Reliability Analysis and Design Considerations for Exposed Column Base Plate Connections Subjected to Flexure and Axial Compression
Publication: Journal of Structural Engineering
Volume 147, Issue 2
Abstract
Exposed column base plate (ECBP) connections are commonly used in steel moment resisting frames. Current approaches for their design are well-established from a mechanistic standpoint. However, the reliability of connections designed as per these approaches is not as well understood. A detailed reliability analysis of the prevalent approach in the United States is performed in this study by using 59 design scenarios from steel moment frames subjected to combinations of dead, live, wind, and seismic loads. The analysis is conducted through Monte Carlo sampling reflecting uncertainties in the loads, material properties, component geometry, as well as demand and capacity models for the various components (e.g., base plate, footing, anchor rods) of the connection. Results indicate that the current design approach leads to unacceptable and inconsistent probabilities of failure across the various components. This is attributed to: (1) the use of a resistance factor for the footing bearing stress that artificially alters flexural demands on the base plate, and (2) the calibration of resistance factors for the plate and anchors without appropriate consideration of variability in demands. Two alternative approaches are examined as prospective refinements to the current approach. One eliminates the resistance factor for the bearing stress when used to determine flexural demands in the base plate, while the other considers overall failure of the connection rather than failure of individual components within the connection. For both approaches, new resistance factors are calibrated to provide consistent and acceptable probabilities of failure across all limit states and all types of loading. Design and cost implications of these alternative approaches are summarized.
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Data Availability Statement
Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
The first author would like to acknowledge the financial support from China Scholarship Council (CSC, under Grant No. 201608330227) and University College London (UCL) through a joint research scholarship for his PhD study. Support from the Pacific Earthquake Engineering Research Center is also gratefully acknowledged by the corresponding author.
References
ACI (American Concrete Institute). 2019. Building code requirements for structural concrete and commentary. ACI 318-19. Farmington Hills, MI: ACI.
AISC (American Institute of Steel Construction). 1986. Load and resistance factor design specification for structural steel buildings. Chicago, IL: AISC.
AISC (American Institute of Steel Construction). 2005. Seismic provisions for structural steel buildings. ANSI/AISC 341-05. Chicago, IL: AISC.
AISC (American Institute of Steel Construction). 2016a. Code of standard practice for steel buildings and bridges. ANSI/AISC 303-16. Chicago, IL: AISC.
AISC (American Institute of Steel Construction). 2016b. Seismic provisions for structural steel buildings. ANSI/AISC 341-16. Chicago, IL: AISC.
AISC (American Institute of Steel Construction). 2016c. Specification for structural steel buildings. ANSI/AISC 360-16. Chicago, IL: AISC.
AISC (American Institute of Steel Construction). 2018. Seismic design manual. 3rd ed. Chicago, IL: AISC.
ASCE. 2006. Minimum design loads for buildings and other structures. ASCE/SEI 7-05. Reston, VA: ASCE.
ASCE. 2016. Minimum design loads for buildings and other structures. ASCE/SEI 7-16. Reston, VA: ASCE.
ASTM. 2018a. Standard specification for anchor bolts, steel, 36, 55, and 105-ksi yield strength. ASTM F1554-18. West Conshohocken, PA: ASTM.
ASTM. 2018b. Standard specification for high-strength low-alloy columbium-vanadium structural steel. ASTM A572/A572M-18. West Conshohocken, PA: ASTM.
ASTM. 2019a. Standard specification for carbon structural steel. ASTM A36/A36M-19. West Conshohocken, PA: ASTM.
ASTM. 2019b. Standard specification for general requirements for rolled structural steel bars, plates, shapes, and sheet piling. ASTM A6/A6M-19. West Conshohocken, PA: ASTM.
ASTM. 2020. Standard specification for structural steel shapes. ASTM A992/A992M-20. West Conshohocken, PA: ASTM.
Aviram, A., B. Stojadinovic, and A. D. Kiureghian. 2010. Performance and reliability of exposed column base plate connections for steel moment-resisting frames. Berkeley, CA: Pacific Earthquake Engineering Research Center.
Choi, J., and K. Ohi. 2005. “Evaluation on interaction surface of plastic resistance for exposed-type steel column bases under biaxial bending.” J. Mech. Sci. Technol. 19 (3): 826–835. https://doi.org/10.1007/BF02916131.
