composite steel and concrete structural systems for seismic engineering and axial loading

8/17/2019 Composite Steel and Concrete Structural Systems for Seismic Engineering and axial loading

http://slidepdf.com/reader/full/composite-steel-and-concrete-structural-systems-for-seismic-engineering-and 1/21

Journal of Constructional Steel Research 58 (2002) 703–723www.elsevier.com/locate/jcsr

Composite steel and concrete structural systemsfor seismic engineering

Jerome F. Hajjar∗

Department of Civil Engineering, 500 Pillsbury Drive SE, University of Minnesota, Minneapolis, MN

55455-0116, USA

Received 23 May 2001; received in revised form 16 August 2001; accepted 19 October 2001

Abstract

Research within the United States on seismic engineering of buildings using compositesteel/concrete structural systems has increased dramatically in the past decade. This paper

summarizes recent research on a number of these composite lateral resistance systems, includ-ing unbraced moment frames consisting of steel girders with concrete-filled steel tube (CFT)or steel reinforced concrete (SRC) columns; braced frames having concrete-filled steel tubecolumns; and a variety of composite and hybrid wall systems. The benefits of these structuralsystems relative to more common systems include their performance characteristics when sub-

jected to service or ultimate loads, and their economy with respect both to material and con-struction. In addition, more in-depth research results will be presented on one of these com-posite systems, consisting of partially-restrained steel frames with composite reinforcedconcrete infill walls. The paper concludes with a summary of probable future design provisionsfor these composite systems. © 2002 Elsevier Science Ltd. All rights reserved.

Keywords: Beam-column; Beam-to-column connection; CFT; Composite construction; Composite wall

system; Concrete-filled steel tube; HWS; Hybrid wall system; Seismic engineering; SRC; Steel

reinforced concrete

1. Introduction

Composite construction in steel and concrete offers significant advantages for useas the primary lateral resistance systems in building structures subjected to seismic

∗ Tel.: +1-612-626-8225; fax: +1-612-626-7750.

E-mail address: [email protected] (J.F. Hajjar).

0143-974X/02/$ - see front matter © 2002 Elsevier Science Ltd. All rights reserved.

PII: S 0 1 4 3 - 9 7 4 X ( 0 1 ) 0 0 0 9 3 - 1



706 J.F. Hajjar / Journal of Constructional Steel Research 58 (2002) 703 – 723

US design provisions, which currently do not permit the use of high strength

materials in composite columns. Research at Lehigh University is continuing on the

testing of multi-story, multi-bay composite CFT braced and unbraced frame struc-

tures that will provide comprehensive data on the performance of this type of system.Roeder et al. [5] at the University of Washington undertook a set of experiments

investigating bond strength along the interface of full-scale circular concrete-filled

steel tubes beam-columns. They conducted a series of twenty push-out studies in

which the concrete core was loaded at the top of the column while only the steel

tube was supported at the bottom. The steel tubes had diameters ranging from 250mm to 650 mm, with ratios of width-to-thickness between approximately 20 and

110. Normal strength materials were used. The primary parameters of interest were

the diameter of the concrete core, the thickness of the steel tube, and the shrinkage

of the concrete core. Roeder et al. [5] also compared their results with prior research

worldwide on bond in CFTs. They then provided a formula for estimating the bond

strength of CFTs subjected to axial force.

Their experiments, coupled with the past research, showed that bond strength in

CFTs was relatively large for CFTs with a small diameter, but signi ficantly smaller

for CFTs with a large diameter, as shown in Fig. 1 (after Roeder et al. [5]). The bond

stress was shown to be distributed relatively uniformly around the tube perimeter at

the ultimate bond strength of the CFT. In addition, shrinkage was seen to be both

noticeable and detrimental to bond strength, particularly in CFTs with larger diam-

eters or high D/t ratios. It was suggested that care should thus be taken with the

concrete mix if bond strength is relied upon in design. Cyclic loading was also shownto decrease the bond strength. Shear connectors were shown to not work well in

conjunction with interface friction; either friction or shear connectors should be relied

upon independently in design. Roeder et al. [5] also noted that bond strength

increases significantly in the presence of bending moment due to the binding action

Fig. 1. Experimental resultings documenting variation in bond stress with circular CFT tube diameter

(after Roeder et al. [5]).




of the steel against the concrete. Together, these recommendations provide a basis

for detailing CFT connection regions, particularly for braced frames in which the

CFTs may be subjected to high axial forces and low bending moments. Research at

the University of Washington is continuing on developing connection details forgirders and braces framing into circular CFTs for use in braced composite CFT struc-

tures.

