For economical design of similar structures a smaller slab thickness leading to values between 60% to 80% of balanced selfweight is generally selected. Design floors and foundations reliably and efficiently, saving time and money, and overcoming the most common concerns you face as a designer. Keep current and future building owners and tenants from damaging post tension slabs along with the structural integrity of your work. Before a posttension slab is poured, highstrength steel strands or cables, called tendons, are laid in a tight grid. Posttensioned concrete in buildings posttensioning institute. Posttensioned pt concrete floors are now widely used in the uk, particularly for highrise buildings. Post tension slabs reduce settling issues this giant checker board is actually the guts of an unbonded post tension slab. Posttensioned pt slabs are typically flat slabs, band beam and slabs or ribbed slabs. Basic steps of analysis and design of building structures including load. A residential posttensioned concrete slab will typically be 8 inches thick and use 3000 psi concrete. Through these examples, it is shown the design methodology.
What is the difference between normal slab and post. First model a flat slab for the entire area, then model the drop panels as separate slabs from the bottom of the flat slab. Concrete slab design software economically design posttensioned and reinforced concrete floors including slabs, mats, and rafts, with exceptional visibility into compliance, efficiency, and practicality. Posttensioned concrete slabs augi the worlds largest. Analyzing the case of a simply supported on the contour slab, the layout design and the stresses that are considered are presented in fig 4. Salunke mgms college of engineering and technology, kamothe, india mgms college of engineering and technology, kamothe, india abstract the use of posttensioned flat slab is increasing day by day, due to its advantages over traditional concrete. Unlike the standards for the conventional reinforced concrete haunched slabs, posttensioned concrete slab design cannot be extended to multispan application in a. A normal slab is basically a rcc reinforce cement concrete slab where as a post tentioned slab is the psc prestressed concret slab. Soil design parameters edge moisture variation distance. Recommendations for advancing the fire safe design of posttensioned. This article provides information on how to scheme a pt slab and how the use of posttensioning affects the rest of the structure. Fundamentals of posttensioned concrete design for buildings part one a suncam online continuing education course. Usually a sign in the garage or stamp in the slab will indicate if your home has a post tension slab. A properly designed post tension slab can design around expansive soils, high water tables, etc.
To get the excel sheet join as loving fansub member to this channel. Although some posttensioned slab structures had been constructed in europe quite early on, the real development took place in the usa and australia. This lab manual was prepared with the help of the renowned text book design of prestressed concrete structures, 3rd edition by t. Ccl carries out complete designs for posttensioned concrete applications. A 5inch posttensioned slab can handle up to 5,000 pounds, and a typical 9inchthick slab will bear a concentrated 9,000pound load. As a separate issue, the posttensioning technique has an inherent weakness. The wooden sides of pt beam or pt slab are marked and drilled by ptsi at specific places.
Posttensioned concrete design spreadsheet program a pdh. There is an excellent tool on their web site for selecting the right pt system. The analysis and design of posttensioned, twoway slabs incorporate the full tributary slab width without the distribution of forces and reinforcement between column strips and middle strips, synonymous with mild reinforced two. The following table of prestress losses is recommended for the design of posttensioned members, and does not include friction or wedge set losses. The main objective of the bulletin is to point out the benefits of using posttensioning for. Tendons today are seven highstrength steel wires wound together and placed inside a plastic duct.
Design method may not be used for twoway, posttensioned slab systems. The need for improved safety under overpass structures by minimizing the number of piers and maximizing horizontal clearance in comparison to rcsh. A combination of these values will determine the slab stresses at the time of stressing and at service loads. The book builds on over three decades of authors observation and design of posttensioning projects in more than 35 countries worldwide. In addition, both the international building codeand the uniform building codeprovide design methods for determining the capacity of a posttensioned slab to. General criteria for the design of posttensioned elements ref aci 318m11, is 43. Inspire a love of reading with prime book box for kids discover delightful childrens books with prime book box, a subscription that delivers new books every 1. The current standards for posttensioned concrete haunched slabs are limited to three 3 continuous span arrangement. A posttension slab is a slab of concrete that has been prestressed using a specific method to increase the strength of the concrete. This book is destined to become the definitive work on the design of post tensioned concrete buildings for many decades to come. Fundamentals of posttensioned concrete design for buildings.
Posttensioning is intended to eliminate the use of steel rebars. This book is destined to become the definitive work on the design of posttensioned concrete buildings for. However, should this happen, it can be repaired and even if not repaired, the slab may still function well. For general design philosophy and analysis of posttensioned concrete, the reader should refer to pdhonline course s127. Course attendees will receive comprehensive course notes and reference material including detailed design examples, as well as a copy of the must have book on posttensioned buildings, design and construction by dr bijan aalami, valued at 120 euros. This book answers the need for a comprehensive treatment of posttensioned floor design.