Cornell, C. A. 1969. “A probability-based structural code.” ACI J. Proc. 66 (12): 974–985. https://doi.org/10.14359/7446.
Cui, Y., T. Nagae, and M. Nakashima. 2009. “Hysteretic behavior and strength capacity of shallowly embedded steel column bases.” J. Struct. Eng. 135 (10): 1231–1238. https://doi.org/10.1061/(ASCE)ST.1943-541X.0000056.
Drake, R. M., and S. J. Elkin. 1999. “Beam-column base plate design—LRFD method.” Eng. J. 36 (1): 29–38.
Ellingwood, B. R., T. Galambos, J. MacGregor, and C. Cornell. 1980. Development of a probability based load criterion for American national standard A58 building code requirements for minimum design loads in buildings and other structures, Special Publication 577. Washington, DC: US Dept. of Commerce.
Ermopoulos, J. C., and G. N. Stamatopoulos. 1996. “Mathematical modelling of column base plate connections.” J. Constr. Steel Res. 36 (2): 79–100. https://doi.org/10.1016/0143-974X(95)00011-J.
Fahmy, M. 2000. “Seismic behavior of moment-resisting steel column bases.” Ph.D. thesis, Dept. of Civil and Environmental Engineering, Univ. of Michigan.
Falborski, T., P. Torres-Rodas, F. Zareian, and A. Kanvinde. 2020. “Effect of base-connection strength and ductility on the seismic performance of steel moment-resisting frames.” J. Struct. Eng. 146 (5): 04020054. https://doi.org/10.1061/(ASCE)ST.1943-541X.0002544.
Fasaee, M. A. K., M. R. Banan, and S. Ghazizadeh. 2018. “Capacity of exposed column base connections subjected to uniaxial and biaxial bending moments.” J. Constr. Steel Res. 148 (Sep): 361–370. https://doi.org/10.1016/j.jcsr.2018.05.025.
Fayaz, J., and F. Zareian. 2019. “Reliability analysis of steel SMRF and SCBF structures considering the vertical component of near-fault ground motions.” J. Struct. Eng. 145 (7): 04019061. https://doi.org/10.1061/(ASCE)ST.1943-541X.0002330.
Fisher, J. M., and L. A. Kloiber. 2006. Design guide 1: Base plate and anchor rod design. 2nd ed. Chicago, IL: American Institute of Steel Construction.
Gomez, I., A. Kanvinde, and G. Deierlein. 2010. Exposed column base connections subjected to axial compression and flexure. Chicago, IL: AISC.
Gomez, I. R. 2010. “Behavior and design of column base connections.” Ph.D. thesis, Dept. of Civil and Environmental Engineering, Univ. of California, Davis.
Gomez, I. R., A. M. Kanvinde, and G. G. Deierlein. 2011. “Experimental investigation of shear transfer in exposed column base connections.” Eng. J. 48 (4): 245–264.
Grilli, D., R. Jones, and A. Kanvinde. 2017. “Seismic performance of embedded column base connections subjected to axial and lateral loads.” J. Struct. Eng. 143 (5): 04017010. https://doi.org/10.1061/(ASCE)ST.1943-541X.0001741.
Hanks, K. N., and P. W. Richards. 2019. “Experimental performance of block-out connections at the base of steel moment frames.” J. Struct. Eng. 145 (7): 04019057. https://doi.org/10.1061/(ASCE)ST.1943-541X.0002333.
Hawkins, N. M. 1968. “The bearing strength of concrete loaded through rigid plates.” Mag. Concr. Res. 20 (62): 31–40. https://doi.org/10.1680/macr.1968.20.62.31.
Iervolino, I., and C. Galasso. 2012. “Comparative assessment of load–resistance factor design of FRP-reinforced cross sections.” Constr. Build. Mater. 34 (Sep): 151–161. https://doi.org/10.1016/j.conbuildmat.2012.02.021.
Kanvinde, A. M., P. Higgins, R. J. Cooke, J. Perez, and J. Higgins. 2015. “Column base connections for hollow steel sections: Seismic performance and strength models.” J. Struct. Eng. 141 (7): 04014171. https://doi.org/10.1061/(ASCE)ST.1943-541X.0001136.