Much recent experimental research in the US has focused on development of new

strategies for connecting steel I-girders to circular and rectangular CFT beam-col-

umns to establish fully-restrained connections for use in moment frames. As anexample of this research, Schneider and Alostaz [6] at the University of Illinois at

Urbana/Champaign conducted a series of experiments focusing on circular CFTs. In

this work, the test set-up consisted of a steel I-girder framing into a CFT having

pin-pin boundary conditions. The girder was then loaded cyclically at its tip. Six

different connection topologies were investigated. These included a simple welded

connection (with the girder flange welded to a flange plate that was in turn welded

to the circular CFT) (Type I); a connection with an external diaphragm plate sur-

rounding the CFT, to which the girder was welded (Type II); a connection similar

to Type I but with the girder web welded to a vertical plate that was continuous

through the CFT (Type III); a connection similar to Type I but with deformed bars

welded to the girder flanges and then embedded into the CFT (Type IV); a connection

similar to Type I but with the flanges passing continuously through the CFT (Type

V); and a connection in which the entire girder was passed through the CFT

(Type VI).The Type I, II, III, and V connections performed poorly due to being susceptible

to substantial deformation and fracture of the steel tube, diaphragm, or web. Types

IV and VI yielded excellent hysteretic behavior, indicating connections that are suit-

able for use in practice, and provide insight into the level of interaction necessary

between the steel and concrete to achieve a reliable fully-restrained connection.

Recent research on FR connections to circular CFTs at the University of Nebraska[7] provided further evidence that the pass-through connection has strong cyclic

response.

Two sets of experiments at full scale have also been completed on steel I-girders

framing into square or rectangular CFTs. Peng et al. [8] at Lehigh University testedeight specimens consisting of two W610×92 girders framing into a 406×406×12.5

CFT. The concrete strength was approximately 62 MPa, and normal strengths steel

materials were used. The pin-pin CFTs in these specimens were loaded first with

2000 kN of axial compression followed by antisymmetric cyclic loading of the gir-der tips.

A variety of welded and bolted connection topologies were tested. Three speci-

mens had girder flanges welded to the tube to transfer force to an interior diaphragm

within the CFT, with two of the specimens having tapered flange plates welded to

the flanges to help transfer the forces to the tube; two specimens had haunches

attached to the girder flanges, and three specimens used a split-tee connection withthe bolts of the split-tee passing through the CFT. Fig. 2 (after Peng et al. [8]) shows

the details of one of the split tee connections. In some of the connections, a shear




Fig. 2. Typical split-tee CFT connection specimen (after Peng et al. [8]).

tab was welded to the CFT and shear connectors ran along the CFT interior opposite

the girder shear tab; however, the results showed that the influence of the shear tab

and shear connectors in these tests was minimal.

The results showed excellent hysteretic response from the split-tee connections; atypical moment-plastic rotation curve is shown in Fig. 3 (after Peng et al. [8]). While

some strength degradation occurred after peak loading, the connections showed sig-

nificant and reliable ductility, providing a cost effective connection strategy for com-

posite CFT frames. The welded and haunched connections also performed well if

tapered plates were used to diminish the stress concentrations.

Fig. 3. Moment vs. plastic rotation for typical split-tee CFT connection specimen (after Peng et al. [8]).




A second set of tests on connections to square CFTs was conducted at the Univer-

sity of Texas at Austin [9]. Fifteen half-scale tests were conducted to study panel

zone behavior of CFTs in the connection region. Six full-scale cruciform tests, simi-

lar in set-up to the Lehigh experiments, were then conducted on CFTs ranging insize from 304 mm to 406 mm, having D/t ratios ranging from 21 to 32. Split-tee

connections were used. In some of the cruciform tests, the connection region was

designed to fail to corroborate findings from the panel zone study. Together, these

experiments provided detailed insight into the response of the split-tees and panel

zone region in these connections. Coupled with the Lehigh research, a significantknowledge base now exists for finalizing specification provisions for the design of

split-tee connections to square or rectangular CFTs.

