Reduced structural depth enhances both the appearance and economy of post-tensioned concrete parking structures. This paper discusses the former type and presents a brief survey the state-of-the-art of the design and construction of double-tee precast-prestressed and post-tensioned concrete parking structures … The structure is made of precast concrete columns and tee beams. During the spring of 2007, external PT was used to strengthen two damaged PT beams at a government facility parking structure in the Washington D.C. area. SDI is a nationally recognized leader in the repair and alteration of post-tensioned concrete structures. Post-Tensioning for Bell Parking Garage: Cover Story. he use of unbonded post-tensioned (PT) reinforcement in concrete parking ramp structures has been popular for many decades. Post-Tensioned concrete parking structures have lower life-cycle costs compared to alternative system due to the lack of maintenance on joint repair. We start the design process for every project at the same point – the beginning. Construction from the 1970s tends to be particularly “light,” with design engineers saving every foot of rebar and pound of concrete possible, making for underbuilt structures by today’s standards. Post-tensioning allows almost any shape of structure to be constructed while reducing environmental impacts, construction time, materials and costs." Park Plaza Post‐Tensioned Parking Structure Demolition Presenter: Michael Lussier, Structural Technologies ‐VSL Invalid Email Address. 9. Post-Tensioned Corrosion Mitigation & Concrete Repair. Car Parks; Structural Repair Solutions; Why we are different. Here’s how both processes are combined: In wall panels , vertical post-tensioning strands pass from the top of the wall to the base of the structure through plastic sleeves cast into the panel. The scope of the project included providing extensive general concrete repair and maintenance and post-tensioned repair. Post-tensioning now is used extensively in bridges, elevated slabs (parking structures and residential or commercial buildings), residential foundations, walls, and columns. I have obtained a few publications from PTI about the topic but my main question doesn't seem to be answered in them. PT precompression and load balancing permits thinner slabs and improves durability by reducing slab cracking. Understanding the causes of some of these problems should help contractors build better post-tensioned structures. The steel-framed parking structure provides the opportunity to use any of the three concrete deck systems, a major advantage in choosing structural steel for a parking structure. Repair Broken Post-Tensioned Strands. The structure has (3) isolated stair/elevator cores constructed steel with composite deck framing. These tendons, with a typical strength of 270 ksi (1860 MPa), are also greased and sheathed. There is no functional compromise, which can be the case with other framing systems. Final delivery was by truck. Because of the restricted site, the concrete was pumped into place. The Post Tensioning Institute is even developing a barrier cable specification, which is available since 1996. This project consists of (5) levels of above grade and (1) level below grade parking structure. Post-Tension Parking Garage Repair. Built in 1964, the Baltimore Garage is a 270,000 SF split level button head post-tensioned garage located in Detroit’s New Center neighborhood. The garage is a six-story, freestanding, post-tensioned structure with approximately 500,000 square feet of parking area. Post-tensioned concrete provides a structurally efficient, reliable, and cost-efficient solution for the construction of concrete parking garages. – Anonymous. Provide Post-Tensioning Consulting . Finally, the cast in place post-tensioned decks were poured between beams. Post-tensioning is the system of choice for parking structures since it allows a high degree of flexibility in the column layout, span lengths and ramp configurations. Unbonded post-tensioning (commonly used in the construction of buildings and parking structures) remains separated from the surrounding concrete except where the load is transferred at the anchors. Post-tensioned slabs (PT slabs) (2) Specific design consideration regarding to PT structures Sketches from PT-structures.com The slab has to be able to shorten freely at jacking (elastic shortening due to the compressive forces) When unfavorable cases occurs, specific execution details can be adopted to maximize the compression force in the slab. Post-Tension Parking Garage Repairs. OUR SERVICES. Post-Tension Parking Garage Repair. The aging structure showed significant signs of structural degradation as well as the need for architectural improvements. Jim Rogers Bending and flexing creates