Hazards of Post-Tensioned Slabs: Post tension slab construction is common in areas wi expansive soils. If your location is an area wi expansive soils, always assume e slab is post tensioned. Once e concrete is poured and sets, e cables are tensioned. Once tensioned, e cables cannot be de-tensioned. e hazard exists when workers cut into e slab and rupture e tensioned cable.2.4/5(17). Signs and barriers must be erected to limit worker access to e post-tensioning area during tensioning operations. o Concrete Buckets: Under no condition employees ride concrete buckets. o Working Under Loads: Never work under concrete buckets while e buckets are traveling, being elevated or lowered into position. Elevated concrete buckets must be routed so at no employee is exposed to . Post-tensioning tendons, which are prestressing steel cables inside plastic ducts or sleeves, are positioned in e forms before e concrete is placed. Afterds, once e concrete has gained streng but before e service loads are applied, e cables are pulled tight, or tensioned, and anchored against e outer edges of e concrete. Post-Tensioning Terminology (PTT) ember Page 2 of 33 Bearing plate, basic Flat steel plate at transfers e tendon force directly into e concrete, meeting e analytical design requirements of PTI Acceptance Standards for Post-Tensioning Systems, Section 3.1. A 2 2Area 2 A' c 2 2 Post-Tensioned Concrete Design Table 1-1 List of Symbols Used in e ACI 318-08 Code cp Area enclosed by e outside perimeter of e 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 e shear flow pa, sq-in A oh Area enclosed by e centerline of e outermost closed. A residential post-tensioned concrete slab will typically be 8 inches ick and use 3000 psi concrete. Once e concrete has gained streng to 2000 psi, typically wi in e 3 to days recommended by PTI, e tendons are stressed. 20, · After ades of building and inspecting in e Post-Tensioning (PT) concrete construction industry, we’ve seen e best and e worst of PT construction. And we keep a (long and growing) list of e mistakes we’ve encountered along e way. Knowing e ways and e extent to which problems can occur helps us implement e most cost. Concrete is one of e most widely used construction materials in e world. Safety issues exist in all phases of concrete production, including e manufacture of portland cement and pre-cast concrete products, as well as during e use of concrete in construction. a) e nature of e hazards associated wi reinforcing steel and post-tensioning activities.. b) e proper procedures and equipment to perform reinforcing steel and post-tensioning activities. c) Employees involved in reinforcing bar and post-tensioning operations shall be certified by a qualified evaluator (ird-party). Post-Tensioning in Prestressed Concrete e alternative to pre-tensioning is post-tensioning. In a post-tensioned beam, e tendons are stressed and each end is anchored to e concrete section after e concrete has been cast and has attained sufficient streng to safely wi stand e prestressing force as shown in fig.2. 01, 2006 · ACI Concrete Terminology. Post-tensioning is a me od of reinforcing (streng ening) concrete or o er materials wi high-streng steel strands or bars, typically referred to as tendons. e materials used to post-tension concrete members are ultra-high-streng steel strands and bars. Horizontal applications (such as beams, slabs, bridges, and . Pre-tensioning: In pre-tensioning, e tendons are first stressed to a given level and en e concrete is cast around em. e tendons be composed of wires, bars or strands. Post-Tensioning: In post-tensioning, e concrete member is first cast wi one or more post-tensioning ducts or tubes for future insertion of tendons. Once e. Apr 26, · Post-tensioning is a form of prestressed concrete in which high-streng steel strands are cast into a concrete slab or beam and tensioned to a high degree of stress following curing. e tensioned strands are anchored at ei er end, resulting in compression of e concrete . Do not dislocate rebar, post-tensioning cables or o er reinforcement while placing concrete. Special precautions be necessary if concrete is being placed wi a bucket due to e surge at e discharge point, or if hoses are being dragged across e k. On ust 12, 1999, Employee 1 was operating an Owatonna post-tensioning device, model B, serial 333487D, at 5,600 psi on a concrete slab. He was releasing e pressure on e 1/2. cable at ran rough e concrete slab when e concrete fractured and e post-tensioning device lost its . Portable hydraulic devices at pull e tendons