aci 550.2r-13: design guide for connections in precast ......aci 550.2r-13 design guide for...

ACI 550.2R-13

Design Guide for Connections in Precast Jointed Systems

Reported by Joint ACI-ASCE Committee 550

Copyright American Concrete Institute Provided by IHS under license with ACI Licensee=University of Texas Revised Sub Account/5620001114, User=erur, ert

Not for Resale, 01/26/2015 02:46:10 MSTNo reproduction or networking permitted without license from IHS

--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

www.daneshlink.com

http://www.daneshlink.com

First PrintingApril 2013


Copyright by the American Concrete Institute, Farmington Hills, MI. All rights reserved. This material may not be reproduced or copied, in whole or part, in any printed, mechanical, electronic, film, or other distribution and storage media, without the written consent of ACI.

The technical committees responsible for ACI committee reports and standards strive to avoid ambiguities, omissions, and errors in these documents. In spite of these efforts, the users of ACI documents occasionally find information or requirements that may be subject to more than one interpretation or may be incomplete or incorrect. Users who have suggestions for the improvement of ACI documents are requested to contact ACI via the errata website at www.concrete.org/committees/errata.asp. Proper use of this document includes periodically checking for errata for the most up-to-date revisions.

ACI committee documents are intended for the use of individuals who are competent to evaluate the significance and limitations of its content and recommendations and who will accept responsibility for the application of the material it contains. Individuals who use this publication in any way assume all risk and accept total responsibility for the application and use of this information.

All information in this publication is provided “as is” without warranty of any kind, either express or implied, including but not limited to, the implied warranties of merchantability, fitness for a particular purpose or non-infringement.

ACI and its members disclaim liability for damages of any kind, including any special, indirect, incidental, or con-sequential damages, including without limitation, lost revenues or lost profits, which may result from the use of this publication.

It is the responsibility of the user of this document to establish health and safety practices appropriate to the specific circumstances involved with its use. ACI does not make any representations with regard to health and safety issues and the use of this document. The user must determine the applicability of all regulatory limitations before applying the document and must comply with all applicable laws and regulations, including but not limited to, United States Occupational Safety and Health Administration (OSHA) health and safety standards.

Participation by governmental representatives in the work of the American Concrete Institute and in the develop-ment of Institute standards does not constitute governmental endorsement of ACI or the standards that it develops.

Order information: ACI documents are available in print, by download, on CD-ROM, through electronic subscription, or reprint and may be obtained by contacting ACI.

Most ACI standards and committee reports are gathered together in the annually revised ACI Manual of Concrete Practice (MCP).

American Concrete Institute38800 Country Club DriveFarmington Hills, MI 48331U.S.A.Phone: 248-848-3700Fax: 248-848-3701

www.concrete.org

ISBN-13: 978-0-87031-812-2ISBN: 0-87031-812-8

American Concrete Institute®

Advancing concrete knowledge



--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

www.concrete.org/committees/errata.asp

http://www.concrete.org

www.daneshlink.com


The proper detailing and design of precast concrete connections are essential to the performance of a precast concrete structure. This guide provides information on design, detailing, and construc-tion of connections between precast members in jointed systems, including moment frame and structural wall systems.

Keywords: bolting; connection; debonding; ductility; erection; moment frame; precast; pretopped; post-tensioning; structural walls; welding.

CONTENTS

CHAPTER 1—INTRODUCTION AND SCOPE, p. 21.1—Introduction, p. 21.2—Scope, p. 2

CHAPTER 2—NOTATION AND DEFINITIONS, p. 22.1—Notation, p. 22.2—Definitions, p. 2

CHAPTER 3—GUIDELINES FOR DESIGN, p. 33.1—Classes of connections, p. 33.2—Principles of connection design, p. 33.3—Anchorage to concrete, p. 53.4—Welding, p. 5

3.5—Debonding, p. 7

CHAPTER 4—PRECAST CONCRETE FLOOR SYSTEMS, p. 7

4.1—Precast systems, p. 74.2—Precast floor diaphragms, p. 7

CHAPTER 5—LATERAL-LOAD-RESISTING SYSTEMS, p. 8

5.1—Structural walls, p. 85.2—Structural walls with large openings, p. 85.3—Moment frames, p. 8

CHAPTER 6—CONNECTIONS, p. 106.1—Strength, p. 106.2—Ductility, p. 106.3—Volume change accommodation, p. 116.4—Durability, p. 116.5—Fire resistance, p. 116.6—Constructibility, p. 116.7—Aesthetics, p. 116.8—Seismic requirements, p. 116.9—Tolerances, p. 116.10—Vertical connections, p. 11

CHAPTER 7—ERECTION CONSIDERATIONS, p. 13

CHAPTER 8—WELDING CONSIDERATIONS, p. 138.1—Steel assemblies, p. 13

ACI 550.2R-13


Reported by Joint ACI-ASCE Committee 550

Te-Lin ChungNed M. Cleland

William K. DoughtyAlvin C. Ericson

Melvyn A. GalinatHarry A. Gleich

Mohammad S. HabibNeil M. Hawkins

Augusto H. HolmbergL. S. Paul JohalJason J. Krohn

Emily B. Lorenz

Kenneth A. LuttrellVilas S. MujumdarFrank A. Nadeau

Clifford R. OhlwilerVictor F. Pizano-Thomen

Jose I. Restrepo

Sami H. RizkallaMario E. RodriguezJoseph C. Sanders

John F. StantonP. Jeffrey Wang

Cloyd E. Warnes

Thomas J. D’Arcy, Chair

1

ACI Committee Reports, Guides, and Commentaries are intended for guidance in planning, designing, executing, and inspecting construction. This document is intended for the use of individuals who are competent to evaluate the significance and limitations of its content and recommendations and who will accept responsibility for the application of the material it contains. The American Concrete Institute disclaims any and all responsibility for the stated principles. The Institute shall not be liable for any loss or damage arising therefrom.

Reference to this document shall not be made in contract documents. If items found in this document are desired by the Architect/Engineer to be a part of the contract documents, they shall be restated in mandatory language for incorporation by the Architect/Engineer.

ACI 550.2R-13 was adopted and published April 2013.Copyright © 2013, American Concrete Institute.All rights reserved including rights of reproduction and use in any form or by any

means, including the making of copies by any photo process, or by electronic or mechanical device, printed, written, or oral, or recording for sound or visual reproduc-tion or for use in any knowledge or retrieval system or device, unless permission in writing is obtained from the copyright proprietors.



--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

www.daneshlink.com


8.2—Galvanized steel, p. 138.3—Stainless steel, p. 148.4—Reinforcement, p. 148.5—Welding practices for epoxy-coated material, p. 15

CHAPTER 9—GROUTING, p. 15

CHAPTER 10—REFERENCES, p. 15

CHAPTER 1—INTRODUCTION AND SCOPE

1.1—IntroductionPrecast concrete structural systems are composed of indi-

vidually fabricated components. Because of the segmental nature of precast concrete construction, connections between individual components are required to support the design loads. Connections are also required to accommodate defor-mations, including rotations and strains.

