Prestressed-Concrete Structure - Indiana
INDIANA DEPARTMENT OF TRANSPORTATION—2013 DESIGN MANUALCHAPTER visionDate13-1117-0820-07May 2013Apr. 2017May 202020-08May 2020Sections Affected406-1.0406-6.0, 406-12.10(01)Figures 406-14A through 406-14ZFigures 406-16A, 406-16B, 406-16D through 406-16 I,and 406-16K through 406-16N
TABLE OF CONTENTSTABLE OF CONTENTS. 2LIST OF FIGURES . 4406-1.0 GENERAL [Rev. May 2013] . 7406-2.0 DEFINITIONS . 7406-3.0 NOTATIONS . 7406-4.0 MATERIAL PROPERTIES . 7406-4.01 General . 7406-4.02 Normal-Weight and Lightweight Concrete [Rev. Oct. 2012] . 7406-4.02(01) Shrinkage and Creep . 8406-4.02(02) Modulus of Elasticity, Poisson’s Ratio, and Modulus of Rupture . 8406-4.03 Lightweight Concrete [Rev. Oct. 2012] . 9406-4.04 Prestressing Steel . 9406-4.05 Post-Tensioning Anchorage and Couplers . 9406-4.06 Ducts . 10406-5.0 LIMIT STATES . 11406-5.01 General . 11406-5.02 Service-Limit State . 11406-5.03 Fatigue-Limit State . 11406-5.04 Strength-Limit State . 11406-5.05 Extreme-Event-Limit State . 11406-6.0 DESIGN CONSIDERATIONS, FLEXURE AND AXIAL FORCE EFFECTS [Rev.Apr. 2017] . 12406-7.0 SHEAR AND TORSION . 12406-7.01 General . 12406-7.02 Sectional-Design Model . 13406-7.03 Interface Shear Transfer – Shear Friction . 13406-7.04 Segmental Concrete Bridge . 13406-8.0 PRESTRESSED CONCRETE . 14406-8.01 General Considerations and Stress Limitations . 14406-8.02 Loss of Prestress . 14406-9.0 PRESTRESSING-REINFORCEMENT REQUIREMENTS . 14406-9.01 Spacing of Prestressing Tendons and Ducts . 14406-9.02 Tendon Confinement and Effects of Curved Tendons . 15Page 22013 Indiana Design Manual, Ch. 406
406-9.03 Post-Tensioned and Pretensioned Anchorage Zone . 15406-10.0 DEVELOPMENT OF PRESTRESSING STRANDS AND DEBONDING . 15406-11.0 DIAPHRAGMS . 16406-11.01 General Requirements . 16406-11.02 Intermediate Diaphragms . 16406-11.03 Structural-Steel and Reinforced-Concrete Interior Diaphragms . 17406-11.04 End Diaphragms . 17406-11.05 Interior Pier or Bent Diaphragms . 18406-12.0 ADDITIONAL DESIGN FEATURES . 19406-12.01 General . 19406-12.02 Prestressed-Concete-Member Sections . 19406-12.02(01) General . 19406-12.02(02) AASHTO I-Beam Type I, II, III, or IV. 19406-12.02(03) Indiana Bulb-Tee Beam [Rev. Oct. 2012] . 20406-12.02(04) Indiana Composite or Non-Composite Box Beam . 20406-12.03 Strand Configuration and Mild-Steel Reinforcement. 21406-12.03(01) General . 21406-12.03(02) Prestressing-Strands Configuration . 21406-12.03(03) Mild-Steel Reinforcement . 22406-12.04 Stage Loading for Pretensioned Construction . 23406-12.04(01) Strands Tensioned in the Stressing Bed . 23406-12.04(02) Strands Released and Force Transferred to the Concrete . 23406-12.04(03) Camber Growth and Prestress Losses . 23406-12.04(04) Maximum Service Load, Minimum-Prestress Stage . 24406-12.05 Continuity for Superimposed Loads . 24406-12.06 Effect of Imposed Deformations . 25406-12.07 Transverse Connection of Precast Box Beams . 26406-12.08 Segmental Construction. 26406-12.09 Dimensioning Precast Beams . 27406-12.10 Other Design Features . 28406-12.10(01) Skew [Rev. Apr. 2017] . 28406-12.10(02) Shortening of Superstructure . 29406-13.0 AASHTO I-BEAMS. 29406-14.0 INDIANA BULB-TEE BEAMS . 29406-15.0 INDIANA COMPOSITE AND NON-COMPOSITE BOX BEAMS . 29406-16.0 MISCELLANEOUS DETAILS . 29FIGURES . 302013 Indiana Design Manual, Ch. 406Page 3
LIST OF -14G406-14H406-14 I406-14 J406-14K406-14L406-14M406-14N406-14 Page 4TitleAdjacent Box Beams with Transverse Tensioning Rods (Section View)Dimensioning Prestressed-Concrete Beam on SlopeI-Beam Type II-Beam Type III-Beam Type IIII-Beam Type IVBulb-Tee Beam Type BT 54 x 48Bulb-Tee Beam Type BT 60 x 48Bulb-Tee Beam Type BT 66 x 48Bulb-Tee Beam Type BT 72 x 48Bulb-Tee Beam Type BT 78 x 48Bulb-Tee Beam Type BT 84 x 48 SectionBulb-Tee Beam Type BT 36 x 49 Sections Showing Prestressing and MildBulb-Tee Beam Type BT 42 x 49 Sections Showing Prestressing and MildReinforcing SteelBulb-Tee Beam Type BT 48 x 49 Sections Showing Prestressing and MildReinforcing SteelBulb-Tee Beam Type BT 54 x 49 Sections Showing Prestressing and MildReinforcing