With respect to computational research geared for analyzing complete composite

CFT frames, Hajjar et al. [10–12] at the University of Minnesota developed two

geometrically and materially nonlinear beam-column finite element models for CFTs,

both suitable for use in three-dimensional monotonic static, cyclic static, or transient

dynamic time history (seismic) analysis of composite CFT structures. The first for-

mulation was a macro beam-column element in which the material model consisted

of a concentrated plasticity bounding surface formulation in three-dimensional stress-

resultant (force) space. A polynomial expression developed to represent the CFT

cross-section strength was incorporated into this material model to represent the

force-space yield surfaces. New formulations were presented for isotropic and kinem-

atic hardening of the loading and bounding surfaces to model strength degradation

and stiffness deterioration seen in CFTs subjected to cyclic loading. The secondmodel was a fiber beam-column element, in which the uniaxial stress–strain response

was tracked throughout the CFT cross section and along the member length. This

element modeled slip explicitly between the concrete core and steel tube, and was

thus able to track the detailed response of CFT beam-columns as part of composite

frames. Both models were verified against a comprehensive set of experimental data,

and were accurate for a wide range of concrete-filled tube cross section sizes andmaterial strengths. Ongoing research involves conducting parametric studies of the

behavior of CFT framing systems to study the deformation and strength demands

placed on components of composite CFT frames, which, together with the recent

experimental research, will provide the data needed to establish more comprehensiveCFT performance-based design recommendations for seismic engineering.

3. Steel-reinforced concrete

A wide range of research has been conducted in recent years on a variety of steel-

reinforced concrete members and connections for use in lateral resistance systems.

Steel reinforced concrete beam-columns have the potential to provide excellent

strength and ductility relative to reinforced concrete members. In addition, the

encased steel section is often erected for several stories above the concrete pour,

enabling steel girders to be framed into the steel columns. This in turn facilitatesongoing construction of the remainder of the steel structure. Longitudinal reinforce-

ment in the columns is also diminished.




As a sample of this research, Xiao et al. [13] at the University of Southern Califor-

nia, conducted a series of tests on large-scale (254 mm square; 2.2 m long) RC and

SRC beam-columns subjected to constant axial force plus cyclic shear, placing the

member into double curvature, as would be exhibited by a beam-column in amoment-resisting frame structure. Concrete strengths of 40 and 70 MPa were used,

along with normal strength steel. The results showed excellent response of the SRC

beam-columns for both concrete strengths, with improved ductility over the corre-

sponding RC member.

A number of different experimental studies were also conducted in recent yearson steel or composite I-girders framing into RC or SRC beam-columns. Two are

presented herein. Chou and Uang [14] at the University of California at San Diego,

developed a new structural system consisting of stubs of I-girders connecting rigidly

to the encased steel column within an SRC beam-column. This tree system would

be preassembled and bolted to steel girders in the field. This construction approach

allows the critical welds of the steel components to be conducted in the shop. In

addition, it facilitates construction of the reinforcing bar cages in the SRC beam-

column, as reinforcing bars must often pass through the girder webs in SRC construc-

tion. However, in one specimen, a steel jacket surrounded the SRC beam-column in

the connection region, in lieu of using stirrups in the column near the connection.

Adequate concrete encasement in this region is critical for good performance. For

all specimens, a reduced beam section (RBS) was used for the girders to provide a

focused location for inelastic response in the girders, away from the connection

region. A cruciform test setup was used; the column was not subjected to axial force.Normal strength materials were used. The results of all three tests were excellent,

with full hysteresis loops extending beyond 3.5% plastic rotation, with little

strength degradation.