1.1.1 Connection methods—Precast components are connected by one of two methods. The first method connects components by reinforcement that protrudes from each component end, spliced using proprietary hardware or by lap-splicing with a small quantity of cast-in-place concrete to complete the connection. This method is referred to as emulation, or a wet connection, because it involves field-placed cast-in-place concrete and mimics the behavior of cast-in-placed monolithic structures. The second, more-common, method of connection is dry and connects compo-nents by welding, bolting, post-tensioning, or doweling without using field-placed concrete. Because dry connec-tions are typically less stiff than their connecting precast components, deformations tend to be concentrated in the connections.

Connections should allow for easy and economical component casting and assembly, fabrication, erection clear-ance, and erection tolerances. They should also tolerate anticipated deformation without significant loss of strength.

1.1.2 Connection groups—Connections are categorized into five groups:

1) Gravity load transfer—Gravity loads alone, such ashollow core members placed on a beam ledge

2) Shear transfer—Either vertical shear, horizontal shear,or both, such as a double-tee flange-to-flange connection

3) Moment transfer—The tension and compressionforces created by moment, such as a connection between a precast moment frame and its foundation

4) Structural integrity—Code-prescribed structuralintegrity forces; typically a connection with combination accommodations

5) Combination connection—A combination of loads,such as moments and shear

In all cases, the load paths and external loads are accom-modated in all elements of connections (Fig. 1.1.2).

Tying all precast members to each adjacent member is essential for structural integrity as required by Chapter 16 of ACI 318-11. Such connections, however, should not be so rigid as to prevent member rotation or volume change strains when required.

1.2—ScopeThis guide provides information on the characteristics and

design of connections between precast concrete components and between precast components and cast-in-place construc-tion. The proper detailing and design of precast concrete connections are essential to the performance of a precast concrete structure.

This guide describes typical precast jointed systems and their connection types, performance, and characteristics, and provides recommendations for design and construc-tion. Three classes of connections are identified and their characteristic and key design considerations given. Also included are guidelines for designing connections and their anchorage, a description of precast systems, typical lateral-load-resisting systems, key design considerations, and erec-tion requirements including special welding considerations.

CHAPTER 2—NOTATION AND DEFINITIONS

2.1—NotationCd = deflection amplification factorfc′ = specified compressive strength of concrete, psi

(MPa)R = response modification factorf = strength reduction factor

2.2—DefinitionsACI provides a comprehensive list of definitions through

an online resource, “ACI Concrete Terminology,” http://terminology.concrete.org. Definitions provided herein complement that resource.

deformable connection—a class of connection between precast members designed to either display significant flex-ibility or to yield, without losing strength, when subjected to expected deformations.

Fig. 1.1.2—Wall panel to foundation connection.

American Concrete Institute Copyrighted Material—www.concrete.org

2 DESIGN GUIDE FOR CONNECTIONS IN PRECAST JOINTED SYSTEMS (ACI 550.2R-13)



--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

http://terminology.concrete.org

http://terminology.concrete.org

www.daneshlink.com


ductile connection—a class of connection between precast members designed to yield and show stable hyster-etic force-deformation response when subjected to expected reversed cyclic deformations.

joint—the location in a precast structural system where precast members intersect.

gravity-only member—a member of a framing system that supports mainly gravity loads and is not part of the lateral-load-resisting system.

pretopped system—a precast flooring system that employs a thickened top flange on precast members (typi-cally double tees) provided in place of field-placed topping.

strong connection—a class of connection between precast members in which the connection between precast members remains elastic while adjoining members experi-ence yielding when subjected to expected deformations.

CHAPTER 3—GUIDELINES FOR DESIGN

3.1—Classes of connectionsSelection of the connection type between precast compo-

nents is essential to precast concrete design. Connection types should be identified early in the design process based on their expected role in the structural system. Yielding of reinforcement is common in reinforced concrete structures in response to severe forces such as earthquakes. Designers should consider the location of inelastic deformation in components and design them to accommodate the defor-mations without loss of service strength. The joint regions where precast members come together are the most likely place for yielding in frames. In emulative concrete construc-tion, they are rendered ductile by the prescriptive detailing requirements of the International Building Code (IBC 2006). Three classes of connections are described: strong, ductile, and deformable.

3.1.1 Strong—Strong connections use a hierarchical design approach to ensure yielding and strain hardening will take place away from the connection. Strong connections do not have to display ductile response. The absolute strength is less important than the ratio of capacity to demand. An example is a one-piece beam and column precast compo-nent connected at midspan of the beam. When the seismic moments at midspan are smaller than at support locations, yielding occurs in the precast beam at the column face. This approach is not employed as frequently as other solutions. The concept of creating strong joints to force yielding in the precast members away from the joint, although feasible, is typically used where jointing occurs at frame inflection points (Fig. 3.1.1).

3.1.2 Ductile—Ductile connections, which possess signif-icant deformation capacity, are detailed in regions where inelastic deformations concentrate to form a part of the seismic-load-resisting system. Ductile connections display stable hysteresis loops when subjected to reversed cyclic loading. Their design follows a strength hierarchy to ensure yielding and cyclic strain hardening occurring at the connec-tion only. Such connections can be welded; however, the strength of welds and embeds need to be stronger than the

connecting plate. Ductile connections can also be made with splicing reinforcing bars by lapping or using proprietary splice sleeves. There should be sufficient strain capacity to sustain resistance through the required movement.

3.1.3 Deformable—Deformable connections undergo deformations when the structure displaces. For example, a precast beam bearing on a rubber pad on a corbel allows rotation with little longitudinal resistance. Although rotation occurs, the vertical load-carrying strength is not impaired. The gravity-only members and connections in many seismic-resistant structures—precast and otherwise—should act this way. In the 1994 Northridge earthquake, a number of connections lost their integrity because they relied on gravity to remain in place (Iverson and Hawkins 1994). Under a horizontal load, unseating of deformable connectors should be prevented; therefore, where movement is expected, some measure of restraint is required. Note that in Fig. 3.1.3, the connection’s vertical support is maintained, but lateral movement is limited by the threaded rod in the sleeve.

3.2—Principles of connection designAn appropriate connection detail can be designed once

its function has been defined. Use of the three classes of connections enables the designer to plan the behavior of the structure, rather than using distributed toughness in the structure to cover all potential behaviors, as is largely done in cast-in-place construction.

To achieve that goal, seven design principles (3.2.1 through 3.2.6) are recommended in this guide

1) Relate connections to the system2) Provide a complete load path through the system3) Avoid eccentricities in load paths where possible4) Use capacity design to control the behavior of the

connection (PCI Committee on Connection Detail 1995, 1998), which is the preferred method; however, strut and tie design methodology is also employed in precast concrete design practice with good results and performances

5) Provide for ductility where needed6) Account for energy dissipation where required7) Consider constructibility

Fig. 3.1.1—Precast moment frame with connection made in column away from beam-to-column joints.