SteelBulb-Tee Beam Type BT 60 x 49 Sections Showing Prestressing and MildReinforcing SteelBulb-Tee Beam Type BT 66 x 49 Sections Showing Prestressing and MildReinforcing SteelBulb-Tee Beam Type BT 54 x 60Bulb-Tee Beam Type BT 60 x 60Bulb-Tee Beam Type BT 66 x 60Bulb-Tee Beam Type BT 72 x 60Bulb-Tee Beam Type BT 78 x 60Bulb-Tee Beam Type BT 84 x 60Wide Bulb-Tee Beam Type BT 36 x 61 Sections Showing Prestressing and MildWide Bulb-Tee Beam Type BT 42 x 61 Sections Showing Prestressing and MildReinforcing SteelWide Bulb-Tee Beam Type BT 48 x 61 Sections Showing Prestressing and MildReinforcing SteelWide Bulb-Tee Beam Type BT 54 x 61 Sections Showing Prestressing and MildReinforcing Steel2013 Indiana Design Manual, Ch. 406
06-15D406-15E406-15F406-15G406-15H406-15 I406-15J406-15K406-15L406-15M406-15N406-15 406-16E406-16F406-16G406-16H406-16 I406-16J406-16K406-16L406-16M406-16N406-16 O406-16P406-16QWide Bulb-Tee Beam Type BT 60 x 61 Sections Showing Prestressing and MildReinforcing SteelWide Bulb-Tee Beam Type BT 66 x 61 Sections Showing Prestressing and MildReinforcing SteelBulb-Tee Beam Elevations Showing End ReinforcementBulb-Tee Beam Section at End Showing Draped StrandsBox Beam Type CB 12 x 36Box Beam Type CB 17 x 36Box Beam Type CB 21 x 36Box Beam Type CB 27 x 36Box Beam Type CB 33 x 36Box Beam Type CB 42 x 36Box Beam Type CB 12 x 48Box Beam Type CB 17 x 48Box Beam Type CB 21 x 48Box Beam Type CB 27 x 48Box Beam Type CB 33 x 48Box Beam Type CB 42 x 48Box Beam Type WS 12 x 48Box Beam Type WS 17 x 48Box Beam Type WS 21 x 48Box Beam Type WS 27 x 48Box Beam Type WS 33 x 48Box Beam Type WS 42 x 48I-Beam Pier Diaphragm, Section Between BeamsI-Beam Pier Diaphragm, Section at BeamsI-Beam Intermediate DiaphragmI-Beam DiaphragmsI-Beam: End Bent Cap Sizing and Bearing Layout DetailsI-Beam: Pier Cap Sizing and Bearing Layout DetailsI-Beam: Holes at Pier DiaphragmBulb-Tee Pier Diaphragm, Section Between BeamsBulb-Tee Pier Diaphragm, Section at BeamsBulb-Tee Intermediate DiaphragmBulb-Tee DiaphragmBulb-Tee: End Bent Cap Sizing and Bearing Layout DetailsBulb-Tee: Pier Cap Sizing and Bearing Layout DetailsBulb-Tee: Holes at Pier DiaphragmBox Beam Pier Diaphragm for Spread Beams, Section Between BeamsBox Beam Pier Diaphragm for Spread Beams, Section at BeamsBox Beam Diaphragm at Pier2013 Indiana Design Manual, Ch. 406Page 5
age 6Box Beam Closure Pour at Pier for Adjacent BeamsBox Beam: End Bent Cap Sizing and Bearing Layout DetailsBox Beam: Pier Cap Sizing and Bearing Layout Details for Spread BeamsBox Beam: Pier Cap Sizing and Bearing LayoutBox Beam Inserts at Pier DiaphragmMild Reinforcement for 36-in Width Skewed-Beam End (45-deg Skew Shown)Mild Reinforcement for 48-in Width Skewed-Beam End (45-deg Skew Shown)2013 Indiana Design Manual, Ch. 406
CHAPTER 406PRESTRESSED CONCRETE406-1.0 GENERAL [REV. MAY 2013]The requirements of this Chapter will apply to each bridge designed with normal or lightweightconcrete reinforced with prestressed or post-tensioned strands. Partial prestressing is notpermitted. The requirements described herein are based on a 28-day concrete strength, f c′ , of 4to 8 ksi.406-2.0 DEFINITIONSSee LRFD 5.2.406-3.0 NOTATIONSSee LRFD 5.3.406-4.0 MATERIAL PROPERTIES406-4.01 GeneralThe material properties cited herein are based on the construction materials specified in LRFD5.4. The minimum acceptable properties and test procedures shall be specified in the contractdocuments.406-4.02 Normal-Weight and Lightweight Concrete [Rev. Oct. 2012]The minimum f c′ for prestressed or post-tensioned concrete components shall be shown on theplans. Such a strength outside the range shown in Section 406-1.0 is not permitted withoutwritten approval of the Director of Bridges. For lightweight concrete, the air dry unit weightshall be shown on the plans as 119 lb/ft3. The modulus of elasticity will be calculated using the119 lb/ft3 value. The unit weight of the lightweight concrete will be taken as 124 lb/ft3. The2013 Indiana Design Manual, Ch. 406Page 7