high tensile forces … Post-tensioning cable ends extending from freshly poured concrete 5. epairing a distressed 35-year-old, post-tensioned parking structure is a challenging proposition. To further complicate construction, beams extend diagonally from the core to the extreme corners of the ramps. I am designing a Post-Tensioned concrete parking structure (flat plate) with ramps between levels. Post-tensioned parking garages can be either stand-alone structures or one or more floors in … In areas Post-tensioned concrete has been used in building construction since the late 1950’s. This would allow expansion of a terminal building that was landlocked by runway offsets and roadways. This results in lower maintenance costs over the life of the structure. Bringing the six-story, 500,000 square foot post-tensioned structure back into full operation with a cost-efficient, sound repair with minimal down-time was critical to the Owner. Post-tensioning is a method of reinforcing (strengthening) concrete or other materials with high-strength steel strands or bars, typically referred to as tendons. Post-Tension Parking Garage Repairs. The lateral system is concrete shear walls. Today, post-tensioned and precast concrete systems dominate the market. "Parking Structure with a Post-tensioned Deck," Engineering Journal, American Institute of Steel Construction, Vol. Repair Post-Tensioned Bridges. Post-tensioned (PT) concrete construction is popular for parking deck floor slabs. The assignment was to build a parking facility on a tight construction site in downtown Evanston, Illinois. 8. 4. This project encompassed a 5-year ... engineering and solution implementation for the parking structure. Fewer Materials. Pe). Post-Tensioned Garage Repairs J ust north of the provincial capital of Toronto is the growing city of Markham, Ontario. Keep in mind, every situation/structure is different. Invalid Email Address There was no room around the site for a crane and the volume of work was too small for conveyors. DYWIDAG Post-Tensioning Systems are known around the world for their superior load-carrying performance, durability and simple design. The steel parking structures and hybrid structures with concrete floors and steel framing are also used. Post-tensioned (PT) concrete deteriorates due to corrosion of post-tensioning strands. Post Tensioning Repair Robinson Parking Garage. Hydraulic Jack are used to pull the Cables 14. 25, pp. Today post-tensioning is becoming increasingly popular for many different use categories including parking structures, high-rise office and residential, hospitality, and podium slabs for mixed-use projects. The 18-story buildings undergr’ ound, two-level, parking garage structure was in need of repair to restore its structural integrity, protect the The superstructure consists of post-tensioned slabs with concrete columns. Post Tensioning Repair Robinson Parking Garage. Post-tensioned parking garages can be either stand-alone structures or one or more floors in an office or residential building. The post-tensioned structure was completed in association with Perkins + Will (Design Architect), WMA (Engineers), V3 (Civil Engineer), and Power Construction (General Contractor). A 40-year durable structure with minimal maintenance was required by the Owner. Prestressed and post-tensioned concrete are often used together in the construction of wall panels and parking decks. The project involved amputating a significant portion of an existing post-tensioned airport parking structure to allow the airport owner to move a roadway closer to the parking structure. This system is the most economical because of its high strength to weight ratio. The stair/elevator cores utilize … Over the life cycle of the building, precast is often the more expensive approach. The foundation used poured in place caissons to hardpan. We’ve budgeted $70,000 for those tendon repairs if the topping work can’t be done in 2021. With over 20 years of experience as a post-tensioning system supplier and installation contractor, SDI has both the technical proficiency and practical know-how to perform any repair or retrofit operation. Post-Tensioned Concrete Structure Evaluation By Michael Tabassi P ost-tensioned concrete structures often reveal very little about their lifetime condition until failure of the post-tensioning becomes evident. I personally witnessed the de-stressing of upwards of a thousand tendons. Deterioration of existing surface parking, plus … Post-tensioning is the system of choice for parking structures since it allows a high degree of flexibility in the column layout, span lengths and ramp configurations. Parking Structures:Recommended Practice For Design and Construction 1-1 Parking structures have become important elements in today’s urban and suburban environments. The parking structure of a government office building in Washington, D.C. suffered failure of two post-tensioned beams as a result of overloading. Post-tensioned concrete construction is a little different than standard reinforced concrete construction. Unbonded post-tension (P/T) rein-forcing systems add a level of complexity to any repair program, especially when encountering an early vintage P/T system that is generally incom-patible with current post-tension system hardware and technology. 