Bonded post tensioned concrete is the descriptive term for a method of applying compression after pouring concrete and the curing. Post tensioning applications include office and apartment buildings, parking structures, slabs onground, bridges, sports stadiums, rock and soil anchors, and watertanks. Pre tensioned concrete is a variant of prestressed concrete where the tendons are tensioned prior to the concrete being cast 25 the concrete bonds to the tendons as it cures, following which the endanchoring of the tendons is released, and the tendon tension forces are transferred to the concrete as compression by static friction. Unbonded post tensioned concrete slabs in fire part ii modelling tendon response and the consequences of localized heating. Posttensioned concrete slabs for buildings youtube. The purpose of this publication is to widen the understanding of posttensioned floor construction and show the. Posttensioned slabs can be designed to be crack free and therefore waterproof slabs are possible. Post tensioned slabs are extremely durable and long lasting, resist cracking, have no intervening joints, and also have better surface uniformity and predictability of play. Check all plumbing locations before the pt is installed and the concrete is placed. This report presents the structural engineering calculations of a post tensioned floor using parallel beams and oneway slab construction. Fundamentals of posttensioned concrete design for buildings part two a suncam online continuing education course.
A definition should clarify which type of post tensioned residential and light commercial slabs onground is intended to be excluded from the aci 318 building code. Professional development series sponsor portland cement association e very major metropolitan area is getting a facelift. Seismic retrofit using externally applied posttensioning tendons. Posttensioned, reinforced concrete slab design software ram. Posttensioned concrete slabs have become a major factor on the construction of floor.
Posttensioning is a method of reinforcing strengthening concrete or other materials with highstrength steel strands rebars, typically referred to as tendons. A condition in which the member is stressed via tensioned tendons prior to application of external loads. Residential and light commercial post tensioned concrete shallow foundations on expansive soils are ribbed or uniformthickness post tensioned foundations built on expansive soils. This article provides information on how to scheme a pt slab and how the use of post tensioning affects the rest of the structure. Amsteele systems offers posttensioned slab systems for elevated slabs or slabs on grade. Pdf unbonded post tensioned concrete slabs in fire. Post tensioned concrete slabs enable us to achieve minimum floor thicknesses thus reducing storey and overall building heights. 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. Achievement of this objective depends upon careful design, detailing and construction.
Fundamentals of post tensioned design for buildings. Post tensioning in buildings foreword working party wp1. Flexural behavior of posttensioned lightweight concrete. Thanks to lift slabs us post tensioning 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, liftslab companies changed to post tensioned slabs. Pdf we designed a posttensioned concrete cantilever with a 6. A residential post tensioned concrete slab will typically be 8 inches thick and use 3000 psi concrete. University of houston master construction specifications. Increased spans and therefore larger columnfree areas, as well as a. The following example illustrates the design methods presented in aci 31805 and ibc 2003. The procedure is an extension of the deemedtocomply spantodepth ratios for reinforced concrete slabs that form part of the deflection control provisions in the new australian standard for concrete structures, as36001988. Ppt posttensioning powerpoint presentation free to. 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. There are several problems that can occur with post tensioning components in balcony and garage slabs in service. Free online education presentations on post tensioning videos openair blast testing of large prestressed concrete slabs.
Pretensioned tendons are stressed prior to casting of concrete. Posttensioning concrete increases the many benefits associated with a concrete framed building. Download free, highquality cad drawings, blocks and details of post tensioned concrete organized by masterformat. After a highly successful first run, the post tensioning institutes design and construction of post tensioned slabs onground has been extensively revised. Longer spans can be achieved due to prestress, which can also be used to counteract deflections. Tps court surfaces best court system in the market.
Pdf unbonded post tensioned concrete slabs in fire part. When the ps tendon was tensioned, this caused the free. Unless otherwise noted, all referenced table, figure, and equation numbers are from these books. 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. Moment transfer from prestressed concrete slabs to interi or column. What does post tensioning do to concrete and masonry. The courts are built with tension cables placed in both directions as per design engineering specifications within the concrete slab. Preparing for concrete placement adequately brace forms check the form layout. Jun 16, 2014 posttensioned concrete slabs for buildings. Post tension slab working principle, components and. Posttensioned concrete was originally developed during the 1930s, and made its way into the tennis industry in the late 70s in northern california where the soils are unstable and expansive. Structural calculations for posttensioned beam and oneway.