additional weight is to account for the mild reinforcing steel and the tensioning strands. SeeLRFD 5.4.2.2 for the coefficient of linear expansion.The following will apply to concrete.1.The design compressive strength of normal-weight and lightweight concrete at 28 days,f c′ , shall be in the range as follows:a.b.c.prestressed box beam:prestressed I-beam:prestressed bulb-tee beam:5 to 7 ksi5 to 7 ksi6 to 8 ksiAn exception to the range shown above will be allowed for a higher strength if the higherstrength can be documented to be of significant benefit to the project, it can be effectivelyproduced, and approval is obtained from the Director of Bridges.2.At release of the prestressing strands, f c′ shall not be less than 4 ksi, and shall bedetermined during the beam design. The specified concrete compressive strength atrelease shall be rounded to the next higher 0.1 ksi.406-4.02(01) Shrinkage and CreepLosses due to shrinkage and creep, for other than than a segmentally-constructed bridge, thatrequire a more-precise estimate including specific materials, structural dimensions, siteconditions, construction methods, and age at various stages of erection, can be estimated bymeans of the methods specified in LRFD 5.4.2.3.2 and 5.4.2.3.3. Other acceptable methods arethose described in the CEB-FIP 1978 / 1990 code. The annual average ambient relative humidityshall be taken as 70%.406-4.02(02) Modulus of Elasticity, Poisson’s Ratio, and Modulus of RuptureThe modulus of elasticity shall be calculated as specified in LRFD Eqn. 5.4.2.4-1. Poisson’sratio shall be taken as 0.2. See LRFD 5.4.2.6 for modulus-of-rupture values depending onwhether the concrete is normal weight or lightweight, and whether the intended application iscontrol of cracking, deflection, camber, or shear resistance.Page 82013 Indiana Design Manual, Ch. 406
406-4.03 Lightweight Concrete [Rev. Oct. 2012]The use of lightweight concrete, with normal-weight sand mixed with lightweight coarseaggregate, is permitted with a specified density of 119 lb/ft3. The use of lightweight concreteshall be demonstrated to be necessary and cost effective during the structure-size-and-type study.The modulus of elasticity will be less than that for normal-weight concrete. Creep, shrinkage,and deflection shall be appropriately evaluated and accounted for if lightweight concrete is to beused. The formula shown in LRFD 5.4.2.6 shall be used in lieu of physical test values formodulus of rupture. The formula for sand-lightweight concrete shall be used for lightweightconcrete.406-4.04 Prestressing SteelPrestressing strands shall be of the low-relaxation type with a minimum tensile strength of 270ksi. Unless there is a reason to do otherwise, only the following three-strand diameters shall beused.1.Nominal 3/8 in., As 0.085 in2, for use in a stay-in-place deck panel.2.Nominal 1/2 in., As 0.167 in2, for use in an I, bulb-tee, or box beam, or post-tensionedmember.3.Nominal 0.6 in., As 0.217 in2, for use in a in a bulb-tee beam or post-tensioned member.See LRFD Table 5.4.4.1-1 for values of yield strength, tensile strength, and modulus of elasticityof prestressing strands or bars.Prestressing threadbars are used for grouted construction. If the bars are used for permanentnon-grouted construction, the bars shall be epoxy coated.406-4.05 Post-Tensioning Anchorage and CouplersSee LRFD 5.4.5 regarding the use of anchorages or couplers. Tendons, anchorages, end fittings,and couplers shall be protected against corrosion. If couplers are used to connect bars, they shallbe enclosed in duct housings long enough to permit the necessary movement.2013 Indiana Design Manual, Ch. 406Page 9