DESIGN GUIDE FOR CONNECTIONS IN PRECAST JOINTED SYSTEMS (ACI 550.2R-13) 3



--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

www.daneshlink.com


Fig. 3.1.3—Doweled beam connection (PCI 2008).





--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

www.daneshlink.com


3.2.1 System connections—The connections control the way a structure behaves so they should be consistent with the complete structural system. For example, in a panel structure, two possible forms of response are rocking at the base or sliding at joints. The designer should decide how the structure should act, rather than only calculating code forces and design connections to ensure that the desired behavior occurs and loads are transferred to the foundations. Rocking at the base or in subsequent panel joints is the preferred solu-tion rather than sliding displacement of the joints.

3.2.2 Load path—A complete load path should be provided for all forces to be transmitted from their point of origin to the foundation and each link in the path judged for adequacy. Compression segments of the path are seldom a problem because of their large surfaces areas and that component ends are typically armored with bearing plates. Tension and shear segments are more likely to prove critical because of their tendency to crack members at or near the connection region.

3.2.3 Load path eccentricity—Offsets in tension load paths create moments that tend to straighten the member or bend the connections; offsets in compression load paths tend to bend members. Such offsets should be avoided or arrangements made to ensure that the moments are resisted by another component. A common example of an offset is a reinforcing bar fillet welded to a plate. If the rotation is not suppressed, this detail is potentially dangerous because, under load, the bar is sharply bent immediately adjacent to the weld, with the possibility of embrittlement. In tests (Stanton et al. 1986), a bar detailed in such a manner frac-tured without any necking down.

3.2.4 Capacity design—Capacity design is a hierar-chical design approach that enables a designer to control the response of a component or a structure as a whole. This approach was first suggested by Park and Paulay (1975). To ensure that yielding occurs in the designated ductile element of the load path, that element should be the weakest link in the connection. Suitable safety factors should be used in designing the adjacent elements not required to display ductility to protect them against yielding. Some overstrength factors are provided in governing codes.

Some common means of connecting steel rods or bars, such as welding or threading, may weaken the connecting element and concentrate the inelastic deformations in the anchorage to the concrete. Failure of the anchorage is undesirable because of its difficulty to repair. Deliberately reducing the connecting element section at a location away from the attachment is one way of providing for greater deformation capacity. An example is shown in Fig. 3.2.4a. A rectangular field splice plate, used to connect two panels in shear, proved stronger than the weld and the anchorage to the concrete when no special measures were taken (Stanton et al. 1986). Failure was brittle and was initiated by fracture of the weld and by pullout of the embedded bars. A modified plate, equipped with slots to reduce the section and circular ends to avoid stress concentrations at the slot ends in the connecting plate, as shown in Fig. 3.2.4b, could provide significant ductility. The connection failed by yielding and

fracture of the plate and protected the anchorage and the weld. Replacement of the damaged plate after an earthquake would also be relatively simple.

3.2.5 Ductility—Particularly in structures exposed to the elements, where temperature change strain occurs, ductile connections (refer to 3.1.2) should be designed and detailed to provide for ductility and the ability to yield without damage to adjacent concrete surfaces.

3.2.6 Constructibility—Connection design should consider the following: standardize connections within a project; use standard hardware items; avoid non-standard production and erection tolerances; provide accessibility; consider constructibility; provide for field adjustment; and avoid penetration of forms.

3.3—Anchorage to concreteAs noted in 3.2.4, it is best to provide yielding in the

connecting element to minimize or eliminate cracking. Anchorage of steel embedments to concrete requires careful consideration. The anchorage length has to be considered, because yielding of bars implies cracking in the concrete. Even if the bar does not yield, cracking may still occur because compatibility of strains in the two materials means that the concrete cracks when the steel stress is approxi-mately 5 ksi (35 MPa). This indicates that calculating bar sizes and embedment lengths on the basis of strength at factored loads will almost certainly lead to concrete damage. For example, if the angle embedded in the concrete in Fig. 3.2.4a is attached to bars embedded in the concrete and capacity design concepts are used with a factor of 1.5 to protect the anchorage, the bar stress will still be 40 ksi (275 MPa) when the field plate yields. That stress is 80 times the 500 psi (3.5 MPa) at which concrete cracking is expected to start. This yielding occurs when the connection is in tension. The bars should have adequate development in the surrounding concrete. The concrete adjacent to the bar may crack if the bar stress results in deformation that leads to concrete cracking. The strut-and-tie method (ACI 318) offers a rational way to choose loads and force path in the vicinity of connections.

The best performance of a connection eliminates cracking. Possible ways to control cracking include prestressing the concrete, debonding the bars with sufficient length of bar beyond the debonded region to ensure full development, or using a mechanical anchor or hooked bars to cause compression on the far end of the concrete rather than tension. Debonding minimizes tension at the member face by allowing uniform strain in the reinforcement in the debonded region. If pretensioning is used, the determination of a potential cracking region should account for the transfer length for the prestressing steel.

3.4—WeldingWelding alters the physical properties of steel and can

cause embrittlement. Before the 1994 Northridge earthquake (Iverson and Hawkins 1994), it was generally believed that a properly designed and executed weld in a structural steel frame could withstand cyclic yielding. Materials with high





--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

www.daneshlink.com


Fig. 3.2.4a—Welded connection (PCI 2008).





--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

www.daneshlink.com


carbon equivalent susceptible to improperly made welds were more likely to have problems (ASTM A615/A615M; Rodriguez and Rodriguez 2006). Because of this, steel framing connections in hundreds of steel-framed structures damaged during the Northridge earthquake were altered to provide for a more gradual load transfer.

Welds should not be used adjacent to a potential yield region or a reinforcing bar bend. Because welding is almost impossible to avoid altogether, detailing of embeds should ensure that the potential yield zone does not impinge on the weld. Welding considerations are discussed in detail in Chapter 8.

3.5—DebondingDeliberate local debonding can relieve local strain concen-

trations and subsequent fracture. Bars that are grouted into ducts do not debond as readily as those cast directly into concrete, so the possibility of premature fracture exists. This was verified in beam-column tests (Cheok and Stone 1994). Bars were grouted into ducts in the beam and column. At large story drifts of ±3 percent, the bar elongation was considerable but was forced to occur over only a short unbonded length of approximately 4 in. (100 mm). The local strain was very high and the bars fractured.

The debonded length should be properly selected and designed as part of the connection. At a length that is too short, the bars fracture; at a length that is too long, the bars never yield and energy is not dissipated. Typical rein-forcing bar debonding lengths are 4 to 8 in. (100 to 200 mm) or four to eight bar diameters. Debonding can be achieved by placing a sleeve over the reinforcing bar, held in place with tape. Tests of precast hybrid frames (beam and column systems) have shown that the debonded length can be determined reliably (Schoettler et al. 2008; Priestley et al. 1999).