It includes practical recommendations for design of post tensioned floor systems in building construction. Advantages and disadvantages of each of these slab designs are provided. Ccl posttensioning results in thinner concrete slabs making the. Furthermore, large, clear internal spans provide flexibility of layout which is attractive to many potential clients. Old buildings are being renovated and converted, while new construction continues to add to the skyline. Unbounded post tensioned concrete slab unbounded post tensioned concrete slab design. 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. This hybridisation helps achieve the formation of a much thinner slab with a longer span devoid of any column free spaces. Posttensioned concrete design spreadsheet program a pdh.
Pdf modern concrete buildings increasingly rely on posttensioned pt concrete for flat plate flooring slab systems. Once the concrete has gained strength to 2000 psi, typically within the 3 to 10 days recommended by pti, the tendons are stressed. 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. Posttension basics how posttensioned slabs are built the. Posttensioning is a method of reinforcing strengthening concrete. Also, because aci 302 says a reasonable level of cracking is from 0% to 3%, it implies that no cracking, 0%, is a possible, reasonable level. 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. Posttensioned concrete court construction general acrylics. The file extension pdf and ranks to the documents category. Drawings and general provisions of contract, including general and supplementary. Post tensioning in buildings is not limited to floor slabs.
This also reduces structural selfweight and produces overall material efficiencies whilst controlling deflections more effectively. Balcony slabs in typical post tension buildings with balconies, the balcony slab is an extension of the concrete. The new and improved slabonground design manual concrete. This method allows for large slabs to be constructed without joints, creating a monolithic slab that can.
Tensioned concrete offers a wide range of post tensioning solutions from mono strand systems typically used in house slabs where the ground is highly reactive, slab systems 12. Cypecads post tensioned concrete slabs for buildings module has been designed to carry out the design of the passive reinforcement of post tensioned slabs, using the forces that have been obtained from analysing the post tensioned tendons bonded or unbonded, whose properties have been introduced by the program users. Economically design post tensioned and reinforced concrete floors including slabs, mats, and rafts, with exceptional visibility into compliance, efficiency, and practicality. This is the 11th in a series of articles examining various.
A more detailed guide to the design of pt floors can be found in the concrete societys technical report 43 tr43. Cracks, cracks, cracks what is a reasonable level of cracking. University of houston master construction specifications insert project name ae project number. As the shear and deflection check is the most important for the posttensioned slabs the detail design for the. Design floors and foundations reliably and efficiently, saving time and money, and overcoming the most common concerns you face as a designer. Determination of slab thickness in suspended posttensioned. Posttensioned slabs are intrinsically waterproof and. Post tensioned slabs prestressed concrete architectural. The design is based on hong kong building code hkcop 2004. The procedure described in the paper is illustrated by several numerical examples. Fundamentals of posttensioned concrete design for buildings. Since the books initial publication in 1980, it has been used by engineers and contractors to successfully design and construct hundreds of thousands of post tensioned slabs on ground. Post tension design of slab there is document post tension design of slab available here for reading and downloading.
Use the download button below or simple online reader. Park plaza post tensioned parking structure demolition. Post tensioning is a method of reinforcing strengthening concrete or other materials with highstrength steel strands or bars, typically referred to as tendons. In an unbonded system the tendon is not grouted and remain free to move. Post tensioning in concrete slab benefits and advantages. The choice of concrete mix and curing methods along with quality workmanship also play a key role. Unbounded post tensioned concrete slab unbounded post. Pt slabs offer the thinnest slab type, as concrete is worked to its strengths, mostly being kept in compression. Construction maintenance of post tensioned slab on ground. It has the following benefits as compared to unbonded post tensioning. Ccl posttensioned slabs can bring unique freedom over conventional. Note the relatively compact section of floor slabs in comparison to some other concrete types. Pdf tests of continuous posttensioned concrete slabs under. Services tensioned concrete post tensioning australia.
Tendons today are seven highstrength steel wires wound together and placed inside a plastic duct. When a concrete or masonry element is prestressed, it means that the steel is being tensioned and. Material related to tr43 is included in the international edition of this book. Developers, architects, engineers, contractors, educators and. Post tensioned slabs use highstrength tensioned steel strands to compress the slabs, keeping the majority of the concrete in compression.
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