406-4.06 DuctsSee LRFD 5.4.6 for types of ducts, radius-of-curvature limits, general considerations for tendons,and size requirements. Polyethylene ducts shall be used in a corrosive environment such as in abridge deck or in a substructure element under a joint. The contract documents shall indicate thetype of duct material to be used.Ducts for a post-tensioned bulb-tee beam shall be of round, semi-rigid, galvanized-metal. Thewall thickness shall not be less than 28 gage. A radius that requires prebending shall be avoidedif possible.If the bridge is to be constructed by means of post-tensioning precast components togetherlongitudinally or transversely by use of a cast-in-place concrete joint, the end of each duct shallbe extended beyond the concrete interface for not less than 3 in. and not more than 6 in. tofacilitate joining the ducts. If necessary, the extension can be in a local blockout at the concreteinterface. Joints between sections of ducts shall be positive metallic connections, which do notresult in angle changes at the joints.The plans shall show all pertinent geometry required for development of working drawings withthe correct tendon alignment in both elevation and plan views. This includes anchorage regionsand areas where there are tight or reverse curvatures of the the tendons.Curved ducts that run parallel to each other or around a void or re-entrant corner shall be encasedin concrete and reinforced as necessary to avoid radial failure, or pullout into another duct orvoid.Upon completion of post-tensioning, the ducts shall be grouted.Ducts or anchorage assemblies for post-tensioning shall be provided with a pipe or other suitableconnection at each end for the injection of grout after prestressing. A duct of over 200 ft inlength shall be in accordance with the recommendations of the PTI. Vents shall be ½-in.minimum diameter standard pipe or suitable plastic pipe. Connections to the ducts shall be madewith metallic or plastic fasteners. Plastic components, if selected and approved, shall not reactwith the concrete or enhance corrosion of the prestressing steel, and shall be free of watersoluble chlorides. The vents shall be mortar tight, taped as necessary, and shall provide meansfor injection of grout through the vents and for positive sealing of the vents. Ends of steel ventsshall be removed at least 1 in. below the concrete deck surface, if appropriate, after the grout hasset. Ends of plastic ven
a. prestressed box beam: 5 to 7 ksi b. prestressed I-beam: 5 to 7 ksi c. prestressed bulb-tee beam: 6 to 8 ksi An exception to the range shown above will be allowed for a higher strength if the higher strength can be documented to be of significant benefit to the project, it can be effectively
Lecture 24 – Prestressed Concrete Prestressed concrete refers to concrete that has applied stresses induced into the member. Typically, wires or “tendons” are stretched and then blocked at the ends creating compressive stresses throughout the member’s entire cross-section. Most Prestressed concrete is precast in a plant.
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Introduction to Prestressed Concrete 1 / 7 In prestressed concrete, compressive stresses are applied to the concrete prior to loading. Under service loads, the entire cross section is essentially in compression, which takes advantage of concrete’s considerable compressive
prestressed concrete members, the bonding action between the prestressing element and the concrete is a result of friction as well as adhesion and mechanical resistance. In the fabrication of a pre-tensioned prestressed concrete member the prestressing strand is first tensioned to the desired stress level. Concrete is then cast about the strand and
PRESTRESSED CONCRETE CONTAINMENT MODEL By Sami H. Rizkallal 1 A. M. ASeE, Sidney H. Simmonds,2 and James G. MacGregor/ Members, ASeE AeSTRACT: The construction and testing of a model of a prestressed concrete containment structure is described. The test structure consisted of a reinforced
Precast/Prestressed Concrete Institute, Design Handbook-Precast and Prestressed Concrete: Code of Standard Practice for Precast/Prestressed Concrete (PCI MNL-120) Structural Material Specifications Concrete Foundations (Pile Caps and Grade Beams): 6,000 p
As prestressed concrete became widely produced and adopted, a second concept was formulated, commonly known as the ultimate strength theory. Under that concept, prestressed concrete is treated as a combination of h\Ph strength con crete and high strength steel, with concrete to carry the compression
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