CHAPTER 4—PRECAST CONCRETE FLOOR SYSTEMS

4.1—Precast systemsPrecast concrete floor systems are typically constructed

with double-tee or hollow-core members with a cast-in-place topping that is 2 to 3 in. (50 to 75 mm) thick. Double tees may also be pretopped where the flange is cast thicker—typically 4 in. (100 mm)—thereby incorporating the topping in the thicker precast flange. Deck members are typically supported by beams, spandrels, or wall panels. In pretopped applications, field pour strips are typically provided over the beams to provide field fit-up tolerances.

4.1.1 Topped systems—Double-tee or hollow-core floor members are erected and a field-placed topping is applied. The topping acts compositely with floor members. It is cast a minimum of 2 in. (50 mm) thick at center span, and either follows the camber or creates a thicker topping at the bearing ends. A minimum fc′ of 3500 psi (24 MPa) is recommended. Topping and deck thickness may also be dictated by fire rating requirements.

To control shrinkage cracking in parking structures, the topping over each precast-to-precast member joint is tooled and the joints are sealed (Fig. 4.1.1). Proper curing of the topping is essential to control shrinkage cracking. The precast member surface is cleaned and moistened before placing the topping. Diaphragm reinforcement and temper-ature and shrinkage reinforcement are placed within the topping. Controlling the concrete topping mixture and alter-nating topping placement in a checkerboard pattern on the floors to break up long shrinkage paths helps to minimize the effects of topping shrinkage. Fiber reinforcement has also been used to control shrinkage cracking (ACI 544.1R-96).

4.1.2 Pretopped systems—To minimize the use of field-placed concrete and to provide the highest quality concrete at the wearing surface, double-tee flanges are cast 4 in. (100 mm) or more in thickness in the precast plant. This system is typically used for parking structures in cold or aggressive environments.

Hollow-core planks are also used without field-placed topping, but the top flange is not thickened. Such systems are typical in housing applications.

Pretopped double-tee systems rely on flange-to-flange welded connections to transfer shear and create a diaphragm. Diaphragm chord reinforcement is located in end-member pour strips. In locales where lateral loading requirements are low, flange-to-flange welded connections are occasionally employed (Schoettler et al. 2008).

4.2—Precast floor diaphragmsPrecast floor diaphragms should be connected to the

seismic-load-resisting elements such as walls. The connec-tion can be achieved in several ways, including welding, bolting, or dowel action. Dowels that extend from the seismic-load-resisting element and are anchored into the diaphragm by cast-in-place concrete should have sufficient length to be developed in the diaphragm.

Fig. 3.2.4b—Modified connection to provide more ductility.





--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

www.daneshlink.com


Continuous reinforcement should be used in the diaphragm to transfer seismic loads to the seismic-load-resisting elements. Topping reinforcement in composite systems should provide sufficient ductility to accommodate floor drift.

Perimeter chord reinforcement is typically used to resist seismic tension and moment forces, and flange connections between double tees typically resist shear forces. Preliminary findings on the performance and design of precast concrete floor system diaphragm are available. The research includes a 1/2-scale, three-story building subjected to seismic loading on a large shake table (Schoettler et al. 2008).

CHAPTER 5—LATERAL-LOAD-RESISTING SYSTEMS

5.1—Structural wallsStructural walls are the most common system used in

precast structures to resist lateral loads. The success of this system in many earthquakes around the world indicates that it is a viable solution. The typical design takes advantage of existing bearing walls either in shafts, parking deck ramp walls, or interior or exterior walls. In some applications, precast walls are connected to form stiffer shapes, such as boxes or cruciforms.

Precast structural walls are connected by several means, depending on the design lateral force level. Bolting, welding, or dowel connections are used for the lower seismic force levels that prevail in the U.S. (Fig. 5.1a, typical dowel connection) for shear wall connections.

For higher seismic force levels, post-tensioning or rein-forcing bar splice mechanisms are used to connect the precast panels to their foundation or to each other, following the requirements of Chapter 21 of ACI 318-11. The crit-ical connection in wall systems is usually the connection between the precast panel and the cast-in-place foundation. This is the location of maximum shear and moment caused by lateral loads.

The University of California, San Diego (UCSD) PRESSS project (Fig. 5.1b) tested a five-story, all-precast struc-tural wall system connected with unbonded vertical post-tensioning with excellent results (Priestley et al. 1999). The five-story walls were connected vertically along panel sides with highly ductile welded connections that allowed

the panels to rock about their base with little damage to the panels. The vertical unbonded post-tensioning righted the panel after lateral loading as described in ACI ITG-5.1.

In parking structures, solid walls have been replaced with panels with large openings for increased visibility and personal safety. These panels can be connected as described previously.

Structural wall systems can be constructed with long horizontal walls (20 to 45 ft [6 to 13.5 m] wide) or narrow vertical walls (7 to 12 ft [2 to 3.5 m] wide). In the latter system, the walls are typically pretensioned.

Horizontal joints in panel-to-panel connections typically contain a combination of grout to resist compressive forces through the joint plus various means of connection to resist the uplift or tension force. In regions of low seismic demands, wind loads may govern the design, and the tension connec-tion is typically a welded, bolted, or doweled connection, as shown in Fig. 3.2.4b and 5.1a. In higher seismic regions, codes require that a ductile, or Type 2, splice connection be employed. Reinforcing bar splice assemblies are often used (ACI 550.1R). Post-tensioning may also be used as a non-emulative method of connection that does not replicate the performance of cast-in-place concrete.

5.2—Structural walls with large openingsIn parking structures where solid structural walls are unde-

sirable because of personal safety concerns, large openings are placed in the structural walls for visibility. The column and beam elements of the wall around an opening are still relatively large in size and are designed to withstand the shears and overturning moments acting on them. Wall piers, which are similar to columns, have an aspect ratio of at least 2.5 length-to-width.

5.3—Moment framesPrecast moment frames take advantage of a larger

response modification factor R as compared with the lower

Fig. 5.1a—Wall panel dowel connection to footing.

Fig. 4.1.1—Tooled joint.





--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

www.daneshlink.com


R-value for structural walls. Precast moment frames are also used for more open structures and to provide more open parking structures. They can be created by either casting beams to their supporting columns to create several shapes (Fig. 5.3) or connecting the frames vertically to one another or by connecting the individual beams to columns with field connections.

ACI 318 and IBC 2006 provide three categories of moment frames:

1) Ordinary: R = 3, Cd = 2-1/22) Intermediate: R = 5, Cd = 4-1/23) Special: R = 8, Cd = 5-1/2The response modification factor, which directly affects

the base shear, is significantly different for each frame type. Increasing the R-value requires more rigorous reinforce-ment detailing to achieve the more ductile performance of the frame implied by the higher R-value. Increasing the R-value increases the degree of difficulty for both design and

Fig. 5.1b—PRESSS test structure with wall panel connection.

Fig. 5.3—Combination of beams and columns to create a moment frame.