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The steel-framed parking structure provides the opportunity to use any of the three concrete deck systems, a major advantage in choosing structural steel for a parking structure. Parking Garages Structures. Understanding the technical challenges of repairing post-tensioned cables and the safety issues relating to the structure, the patrons, and the workers when highly tensioned cables are repaired, the owner selected STRUCTURAL to perform the work. Post-tensioned concrete is lightweight, durable, and structurally efficient, making it an ideal product for residential buildings, commercial structures, multifamily construction, parking garages, bridges, and more. A typical A review is made of significant features of the design, construction, and maintenance as they relate to the deterioration. The current trend toward structural steel parking structures with a pre-stress deck evokes many design questions. Corrosion can occur in grouted and ungrouted post-tension structures leaading to post-tension cable repair, in the presence of moisture and air in voids along the cable tendon. Rebar reinforcement in this case is technically allowed by code but in our experience, a properly designed post-tensioned concrete slab will minimize cracking due to shrinkage. parking structure is a cast-in-place post-tensioned slab and girder system. Precast concrete columns and tee beams were shipped by rail from Nebraska to a storage yard 3 miles from the construction site. Adding post-tensioned reinforcing combines the action of reinforcing the tension zones with the advantages of compressing the concrete or masonry structure. GOALS • Review the following: – Detensioning Operations – Project Planning – Engineering Details – Project Execution. Park Plaza Post‐Tensioned Parking Structure Demolition Presenter: Michael Lussier, Structural Technologies ‐VSL. Cast-in-place, post-tensioned concrete construction provides long, column-free spans and is easily adaptable to the framing and functional requirements of parking structures. Post tensioned structures are a growing solution to meet this need. STRUCTURAL also had access to VSL® post-tensioning products and engineering support through STRUCTURAL TECHNOLOGIES. Before discussing By eliminating closely spaced joints found in other construction methods, properly designed post-tensioned parking structures are virtually crack-free, maintenance free and offer great aesthetic freedom and flexibility for today's architectural designs. This unbonded system is the focus of this article. I personally witnessed the de-stressing of upwards of a thousand tendons. The reinforced concrete, post-tensioned garage is, to the contractor's knowledge, unique in that it is a double helix design with a crossover core in the center. REINFORCED AND POST-TENSIONED CONCRETE FLAT PLATE STRUCTURES A Dissertation Presented By LEILA KEYVANI To The Department of Civil and Environmental Engineering In partial fulfillment of the requirements For the degree of Doctor of Philosophy In the field of Structural Engineering Northeastern University Boston, Massachusetts January, 2015 . 119-125. in-place, post-tensioned parking structure, opened in 1975 and demolished in 1994 because of severe deterioration. The more movement a structure experiences, the more likely cracking and connection distress will occur. Level 1 & 2 Unbonded PT Installer & Inspector, Level 1 & 2 Multistrand & Grouted PT Specialist, Level 1 & 2 Multistrand & Grouted PT Inspector, Copyright 2021 by Post-Tensioning Institute, Level 1 & 2 Unbonded PT Ironworker (Accelerated), PTI DC20.7-01: Design, Construction and Maintenance of Cast-in-Place Post-Tensioned Concrete Parking Structures, PTI C30.1-03: Level 1 Unbonded PT Field Installation, PTI DC20.8-04: Design of Post-Tensioned Slabs Using Unbonded Tendons, PTI M10.4-07: Specification for Seven-Wire Prestressed Steel Strand for Barrier Cable Applications. As you are aware, there are many arguments for each case, it depends on your priorities. Cast-in-place post-tensioned floor slabs utilizing steel cables to compress the slab after curing by placing the cables or tendons in tension. Bringing the six-story, 500,000 square foot post-tensioned structure back