This way we have one view for the mild steel reinforcement and another for the post tension tendons. Jim rogers, editor and publisher of post tension magazine, says that until housing construction ground to a halt last year, about half of all post tensioning work was slabs on ground for homes. Information about how posttensioned concrete is constructed. Posttensioned foundations are designed using the posttensioning institute pti method first published in 1980 and recently updated with its 3rd edition.
Design fundamentals of posttensioned concrete slabs. For example, precast posttensioned supported bent caps with an inverted tsection with. Post tensioned slab technical specificaitons post tensioning of the slabs will be carried out in accordance with. It will have minimal movement with normal soil moisture fluctuations but there are many unpredictable postconstruction and climate related factors that can affect soil moisture content. The builder used a post tension foundation with footings. Segment as in2 bars spacing in interior column strip top bot 12. This course provides the documentation to enable the use of a posttension design spreadsheet program for oneway concrete beam and slab and twoway concrete slab systems. This list is compiled from field notes and observations. Market for post tensioning tendons over 40% of all pt tendons sold in the usa are for residential foundations. These strands or cables are also referred to as tendons.
Design and analysis of slabonground foundations on both. Program scope, design assumptions, design methodology, program limitations, description of inputoutput, hardware requirements. A 5inch posttensioned slab can handle up to 5,000 pounds, and a typical 9inchthick slab will bear a concentrated 9,000pound load. The thin post tension slab on grade is not a good solution for the foundation of light. Onscreen warning messages for out of compliance conditions. Posttension basics how posttensioned slabs are built.
Slabongrade and posttensioned slab software adaptsog. The largest post tensioned slab on grade made by vsl without expansion joints covered the area of 30,000 square metres. With capabilities to support residential projects from design through construction, spt provides national home and apartment builders, as well as custom home professionals, with the best protection for their new construction investments. Slab on grade post tensioning systems tendon systems. A 5inch post tensioned slab can handle up to 5,000 pounds, and a typical 9inchthick slab will bear a concentrated 9,000pound load. Vsl designes the post tensioning of slabs to avoid tensile rupture of concrete under the most unfavourable combination of loads, i.
It will have minimal movement with normal soil moisture fluctuations but there are many unpredictable post construction and climate related factors that can affect soil moisture content. Post tensioned slab on grade is more durable and economical than conventional slab reinforcement. Posttensioning institutes design of posttensioned slabsonground, pti design procedure 3rd edition. Adaptpt designs posttensioned slabs and beam frames using equivalent frame. In continuous or indeterminate post tensioned structures the moments due to the prestressing. Posttensioned twoway slab pennsylvania state university.
This course provides the documentation to enable the use of a post tension design spreadsheet program for oneway concrete beam and slab and twoway concrete slab systems. Shrinkage crack considerations for posttensioned foundations june 1, 2015 shrinkage cracks in concrete slabonground foundations are a significant public relations problem to home builders. Chapter 9design of post tensioned slabs onground, p. Posttensioned, reinforced concrete slab design software ram. Design fundamentals of posttensioned concrete slabs bommer, allan, aalami, bijan on. Your goto concrete slab and foundation design workhorse. Posttensioning institute education pt applications slabon. For example, precast posttensioned supported bent caps with an inverted t section with. Post tension slab design software structural engineering. Posttension slabs on grade, policy phoenix, arizona. Posttensioning cant be used in belowgrade applications. The largest posttensioned slab on grade made by vsl without expansion joints covered the area of 30,000 square metres. Structural calculation for the post tensioned slab on ground of sunshine project california march 2006 reference.
This course is intended to be an introductory course for structural engineers new to post tensioned. Comparative analysis of castinplace posttensioned and steel. Shrinkage crack considerations for posttensioned foundations. The webinar covers the engineering and construction aspects of posttensioned slab on ground foundations for residential buildings that are. Design publications and software for post tensioned slabs on. The benefits of faster construction schedules while decreasing the quantity of concrete and rebar saves money. What is post tensioning introduction post tensioning is a method of producing prestressed concrete, masonry and other structural elements. A posttension slab is a slab of concrete which has been prestressed using a specific method to increase the strength of the concrete. Standard requirements for design and analysis of shallow post tensioned concrete foundations on expansive soils.