--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

www.daneshlink.com


detailing, but yields a significant reduction in the base shear, which can yield significant savings in the overall seismic-load-resisting system. Lateral drift limits remain the same for all frame systems. The Cd multiplier increases with system ductility so the elastic displacement of ductile systems is lower.

ACI 318 provides design requirements for the three afore-mentioned frame types. As required by ACI 318, the designer should, for the special moment frame connections, emulate a cast-in-place moment frame with either Type 2 reinforcing bar splice assemblies or post-tensioning.

5.3.1 Ordinary frame—The ordinary frame is designed for Seismic Design Categories A and B (ASCE/SEI 7-05) and only needs to meet the requirements in ACI 318-11, Chap-ters 1 to 18. Typical precast moment frame shapes are shown in Fig. 5.3, and a moment frame is shown in Fig. 5.3.1.

5.3.2 Intermediate and special frames—Frames in higher seismic activity regions are typically connected using rein-forcing bar splice components. Section 21.6 of ACI 318-11 provides requirements for the design of special moment frames constructed using precast concrete. As noted, precast moment frames not meeting these criteria should follow ACI T1.2/T1.2M and ACI 374.1. This requires control of dowel bar installation in the cast-in-place foundation, which is accomplished by using templates fabricated and installed to maintain tight tolerances. The dowel bars are installed in the precast member or in the mating cast-in-place element. When the project superintendent is informed that the required tolerances for the dowels is ±1/4 in. (±6 mm), which is more stringent than ACI 117 and ACI ITG-7, successful place-ment of dowel bars can be achieved. As many as 24 sleeves per frame have been used successfully. Bars should be held in place with a bi-level template both above and below the concrete surface to keep them straight and oriented properly. An oversized sleeve by up to two bar sizes can be cast in the foundation to allow for extra tolerance. The cast-in-place embedded bars are detailed longer than required and sawed to the required length after the concrete has set. Note that ACI 318 requires that reinforcement in ductile connections be made continuous by using Type 2 mechanical splices that provide development in tension or compression of at least 150 percent of the specified yield strength of the bars.

Special moment frames should be designed in accor-dance with Chapter 21 of ACI 318-11. Examples of special reinforcement requirements are 135-degree hooks and maximum spacing of transverse reinforcement of 6 in. (150 mm) over a specified length at each end of members. Other special requirements include maximum spacing of crossties, special requirements for development length of reinforcing bars, shear strength, and confining reinforce-ment. The general intent is to produce a member according to ACI 318-11 design requirements with adequate toughness for this special response.

CHAPTER 6—CONNECTIONSDesign criteria for connections in precast concrete should

be selected on the basis of the connections’ intended func-tion. Because the functions vary, different criteria will apply to different types of connections.

6.1—StrengthConnections should be designed to transfer the forces to

which they will be subjected during their lifetime. These forces include those caused by volume change and those required to maintain stability.

In terms of flexure, axial load, shear, and torsion, the design strength of a member’s connections should be taken as the nominal strength calculated in accordance with ACI 318, multiplied by a strength reduction factor f. PCI (2008) provides detailed information on connection design.

Strength reduction factors f are provided in Section 9.3 of ACI 318-11:

Tension controlled sections .........................................0.90Compression controlled sections: Members with spiral reinforcement .........................0.70Other reinforced members ...........................................0.65Shear and torsion .........................................................0.75Bearing on concrete .....................................................0.65The f factors for steel construction are provided in AISC

325-05.Tension and shear ........................................................0.90Welds ...........................................................................0.75Bolts and threaded fasteners ........................................0.75

6.2—DuctilityDuctility of a connection is the ability to undergo rela-

tively large, inelastic deformations before failure. In struc-tures, ductility is measured by the amount of deformation between first yield and failure. Ductility in the overall struc-ture may result from the ductility of the structural members, their connections, or both. In precast concrete structures, connection ductility can be used to contribute to the overall structure ductility. Connection ductility is achieved by ensuring that embedded load-transfer elements, such as deformed bar and headed stud anchors, welded wire rein-forcement, and other inserts are adequately anchored in the concrete, and that the erection connecting plate or bar yields. In certain situations where member depth is limited, inserts are located close to concrete member edges, to each other, or a combination of these, concrete failures may precede insert material failure. In such cases, consideration should be given to the feasibility of attaching connection inserts to member

Fig. 5.3.1—Example of precast moment frame.





--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

www.daneshlink.com


reinforcement or providing supplementary reinforcing steel for confinement. Connection failures resulting from failure of concrete are typically brittle and, as a general rule, should be avoided.

6.3—Volume change accommodationRestraint of strains caused by creep, shrinkage, and

temperature change can cause large stresses in precast concrete members and their connections. Much of the strain associated with member creep and shrinkage typically takes place before making the final connection of precast concrete members. Strains caused by temperature change, however, can be particularly damaging in exposed structures, such as parking structures. The effects of these strains should be considered in design. The connection should allow move-ment to take place to relieve the strain. In members particu-larly susceptible to sun effect, such as spandrels, bolted connections to supporting columns have been very effective (Fig. 6.3). This connection allows expansion and contrac-tion of the spandrel through tolerance in the oversized sleeve through the column.

6.4—DurabilityPlates exposed on the surface of precast units, particularly

in parking decks where deicing salts are used, should be protected by coatings such as epoxy, zinc-enriched paints, or galvanizing. Stainless steel plates may also be used in severe corrosive environments. One example of exposed plates is flange-to-flange connections in pretopped double-tee systems. Care should be taken when galvanized assemblies are used in conjunction with mild steel reinforcement. When assemblies are galvanized, strict adherence to ASTM A153/A153M will avoid possible strain and hydrogen embrittle-ment. The concrete surrounding the embed in precast members is typically of the same durable, high quality as the member with a minimum strength of the same 5000 psi (35 MPa) and a water-cementitious material ratio (w/cm) of 0.40 or less.

6.5—Fire resistanceConnections that jeopardize the structure’s stability if

weakened by fire should be protected to the same degree as required for each of the members they connect.

6.6—ConstructibilityDesign considerations for connections include:a) Standardizing products or connectionsb) Avoiding reinforcement and hardware congestionc) Checking material and size availabilityd) Avoiding penetration of forms, where possiblee) Reducing post-stripping workf) Being aware of material sizes and limitationsg) Considering clearances and tolerancesh) Avoiding nonstandard production and erection tolerancesi) Using standard hardware items and as few sizes as

possiblej) Using repetitive detailsk) Planning for the shortest possible hoist hook-up time

l) Providing for field adjustmentm) Providing accessibilityn) Using connections that are not susceptible to damage

in handlingo) Preventing the pad from walking out of the connection

where design is dependent on shims or pads to transfer loadsp) Accounting for available hoisting and shipping equip-

ment capacity when sizing members and determining joint locations

q) Performing inspections to insure a good quality control and quality assurance

r) Personnel safety

6.7—AestheticsThe final appearance should be considered in the design.

When considering production practices and erection methods, incorporate a visually pleasing final product.