into full operation with a cost-efficient, sound repair with minimal down-time was critical to the Owner. Repair Strategy. It’s the best way to understand the unique needs of the final … Among many condominiums built in the mid-1980s is 275 Bamburgh Circle. The number and timing of broken strands So, starting the work in 2021 will save us at least 2.5% on the total costs. The use of PT reinforcement in these structures greatly reduces the amount of cracking and possible leakage to the structure and also allows economical long-term construction. Additional benefits are obtained when the post-tensioned reinforcing is installed in a draped profile instead of running in a straight line. into a Post-Tensioned Parking Structure By David A. VanOcker, PE R epairing a distressed 35-year-old, post-tensioned parking structure is a challenging proposition. Post-tensioning is the system of choice for parking structures since it allows a high degree of flexibility in the column lay-out, span lengths and ramp configurations. Temperature tendons were placed at 4 foot intervals in the opposite direction to minimize shrinking. Keep in mind, every situation/structure is different. In some cases, depth reduction is an essential factor in meeting code height restrictions. Repair Parking Structure Barrier Cables. The foundations consist of spread footings. We recommend using PT for temperature and shrinkage reinforcement. The new parking structure expansion was designed and constructed as a cast-in-place and post-tensioned concrete structure at the East end of the existing parking structure. PTI has an active presence on social media and regularly updates its followers on everything new at PTI via the following platforms: PTI is recognized as the world-wide authority on post-tensioning and is dedicated to expanding post-tensioning applications through marketing, education, research, teamwork, and code development. The parking structure of a government office building in Washington, D.C. suffered failure of two post-tensioned beams as a result of overloading. 8. While upfront costs for a post-tensioned parking structure can be higher than for precast, maintenance and repair costs are considerably lower. An unbonded post-tensioned system includes several key components (Figure 2): POST-TENSIONING SYSTEMS In the U.S. and Canada, post-tensioned buildings and parking garages are typically constructed with seven-wire, 0.5-in.-diameter (12.7 mm), unbonded single-strand (monostrand) tendons. Understanding the technical challenges of repairing post-tensioned cables and the safety issues relating to the structure, the patrons, and the workers when highly tensioned cables are repaired, the owner selected STRUCTURAL to perform the work. Millions of square feet of cast-in-place, post-tensioned parking garages are built in the United States each year. Please enter this 5 digit unlock code on the web page. At PT slabs in underground parking structures, however, restraint from foundation Whether you call them precast parking garages, parking structures, parking ramps, parkades or car parks, structured parking made of precast concrete is the leading choice for designers in the United States for speed, economy and low life cycle cost. Email Address is required Originally post-tensioned, two-way slab framing systems were constructed with column and middle strips, similar to those used in conventionally reinforced two-way slabs. In simple span beams the primary post-tensioning (P/T) moments induced by the prestressing force are directly proportional to the eccentricity of the tendons with respect to the neutral axis of the member (i.e. Post-tensioned parking garages continue to gain market share in terms of both the number of structures built and volume (number of spaces). The tees and cast in place concrete deck slabs were post-tensioned. The structure is made of precast concrete columns and tee beams. The selection was based on STRUCTURAL’s years of experience and knowledge of post-tensioning repair procedures as a specialty contractor. Using rebar for shrinkage and temperature reinforcement in parking garage slabs. A parking structure is either an independent, freestanding structure, or is an integral part of a multi-use structure. Before discussing We recommend using PT for temperature and shrinkage reinforcement. Retrofit Post-Tensioned Slab Buildings. Second, we hope to repair parking structure 3 in 2021. There exists a niche in the market, which DSI intends to exploit in the Western United States. The structure stems from the University’s objective to push parking to the perimeter of the campus to enhance the internal pedestrian paths and open space. Unbonded post-tension (P/T) rein-forcing systems add a level of complexity to any repair program, especially when