Concrete is the most widely used building material in the world. In addition to understanding concrete, today's construction professional needs to understand the principles of concrete reinforcing and how prestressed concrete works. This includes both pre-tensioned concrete that is typically manufactured in a precast plant, and post-tensioned concrete that is cast-in-place. Post-tensioned concrete is being used more and more throughout the world to build multi-story structures, slabs-on-ground, and bridges, while precast prestressed concrete continues to be used in rapidly built structures like parking garages. Understanding how and why reinforcing and prestressing works in a concrete structure.
Gain a better understanding of the principle and theory behind concrete reinforcing and prestressing to help you be a better construction management professional.
After completing this course you will be able to...
Learn from a professional
My courses have been created as a place where everyone, whether you are an experienced professional, a young project engineer, new to a trade or a seasoned journeyman, can come to learn more about the industry that we have chosen as our profession. That's what this platform is about. These courses are meant to be a way for you to increase your knowledge of the construction industry in a variety of cutting edge topics from concrete reinforcing and prestressing, to micro trenching, to safety management systems. This is not a course that teaches you how to install rebar or prestressing steel. It is a course that educates you on why we reinforce concrete and how it works. This is information you need as a construction professional in order to talk to designers, owners and subcontractors.
This course is a great way for you to increase your knowledge about concrete reinforcing and prestressing.
So you know a little but about concrete. Maybe you even took our Understanding Concrete course here on Udemy? But do you really understand the strengths and weaknesses of concrete? Do you understand how and why it cracks?
This brief quiz will test you on how much you already know about reinforcing and prestressing, and will set the stage for some of the things we will discuss in the following lectures.
In this section we will introduce the concepts that will be covered in this course. The idea is to get you thinking about the concepts and the learning objectives. Also included are the first handouts that are included with this course. Make sure to check them out and get them downloaded! This supplemental material makes a great set of resources to take away from this class. Access it by clicking on the RESOURCES tab at the top of each lecture.
Learning objectives are concise, measurable outcomes. These are the things you should be able to do after completing this course:
This lecture contains the vocuabulary refernece material for the course and discusses safety considerations.
Concrete is the most widely used building material on the planet! Learn why here.
This section gives a brief introduction and overview of concrete; what's in it and how it works. This section introduces the chemical reaction known as "hydration" which is the chemical reaction between cement and water that results in the concrete getting hard. We also introduce the concept of using industrial by-products as a partial replacement for cement. Download the PDF file in the Resources tab to learn more about one of the most common by-products used in concrete.
Want a more in depth look at concrete? Check out our course here on Udemy titled "Become a Better Construction Manager - Learn About Concrete".
Concrete is strong in compression and weak in tension. Compression is the force that squeezes something together and tension is the force that pulls it apart.
This section looks at the forces and stresses that cause concrete to crack. Both tension and shear are discussed.
We use different techniques, including control joints and passive reinforcing like rebar and wire mesh to control cracking. These methods will not stop concrete from cracking, but if utilized correctly they will control the cracking, limit the crack widths, and prevent cracking from leading to failure.
This final lecture on passive reinforcing pulls together the concepts learned so far, and explains the reasoning behind the use of the term "passive" reinforcing.
Take this short quiz to see what you have learned so far!
Prestressed concrete is actively reinforced. This means that we are applying forces to the concrete before we place it in service in order to enhance its performance.
Increasing the tensile capacity of the concrete member results in several advantages including longer spans, shallower members and better crack control. All of these things combine to result in economic advantages and savings in concrete.
Be sure to check out the handout material in the Resources tab for a paper published by the Post-Tensioning Institute about the sustainability benefits of prestressed post-tensioned concrete,
Active and Passive reinforcing are often used together to create a concrete structure that is economical and meets the performance requirements.
Today, the use of prestressing is common in concrete structures due to its economic advantages. Hotels, office buildings, bridges, parking structures and even residential foundations are all common uses for prestressed concrete.
The White Paper included in the Resources tab introduces the concept of prestressed concrete to build "high performance" structures.
Layout is determined by the designer, with proper placement being critical to the performance of the structure.
Prestressing steel is tensioned to a very high force (33,000 pounds or more). Safety is extremely important. Personnel who are not a part of the stressing operation should not be permitted in the area. Personel working on the stressing operation need to be properly trained.
Let's see how much you learned about prestressed concrete!
We use some form of passive reinforcing in virtually all types of concrete structures; any time we expect tensile stresses to exceed the strength of the concrete. We add active reinforcing to further enhance the properties and the performance of some concrete structures when we want longer spans, thinner concrete sections and stiffer beams and slabs.
This lecture sumarizes the strenghts of the various materials discussed in this course and wraps up the discussion on the advantages and limitations of prestressed concrete.
Take this final quiz to check your knowledge against the learning objectives listed at the begining of this course.
Thank you for completing this course. You should now have a good understanding of why we reinforce concrete and of the benefits of prestressed concrete. You should understand why a designer might make the decision to utilize prestressed concrete and what the differences are between precast, pre-stressed, concrete and cast-in-place, post-tensioned concrete.
If you enjoyed this course, please consider leaving a positive review! If you have questions, make sure to post them in the discussion board for this course. I check for questions everyday; or you can use the message feature to send me a note or question.
Thanks, and be sure to look for our other courses. Additional topics are added each month.
I work in the School of Sustainable Engineering and the Built Environment at Arizona State University. I have been a faculty associate in the construction management program and have taught many undergraduate and graduate courses in that program, including courses in concrete, scheduling, productivity and safety. I am currently the Director of the school's OSHA Training Institute Education Center where I develop, produce and teach many courses in occupational safety and health for construction and general industry.
Prior to joining ASU, I spent many years in the construction industry including roles managing a public works contractor in California, a large concrete contractor in Arizona and I managed a division of one of the largest post-tensioning companies in North America. In between my industry roles and my latest role teaching, I spent some time working for industry associations and acting as a consultant for a large construction union. I learned a lot in these different roles and as I have progressed I have come to realize that our industry has a real need to do a better job disseminating knowledge.
My teaching experience includes the following academic courses taught at Arizona State University:
--CON 100 - Introduction to Construction
--CON 271 - Construction Safety
--CIM 205 - Concrete Construction Methods
--CIM 306 - Concrete Plant Management
--CIM 494 - Reinforcing and Post-Tensioning
--CON 494 - Temporary Structures and Reinforcing Methods
--CON 495 - Planning and Scheduling
--CON 540 - Construction Productivity
I also have a number of published articles and write a regular construction safety collumn for Concrete Construction Magazine.