Csi etabs 2016flat slab design, strip design and punching shear check duration. Posttensioning concrete increases the many benefits associated with a concrete framed building. 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, jointfree, crackfree. Suncoast posttension is the largest manufacturer of pt strandtheir web site has lots of good information vsl was purchased a few years ago by structural group. There is a danger that if a nonprofessional cuts or drills into the slab, that they may sever, cut or damage the post tension cable. Its more user friendly compared to other pt design softwares. This may weaken the structural strength of the slab. Posttensioned, reinforced concrete slab design software ram. Anchorage assembly is fixed at the wooden side by ptsi. Experience and expertise gained from working on projects.
Several methods exist for prestressing concrete, with posttensioning being a very common one. The intended audiences for the use of this document are members of ptis slabonground committee as well as engineers and others involved in the design of foundations for residential and other lowrise structures. Institute pti design procedure for designing posttensioned slabsonground. The medical office building malvern, pa 17 brendon burley structural option posttensioned twoway slab figure 23 details of the twoway slab.
Structural fire performance of contemporary posttensioned. Best posttensioned pt concrete design books youtube. Posttensioned concrete haunched slab bridge standards. Analysis of posttensioned flat slab by using safe shriraj s. It is substantially prestressed during production, in a manner that strengthens it against tensile forces which will exist when in service 35 this compression is produced by the tensioning of highstrength tendons located within or adjacent to the concrete and is done to improve the performance of the concrete in service. And from what ive seen the cost of conventional vs post tension is about a wash.
Post tension slabs are used to create a monolithic slab that is stronger than the typical slab and foundation that is poured in stages. Because this course is intended to illustrate simplified analysis methods, we will use the efm exclusively. This course is intended to be an introductory course for structural engineers new to posttensioned concrete design, and is a good refresher for experienced structural engineers. Post tension slabs are used in many parts of the country continue reading why post tension slabs are used in phoenix. Post tension slabs answers to questions buyers ask. Posttensioned done properly can be better, but it is never done properly, at least for residential structures. Fundamentals of posttensioned concrete design for buildings part one. Posttensioned concrete haunched slab bridge users manual kdot bridge section page 4 ver 2.
In addition to slabs with steel rebar reinforcement, posttensioned slabs are intended by design to be minimally functional. A more detailed guide to the design of pt floors can be found in the concrete societys technical report 43 tr43. Part three continues with the study of twoway, posttensioned slab systems, including. What is the best software to design a post tension slab. Pdf new methods in efficient posttensioned slab design using. Course content this spreadsheet program provides for the design and analysis of posttensioned concrete oneway beam and slab systems and twoway flat plate slab systems.
A study on a twoway posttensioned concrete waffle slab. Posttension basics how posttensioned slabs are built. Objectives the objective of the present report is to summarize the experience available today in the field of posttensioning in building construction and in particular to discuss the design and construction of post tensioned slab structures, especially post tensioned flat slabs a detailed explanation will be given of the checks to be carried. This book is destined to become the definitive work on the design of posttensioned concrete buildings for many decades to come. Interior left, exterior right deflection analysis the final consideration in the design of the twoway slabs is deflection. Longer spans can be achieved due to prestress, which can also be used to counteract deflections. Fundamentals of post tensioned design for buildings. Design fundamentals of posttensioned concrete slabs. Once the concrete has gained strength to 2000 psi, typically within the 3 to 10 days recommended by pti, the tendons are stressed.
Posttensioning in buildings foreword working party wp1. A psc is applied with a compressive stress on the cross section in advance before the application of loading on. Post tensioning design and construction administration. For most large pt slabs, we also have to model the drop panels at the column supports. Banded tendons when designing twoway, posttensioned slab systems, in addition to the code. The waffle slab presented in this paper has been reinforced with tbp 9 posttensioned tendons, vertically placed inside the slabs ribs with a parabolic layout.
This is part one of a threepart course that covers the fundamentals of posttensioned concrete for building structures using unbonded tendons. Post tension cable warning markers recommended for posttension concrete contractors. Actual losses, whether greater or smaller than computed values, have little effect on the design strength of the member but do affect service load conditions i. Why post tension slabs are used in phoenix, gilbert, and. Started a long career as a specialist in post tensioned concrete design and. This course is intended to be an introductory course for structural engineers new to post. Written by structural engineers who design posttensioned concrete buildings for a living and teach how to design them at the university level, there has simply never been anything like this book. This is part three of a threepart course that covers the fundamentals of posttensioned concrete for building structures using unbonded tendons. Calculation and the theory by which the software works are attached with this softwares index, this thing is not seen. Rapt is a two dimensional post tension beamslab design software. Design of posttensioned slabs posttensioning institute. Book on posttensioned building design and construction by dr. Prestressed concrete is a form of concrete used in construction.