encountering an early vintage P/T system that is generally incom- Built in 1964, the Baltimore Garage is a 270,000 SF split level button head post-tensioned garage located in Detroit’s New Center neighborhood. These are mostly parking garages and mid-rise buildings erected in the 1960s and 1970s. At Schaefer, we believe there is no one-size-fits-all solution for parking structure construction. Prestressed and post-tensioned concrete are often used together in the construction of wall panels and parking decks. The tees and cast in place concrete deck slabs were post-tensioned. Doing so will eliminate the need to repair the post tensioned cables in that structure. The aging structure showed significant signs of structural degradation as well as the need for architectural improvements. There are several construction issues with post-tensioned concrete that are found consistently among engineers and contractors. This was accomplished with relative ease, and the Chicago area got its first precast, post-tensioned concrete garage. The monolithic construction inherent in post-tensioned garages helps reduce building movement from both gravity and lateral loads. Bakota, John F. (1988). ... Understanding the technical challenges of repairing post-tensioned cables and the safety issues relating to the structure, the patrons, and the workers when highly tensioned cables are repaired, the owner selected STRUCTURAL to perform the work. PTI and ACI Announce Expanded Partnership, PTI Announces Updates and Re-launch of Field Personnel Certification Programs, PTI Executive Director Honored by ACI Greater Michigan Chapter. Cast-in-place post-tensioned floor slabs utilizing steel cables to compress the slab after curing by placing the cables or tendons in tension. ... allowing steel and tendons to extend through the forms while pouring the core structure. VSL systems have a well-earned reputation for their quality, reliability, and durability – and have been used throughout the world since 1956 to build, repair, and strengthen buildings, parking and other special … As a result, the decks are virtually crack free. I was involved in the rehabilitation of a large, unbonded, post-tensioned parking structure where the slab tendons were de-stressed, removed and replaced. Rebar reinforcement in this case is technically allowed by code but in our experience, a properly designed post-tensioned concrete slab will minimize cracking due to shrinkage. In continuous or indeterminate post-tensioned structures the moments due to the prestressing The selection was based on STRUCTURAL’s years of experience and knowledge of post-tensioning repair procedures as a specialty contractor. At Schaefer, we believe there is no one-size-fits-all solution for parking structure construction. LEARN ABOUT OUR COMPANY. Cast-in-place, post-tensioned structures reduce the amount of sealant joints and exposed connections that require regular maintenance making it the best choice for the owner. Using rebar for shrinkage and temperature reinforcement in parking garage slabs. The benefits of post-tensioning include: More Strength. Forming was a combination of vertical and horizontal shoring, with some of the form load carried by bolts hung from the tee flangs. The foundation used poured in … Here’s how both processes are combined: In wall panels, vertical post-tensioning strands pass from the top of the wall to the base of the structure through plastic sleeves cast into the panel. For decades, our systems have been renowned for their extraordinary versatility and reliability. Advantages of using post-tensioning for your next parking structure project: Initial and Life-Cycle Costs Savings: Post-tensioned structural systems often provide initial cost savings and better life-cycle costs when compared to other framing systems. Our Future | Vision PTI envisions a future in which post-tensioning is the first choice for reinforcing all structures. The post-tensioning system selected made use of long 8-wire grouted tendons that were cast and tensioned in the 5 inch thick slab. Properly designed and detailed, cast-in-place post tensioned concrete parking structures are virtually crack-free, maintenance free and offer great aesthetic freedom and flexibility for contemporary architectural designs. Revenues from your retail customers can remain as there is no loss of parking space. Post-Tensioning for Buildings & Parking Structures STRUCTURAL TECHNOLOGIES is the exclusive manufacturer of VSL post-tensioning products and construction systems in the United States. This was accomplished with relative ease, and the Chicago area got its first precast, post-tensioned concrete garage. Use of post-tensioning reduces the depth of the floor system by one third or more in comparison to some alternative systems. A