Researchers at Texas A&M University [15,16] tested six large-scale three-dimen-

sional subassemblages consisting of composite girders framing into SRC beam-col-

umns. Fig. 4 (after Bugeja et al. [16]) shows the details of one of the specimens. Inthese tests, one W310×33 steel girder was continuous through the column in one

direction. For the two W310×33 girders in the other direction, various details were

used involving a bolted shear tab, top and seat angles, and different configurations

of face bearing plates (FBPs). The W200×15 steel wide-flange member, embeddedwithin a 380 mm square SRC column, framed into the top and bottom of the through-

girder. A 90 mm reinforced concrete slab on metal deck was cast compositely with

the girders, and composite action was assumed for transferring the top girder flange

force into the connection for four of the specimens. One specimen represented anexterior connection, with only two quadrants of the slab shown in Fig. 4 being poured

for that specimen. For reinforcing the connection region, the specimen shown in Fig.

4 used bent FBP’s to permit the use of fillet welds rather than joint penetration welds

to the girder webs. Normal strength materials were used.

With the column pinned at each end, antisymmetric cyclic loading was imposed

on the through-girder in-plane until some strength degradation was seen betweentwo cycles at the same deformation level. Cyclic loading was then imposed on the

two discontinuous girders in the perpendicular direction until failure of the specimen.




Fig. 4. Typical SRC connection specimen (after Bugeja et al. [16]).

Axial compression was applied to the column throughout the test. A typical moment-rotation response is shown in Fig. 5 (after Bugeja et al. [16]) for cycling of the two

discontinuous girders of the specimen shown in Fig. 4. Plastic hinges formed in the

composite girders away from the connection, leading to strong performance of this

connection detail. Careful consideration was given in this research to constructionsequencing and providing a range of cost-effective connection details.

Fig. 5. Moment vs. rotation of typical SRC connection specimen (after Bugeja et al. [16]).




Recent computational research for SRC lateral resistance systems has included the

work of Mehanney and Deierlein [17] at Stanford University, who conducted exten-

sive transient dynamic analyses of SRC frame structures to assess seismic demand

through characterization of damage. Through this work, they were able to study theresponse modification factors and seismic stability of these systems.

4. Composite and hybrid wall systems

Several recent research projects have focused on composite and hybrid wall struc-

tures. Composite walls systems in particular offer outstanding advantages as lateral

resistance systems in areas ranging from low to high seismicity. These include ease

of construction through use ductile wall system details that potentially offer less

congestion of reinforcing bars than in RC frames, coupled with gravity steel framing

throughout the rest of the building; ability to use the walls as architectural partitions

in a wide range of configurations in contrast to, for example, steel braced frames;

high initial stiffness to help reduce drift; good damping characteristics; and poten-

tially easier repairs after moderate damage through using epoxy on the cracked wall.

Shahrooz et al. [18] at the University of Cincinnati conducted extensive research

on the connection of steel gravity beams or trusses to reinforced concrete shear walls,

with the beam framing into the wall either in-plane or out-of-plane. Achieving robust

and ductile connections of this common type of connection is critical for reliable

and safe performance of hybrid structures. This work complements extensive paststudies conducted by the researchers on coupling beams for shear walls.

In the first phase of this research, seven specimens were tested that represented

the beam-wall connections, subjected to combined shear due to gravity and cyclic

axial tension load representing diaphragm forces. A variety of different connection

details were investigated. Although current design provisions underpredicted the con-

nection strength of all specimens, the mode of failure was brittle in several of thespecimens that did not have adequate embedment details. The confinement and

detailing of the embedded portions of the connection were critical to good perform-

ance. In the second phase of research, a test setup was developed that could further

test these connections, but with the wall also subjected to cyclic forces inducingpotential cracking and crushing in the region of the beam-wall connection; this

research is ongoing.

There is also extensive ongoing research on composite wall systems. Wallace [19]

at the University of California at Los Angeles is investigating the cyclic responseof reinforced concrete shear walls having encased steel wide-flange sections as the

boundary elements. Six specimens at approximately one-third scale will be tested

during the project. This system offers ease of construction through being able to

frame the gravity steel framing into the erection columns in the boundary elements.

