Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicidad

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

XI Simposio – Intenacional de Estructurasde Acer

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad Presented by Thomas M. Murray, Ph.D., P.E. Department of Civil and Environmental Engineering Virginia Tech, Blacksburg, Virginia thmurray@vt.edu

XI SIMPOSIO-INTERNACIONAL DE ESTRUCTURASDE ACER 09 March 2011 1

AISC Seismic – SMF Connections

Refers to

Relies on

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

Beam-to-column connections shall satisfy the following Section 9.2a requirements: •

The connection shall be capable of sustaining an interstory drift angle of at least 0.04 radians.

•

The measured flexural resistance of the connection, determined at the column face, shall equal at least 0.80 Mp of the connected beam at an interstory drift angle of 0.04 radians.

1

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

XI Simposio – Intenacional de Estructurasde Acer

AISC Seismic – SMF Connections

AISC Seismic – SMF Connections

Requirements of Sect. 9.2a are to be satisfied by one of the following methods: 1. Conduct qualifying cyclic tests in accordance with Appendix S.

•

Tests conducted specifically for the project, with test specimens that are representative of project conditions. or Tests reported in the literature (research literature or other documented test programs), where the test specimens are representative of project conditions.

Flush Moment End-Plate w/ Sixteen 1–½ in A490 Bolts

AISC Seismic – SMF Connections 2. Use connections prequalified for SMF in accordance with Appendix P •

•

Use connection prequalified by an alternative review panel that is approved by the Authority Having Jurisdiction. or Use connections prequalified by the AISC Connection Prequalification Review Panel (CPRP) and documented in Standard ANSI/AISC 358

Seismic App. S Qualifying Cyclic Tests Permitted Test Subassemblages: Actuator Mount

Single Beam Single Column Without a concrete slab

Lateral Brace Points

Test Beam

Reaction Floor

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

Actuator Load Cell

Test Column

•

Project Specific Cyclic Test

Reaction Floor

Reaction Floor

2

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

XI Simposio – Intenacional de Estructurasde Acer

Seismic App. S Qualifying Cyclic Tests

Test Column Lateral Support Typ.

Composite Slab

W14x257

Rigid Link

Rigid Link

W24x68

W24x68

Load Step Number

Interstory Drift Angle, θ (rad)

Number of Loading Cycles

1

0.00375

6

2

0.005

6

3

0.0075

6

4

0.01

4

5

0.015

2

6

0.02

2

7 0.03 2 Continue with increments in θ of 0.01, and perform two cycles at each step

0.06 0.05 0.04 0.03 0.02 0.01 0

Angle

Actuator

Test Frame

Pin Support

Loading Protocol:

Interstory Drift

Permitted Test Subassemblages:

Seismic App. S Qualifying Cyclic Tests

-0.01 -0.02 -0.03 -0.04 -0.05 -0.06

6

6

6

4

2 2 2 2 2

Number of cycles

Reaction Frame

Note: Quasi-static testing is permitted.

There is not a required number of tests.

Seismic App. S Qualifying Cyclic Tests

Seismic App. S Qualifying Cyclic Tests

Interior subassemblage test at UT-Austin

Interior subassemblage test with concrete slab

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

3

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

Seismic App. S Qualifying Cyclic Tests Successful Conformance Test

XI Simposio – Intenacional de Estructurasde Acer

Seismic App. S Qualifying Cyclic Tests Quasi static test conducted at Virginia Tech

M 0.04 ≥0.8 M p

0.8 Mp

- 0.8 Mp

M 0.04 ≥0.8 M p

Seismic App. S Qualifying Cyclic Tests Quasi static test conducted at Virginia Tech

Column Tip Load vs.Total Rotation

Seismic App. S Qualifying Cyclic Tests Dynamic test conducted at UC San Diego

Column Tip Load vs. Plastic Rotation

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

4

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

ANSI/AISC 358 Prequalified Connections for Special and Intermediate Steel Moment Frames for Seismic Applications

XI Simposio – Intenacional de Estructurasde Acer

Connections Prequalified Including Supplement No. 1 • Reduced Beam Section (RBS) Connection • Bolted Unstiffened and Stiffened Extended End-Plate Connection • Welded Unreinforced Flange – Welded Web • Bolted Flange Plate • Kaiser Bolted Bracket Note: The Conxtech Moment Connection is currently being balloted.