associated wi post-tensioning concrete to create a permanent tension load. Tendon. A metal element, usually of steel such as wire, stranded components (such as wires), bars or rods used in pre-stressing or post-tensioning concrete. Safety Executive. is Code will be updated online. Stressing of prestressed concrete is acknowledged to be a potentially high-risk activity, as it involves e use of industrial prestressing equipment at uses hydraulic rams to stretch high-yield wires and strands wi forces at can be in excess of 1500 tonnes. Post-tensioning Operations. A me od of stressing reinforced concrete in which tendons running rough e concrete are tensioned after e concrete has hardened. Qualified Person, Attendant or Operator. A person designated by e employer who by reason of training, experience or instruction has demonstrated e ability to safely perform all assigned. GTI is e industry leader in manufacturing components and equipment used in concrete post-tensioning operations and rebar support. Wi a focus on in ation and quality, GTI continues to accelerate e industry to new levels of performance, efficiency and safety rough rigorous R&D and advances in automation. Safety Considerations. Condominium, townhouse and highrise construction often incorporate post-tensioned concrete. is creates serious considerations when it comes to owner remodel projects and general maintenance issues. Careless drilling rough a concrete slab could result in injuries as well serious degradation of structural streng of. Similarly, e use of post-tensioned concrete can create a starting point for efficient construction, resulting in significant monetary and time savings roughout e entire design and construction process. e PTI's sustainability committee was formed by consensus at e 2009 PTI Technical Advisory Board meeting. Post-tensioning is done at a project site and requires little to no modifications of e same forming system at would be used to construct non-prestressed concrete. e systems used to post-tension concrete and masonry consist of prestressing steel at is housed inside a duct or shea, which allows. 30 Post-tensioning Operations is a me od of stressing reinforced concrete in which tendons 31 running rough e concrete are tensioned after e concrete has hardened. 32 Precast concrete is concrete members (such as walls, panels, slabs, columns, and beams) which 33 have been formed, cast, and cured prior to final placement in a structure. As a leading post-tensioning supplier, we are dedicated to provide value wi our products and engineering services at competitive prices. AMSYSCO’s goal is to be your post-tension partner on your concrete construction project. Our manufacturing plant is PTI-Certified to satisfy specifications by structural engineers and architects. Prestressing is e introduction of a compressive force to e concrete to counteract e stresses at will result from an applied load. ere are two me ods of introducing prestressing to a concrete, namely pre tensioning and post tensioning.. Pre tensioning happens before e casting of e concrete. is is done by placing of high tensile steel tendons in a desired profile in which e. Post-tensioned flat slab. Post-tensioning is a me od of prestressing at offers e innest slab type, as concrete is worked to its streng s, mostly being kept in compression. Longer spans can be achieved due to prestress, which can be used to control deflections. Fur er information on post-tensioning can be found in e publication Post. STRUCTURAL provides industry leadership in e areas of quality, safety, and in ation. ese standards, along wi years of experience, a skilled trades training program, and an industry-leading safety program, instill confidence in clients looking for quality long-term solutions for eir concrete infrastructure problems. 29, · Image via Checkers Safety. Rebar or mesh-enforced concrete is good for ings like parking lot blocks and roads, but it still fails before it ought. post-tensioning is done after e. Section 50 Prestressing Concrete 4-5001 General. Section 50, Prestressing Concrete, of e Standard Specifications includes specifications for prestressing precast or cast-in-place concrete by tensioning prestressing steel. For detailed information regarding prestressed concrete, refer to Section 160, Prestressed Concrete, of Structure Construction’s Bridge Construction Records. Safety 24/7 is an integral part of a STRUCTURAL employee’s personal commitment to his or her own safety, as well as to e safety of friends, family, and co-workers. is commitment creates a culture of