Astaneh-Asl and Zhao [20] at the University of California at Berkeley are

investigating steel framing with steel plate shear walls. A concrete wall is cast paral-lel to and in contact with the steel plate shear wall to provide stability to the wall,

with bolts used to connect the two components throughout. In addition, a gap is




retained along the interface between the concrete panel and the steel framing to help

mitigate damage in that region. Several specimens are due to be tested.

Researchers at the University of Minnesota [21,22] have investigated the cyclic

response of partially-restrained steel frames with reinforced concrete infill walls (S-RCW). The infill walls are attached to the steel frame with shear connectors to form

a composite wall system. The testing program included twelve tests of shear connec-

tors in infill wall panels, and one test of a two-story, one-bay, one-third scale speci-

men representing the structural system. More in-depth results of this project are

presented below.In addition to the advantages listed above for composite wall systems, in the S-

RCW system, the concrete provides protection to the steel girder and PR connection

at low levels of earthquake loading, thus enhancing the integrity of the system for

smaller seismic events. Energy dissipation is achieved initially through cracking in

the concrete wall. For larger drift demands, inelastic response along the composite

interface, coupled with yielding in the steel frame, insure ductile response of the

system. A primary advantage of this system is that the infill wall is easily repairable

after cracking in low to moderate earthquakes, and is potentially replaceable after

more substantial events if the steel frame retains its integrity.

Having lightweight, exposed steel framing eliminates the use of costly boundary

elements in the wall, which is an important advantage of this system. Unlike braced

frames, there is no risk of excessive buckling or fracture of the braces; in contrast,

the S-RCW system has significant redundancy within each panel. In addition, in

contrast to using reinforced concrete shear walls, retaining the girders in this systemat each floor level and connecting them to the columns with inexpensive PR connec-

tions using standard connection detailing enables the steel frame to retain its integrity

for the duration of the earthquake. This progressive response thus offers an excellent

combination of features: the S-RCW system is easily constructible, is highly redun-

dant, offers several straightforward options for repair after low to moderate seismic

ground motions, and utilizes the cyclic characteristics of both the concrete and thesteel to maximum advantage.

The research initiated with a study of several prototype structures using linear

analysis and existing design provisions to determine typical member sizes and basic

system response. Fig. 6 shows a plan view of the prototype structure. Buildings of three, six, and fifteen stories were investigated. An elevation of the central wall, W1,

in the six story prototype structure is shown in the figure. The results from this study

highlighted the relative initial stiffness of the steel columns versus the infill wall,

particularly with respect to overturning moment. Different models were investigatedrelative to how the composite interaction may be modeled within the context of

linear analysis, including releasing shear connectors in the corners that were deemed

to exceed their nominal strength due to combined axial tension and shear. The

resulting component proportions of the six story prototype structure were then scaled

down to determine appropriate sizes for use in the two-story experiment, which is

intended to represent the bottom two stories of the system.Fig. 7 shows the experimental test set up for the experiments of the monotonic

and cyclic response of shear connectors in infill walls. Four shear connectors (two




Fig. 6. Prototype S-RCW structure.

on each column, spaced at 356 mm) were included within each concrete panel, which

represents a portion of the infill wall at full scale. The columns had shear connectors

on the outer flange as well, as shown in the figure, as they were turned around andreused for subsequent specimens. The test setup permitted application of constant

axial tension plus either monotonic or cyclic shear. The parameters of these experi-

ments included: application of monotonic versus cyclic shear loading; two confining

reinforcement schemes (including a lightly reinforced perimeter bar scheme, and a

confining cage); magnitude of axial tension (including 0 and 50% of the nominal

axial strength of the studs); and use of ductility enhancing devices (in the form of

polymer cones) around the shaft of the shear connectors. The average 28 day strength

of the dry-cured concrete cylinders was 32 MPa. Details of the experiments are

provided in Saari et al. [23] and Hajjar et al. [22].