6.8—Seismic requirementsConnections located in regions of the structure where large,

inelastic displacements will develop during a seismic event are classified as seismic connections. Seismic design proce-dures assume energy dissipation by the formation of plastic mechanisms. When mechanisms occur at joints connected by seismic connections, energy is dissipated through inelastic deformations of connections. The seismic design of connec-tions may be necessary in regions of low seismic intensity because the large mass of concrete structures combined with poor soils can generate significant lateral forces. Proper design of seismic connections is required to ensure the satisfactory performance of commonly used seismic-load-resisting systems.

6.9—TolerancesTolerances are specified to permit acceptable deviations

in the dimensions of products during their fabrication and installation considering economical and practical produc-tion, erection, and interfacing aspects. The designer should realize that normal fabrication, erection, and interfacing tolerance preclude the possibility of a perfect fit in the field. The connection should satisfy structural integrity concerns considering the specified tolerances.

6.10—Vertical connectionsNarrow vertical wall panels can be connected rigidly to

create a single wall if connected by ductile connections. Where the wall panels are linked with ductile connections, the connections should be able to withstand extreme defor-mation. Several types of connections have been tested; the X weld plate and the U weld plate (Fig. 6.10) have been the most successful. The U plate was used in the PRESSS test (Priestley et al. 1999) and withstood the extreme drift and deformation that resulted from forces associated with the equivalent to 1-1/2 times a Zone 4 earthquake (Fig. 5.1b). The embedded anchor should be oversized, thereby causing all deformations to occur in the connecting plate that creates the connection between the panels.





--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

www.daneshlink.com


Fig. 6.3—Bolted connection.





--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

www.daneshlink.com


CHAPTER 7—ERECTION CONSIDERATIONSErection procedures should be considered by consulta-

tion with the erector when precast concrete connections are designed. If more than one connection detail satisfies struc-tural requirements, the selected detail should be one that expedites both production and erection. Details best suited for erection may require compromise of some production consid-erations. If possible, the same connection methods and mate-rials should be used throughout the project. As an example, if some spandrels are bolted to the columns, all spandrels should be bolted—both load-bearing and non-load-bearing—with the same size bolt. The number of different sizes of field connection hardware, standardize plate sizes, weld sizes, and bolt sizes should be as small as possible. Connections should be designed so that a member can be unhooked from the crane in the shortest amount of time.

The following erection items should be considered when designing connections:

a) Planning for the shortest possible hoist hook-up timeb) Providing for field adjustmentc) Providing accessibilityd) Using connections that are not susceptible to damage

from handlinge) Identifying proper design, location, use, and restraint

of shimsf) Determining when to shim and when to dry-packg) Avoiding unbalanced loading due to loading on one

side of member if possibleh) Determining temporary bracing/erection stabilityi) Identifying location of weldsj) Considering hoisting equipment capability and capacity

when determining the connection locationPractice has shown that when member bearing plates

are welded to supports, excess stresses can build up due to

shrinkage, creep, or loading. If this can affect stability, atten-tion should be given to detailing the welded members. As a solution, alternate ends of alternate tees should be welded if the ends have to be welded to the support.

CHAPTER 8—WELDING CONSIDERATIONS

8.1—Steel assembliesWelded connections are structurally efficient and easily

adjust to varying field conditions. The strength of a welded connection depends on reliable workmanship and the compatibility of welding materials to the metals to be joined. As in all assemblies, welding in temperatures below 32°F (0°C) may require heating of materials to be joined because of the possibility of fractured welds. Surfaces to be welded, and surfaces adjacent to a weld, should be uniform and free from fins, tears, cracks, loose or thick scale, slag, rust, moisture, grease, paint, or other foreign material that would prevent proper welding or produce objectionable fumes.

When reinforcing steel is welded to structural steel members, the project specification for structural steel should apply. When joining different grades of steel, the filler metal should be selected for the lower-strength base metal.

8.2—Galvanized steelGalvanized metal is a material requiring proper surface

treatment of the connecting plates prior to welding. One of the three following methods should be used for welding galvanized steel.

8.2.1 Welding with zinc coating removed—When galva-nizing on mating surfaces should be removed, AWS D1.1/D1.1M and D1.4/D1.4M should be used. The zinc should be removed at least 2 to 4 in. (50 to 100 mm) from either side of the intended weld zone and on both sides of the work piece, if possible.

When galvanized steel is welded, some of the zinc is vola-tilized on each side of the weld and while a thin layer of zinc-iron alloy remains, there is a loss in corrosion resis-tance. In the cases of zinc-rich painted steel, welding causes decomposition of the paint film, which is burnt off for some distance on each side of the weld. The width of the damaged zone will depend on the heat input and preheat.

Removing zinc at the weld location is the most conserva-tive approach in welding galvanized steel. Welding proce-dures will then be the same as for uncoated steel. Zinc can be removed by burning with a carbon arc or an acetylene torch while using an oxidizing flame, by shot blasting with portable equipment, or by grinding with silicone carbide abrasive disks. Replace the zinc in the removed region with a zinc-rich coating after welding is completed.

8.2.2 Welding with zinc coating intact—It is possible to leave the galvanized coating and weld using galvanized base metal with the thickest coating anticipated and qualified by test in accordance with AWS D1.1/D1.1M or D1.4/D1.4M. AWS D1.1/D1.1M and D1.4/D1.4M permits welding over surfaces with coatings equal to or less than the zinc-rich paints. There are zinc-rich paints specially formulated to eliminate the need to remove the coating from the weld path

Fig. 6.10—Deformable connection used in PRESSS research. Uplates deform as connection accepts load.





--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

www.daneshlink.com


before welding. A letter should be obtained from the coating manufacturer stating it is weldable. Porosity may occur in certain weld joint designs in galvanized steel, depending on coating thickness, due to volatilization of the zinc in the coating and entrapment of gas in the weld. This type of joint with coatings affects porosity because gasses cannot readily escape from tee joints or from butt joints in thick materials. In the case of tee or butt joints, a “V” edge preparation or a gap between the plates allows the gasses to escape and minimizes porosity. Pore formation is also influenced by the thickness of the galvanized coating relative to the base material.

8.2.3 Welding galvanized steel—In general, manual metal arc welding procedures for galvanized steel are similar to those for welding uncoated steel. Welding of galvanized steel requires that the welder receive specialized training. In addition to the added qualifications of the welder and the welding procedure itself, using the thickest coating antici-pated is strongly recommended.

In either case, the weld areas should be given a coat of zinc-rich paint (95 percent) or epoxy paint immediately after welding and chipping off the slag to replace the galvanizing that was removed earlier. Hardware should be properly cleaned before applying a protective treatment. Paint all weld areas on primed, exposed, or accessible steel anchorage devices with a rust-inhibitive primer. Care should be taken when welding in the vicinity of a bearing pad to avoid damage to the pad.