Kanvinde, A. M., S. J. Jordan, and R. J. Cooke. 2013. “Exposed column base plate connections in moment frames—Simulations and behavioral insights.” J. Constr. Steel Res. 84 (May): 82–93. https://doi.org/10.1016/j.jcsr.2013.02.015.
Lee, D. Y., S. C. Geol, and B. Stojadinovic. 2008a. “Exposed column-base plate connections bending about weak axis. I: Numerical parametric study.” Int. J. Steel Struct. 8 (1): 11–27.
Lee, D. Y., S. C. Goel, and B. Stojadinovic. 2008b. “Exposed column-base plate connections bending about weak axis. II: Experimental study.” Int. J. Steel Struct. 8 (1): 29–41.
Liu, J., R. Sabelli, R. L. Brockenbrough, and T. P. Fraser. 2007. “Expected yield stress and tensile strength ratios for determination of expected member capacity in the 2005 AISC seismic provisions.” Eng. J. 44 (1): 15–26.
Myers, A. T., A. M. Kanvinde, G. G. Deierlein, and B. V. Fell. 2009. “Effect of weld details on the ductility of steel column baseplate connections.” J. Constr. Steel Res. 65 (6): 1366–1373. https://doi.org/10.1016/j.jcsr.2008.08.004.
NEHRP (National Earthquake Hazards Reduction Program). 2010. Evaluation of the FEMA P-695 methodology for quantification of building seismic performance factors. Washington, DC: NEHRP.
Nowak, A. S., and K. R. Collins. 2012. Reliability of structures. 2nd ed. Boca Raton, FL: CRC Press.
Nowak, A. S., and M. M. Szerszen. 2003. “Calibration of design code for buildings (ACI 318): Part 1—Statistical models for resistance.” ACI Struct. J. 100 (3): 377–382. https://doi.org/10.14359/12613.
OSHA (Occupational Safety and Health Administration). 2001. Safety standards for steel erection, (Subpart R of 29 CFR Part 1926). Washington, DC: Occupational Safety and Health Administration.
Petrone, F., P. S. Higgins, N. P. Bissonnette, and A. M. Kanvinde. 2016. “The cross-aisle seismic performance of storage rack base connections.” J. Constr. Steel Res. 122 (Jul): 520–531. https://doi.org/10.1016/j.jcsr.2016.04.014.
Schmidt, B. J., and F. M. Bartlett. 2002. “Review of resistance factor for steel: Data collection.” Can. J. Civ. Eng. 29 (1): 98–108. https://doi.org/10.1139/l01-081.
SEAOC (Structural Engineers Association of California). 2015. 2015 IBC SEAOC structural/seismic design manual volume 1: Code application examples. Sacramento, CA: SEAOC.
Torres-Rodas, P., J. Fayaz, and F. Zareian. 2020. “Strength resistance factors for seismic design of exposed based plate connections in special steel moment resisting frames.” Earthquake Spectra 36 (2): 537–553. https://doi.org/10.1177/8755293019891714.
Torres-Rodas, P., F. Zareian, and A. Kanvinde. 2018. “Seismic demands in column base connections of steel moment frames.” Earthquake Spectra 34 (3): 1383–1403. https://doi.org/10.1193/062317EQS127M.
Trautner, C. A., T. Hutchinson, P. R. Grosser, and J. F. Silva. 2016. “Effects of detailing on the cyclic behavior of steel base plate connections designed to promote anchor yielding.” J. Struct. Eng. 142 (2): 04015117. https://doi.org/10.1061/(ASCE)ST.1943-541X.0001361.
Victorsson, V. K. 2011. “The reliability of capacity-designed components in seismic resistant systems.” Ph.D. thesis, Dept. of Civil and Environmental Engineering, Stanford Univ.
Wald, F. 2000. “Column base modelling.” In Semi-rigid joints in structural steelwork, 227–288. Berlin: Springer.
Zareian, F., and A. Kanvinde. 2013. “Effect of column-base flexibility on the seismic response and safety of steel moment-resisting frames.” Earthquake Spectra 29 (4): 1537–1559. https://doi.org/10.1193/030512EQS062M.
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Published In
Journal of Structural Engineering
Volume 147 • Issue 2 • February 2021
Copyright
© 2020 American Society of Civil Engineers.
History
Received: Mar 9, 2020
Accepted: Sep 2, 2020
Published online: Nov 30, 2020
Published in print: Feb 1, 2021
Discussion open until: Apr 30, 2021
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