Chakrabarti in phasei, a total of six unbonded post tensioned pt slab specimens were tested. Tensioned bonded strands bonded tendons unbonded tendons internal internal external. The present study focuses on posttensioned flat slab systems with respect to strength, service and cost estimation. The use of posttensioned pt slabs in structures was proven to have many advantages, such as construction of large spans, speeding the erection of structures, and reduction of selfweight due to decrease in slab thickness compared to reinforced concrete slabs. The program is developed around the robust computational core of two popular programs ptdata. Developers, architects, engineers, contractors, educators and. Pdf posttensioned concrete longspan slabs in projects of. Post tensioning in buildings is not limited to floor slabs. Posttensioning is a special form of prestressed concrete in which the prestressing tendons are stressed after the concrete is cast. What is the difference between normal slab and post.
Best posttensioned pt concrete design books youtube. Post tensioning utilizes high quality high strength steel such that 1 kg of post tensioning strand may replace 3 or 4 kg of ordinary nonprestressed reinforcement. Posttensioning institutes design of posttensioned slabsonground, pti design procedure 3rd edition. In the succeeding years numerous posttensioned slabs were designed and constructed in. Us posttensioning industry owes its existence to liftslab construction first liftslab buildings in the us were built in the mid 1950s using nonprestressed slabs problems with deflections and slab weight in long 2way spans to solve deflection and weight problems, lift. This book is destined to become the definitive work on the design of post tensioned concrete buildings for many decades to come. Usually a sign in the garage or stamp in the slab will indicate if your home has a post tension slab. To ensure an enduring, maintenancefree, life of 75 years fiber reinforced plastic. Fundamentals of posttensioned concrete design for buildings. There are different areas of implementation for pretensioned and posttensioned concrete. Posttensioning concrete increases the many benefits associated with a concrete framed building. Pti 3 structural material types structural steel prestressed concrete reinforced concrete pre.
The impossibility comes from the unknown location of the tendons and anchors. Part three continues with the study of twoway, posttensioned slab systems, including. Total annual post tensioning consumption and percentage used in building structures in various countries 1990 figures 3 chapter 7 presents two examples that reiterate the contents of chapters 3, 5 and 6. Posttensioned pt slabs posttensioned pt slabs are typically flat slabs, band beam and slabs or ribbed slabs. Post tensioning with or without bonding of tendons 3 1. Posttensionmg enabled the lifting weight to be reduced and the deflection and cracking performance to be improved. This method of reinforcing concrete enables a designer to take advantage of the considerable benefits provided by prestressed concrete while retaining the flexibility afforded by the castinplace method of building concrete structures. General principales local zone design general zone design. Net, which many engineers have come to trust over the years for its accuracy and flexibility. The present study focuses on post tensioned flat slab systems with respect to strength, service and cost estimation. Post tensioning is a special form of prestressed concrete in which the prestressing tendons are stressed after the concrete is cast.
The designs were analysed using adapt builder software with different panel sizes. 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. A post tension slab is a concrete slab or foundation that contains high tension cables running through the concrete to increase strength and reduce cracking typically in areas with poor soil conditions. The parametric study of the post tensioned flat slab by varying the span by 0. Pt slabs offer the thinnest slab type, as concrete is worked to its strengths, mostly being kept in compression. Tanks can also be designed to withstand differential backfill. Attempts were made to improve knowledge in depth by theoretical studies and experiments on post tensioned plates see chapter 2. This hybridisation helps achieve the formation of a much thinner slab with a longer span devoid of any column free spaces. Precast posttensioned tanks can be constructed above ground with the base slab below frost, completely buried, or partially outofgrade. Drilling into a posttensioned slab there are several myths about posttensioned concrete, but the most prevalent one i hear is that it is practically impossible to drill into a posttensioned slab. Post tensionmg enabled the lifting weight to be reduced and the deflection and cracking performance to be improved. Similarly, a freebody diagram of the tendon would show the concentric force. Figure s42 three dimensional view of the posttensioned slab and its support arrangement s5 loading assumptions and values from the design criteria, the posttensioned slab is designed for a uniformly distributed superimposed dead load of 3.