Posttensioning and prestressed design and software expertise for. Fundamentals of posttensioned concrete design for buildings. The price varies depending on the size, the angles, and the location. What is the difference between normal slab and post. A residential slab on grade foundation is designed to float on the surface of the soil. Hightension steel tendons enable slab foundations to withstand the stresses of expansive and compressive soil conditions that are prevalent in texas. Grade the lot for positive drainage away from the foundation during and afterconstruction. I suppose this is not unusual, based on other posts ive read. Brendon burley structural option posttensioned twoway slab posttension investigation besides shear strength it is also important to consider the moment capacity of each of the sections. Slab on grade post tensioned concrete slabs on grade have become an integral part of building large cost effective and durable floor slabs. Construction of posttensioned slabs on grade is very similar to using reinforcing steel, except for the tensioning step.
Jim rogers, editor and publisher of post tension magazine, says that until housing construction ground to a halt last year, about half of all posttensioning work was slabsonground for homes. Cables are arranged as indicated by the engineer and chaired to run through the center of the slab. Economically design posttensioned and reinforced concrete floors including slabs, mats, and rafts. Post tension is active reinforcement, meaning that it is constantly under. Before a posttension slab is poured, highstrength steel strands or cables, called tendons, are laid in a tight grid. Design floors and foundations reliably and efficiently, saving time and money, and overcoming the most common concerns you face as a designer. The compressive stresses resist the anticipated tension stresses induced by the soil movements, enhancing the performance over a nonprestressed foundation. Brendon burley structural option post tensioned twoway slab post tension investigation besides shear strength it is also important to consider the moment capacity of each of the sections.
The post tensioning bonded flat slab system shall consist of high tensile strands of 12. What is the difference between rebar and post tension. A normal slab is basically a rcc reinforce cement concrete slab where as a post tentioned slab is the psc prestressed concret slab. The term prestressing is used to describe the process of introducing internal forces or stress into a concrete or masonry element during the construction process in order to. Adaptsog software for the design of posttensioned slabs on grade foundations on expansive and compressible soils. I too, was looking for the best solution for my home. Posttensioned slab on grade is more durable and economical than conventional slab reinforcement. A residential slabongrade foundation is designed to float on the surface of the soil. Standard requirements for design and analysis of shallow posttensioned concrete foundations on expansive soils.
In simple span beams the primary posttensioning pt moments induced by the prestressing force are directly proportional to the eccentricity of the tendons with respect to the neutral axis of the member i. Conventional posttensioning for a typical flat plate slab. Ptislab can be used to design or analyze both posttensioned and conventionally reinforced slabsonground for single and multifamily residential and. The fem software abaqus 23 includes several material models that were considered herein. What is posttensioning introduction posttensioning is a method of producing prestressed concrete, masonry and other structural elements.
Today, pt is used extensively for slabs on grade where soils are likely to move expansive soilsespecially in the american southwest. Fundamentals of post tensioned design for buildings. Slabonground posttensioned slabsonground provide a costefficient, highperformance solution for problems associated with groundsupported residential foundations on shrinkswell soils. Nov 02, 2017 applications of gpr to posttensioned slab assessment posteck prestressing. The pti design procedure is used to design a slabon grade foundation that will respond elastically to forces the foundation is exposed to including those that are the consequence of soil pressure and soil deformation. Concrete slab design software economically design post tensioned and reinforced concrete floors including slabs, mats, and rafts, with exceptional visibility into compliance, efficiency, and practicality.
A practical approach, 2e is the only canadian textbook which covers the design of reinforced concrete structural members in accordance with the csa standard a23. In continuous or indeterminate posttensioned structures the moments due to the prestressing. Adapt corporation specializes in structural concrete design software for post tensioning, reinforced concrete, and prestressed beam, slab, foundation, building and bridge structures using finite element or equivalent frame analysis. Optimization of posttensioned concrete floor slabs politesi. Design fundamentals of post tensioned concrete slabs. Posttension basics how posttensioned slabs are built the. It is a concrete slab that has steel cables running through it that have been put under lots of stress to reduce cracking of the concrete and increases the strength of the slab. This way we have one view for the mild steel reinforcement and another for the posttension tendons. Adapt is a world leader in posttensioning and prestressed software and. A suncam online continuing education course fundamentals of post. This tension makes the concrete slab and foundation much stronger than concrete without reinforcement and helps reduce cracking. Im adding more comments as i see issues in search inquiries. A combination of these values will determine the slab stresses at the time of stressing and at service loads.