Reduced Beam Section (RBS) Connection

End Plate Moment Connections

Unstiffened 4-Bolt: 4E

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

Stiffened 4-Bolt: 4ES

Stiffened 8-Bolt: 8ES

5

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad Bolted Flange Plate Connection

Kaiser Bolted Bracket Connection

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

XI Simposio – Intenacional de Estructurasde Acer

Welded Unreinforced Flange – Welded Web Connection

ConXTech Moment Connection

6

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

Prequalified Unique Requirements • • • • • • •

Provisions apply only to the prequalified connections.

Beam and Column cross-section limitations based on specific test matrices Rolled and Built-up Members permitted Specific welding requirements for built-up members Probable maximum moment at hinge specified Plastic hinge location specified for each connection Resistance Factors differ from AISC Specification

XI Simposio – Intenacional de Estructurasde Acer

Probable Maximum Moment at Hinge Based upon connecting beam strength: Mpr = Cpr Ry Fy Zx where: Mpr = probable maximum beam moment Ry = 1.1 for Fy = 50 ksi Zx = plastic section modulus of beam

Probable Maximum Moment at Hinge

Connection Design Moment

⎛ F + Fu ⎞ ⎟ < 1 .2 Cpr = ⎜⎜ y ⎟ ⎝ 2Fy ⎠

where: Fy = yield strength Fu = tensile strength

Plastic Hinge

Sh

Plastic Hinge

L’ = distance between plastic hinges

Sh

L = distance between centerline of columns

For A572 Gr 50, CprRy = 1.1 x 1.15 = 1.27 Mpr = 1.27 Fy Zx or 27% increase

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

Sh is specified for each prequalified connection.

7

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

Connection Design Moment

Plastic Hinge

XI Simposio – Intenacional de Estructurasde Acer

Connection Design Moment The connection design moment is the moment at the face of the column: Mf = Mpr + Vu Sh

Vu Mpr Sh

Mf = Mpr + Vu Sh

where: Mpr = probable maximum beam moment Vu = max. shear at the end of the beam = 2Mpr + VuSh Sh = distance from face of the column to plastic hinge location

Resistance Factors

Resistance Factors

Different resistance factors in 358 Prequalified:

Different resistance factors in 358 Prequalified:

Specification:

Ductile Limit States φd = 0.9 Non-Ductile Limit State φn = 0.75

Specification:

Ductile Limit States φd = 0.9 Non-Ductile Limit State φn = 0.75

Specification:

Ductile Limit States φd = 1.0 Non-Ductile Limit States φn = 0.9

Prequalified:

Ductile Limit States φd = 1.0 Non-Ductile Limit States φn = 0.9

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

8

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

XI Simposio – Intenacional de Estructurasde Acer

Resistance Factors Reason: Specification limit states represent maximum expected under strength, i.e. φd = 0.9 and φn = 0.75.

Whereas, Mpr = Cpr Ry Fy Zx = 1.27 Fy Zx, represents the maximum expected over strength including some strain hardening.

Specific Prequalified Connections Reduced Beam Section (RBS)

If both are used, very conservative designs result.

Therefore, the Prequalified resistance factors were increased to φd = 1.0 and φn = 0.90, but only for limit states included in the Prequalified Standard.

Reduced Beam Section (RBS)

Reduced Beam Section (RBS)

RBS Concept:

• Trim Beam Flanges Near Connection

• Reduce Moment at Connection

• Force Plastic Hinge Away from Connection

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

9

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

Connection was Prequalified at UT - Austin

Whitewashed connection prior to testing.

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

XI Simposio – Intenacional de Estructurasde Acer

Whitewashed connection prior to testing.

Connection at θ ≅ 0.02 radian.

10

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

XI Simposio – Intenacional de Estructurasde Acer

Connection at θ ≅ 0.02 radian.

Connection at θ ≅ 0.03 radian.

Connection at θ ≅ 0.04 radian.

Conformance Results 5000 4000

Mp

Bending Moment (kN-m)

3000 2000 1000 0 -1000 -2000 -3000

Mp

-4000

RBS Connection

-5000 -0.05

-0.04

-0.03

-0.02

-0.01

0

0.01

0.02

0.03

0.04

0.05

Drift Angle (radian)

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

11

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

XI Simposio – Intenacional de Estructurasde Acer

Reduced Beam Section (RBS) Prequalification Requirements for RBS in SMF • Beam depth:

up to W36

• Beam weight:

up to 300 lb/ft

• Column depth:

up to W36 for wide-flange up to 24-inches for box columns

• Beam connected to column flange (connections to column web not prequalified) • RBS shape:

circular

• RBS dimensions:

per specified design procedure

Reduced Beam Section (RBS) Prequalification Requirements for RBS in SMF Beam flange welds: - CJP groove welds - Treat welds as Demand Critical - Remove bottom flange backing and provide reinforcing fillet weld - Leave top flange backing in-place; fillet weld backing to column flange - Remove weld tabs at top and bottom flanges Beam web to column connection: - Use fully welded web connection (CJP weld between beam web and column flange) See ANSI/AISC 358 for additional requirements (continuity plates, beam lateral bracing, RBS cut finish, etc.)

