The behaviour and response of flat slab and post tensioned flat slab during earthquake is an important aspect which needs to be explored. The committee is also aware of projects on which design professionals have specified temperature tendons between the bands in twoway post tensioned slabs. Originally post tensioned, twoway slab framing systems were constructed with column and middle strips, similar to those used in conventionally reinforced twoway slabs. Posttensioned twoway slab pennsylvania state university. Slab posttensioning coles myer, eastern creek, australia lion nathan brewery, auckland, new zealand mornington tank, victoria, australia.
Pti, posttensioning manual, 5th edition, post tensioning. Crsi design of slabonground foundations and posttensioned slabonground, mat or raft foundations on expansive soils shall be designed in accordance with pti dc 10. It is possible that designers who specify these arrangements of reinforcement in twoway post tensioned. Posttensioned concrete design spreadsheet program a pdh. Identifying problems with post tension concrete post tensioning is a technique for reinforcing concrete with steel cables, typically referred to as tendons. This is part one of a threepart course that covers the fundamentals of post tensioned concrete design for building structures using unbonded tendons. Brendon burley structural option post tensioned twoway slab load analysis when considering twoway slabs in a post tensioned system, it is important to perform an advanced analysis of the loads and their effects at different locations in the building. Shrinkage and temperature reinforcement in twoway post. Most modern browsers have builtin pdf readers if you have problems opening this file in your browser, check your browsers or computer systems settings. Structural calculations for posttensioned flat slab. Once the concrete has gained strength to 2000 psi, typically within the 3 to 10 days recommended by pti, the tendons are stressed. Jurgens his article presents a set of guidelines intended to t assist designers in routine post tensioning design, beginning with a discussion of the initial decisions that must be made to design post tensioned floor members.
One hundred twenty ft 37 m long posttensioned concrete truss. Guidelines for the design of post tensioned floors by bijan o. The program is divided into three separate screens, which correspond to the three major areas of concern in the design of a posttensioned member. When moment is drawn on the tension side, the diagram matches the general drape of the tendons. Posttensioning in buildings foreword working party wp1. Posttensioned concrete foundations designed by thi s standard generally meet. The main objective of the bulletin is to point out the benefits of using posttensioning for. This was achieved by using a post tensioned concrete slab with post tensioned upturn concrete beams. This was achieved by using a posttensioned concrete slab with posttensioned upturn concrete beams. In texas, post tensioned foundations are ribbed foundations that consist of a uniformthickness slab with stiffening ribs in both directions.
There was concrete all over the floor and in the hole was 1 strand of a post tension cable that had shot out of the slab and left a loop about 9 inches long. For the specified concrete material of 40 mpa cube strength, this translates to tensile stresses exceeding 5. When planning for point loads, a safe rule of thumb is to figure on 1,000 pounds per inch of slab thickness. A residential posttensioned concrete slab will typically be 8 inches thick and use 3000 psi concrete. This course is intended to be an introductory course for structural engineers new to post tensioned concrete design, and is a good refresher for experienced structural engineers. The tensile face indicates what portion of the beam requires reinforcing for strength. Posttensioned concrete foundations designed by thi s standard generally meet the requirements for plain concrete specified in chapter of aci 31814 14 1. Pdf the posttensioning method is now a days increasing widely, due to its application. Posttensioned transfer slab in vertically irregular building. Twoway posttensioned design amsysco post tensioning. Apart from shorter overall construction time and savings in material and labour cost, posttensioning allows more architectural freedom.
Since revisions or additions to the design file drawings may occur at any time, the receiver agrees to indemnify, defend and hold. Two way posttensioned slabs with bonded tendons pdf. Post tensioning tendons, which are highstrength steel cables inside plastic sheathing, are positioned in the forms before the concrete is placed. The general criteria used for the design, such as details of material. A definition should clarify which type of posttensioned residential and light commercial slabsonground is intended to be excluded from the aci 318 building code. Post tensioned transfer slab in vertically irregular building jang keun yoon, p. 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. Originally posttensioned, twoway slab framing systems were constructed with column and middle strips, similar to those used in conventionally reinforced twoway slabs.
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. Prestressed concrete is a form of concrete used in construction. When the cables are tensioned, the concrete is placed in compression. The program is divided into three separate screens, which correspond to the three major areas of concern in the design of a post tensioned member. Halling professor utah state university logan ut 84332 external project manager russ scovil utah department of transportation in cooperation with. Pt designer builds upon that by incorporating a userfriendly interface and attractive pdf outputs for a more efficient use of the program. Post tensioning tendon installation and grouting manual fhwa. What links here related changes upload file special pages permanent link page. The vsl posttensioned concrete slab on grade is cast in very large areas, often exceeding 2,500m 2 with no joints. This alternate interpretation is further supported by the analogy between oneway beam and slab. Guidelines for the design of posttensioned floors by bijan o. Posttensioned foundations can be used for these types of soils by using other rational design methods.