Fig. 8 shows the monotonic load-slip relation of the two reinforcing schemes, aswell as the envelope for the cyclic shear response (the reinforcing cage specimens

are 5 and 8 in the figure). The cyclic results with the reinforcing cage include constant




Fig. 7. Experimental test setup fo shear connector experiments.

axial tension applied to the stud during cyclic loading. With the reinforcing cage in

place, the failure mode of the stud was always fracture of the base metal of the stud,

either in shear or tension during monotonic loading, and in low cycle fatigue during

cyclic loading. The perimeter bar scheme, in contrast, provided poor strength andductility when axial tension was applied to the stud, with complete fracturing and

separation of the concrete along the full height of the panel along a line just above

the stud head. Even with the reinforcing cage, the low cycle fatigue failure mode

limited the cyclic deformation capacity of the shear connectors to approximately 3.2

mm. The ductility enhancing device increased this cyclic shear deformation capacity

by approximately 60%. These experiments thus showed that adequate confiningreinforcement is critical to achieve strength and ductility for studs in infill wall

panels, but that low cycle fatigue of headed shear connectors may still limit the

performance of the composite interface if local demands placed on the studs are

substantial during cyclic response of the structural system as a whole. A key aspectof the two-story specimen was to determine local demand on the studs at different

levels of global response.

Fig. 9 shows the test setup for the one-bay two-story specimen. The details of the

PR connections are shown in Fig. 10, and the details of the in fill walls are shown

in Fig. 11. The dry-cured concrete strength on the day of the test, averaged from

six cylinder tests, was 25.8 MPa. The W130×28.1 (W5×19) steel columns were fabri-

cated from A572/50 steel, with an average measured steel strength in the flanges of

312 MPa; the W200×19.3 (W8×13) steel beams were fabricated from A36 steel,

with an average measured yield strength in the flanges of 340 MPa. The top and

seat angles were A36 steel and had an average measured yield strength of 363 MPa.The double web angles were A36 steel and had an average measured yield strength

of 243 MPa. The cyclic loading history included three cycles at a total drift of 0.05%,




Fig. 8. Shear-slip relations from stud connection tests.

0.20%, 0.35%, 0.50%, 0.35% repeated, 0.75%, 1.00%, and 1.25%, followed by two

cycles each at a total drift of 1.50% and 1.75%. Further details of this experiment

are given in Tong et al. [24] and Hajjar et al. [22].

Fig. 12 shows a plot of the lateral load at the top of the two-story specimen versus

total drift of the specimen. Fig. 13 shows the interstory drift of each story versus

the lateral load at the top of the structure. Through the 0.75% drift cycles, energy

dissipation occurred largely through cracking in the concrete wall and negligible

yielding occurred in the steel frame. Fig. 14 shows the progression of cracking in

the infill walls. The peak load in the structure occurred during the 0.75% drift cycles,

during which a small amount of crushing in the corners of the second story alsoinitiated. The majority of the drift occurred in the second story, which achieved a

ductility of approximately 4 at 3% interstory drift of that story. Strength degradation




Fig. 10. Partially-restrained connection detail in S-RCW specimen.

Fig. 11. Reinforcement detailing of infill wall of S-RCW specimen.




Fig. 12. Total drift versus lateral load of S-RCW specimen.

final cycles, the interstory drift of the second story was just above 3%, and the

system as a whole had stabilized its cyclic strength and stiffness characteristics.Ongoing computational research on composite wall systems is being conducted

by Kunnath and El-Tawil [25], Shahrooz et al. [18], Wallace [19], and Hajjar et al.

[22]. Together, these projects promise to substantially improve the ability to predict

the response of these lateral resistance systems. Design provisions on all of these

systems are also forthcoming.

5. Conclusion

Over the past decade there has been a significant amount of research on the

behavior and design of composite steel/concrete lateral-resistance systems for seismic

loading. Within the US, substantial progress has been made on documenting the

response of a wide range of systems that are practical for US practice. This paper

has summarized representative recent research projects focusing on three types of

structural systems: steel girders framing into concrete-filled steel tube beam-columns

for unbraced and braced frames; steel girders framing into steel-reinforced concrete

beam-columns for unbraced frames; and composite and hybrid wall systems. Both

member and connection response has been documented, and a number of compu-tational research projects are underway to corroborate the experimental research and

to provide assessments of seismic demand of these structural systems. Research




Fig. 13. Interstory drift versus lateral load of S-RCW specimen.

remains ongoing on a variety of systems, and design provisions for both non-seismic

and seismic construction are forthcoming.