Notice the assumptions required for the post tensioned design fig. Tn342 design example 2way mondada 093090 adapt corporation. Posttensioning in buildings is not limited to floor slabs. There are different areas of implementation for pre tensioned and post tensioned concrete. Shrinkage and temperature reinforcement in twoway post. 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. Originally post tensioned, twoway slab framing systems were constructed with column and middle strips, similar to those used in conventionally reinforced twoway slabs.
Stressing method of posttensioned slab step by step snp post tension co. Pt designer is a computer program for the design and analysis of linear posttensioned concrete floor systems. Originally posttensioned, twoway slab framing systems were constructed with column and middle strips, similar to those used in conventionally reinforced twoway slabs. Posttensioning utilizes high quality high strength steel such that 1 kg of posttensioning strand may replace 3 or 4 kg of ordinary nonprestressed reinforcement. Us post tensioning industry owes its existence to lift slab construction first lift slab buildings in the us were built in the mid 1950s using nonprestressed slabs problems with deflections and slab weight in long 2way spans to solve deflection and weight problems, lift slab companies changed to post tensioned slabs. Fundamentals of posttensioned concrete design for buildings part one fundamentals of posttensioned concrete design for buildings part one. Drilling into a post tensioned slab there are several myths about post tensioned concrete, but the most prevalent one i hear is that it is practically impossible to drill into a post tensioned slab. Five underlying features of post tensioned construction allow greater flexibility in reinforcement layout. Post tensioned concrete design for aci 31808 contents. Chakrabarti in phasei, a total of six unbonded posttensioned pt slab specimens were tested.
Tensioned bonded strands bonded tendons unbonded tendons internal. In post tensioned floor slab construction, the placement of post tensioning tendons and associated nonprestressed reinforcement does not strictly follow the practice of nonprestressed slabs. Basic and applied soil mechanics is intended for use as an uptodate text for the twocourse sequence of soil mechanics and foundation engineering offered to undergraduate civil engineering students. A combination of these values will determine the slab stresses at the time of stressing and at service loads.
Posttensioned walkways provide a structural upper fixed beam capping all walls and also provide for superior accessibility. Download free, highquality cad drawings, blocks and details of posttensioned concrete organized by masterformat. Post tension slab is a combination of conventional slab reinforcement and additional protruding highstrength steel tendons, which are consequently subjected to tension after the concrete has set. Jul 15, 2016 in this free webinar dirk bondy and bryan allred discusses the latest edition of their book, posttensioned concrete principles and practice 3rd edition as well as present the latest version. The actual position of tendons must be known accurately in both plan and elevation so that tendon damage can be avoided. Pdf fundamentals of posttensioned concrete design for.
For commercial buildings flat slab rising up to 10 to 20 stories is quite popular. The above spreadsheet program and users manual can be downloaded and be printed free of charge. Post tensioning of foundations, transfer beams and plates, post tensioned masonry and the combination of precast elements with castinplace concrete by means of post tensioning offer other interesting opportunities. Fundamentals of post tensioned design for buildings. A 2 2area 2 a c 2 2 posttensioned concrete design table 11 list of symbols used in the aci 31808 code cp area enclosed by the outside perimeter of the section, in a g gross area of concrete, in a 2 l total area of longitudinal reinforcement to resist torsion, in a o area enclosed by the shear flow path, sqin a oh area enclosed by the centerline of the outermost closed. First liftslab buildings in the us were built in the mid 1950s using. Design floors and foundations reliably and efficiently, saving time and money, and overcoming the most common concerns you face as a designer.
The purpose of this publication is to widen the understanding of posttensioned floor construction and show the considerable benefits which include minimum storey heights, rapid construction, economy, maximum design flexibility, minimum number of columns, optimum clear spans, joint free, crack free. While post tensioning is a very attractive repair and. Longer spans can be achieved due to pre stress, which can be. Posttensioned, reinforced concrete slab design software ram. Fundamentals of posttensioned concrete design for buildings part one.