Structural calculations for posttensioned beam and oneway. This report presents the structural engineering calculations of a post tensioned floor using parallel beams and oneway slab construction. What are the drawings presented for a posttensioned slab. Signature document is posttensioning manual in its sixth edition. Posttensioned concrete in buildings posttensioning institute. Trove of technical documents produced through the technical committees. Unbonded post tensioning system technology in building. Unlike those of posttensioned concrete see below, the tendons of. However, no attempt has been made to ensure that there were no errors in the conversion process.
The design is based on hong kong building code hkcop 2004 and its amendment of june 2007. Tn462 temperature design 060116 adapt software help. In the succeeding years numerous posttensioned slabs were designed and constructed in. Once the slab cures, qualified personnel apply tension and grout the cables. Posttensioned concrete can be thinner and longer without risk to its strength or structural integrity, since the cables inside help stabilize it. Net is a windowsbased computer program for the design and analysis of linear post tensioned concrete frames. Fundamentals of posttensioned concrete design for buildings part one a suncam online continuing education course. In most of these areas, the soils are varying degrees of expansive clays. For economical design of similar structures a smaller slab thickness leading to values between 60% to 80% of balanced selfweight is generally selected. Maybe you have knowledge that, people have look numerous period for their favorite books in the same way as this pti post tensioning manual. 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.
Once the concrete is poured and sets, the cables are tensioned. Design floors and foundations reliably and efficiently, saving time and money, and overcoming the most common concerns you face as a designer. Finally, an example of a flat slab floor system is presented to illustrate the practice. 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.
The slab and ribs are considered to act monolithically. California building code cbc 2016 9also requires design of posttensioned slabonground, mat, or raft foundations on. If a primary punching shear failure occurs at a column due to overloading or some catastrophic event, the slab outside the critical shear. Warehouses, distribution centres, container terminals, airports, pavements, residential slabs and recreational slabs for tennis courts and skating rinks are common applications. Posttension basics how posttensioned slabs are built.
The punching and post punching failure of an isolated and simply supported slab column specimen is analytically evaluated. Crack free performance vsl post tensioning axially compresses the concrete slab to counteract tensile stresses which. Sloping wshaped columns cupped with a posttensioned restraint beam fig. Twoway posttensioned slabs with unbonded tendons offer further advantages in the prevention of local or progressive punching shear collapse. Pdf posttensioned concrete longspan slabs in projects of. These tendons run the full length of the slab between bands and are specified to be at the center of the slab with no vertical curved profile, as shown in fig. Posttension cables are steel wires inserted into plastic sheathing laid in place while pouring the concrete slab. Slab on grade the vsl post tensioning system is widely used in the construction of slabs on grade.
Started career in 1994 in posttensioning after doing doctoral research work. Receiver agrees that wsdot cannot be held responsible for problems arising from files which have been converted. It allows slabs and other structural members to be thinner. Guidelines for the design of posttensioned concrete floors. However, because the continuous twoway tendons had to be placed in a draped parabolic profile near the top of. Unbonded posttensioning system technology in building construction 123 fabrication of monostrand sheathing was supplied until the early to mid1990s. Concrete slab design software economically design posttensioned and reinforced concrete floors including slabs, mats, and rafts, with exceptional visibility into compliance, efficiency, and practicality. But i have to first modify the pdf files to delete the title blocks etc project the guilty. Technical notes in any specifications, contract documents, purchase orders, drawings or job details. Due to various restrictions on placing files in this manual onto the internet.
Draped harped profiles temporarily held in place before concrete is hardened debonding not all strands are active at end of span strategies for posttensioned systems. Forensic testing of post tensioned concrete girders. Post tension slab construction is common in areas with expansive soils. The default load combinations for posttensioning are defined in the following sections. The software is extremely easy to use and is intended for both occasional and regular designers of post tensioned concrete floor systems. This is part two of a threepart course that covers the fundamentals of post tensioned concrete for building structures using unbonded tendons. To maximize views for the premium units in the upper floors, more glazing and less concrete wall had to be incorporated into the design of the north back face of the tower at levels 30 through 38. Part three continues with the study of twoway, posttensioned slab systems, including. In post tensioned floor slab construction, the placement of postten. This report presents the structural engineering calculations of a posttensioned floor using parallel beams and oneway slab construction.
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. Fundamentals of posttensioned concrete design for buildings. It reduces or eliminates shrinkage crackingtherefore no joints, or fewer joints, are needed. This spreadsheet program provides for the design and analysis of post tensioned concrete oneway beam and slab systems and twoway flat plate slab systems. Ce 416 prestressed concrete sessional lab manual department of civil engineering ahsanullah university of science and. Prestressed concrete bridge beams typically use 15. A posttensioned slabonground foundation is simply a groundsupported concrete slab foundation that is reinforced with flexible cables that are tensioned after the concrete hardens.