Reduced Beam Section (RBS)

Reduced Beam Section (RBS) Protected Zone

Reduced Section Geometry

0.5bf < a < 0.75bf 0.5d < b < 0.85d 0.1bf < c < 0.25bf

No Shear Studs.

No welded, bolted, screwed or shot-in attachments for perimeter edge angles, exterior facades, partitions, duct work, piping or other construction.

Decking arc-spot welds are permitted.

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

12

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

XI Simposio – Intenacional de Estructurasde Acer

Lateral Brace at Center of RBS Violates Protected Zone

Lateral Brace at Center of RBS Violates Protected Zone

End-Plate Moment Connections

Specific Prequalified Connections End-Plate Concept:

End-Plate Moment Connections

• No Field Welding • Simple Erection • Connection is Stronger than Beam

Unstiffened 4-Bolt: 4E

Stiffened 4-Bolt: 4ES

Stiffened 8-Bolt: 8ES

• Special welding requirements • Concrete slab requirements

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

Connections were prequalified at Virginia Tech

13

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

XI Simposio â&#x20AC;&#x201C; Intenacional de Estructurasde Acer

8-Bolt Stiffened Moment End-Plate, 8ES

8-Bolt Stiffened Moment End-Plate, 8ES

8-Bolt Stiffened Moment End-Plate, 8ES 25000

25000

20000

20000

Moment at Column Centerline (in-kips)

Moment at Column Centerline (in-kips)

End-Plate Moment Connections

15000 10000 5000 0 -5000 -10000 -15000 -20000 -25000 -0.08

15000 10000 5000 0 -5000 -10000 -15000 -20000

-0.06

-0.04

-0.02

0.00

0.02

0.04

0.06

0.08

Total Rotation (rad)

Moment at Column Centerline vs Total Rotation

-25000 -0.08

-0.06

-0.04

-0.02

0.00

0.02

0.04

0.06

0.08

Total Plastic Rotation (rad)

Moment at Column Centerline vs Plastic Rotation

8ES-1.25-1.75-30

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

14

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

XI Simposio – Intenacional de Estructurasde Acer

Connection Test with Concrete Slab

Actuator

Test Frame Test Column Lateral Support Typ.

Composite Slab

W14x257 Pin Support

Rigid Link

W24x68

W24x68 Rigid Link

Connection Test with Concrete Slab

Reaction Frame

End-Plate Moment Connections

End-Plate Moment Connections

Prequalification Requirements: • Beam depth:

Min. and max. in Table 6.1

• Beam weight:

No limit

• Column depth:

Up to W36

• Beam connected to column flange (connections to column web not prequalified) • Bolts:

A325 or A490

• Finger Shims:

Permitted

Prequalification Requirements: Beam flange welds:- CJP groove welds except over web - Weld access holes not permitted - Back gouging not required at web Beam web to column connection: - CJP or fillet welds are permitted See ANSI/AISC 358 for additional requirements: (continuity plates, beam lateral bracing, etc.)

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

15

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

XI Simposio – Intenacional de Estructurasde Acer

End-Plate Moment Connections

End-Plate Moment Connections

Weld access hole not permitted because of ruptures that occurred during testing.

Rupture

Rupture

End-Plate Moment Connections Recommended welding procedure: • No weld access holes • Surface Preparation: – All surfaces ground clean – Flanges beveled 45º full depth • Minimum root opening

End-Plate Moment Connections Recommended welding procedure:

45°

Typical Beam 45°

Welding Sequence: 1. Fillet welds on both sides of web 1 installed.

2. Fillet welds on inside of flanges installed.

3. Flange groove weld root backgouged and flange groove welds installed.

Backgouge

3

2

Backgouge

3

Note: Welds over webs are not CJP.

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

16

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

XI Simposio – Intenacional de Estructurasde Acer

End-Plate Moment Connections

End-Plate Moment Connections

Test 1 with Concrete Slab

Test 1 with Concrete Slab

End-Plate Moment Connections

End-Plate Moment Connections

Test1 with Concrete Slab

Test 2 with Concrete Slab 1'-11 1/4" 3'-4 1/2" NO STUDS HINGE ZONE

4'-8 1/4"

3'-0"

END OF STIFFENER

END OF STIFFENER

4'-8 1/4"

10'-0"

1'-11 1/4" 3'-4 1/2" NO STUDS HINGE ZONE

3'-0"

10'-0"

Premature Bolt Failure

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

5" COMPOSITE SLAB (3" COVER ON 2 COMPOSITE METAL DECK) REINFORCED W/ 4x4-W2.9xW2.9 WWF

1/2" MIN. GAP FORMED W/ NEOPRENE FILLED W/ FOAM INSUL.