safety on our jobsites, in our manufacturing facilities, offices, and in our private lives. Frontline Safety puts into action e principles of Safety 24/7. Understanding of e most common post-tension - ing systems and components such as types of pre-s t ressing steel, anchora g e s, shea ing and corro s i o n p r otection, stressing equipment, and proper term i - n o l o g y. 2. Kn o wledge of e post-tensioning design p ro c e s s and basic pri n c i p l e s. While e front-line inspector. For e repair and modification of post tensioning (PT) systems as well as post-tensioned concrete structure repair and protection, STRUCTURAL TECHNOLOGIES offers highly specialized products and services including investigation, repair design support, repair and replacement components, corrosion protection products, streng ening solutions as well as new or replacement post-tensioning systems. STRUCTURAL TECHNOLOGIES is e exclusive manufacturer of VSL post-tensioning and construction systems in e United States. VSL systems have a well-earned reputation for eir quality, reliability, and durability – and have been used roughout e world since 1956 to build, repair, and streng en buildings, tanks, bridges, and special structures. e Department of Labor and Industries conducted rulemaking to update e requirements for reinforcing steel and post-tensioning activities contained in Chapter 296-155 WAC Standards for Construction Work, Part O, Concrete, Concrete forms, Shoring, and Masonry Construction. Grouting of e post-tensioned cables in e post or prestressed concrete is carried out to provide permanent protection to e steel cables against corrosion. It also develops a bond between cables and surrounding concrete which fills e duct space and prevents water collection and freezing. In is article we discuss, materials, equipment, properties, and procedure [ ]. SRG CIVIL PTY LTD CONSTRUCTION SAFETY STUDY REPORT Page 4 of 86 EXECUTIVE SUM Y Description of Proposal e proposal is Keepit Dam Upgrade Works Stage 2, Package 2 and includes streng ening e concrete gravity sections and spillway piers via post tensioning works to be referred to as Stage 2, Package 2 - Post Tensioning Works. Williams’ Post-Tensioning System. Williams PreStressing / Post Tensioning Systems consist of high tensile steel bars available in seven diameters from 1 (26 mm) to 3 (75 mm) wi guaranteed tensile streng s to 27 kips (4568 kN). ey are provided wi cold-rolled reads over all or a . e post-tensioning me od is e best way to create stronger, more reliable concrete slabs. is me od is a better way to construct a slab foundation to be more resistant to cracking and deflection. is stronger, inner slab also saves money on concrete. To create a slab using is me od, plastic sleeve-covered steel cables are laid in a grid running in bo directions. en concrete. GN05 – Monostrand Post-Tensioning of Concrete Buildings Stressing should only be carried out by experienced personnel who have been assessed as competent to operate stressing equipment and have acquired knowledge of all safety requirements necessary during e stressing operation. 19, · Poured concrete for e deviator blocks, which will keep e post-tensioning strands from touching e bottom of e girder as ey travel between anchor locations. poured concrete for e last grout pads to cement e post-tensioning brackets to e interior girder floor. received post-tensioning tendons. and installed mounting harde on e. Monostrand Post-Tensioning System e streng, serviceability and design flexibility of concrete are greatly enhanced by e DYWIDAG Monostrand Post-Tensioning System. DYWIDAG Monostrands are made up of cold-drawn, low-relaxation, seven wire strands of 0.5 (12.7 mm) or 0.6 (15.2 mm) diameter, conforming to ASTM A 416. Review of Moment Distribution. 18.17—Post-tensioning ducts. 18.18—Grout for bonded tendons. 18.19—Protection for prestressing steel. 18.20—Application and measurement of prestressing force. 18.21—Post-tensioning anchorages and couplers. 18.22—External post-tensioning. CHAPTER 19—SHELLS. 19.1—Scope and definitions. 19.2—General. 19.3—Design streng of. e Post-Tensioning Institute is recognized as e worldwide au ority on post-tensioning. We are dedicated to expanding post-tensioning (PT) applications rough keting, education, research, teamwork, and code development while advancing e quality, safety, efficiency, profitability, and use of post-tensioning systems. Monostrand Post-Tensioning System Stressing Data Strand Capacity 0.5 in 12.7 mm 0.6 in 15.2 mm Jacking Force (tons short) 20 tons 20 tons 30 tons 30 t.