Twoway posttensioned design amsysco post tensioning. This overlay will show up while the video is playing. Post tensioning imparts an internal compressive force into the concrete. Balcony slabs in typical post tension buildings with balconies, the balcony slab is an extension of the concrete floor slab and usually cantilevered with a guardrail or parapet on the outer edge. Several methods exist for prestressing concrete, with posttensioning being a very common one. For residential construction, tendons at 48 inches on center are common. Typical posttensioned ribbed foundation for residential construction with tendons placed in the center of the slab at approximately 48 inches on center in each direction. Reinforcement helps extend the life of concrete, overcoming cracking that is inherent in the material and preventing its failure. Market for posttensioning tendons over 40% of all pt tendons sold in the usa are for residential foundations. Post tensioned concrete slabs on grade offer the building owner large areas up to 4000m2 in single pours and up to 10,000m2 in coupled jointed slabs. Effects of slab posttensioning on supporting steel beams aisc. A psc is applied with a compressive stress on the cross section in advance before the application of loading on. Posttensioned prestressed concrete as a building material, concrete is strong in compression, but weak in tension.
Posttensioned concrete has been used in building construction since the late 1950s. Calculation and analysis of uniform thickness slabs, sometimes. Very good video showing step by step post tension slab duration. This knowledge was obtained over many years of working on our own projects and listening and learning from the the pioneers of posttensioned concrete. Chapter 15 covers the slab on grade industry, which represents more sales of posttensioning tendons than all other posttensioning applications combined. Rebar is passive reinforcement, meaning it just sits in your slab. The company uses the latest design software which is continually updated to reflect current international construction codes of practice. For commercial buildings flat slab rising up to 10 to 20 stories is quite popular.
What is the difference between rebar and posttension. Post tension slab design software calvinandhobbes10 structural 26 aug 16 15. Posttensioning imparts an internal compressive force into the concrete. In simple span beams the primary post tensioning pt moments induced by the prestressing force are directly proportional to the eccentricity of the tendons with respect to the neutral axis of the member i. Posttensioning is a method of reinforcing strengthening a concrete slab on grade with highstrength steel strands. Post tension pt slab there has recently been a lot of discussion regarding to a post tension, or pt slab on grade and a pier and beam foundation. Optimization of twoway posttensioned concrete floor systems. Safe is in fact a performing tool for designing concrete floor and foundation systems. Design fundamentals of post tensioned concrete slabs bommer, allan, aalami, bijan on. Design and construction of posttensioned slabs on ground using. Posttensioned concrete design spreadsheet program a pdh. The flat slab or post tensioned slab buildings in which slab is directly rested on columns, have been adopted in many buildings constructed recently due to the advantage of reduced floor to floor heights to meet the economical and architectural demands. Post tension slabs answers to questions buyers ask. All concrete will shrink during the curing process which lasts up to a.
Vsl designes the posttensioning of slabs to avoid tensile rupture of concrete under the most unfavourable combination of loads, i. An analysis of the bulk cross section of each segment of slab is summarized in table 22. Superior post tension specializes in fullservice fabrication and installation of slab on grade post tension applications. Pti has certification programs for manufacturing plants and for individuals. High tension steel tendons enable slab foundations to withstand the stresses of expansive and compressive soil conditions that are prevalent in texas. Posttension is active reinforcement, meaning that it is constantly under. When we have finished modeling the slab itself, we duplicate the plan view do not use duplicate with detailing. Construction maintenance of post tensioned slab on ground. Structural calculation for the posttensioned slabonground of sunshine project california march 2006 reference. Post tensioning is a method of reinforcing strengthening a concrete slab on grade with highstrength steel strands.
Tensioned concrete design for buildings part three by john p. Posttensioned concrete slabs augi the worlds largest. Applications of gpr to posttensioned slab assessment youtube. Construction of posttensioned slabs on grade is very similar to using. Concrete grade beams span from column pile cap to pile cap and support the exterior walls of the building. Mechanics and design, 4th edition, pearson scientific. Analysis of a slabs capacity to support on interior line load or. When planning for point loads, a safe rule of thumb is to figure on 1,000 pounds per inch of slab thickness. This course is intended to be an introductory course for structural engineers new to posttensioned.
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