, which increases the speed and efficiencyconsiderably. The fib Bullitin 43  describes many of the commontechniques for precast concrete elements. The production of precastelements at the manufacturer also means that the construction isless labour intensive. Some work is nevertheless still required atthe construction site as the precast elements need assembly, whichis handled by various kinds of concrete or mortar joints cast inplace. These joints are often crucial to the overall behaviour of thestructure; however, they also introduce additional complexity tothe structure for the structural engineer. For practical design andanalysis of precast concrete structures, conventional finite elementanalysis is rarely used. Adopting a simple linear elastic approachleads to a far too conservative design. More advanced models,however, requires expert knowledge by the user as well as materialmodels capable of handling the complexity of the precast structureand joints. Moreover, non-linear finite element models can be proneto numerical difficulties. The engineers are therefore left withsimplified methods based on limit analysis, i.e. the assumption of arigid-plastic material, e.g. the yield line method [2,3] or stress fieldmethods . While being easy to use, these methods are difficultto master, and the solutions will depend heavily on the skill andintuition of the individual structural engineer.
Finite element limit analysis (FELA) combines the rigid-plasticmaterial model of limit analysis with the discretisation known fromfinite element analysis (FEA). The result is a so-called direct method,where the limit load is calculated in a single step rather than theconventional load step scheme of FEA. The formulation of FELA isa convex optimization problem, and Anderheggen and Knöpfel were some of the first to present this for linear optimisation. Duringthe 90s optimisation techniques and algorithms were extendedtremendously [6-8], and solving convex programs is an establishedtechnology at this point. During the 2000s various researchersextended the scope of FELA from the original formulation oflinear programming to both second-order conic programs and semidefinite programs [9-11]. Limit analysis and FELA assumea simplified material behaviour, i.e. rigid plasticity, however, theresult is an elegant formulation which allows rigorous bounds onthe exact limit load. Naturally, lower bound solutions are appealingsince they ensure a safe and statically admissible stress field.Moreover, complex features such as joints, interfaces, and variousreinforcement layouts can be dealt with in a simple and efficientmanner within FELA making it an alluring design tool [12,13]. Inthis paper, an overview of design of precast concrete structuresusing FELA and the newly developed software Optum Concretesolution is given. More precisely, the case of shear walls comprisedof precast panels is considered. Such structures, while common,pose a considerable challenge in the ultimate limit state, hence,leading to suboptimal designs and wasted resources.
As discussed in the introduction, shear walls are crucial inprecast structures, yet difficult to design and analyses usingconventional methods. Computationally, a panel can be representedaccurately using plane stress triangles, whereas several has beendeveloped for FELA [14-16] (Figure 1). 041b061a72