3/4"Ø X 4" SHEAR STUDS @ 1'-0" MAX.

17

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

XI Simposio â&#x20AC;&#x201C; Intenacional de Estructurasde Acer

End-Plate Moment Connections

Test 2 with Concrete Slab

Test 2 with Concrete Slab 250

250

200

200

150

150

Column Tip Load (kips)

Column Tip Load (kips)

End-Plate Moment Connections

100 50 0 -50 -100

100 50 0 -50 -100 -150

-150 -200

-200

-250 -0.05 -0.04 -0.03 -0.02 -0.01 0.00

0.01

0.02

0.03

Total Rotation (rad.)

Column Tip Load vs Total Rotation

0.04

0.05

-250 -0.06

-0.04

-0.02

0.00

0.02

0.04

0.06

Beam Rotation (rad.)

Column Tip Load vs Beam Rotation

End-Plate Moment Connections

Specific Prequalified Connections

Requirement for all prequalified bolted connections:

Compressible expansion joint material, at least 1 in. thick, shall be installed to isolate the column/connection from the concrete slab.

Bolted Flange Plate (BFP)

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

18

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

Bolted Flange Plate (BFP)

XI Simposio – Intenacional de Estructurasde Acer

Bolted Flange Plate (BFP)

BFP Concept:

• Shop Welded/Field Bolted • A325 or A490 bolts • Top and bottom flange

Prequalified at U. of California at San Diego

plates must be identical

• Hinge at end of flange plates

Bolted Flange Plate (BFP)

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

Bolted Flange Plate (BFP)

19

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

XI Simposio â&#x20AC;&#x201C; Intenacional de Estructurasde Acer

Bolted Flange Plate (BFP)

Bolted Flange Plate (BFP)

Bolted Flange Plate (BFP)

Bolted Flange Plate (BFP)

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

20

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

XI Simposio – Intenacional de Estructurasde Acer

Bolted Flange Plate (BFP)

Bolted Flange Plate (BFP)

Fracture Location Close-up of Fracture Location

Welded Unreinforced Flange- Welded Web (WUF-W)

Specific Prequalified Connections

WUF-W Concept:

Welded Unreinforced Flange - Welded Web (WUF–W)

• Full beam strength • Shop welded single plate • • •

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

with bolts for erection Field welded beam flange to column flange Field welded single plate to beam web Similar to post-Northridge connection

21

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

XI Simposio – Intenacional de Estructurasde Acer

Welded Unreinforced Flange- Welded Web (WUF-W)

Specific Prequalified Connections Kaiser Bolted Bracket (KBB)

Erection Bolts

Flange Welded

Kaiser Bolted Bracket (KBB)

Flange Bolted

Kaiser Bolted Bracket (KBB)

KBB Concept:

• Proprietary • Cast steel bracket • Welded or bolted to • • • •

beam flange Bolted to column flange Shop welded single plate web connection Pretensioned 1-3/8 or 1-1/2 in. diameter A490 or A354 bracket bolts Used for retrofiting

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

22

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

XI Simposio – Intenacional de Estructurasde Acer

ConXtech® CONXLTM Moment Connection

Specific Prequalified Connections

Concept: • Propriety • Full strength/biaxial • 16 in. square HSS or built-up box concrete filled columns • Shop welded forged steel fittings on beams and columns • Field bolted with 1-1/2 in. A574 bolts • All beams must be of same nominal depth • Extremely fast erection

ConXtech® CONXLTM Moment Connection

ConXtech® CONXLTM Moment Connection

ConXtech® CONXLTM Moment Connection

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

23

Conexiones Precalificadas para Estructuras en Zonas de Alta Sismicldad

ConXtech® CONXLTM Moment Connection

XI Simposio – Intenacional de Estructurasde Acer

ConXtech® CONXLTM Moment Connection

Achknowledgements

Slides provided by Michael Engelhardt, University of Texas – Austin Chia-Ming Uang, University of California, San Diego

Thank You!!

Scott Adan, Adan Engineering Raymond Kitasoe, ConXtech

Presented by ProfessorThomas M. Murray, Virginia Tech 09 March 2011

24