Specific areas in which new non-seismic and seismic design provisions are likely

to be developed in the coming decade include:

For concrete-filled steel tube and steel reinforced concrete beam-columns, more

accurate axial, flexural, and interactive strength formulas are probable, and endors-

ing the use of high strength concrete and high performance steel is likely immi-

nent.

For connections to concrete-filled steel tubes, development of more detailed designprovisions for both braced and unbraced frames are underway that should greatly

facilitate the design of these types of systems.




author at the University of Minnesota. The author would like to thank the following

for their assistance with this research: K. Nozaka, N. Ojard, and P. Bergson of the

University of Minnesota, L. Kloiber of LeJeune Steel Company, Minneapolis, Min-

nesota, Prof. S. Mahin of the University of California at Berkeley, Prof. S. Goel of the University of Michigan, L. Wyllie, Jr., of Degenkolb Engineers, San Francisco,

California, and V. Mujumdar, Sacramento, California. The author would also like

to thank the following for providing information for this paper: Prof. G. Deierlein,

Stanford University, Prof. C. Roeder, University of Washington, Prof. J. Wallace,

University of California at Los Angeles, Prof. J. Bracci, Texas A&M University,and Prof. J. Ricles, Lehigh University.

References

[1] Grif fis LG. Composite frame construction. In: Dowling PJ, Harding JE, Bjorhovde R, editors. Con-

structional Steel Design: An International Guide. London, UK: Elsevier Applied Science; 1992. p.

523–53.

[2] Roeder CW. Overview of hybrid and composite systems for seismic design in the United States.

Engineering Structures 1998;20(4–6):355–63.

[3] Hajjar JF. Concrete-filled steel tube columns under earthquake loads. Progress in Structural Engineer-

ing and Materials 2000;2(1):72–82.

[4] Varma AH, Ricles JM, Sause R, Lu L-W. Seismic behavior of high strength square CFT beam-

columns. In: Xiao Y, Mahin SA, editors. Composite and Hybrid Structures. Los Angeles, California:

Association for International Cooperation and Research in Steel-Concrete Composite Structures;

2000. p. 547–56.[5] Roeder CW, Cameron B, Brown CB. Composite action in concrete filled tubes. Journal of Structural

Engineering, ASCE 1999;125(5):477–84.

[6] Schneider SP, Alostaz YM. Experimental behavior of connections to concrete-filled steel tubes.

Journal of Constructional Steel Research 1998;45(3):321–52.

[7] El-Remaily AF, Azizinamini A. Development of detail and design criteria for steel beam to concrete

filled tube column connections in seismic regions. Final Report to the NSF, Department of Civil

Engineering, University of Nebraska, Lincoln, Nebraska, 2000.

[8] Peng SW, Ricles JM, Lu LW. Full-scale testing of seismically resistant moment connections for

concrete filled tube column-to-wf beam hybrid systems. In: Xiao Y, Mahin SA, editors. Composite

and Hybrid Structures. Los Angeles, California: Association for International Cooperation and

Research in Steel-Concrete Composite Structures; 2000. p. 591–8.

[9] Koester BD, Uchida K, Noguchi H, Yura JA, Jirsa JO. Panel zone behavior of moment connectionsbetween steel beams and concrete-filled steel tube columns. Paper No. T169-4, Proceedings of the

First Structural Engineers World Congress, San Francisco, California, July 19–23 1998. Oxford,

UK: Elsevier Science Ltd., 1998.

[10] Hajjar JF, Gourley BC, Olson MC. A cyclic nonlinear model for concrete-filled tubes. I. Formulation.

II. Verification. Journal of Structural Engineering, ASCE 1997;123(6):736–54.

[11] Hajjar JF, Molodan A, Schiller PH. A distributed plasticity model for cyclic analysis of concrete-

filled steel tube beam-columns and composite frames. Engineering Structures 1998;20(4 –6):398–412.

[12] Hajjar JF, Schiller PH, Molodan A. A distributed plasticity model for concrete-filled steel tube beam-

columns with interlayer slip. Engineering Structures 1998;20(8):663–76.