Welding electrodes EXX10 and EXX11S should be applied slower than usual with a whipping action that moves the electrodes forward 1/8 to 5/16 in. (3 to 8 mm) along the seam in the direction of progression and then back into the molten pool. All volatilization of the galvanized coating should be complete before the bead progresses. This will prevent zinc entrapment in the weld metal.

A short arc length is recommended for welding in all posi-tions to give better control of the weld pool and to prevent either intermittent excess penetration or undercutting.

Slightly wider gaps, up to 3/32 in. (2 mm), are required in butt joints or a 15-degree angle on the edge of a standing plate for complete penetration. A gap also allows the zinc and its gases to escape, and reduces cracking caused by restraint as the weld thickness increases.

Avoid weaving and multiple weld beads. Heat input into the joint should be kept to a minimum to avoid undue damage to the adjacent coating.

When welding galvanized steel, hydrogen-induced cracking of the heat-affected zone may occur in the base plate adjacent to the weld. Cracking can be avoided by using precautionary measures such as reducing the cooling rate of the joint, preheating, or using large-diameter elec-trodes at high currents. The hydrogen content of a weld can be increased when it is deposited on galvanized or zinc-rich primed steel. This extra hydrogen originates from the pickling process in galvanizing, or from the decomposition products of primers. It may be necessary to either remove primers from the vicinity of the joint before welding or use a higher preheating temperature than would be used on uncoated steel.

8.3—Stainless steelThe general procedure for welding low-carbon steels

should be followed when welding stainless steel plates to other stainless steel plates or to low-carbon steel, bearing in mind the differences in stainless steel characteristics, such as higher thermal expansion and lower thermal conductivity. Stainless steel welding should be done by qualified welders familiar with the weld requirements of these alloys. Austen-itic stainless steels are best welded without preheat, except to reduce shrinkage stresses on sections over 1-1/4 in. (30 mm) thick or on restrained joints. Because preheat, interpass temperature below 350°F (177°C), or stinger-bead technique will reduce the time the heat-effected zone is in the sensi-tizing range (800 to 1400°F [427 to 760°C]), the amount of carbon precipitation and warpage are reduced. Preheating is necessary when carbon steel is welded or the temperature of the components to be welded is less than 32°F (0°C).

Stainless welds are not as penetrating as those in carbon steels and the weld metal is slightly more sluggish leaving the weld rod. Joints in stainless welds need to be more open to obtain penetration and fusion.

For vertical and overhead welding positions, electrodes should be 5/32 in. (4 mm) in diameter or less. For vertical welds on a 3/16 in. (5 mm) (or less) thick plate, make the weld vertically down using small beads; on thicker plates, the triangular weave technique should be used while welding vertically upward.

With relatively high coefficient of thermal expansion and lower thermal conductivity of austenitic stainless steel, take precautions to avoid weld bead cracking, minimize the distortion of steel, and avoid cracking of the concrete.

The following guidelines should be followed to minimize these problems:

a) Lower the weld current consistent with sufficient pene-tration to reduce the heat input to the work

b) Use skip-weld techniques to minimize heat concentrationc) Apply other cooling techniques to dissipate heatd) Use tack welding to hold the parts in alignment during

weldinge) Vary the sequence of weldingf) Keep edges free from adjacent concrete to allow for

expansion during welding when stainless steel connection plates are used

8.4—ReinforcementWhen welding of reinforcement is used to make a connec-

tion, weldability characteristics of the reinforcement should be considered especially for ASTM A615/A615M reinforcing bars (Rodriguez and Rodriguez 2006). Minimum preheating and interpass temperatures for welding reinforcing bars, when required, should consider the highest carbon equiva-lent number of the base metal. A chemical analysis estab-lishes the weldability of reinforcing bars. The results of the analysis determine the applicable welding procedures and preheat and interpass temperature requirements. Striking an arc outside of the weld area of the reinforcing bar should be avoided. One practical method of preheating reinforcing bar and insert plates is to use an oscillating torch while





--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

www.daneshlink.com


measuring preheat with a temperature level or heat-sensitive chalk. By using the torch, a localized preheated area can be obtained. This will simplify the welding process. The entire plate or bar does not need to be heated. Heat-sensitive chalk is designed to change color or melt when the desired temper-ature is reached (Soudki et al. 1995).

If preheating is required, heat the reinforcing bar until the cross section of the bar is at or above the minimum tempera-ture for at least 6 in. (150 mm) at the intended weld location.

As is typical for all welded surfaces, surfaces of reinforcing bars to be welded and surfaces adjacent to welds should be free from loose or thick scale, slag, rust, moisture, grease, epoxy coating, or other foreign material that would prevent proper welding or produce objectionable fumes. Mill scale that withstands vigorous wire brushing, a thin rust-inhibitive coating, or anti-spatter compound, may remain. Shape the ends of reinforcing bars in direct butt joints to form the weld groove by oxygen cutting, air carbon arc cutting, sawing, or other mechanical means. Bars for direct butt joints that have sheared ends should be trimmed back beyond the area deformed by shearing.

Welding galvanized reinforcing bars without prior removal of the coating should be performed in accordance with AWS D1.4/D1.4M. Welding of galvanized metal may also be done after all coating is removed from within 2 in. (50 mm) of the weld joint. Remove the galvanized coating with oxyfuel gas flame, abrasive shot blasting, or other suitable means.

8.5—Welding practices for epoxy-coated materialWhen welding or preheating an epoxy-coated base mate-

rial, remove the epoxy coating from the surfaces to be heated. After welding, apply a suitable protective coating of zinc-rich or epoxy paint to the finished joint to restore the corrosion-resistance properties of the coated bars.

CHAPTER 9—GROUTINGField-placed grout is used in both tension and compression

connections to fill horizontal and vertical spaces between members, protect connections, and provide the load-transfer material in reinforcing bar splice sleeves and dowels. Proprietary grouts are frequently required in proprietary connection devices. In typical compression connections, the grout exceeds the strength of the supporting members by a minimum of 1000 psi (7 MPa). Grout should be subject to quality-control testing to ensure that adequate strength can be attained.

Precast wall panels are often erected by stacking on shims placed to align and level the assembly. The resulting joints are subsequently grouted. Place the grout in the joint as soon as practical after the panel is erected, ensuring that subsequent loads do not overstress the bearing under the shims and the load is distributed over the intended joint. Precast columns are also erected with a grouted joint base. Complete the connection between anchor bolts and shims before grouting, and grout the column base as soon as possible because the anchor bolts and shims are usually not suitable to take the full column dead load without distress in the supporting pier.

The maximum erection progress before grouting should be established as part of the erection procedure.

Most grouting is gravity placed. When grout is pumped into a sleeve or cavity, however, pump it from the bottom until grout escapes from a port at the top of the sleeve. In some instances where increased performance is necessary, such as in hybrid frames, fibers are added to the grout to toughen the joint and improve performance. Shrinkage of grout as it cures can be detrimental to the performance of the joint. Shrinkage can be compensated for by the use of commercially available, nonshrink, premixed grout.