Post tensioned concrete is a term heard more and more in the construction industry today. This book is destined to become the definitive work on the design of posttensioned concrete buildings for. A normal slab is basically a rcc reinforce cement concrete slab where as a post tentioned slab is the psc prestressed concret slab. Schematic comparing a conventially reinforced concrete member to a post tensioned membaer. Slab post tensioning systems page 5 38 reinforcing savings as steel and concrete increase in pricing, the savings with a post tensioned slab will increase, because the quantity of steel and concrete required for a post tensioned slab is less than for a conventionally reinforced foundation. 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. Nov 25, 2008 post tensioned concrete is a term heard more and more in the construction industry today. The use of post tensioning can reduce the depth of slabs and story height, as well as. Total annual posttensioning consumption and percentage used in building structures in various countries 1990 figures 3 chapter 7 presents two examples that reiterate the contents of chapters 3, 5 and 6. Tensioning building structures march 12, 2020 2020 educode las vegas. Attempts were made to improve knowledge in depth by theoretical studies and experiments on posttensioned plates see chapter 2. Fundamentals of posttensioned concrete design for buildings part one a suncam online continuing education course. Model specification bonded and unbonded posttensioned. Slab posttensioning systems page 5 38 reinforcing savings as steel and concrete increase in pricing, the savings with a post tensioned slab will increase, because the quantity of steel and concrete required for a posttensioned slab is less than for a conventionally reinforced foundation.
Twoway posttensioned design amsysco post tensioning. In this free webinar dirk bondy and bryan allred discusses the latest edition of their book, posttensioned concrete principles and practice 3rd edition as well as present the latest version. Experimental investigation on the effect of impact loading. Pti journal december 2012 5 technical paper rehabilitation of unbonded posttensioned slabs with different boundary conditions byuk ksun im, thomas h. A 2 2area 2 a c 2 2 post tensioned concrete design table 11 list of symbols used in the aci 31808 code cp area enclosed by the outside perimeter of the section, in a g gross area of concrete, in a 2 l total area of longitudinal reinforcement to resist torsion, in a o area enclosed by the shear flow path, sqin a oh area enclosed by the centerline of the outermost closed. Ccl posttensioned slabs can bring unique freedom over conventional building. Although some posttensioned slab structures had been constructed in europe quite early on, the real development took place in the usa and australia. The most suitable solution for above requirements are the posttensioned slabs with unbounded tendons. While posttensioning is a very attractive repair and. Interior left, exterior right deflection analysis the final consideration in the design of the twoway slabs is deflection. A psc is applied with a compressive stress on the cross section in advance before the application of loading on. Pdf nowadays, design of modern an architectural building structures requires the use of slender and free from numerous supports slabs. Posttensioning technique is widely used in many structural elements such as slabs, beams, bridges decks and others.
Serviceability limit state 11 41 crack limitation 11 42. However, because the continuous twoway tendons had to be placed in a draped parabolic profile near the top of. Thanks to liftslabs us posttensioning industry owes its existence to liftslab construction. Post tensioning is used for many reasons, including economy and building efficiency as well as the reduction of deflection and cracking it provides. A typical draped profile in an elevated concrete slab would route the posttensioned reinforcing through a high point over the slabs supports, and through a low point in between those supports. Tributaries used when computing average precompression. It provides a modern coverage of the engineering properties of soils and makes extensive reference to the indian standard codes of practice while.
The parametric study of the posttensioned flat slab by varying the span by 0. Post tensioning tendon installation and grouting manual fhwa. Pti journal december 2012 5 technical paper rehabilitation of unbonded post tensioned slabs with different boundary conditions byuk ksun im, thomas h. Concrete slab design software economically design posttensioned and reinforced concrete floors including slabs, mats, and rafts, with exceptional visibility into compliance, efficiency, and practicality.