The software is extremely easy to use and is intended for both occasional and regular designers of posttensioned concrete floor systems. In corrosive environments, stuffed and heatsealed tendons have the inherent shortcoming of either trapping or allowing access of corrosive substances in the oversized sheathing. This article provides information on how to scheme a pt slab and how the use of post tensioning affects the rest of the structure. Pti post tensioning manual 6th thank you enormously much for downloading pti post tensioning manual 6th edition. A psc is applied with a compressive stress on the cross section in advance before the application of loading on. Posttensioning, which is a form of prestressing, has several advantages over standard reinforcing steel rebars. In texas, posttensioned foundations are ribbed foundations that consist of a uniformthickness slab with stiffening ribs in both directions. Jurgens his article presents a set of guidelines intended to t assist designers in routine posttensioning design, beginning with a discussion of the initial decisions that must be made to. Many of these changes are made possible through the use of new.
What is the difference between normal slab and posttensioned. This tutorial deals with a simple 2span post tensioned concrete double tbeam bridge. Posttensioned concrete is a very common type of concrete structure for parking garages today and can be constructed below grade or above grade. We are sure that you will quickly notice the many changes that have been made to the layout and data. Fyi i was was not the eor on this project we just did the pt repairs consisting of destressing, degreasing, regreasing and restressing of several hundred. Forensic testing of post tensioned concrete girders final report july 2014 wing hong louis lo graduate student utah state university logan ut 84332 paul j. Eliminate joints joints in reinforced concrete slabs on.
Download free, highquality cad drawings, blocks and details of post tensioned concrete organized by masterformat. The tendons change their vertical location in the beam to follow the tensile moment diagram. 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. A 5inch posttensioned slab can handle up to 5,000 pounds, and a typical 9inchthick slab will bear a concentrated 9,000pound load. It is possible that designers who specify these arrangements of reinforcement in twoway posttensioned. For posttensioned concrete design, the user can specify the prestressing load pt by providing the tendon profile. States, posttensioned slabonground foundations are the most common type of residential foundations. States, post tensioned slab onground foundations are the most common type of residential foundations. Contractors sometimes need to drill or cut into a posttensioned slab for repair or renovation work. In certain applications, slabs in the order of 10,000m 2 have been constructed without movement joints. Posttensioned, reinforced concrete slab design software ram. Unbonded post tensioning system technology in building construction 123 fabrication of monostrand sheathing was supplied until the early to mid1990s.
A more detailed guide to the design of pt floors can be found in the concrete societys technical report 43 tr43. Joint aciasce committee 352 is therefore currently revising aci. The new bridge log book format and distribution we are pleased to announce the release of the 2002 inventory of bridges, state highway system of indiana. Pt designer design of posttensioned concrete floors. Pt designer is extremely easy to use and is intended for both occasional and regular designers of posttensioned concrete floor systems. These foundations will typically contain less reinforcement prestressed and. Given the widespread use of pt flat plate systems in the u. If your location is an area with expansive soils, always assume the slab is post tensioned. This tension makes the concrete slab and foundation much stronger than concrete without reinforcement and helps reduce cracking. Double tbeam post tensioned concrete bridge sofistik.
To maximize views for the premium units in the upper floors, more glazing and less concrete wall had to be incorporated into the design of the north back face of the tower at. Download free, highquality cad drawings, blocks and details of posttensioned concrete organized by masterformat. Tn342 design example 2way mondada 093090 adapt corporation. This spreadsheet program provides for the design and analysis of posttensioned concrete oneway beam and slab systems and twoway flat plate slab systems. Residential and light commercial posttensioned concrete shallow foundations on expansive soils are ribbed or uniformthickness posttensioned foundations built on expansive soils. Net is a windowsbased computer program for the design and analysis of linear posttensioned concrete frames. A 5inch post tensioned slab can handle up to 5,000 pounds, and a typical 9inchthick slab will bear a concentrated 9,000pound load.
Advantages and disadvantages of each of these slab designs are provided. Hazards of post tensioned concrete slabs safety toolbox. I arrived within minutes and was led to a corner unit on the 2nd floor. This technical note presents the layout and profile of posttensioning. Now optimum efficiency is obtained because the posttensioned reinforcing is located in the tension zones, the concrete is being compressed, and the posttensioned reinforcing is creating an uplift force in the middle of the spans where it is needed the most. A normal slab is basically a rcc reinforce cement concrete slab where as a post tentioned slab is the psc prestressed concret slab. The vsl post tensioned concrete slab on grade is cast in very large areas, often exceeding 2,500m 2 with no joints. Project specific documents should specify when and where. The analytical model of the bridge consists of beam elements and a slab to connect the two tbeams. Fundamentals of posttensioned concrete design for buildings part one. Framing dead load selfweight superrimposed dead load 25 psf partitions, me, misc.
Posttensioning institutes design of posttensioned slabsonground, pti design procedure 3rd edition. Progressive collapse resistance of reinforced and post. To provide a complete idea, the stress computation, the reinforcement. Once inside i observed a hole in the ceiling about 5 inches in diameter and 1 inch deep. Pdf nowadays, design of modern an architectural building structures requires the use of slender and free from numerous supports slabs. Although some posttensioned slab structures had been constructed in europe quite early on, the real development took place in the usa and australia.
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