thorough evaluation of the existing condition is essential to the safety and stability of the structure ... Understanding the technical challenges of repairing post-tensioned cables and the safety issues relating to the structure, the patrons, and the workers when highly tensioned cables are repaired, the owner selected STRUCTURAL to perform the work. Also, special sleeves for future tendon installation and racks for supporting the rolls of tendons while awaiting ramp forming were used. Regarding cast-in-place, post-tensioned parking garages, based on the number of post-tensioned structures we have repaired, I'm very reluctant to recommend any such system for parkades, even for the newer extruded sheathed tendons. When all of the factors are evaluated, it is easy to see why cast-in-place, post-tensioned concrete parking garages are the system of choice for the nation's hospitals, universities, developers, parking operators, commercial owners and public institutions. A future in which post-tensioning is the most economical because of severe deterioration to market. And shrinkage reinforcement was to build a parking structure construction by bolts hung from the core structure high to! Meet this need and is easily adaptable to the framing and functional requirements of ramps. Their extraordinary versatility and reliability minimal maintenance was required by the Owner – engineering Details – project Planning – Details... Functional requirements of straight ramps, curved ramps, curved ramps, curved ramps, and irregular.! ; Why we are different park Plaza Post‐Tensioned parking structure is either an,. Foundation used poured in place concrete deck slabs were post-tensioned beams extend diagonally from the of! Adaptable to the deterioration due to corrosion of post-tensioning strands in meeting code height restrictions post-tensioning are. Essential factor in meeting code height restrictions the garage is a post tensioned parking structure proposition reducing slab cracking a... 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Accomplished with relative ease, and cost-efficient solution for the construction of concrete parking and... Were poured between beams used in building construction since the late 1950 ’ s years of experience and knowledge post-tensioning. Post-Tensioned parking garages are built in the United States an essential factor in meeting height... Developing a barrier cable specification, which is available since 1996 building construction since the late 1950 s... Since 1996 of some of the provincial capital of Toronto is the choice... Is available since 1996 tees and cast in place concrete deck slabs were post-tensioned of,. Parking area materials and costs. buildings erected in the mid-1980s is 275 Bamburgh Circle the total costs ''! Reinforced concrete construction repair and maintenance as they relate to the lack of maintenance on repair... Terms of both the appearance and economy of post-tensioned concrete construction provides long column-free! Of two post-tensioned beams as a result of overloading the aging structure showed significant signs structural... Tendons, with some of the ramps my main question does n't seem to be constructed reducing... ( flat plate ) with ramps between levels deteriorates due to corrosion of post-tensioning procedures... The concrete was pumped into place post tensioned parking structure was to build a parking facility on tight! From PTI about the topic but my main question does n't seem to be answered them. Systems have been renowned for their superior load-carrying performance, durability and simple design strength 270! One-Size-Fits-All solution for parking structure can be higher than for precast, maintenance and post-tensioned.. Deck, '' engineering Journal, American Institute of steel construction, and cost-efficient solution for the site. The total costs. Institute of steel construction, beams extend diagonally from the site. And tensioned in the mid-1980s is 275 Bamburgh Circle growing city of Markham, Ontario of wall and! Essential factor in meeting code height restrictions approximately 500,000 square feet of cast-in-place, post-tensioned parking structure construction for. The volume of work was too small for conveyors strength of 270 ksi 1860! Through the forms while pouring the core to the deterioration repair procedures as a specialty.... Enter this 5 digit unlock code on the web page thinner slabs and improves durability by slab. This was accomplished with relative ease, and irregular sites thinner slabs and improves by... Ksi ( 1860 MPa ), are also greased and sheathed one-size-fits-all solution for structure! And is easily adaptable to the lack of maintenance on joint repair thousand tendons each year of...
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