CHAPTER 10—REFERENCESCommittee documents are listed first by document number

and year of publication followed by authored documents listed alphabetically.

American Concrete InstituteACI 117-10—Specification for Tolerances for Concrete

Construction and Materials (ACI 117-10) and CommentaryACI 318-11—Building Code Requirements for Structural

Concrete (ACI 318-11) and CommentaryACI 374.1-05—Acceptance Criteria for Moment Frames

Based on Structural Testing and CommentaryACI 550.1R-09—Guide to Emulating Cast-in-Place

Detailing for Seismic Design of Precast Concrete StructuresACI 544.1R-96—Report on Fiber Reinforced Concrete

(Reapproved 2009)ACI ITG-5.1-07—Acceptance Criteria for Special

Unbonded Post-Tensioned Precast Structural Walls Based on Validation Testing

ACI ITG-7-09—Specification for Tolerances for Precast Concrete

ACI T1.2/T1.2R-03—Special Hybrid Moment Frames Composed of Discretely Jointed Precast and Post-Tensioned Concrete Members

American Institute of Steel ConstructionAISC 325-05—Steel Construction Manual

American Society of Civil EngineersASCE/SEI 7-05—Minimum Design Loads for Buildings

and Other Structures

American Welding SocietyD1.1/D1.1M:2010—Structural Welding Code—SteelD1.4/D1.4M:2005—Structural Welding Code—Rein-

forcing Steel

ASTM InternationalASTM A153/A153M-09—Standard Specification for

Zinc Coating (Hot-Dip) on Iron and Steel HardwareASTM A615/A615M-12—Standard Specification for

Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement

International Code CouncilIBC 2006—International Building Code





--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

http://www.concrete.org

http://www.aisc.org/

http://www.asce.org/

http://www.aws.org/w/a/

http://www.astm.org

http://www.iccsafe.org/Pages/default.aspx

www.daneshlink.com


Cheok, G. S., and Stone, W. C., 1994, “Performance of 1/3 Scale Model Precast Concrete Beam Column Connection Subjected to Cyclic Inelastic Loads—Report No. 4,” Report No. NISTIR 5436, Building and Fire Research Laboratory, NIST, Gaithersburg, MD, 59 pp.

Iverson, J. K., and Hawkins, N. M., 1994, “Performance of Structures During the Northridge Earthquake,” PCI Journal, V. 39, No. 2, pp. 38-55.

Park, R., and Paulay, T., 1975, Reinforced Concrete Struc-tures, John Wiley and Sons, Inc., New York, 792 pp.

PCI, 2008, Connections Manual MNL-138-08—For Precast and Prestressed Concrete Construction, Precast/Prestressed Concrete Institute, 449 pp.

PCI Committee on Connection Detail, 1995, addendum to “Design and Typical Details of Connections for Precast/Prestressed Concrete,” PCI Journal, Sept.-Oct., pp. 46-57.

PCI Committee on Connection Detail, 1998, “Standard Precast Connections—PCI Committee on Connection Details,” PCI Journal, V. 43, No. 3, July-Aug., pp. 42-58.

Priestley, M. J. N.; Sritharan, S.; Conley, J. R.; and Pampanin, S., 1999, “Preliminary Results and Conclu-

sions from the PRESSS Five-Story Precast Concrete Test Building,” PCI Journal, V. 44, No. 6, Nov.-Dec., pp. 42-67.

Rodriguez, M. E., and Rodriguez, A., 2006, “Welding of Rebars in Reinforced Concrete Structures in Seismic Zones of Mexico Must be Avoided,” Revista de Ingenieria Sismica, Sociedad Mexicana de Ingenieria Sismica, V. 75, pp. 69-95.

Schoettler, M. J.; Belleri, A.; Zhang, D.; Restrepo, J. L.; and Fleischman, R. B., 2008, “Preliminary Results of the Shake-Table Testing for the Development of a Diaphragm Seismic Design Methodology,” PCI Journal, Winter, pp. 100-124.

Soudki, K.; Rizkalla, S.; and LeBlanc, B., 1995, “Hori-zontal Connections for Precast Concrete Shear Walls Subjected to Cyclic Deformations—Part I; Mild Steel Connections,” PCI Journal, V. 40, No. 3, pp. 78-96.

Stanton, J. F.; Anderson, R. G.; Dolan, C. W.; and McCleary, D. E., 1986, “Moment Resistant Connections and Simple Connections: A Summary of PCISFRAD Projects 1 and 4,” PCI Journal, V. 32, No. 2, Mar.-Apr., pp. 62-74.





--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

www.daneshlink.com


As ACI begins its second century of advancing concrete knowledge, its original chartered purpose remains “to provide a comradeship in finding the best ways to do concrete work of all kinds and in spreading knowledge.” In keeping with this purpose, ACI supports the following activities:

· Technical committees that produce consensus reports, guides, specifications, and codes.

· Spring and fall conventions to facilitate the work of its committees.

· Educational seminars that disseminate reliable information on concrete.

· Certification programs for personnel employed within the concrete industry.

· Student programs such as scholarships, internships, and competitions.

· Sponsoring and co-sponsoring international conferences and symposia.

· Formal coordination with several international concrete related societies.

· Periodicals: the ACI Structural Journal and the ACI Materials Journal, and Concrete International.

Benefits of membership include a subscription to Concrete International and to an ACI Journal. ACI members receive discounts of up to 40% on all ACI products and services, including documents, seminars and convention registration fees.

As a member of ACI, you join thousands of practitioners and professionals worldwide who share a commitment to maintain the highest industry standards for concrete technology, construction, and practices. In addition, ACI chapters provide opportunities for interaction of professionals and practitioners at a local level.

American Concrete Institute38800 Country Club DriveFarmington Hills, MI 48331U.S.A.Phone: 248-848-3700Fax: 248-848-3701

www.concrete.org





--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

www.concrete.org

www.daneshlink.com



The AMERICAN CONCRETE INSTITUTE

was founded in 1904 as a nonprofit membership organization dedicated to public service and representing the user interest in the field of concrete. ACI gathers and distributes information on the improvement of design, construction and maintenance of concrete products and structures. The work of ACI is conducted by individual ACI members and through volunteer committees composed of both members and non-members.

The committees, as well as ACI as a whole, operate under a consensus format, which assures all participants the right to have their views considered. Committee activities include the development of building codes and specifications; analysis of research and development results; presentation of construction and repair techniques; and education.

Individuals interested in the activities of ACI are encouraged to become a member. There are no educational or employment requirements. ACI’s membership is composed of engineers, architects, scientists, contractors, educators, and representatives from a variety of companies and organizations.

Members are encouraged to participate in committee activities that relate to their specific areas of interest. For more information, contact ACI.

www.concrete.org





--``,```,`,`,`,,,,`,`````,`,,`,,-`-`,,`,,`,`,,`---

daneshlink.com

Daneshlink.com

www.concrete.org

www.daneshlink.com


aci 550.2r-13: design guide for connections in precast ......aci 550.2r-13 design guide for...

Documents