[13] Xiao Y, Anderson JC, Yaprak TT. Seismic behavior of high-strength steel reinforced concrete com-

posite columns. In: Xiao Y, Mahin SA, editors. Composite and Hybrid Structures. Los Angeles,

CA: Association for International Cooperation and Research in Steel-Concrete Composite Structures;

2000. p. 383-392.

[14] Chou C-C, Uang C-M. Experimental studies of composite-smf connections with reinforced-concrete-




encased column and steel beams. In: Xiao Y, Mahin SA, editors. Composite and Hybrid Structures.

Los Angeles, California: Association for International Cooperation and Research in Steel-Concrete

Composite Structures; 2000. p. 729–36.

[15] Bracci JM, Moore WP, Bugeja MN. Seismic design and constructability of RCS special momentframes. Journal of Structural Engineering, ASCE 1999;125(4):385–92.

[16] Bugeja MN, Bracci JM, Moore WP, Jr. Seismic behavior of composite moment resisting frames.

Report No. CBDC-99-01, Department of Civil Engineering, Texas A&M University, College Station,

Texas, 1999.

[17] Mehanney SSF, Deierlein GG. Seismic damage indices and near-collapse performance assessment

in composite moment frames. In: Xiao Y, Mahin SA, editors. Composite and Hybrid Structures.

Los Angeles, California: Association for International Cooperation and Research in Steel-Concrete

Composite Structures; 2000. p. 111–8.

[18] Shahrooz BM, Deason JT, Tunc G. Cyclic behavior of outrigger beam-wall connections. In: Xiao

Y, Mahin SA, editors. Composite and Hybrid Structures. Los Angeles, California: Association for

International Cooperation and Research in Steel-Concrete Composite Structures; 2000. p. 785–92.

[19] Wallace JW. Lateral-load behavior of shear walls with structural steel boundary columns. In: XiaoY, Mahin SA, editors. Composite and Hybrid Structures. Los Angeles, California: Association for

International Cooperation and Research in Steel-Concrete Composite Structures; 2000. p. 801–8.

[20] Astaneh-Asl A, Zhao Q. Seismic studies of an innovative and traditional composite shear walls. In:

Xiao Y, Mahin SA, editors. Composite and Hybrid Structures. Los Angeles, California: Association

for International Cooperation and Research in Steel-Concrete Composite Structures; 2000. p.

1009–16.

[21] Schultz AE, Hajjar JF, Shield CK, Saari W, Tong X. Study of the cyclic interaction in steel frames

with composite rc infill walls, Paper No. 2727. Proceedings of the Twelfth World Conference on

Earthquake Engineering, Auckland, New Zealand, January 30–February 4 2000. Auckland, New

Zealand: New Zealand Society of Earthquake Engineering, 2000.

[22] Hajjar JF, Tong X, Schultz AE, Shield CK, Saari WK. cyclic behavior of steel frames with composite

reinforced concrete infill walls. In: Hajjar JF, Hosain M, Easterling WS, Shahrooz BM, editors.Reston, Virginia: Composite Construction in Steel and Concrete IV, ASCE. 2002, in press.

[23] Saari WK, Schultz AE, Hajjar JF, Shield CK. Behavior of shear connectors in steel frames with

reinforced concrete infill walls. Structural Engineering Report No. ST-99-1. Minneapolis, Minnesota:

Department of Civil Engineering, University of Minnesota, 1999.

[24] Tong X, Schultz AE, Hajjar JF, Shield CK. Seismic behavior of composite steel frame with

reinforced concrete infill wall (S-RCW) structural system. Report No. ST-01-1. Minneapolis, Minne-

sota: Department of Civil Engineering, University of Minnesota, 2001.

[25] Kunnath S, El-Tawil S. A connection macro-element for inelastic dynamic analysis of hybrid walls.

In: Xiao Y, Mahin SA, editors. Composite and Hybrid Structures. Los Angeles, California: Associ-

ation for International Cooperation and Research in Steel-Concrete Composite Structures; 2000. p.

127–34.

composite steel and concrete structural systems for seismic engineering and axial loading

Documents