Excessive Long-Time Deflections of Prestressed Box Girders. I: Record-Span Bridge in Palau and Other Paradigms
Publication: Journal of Structural Engineering
Volume 138, Issue 6
Abstract
The segmental prestressed concrete box girder of Koror-Babeldaob (KB) Bridge in Palau, which had a record span of 241 m (791 ft), presents a striking paradigm of serviceability loss because of excessive multidecade deflections. The data required for analysis have recently been released and are here exploited to show how the analysis and design could be improved. Erected segmentally in 1977, this girder developed a midspan deflection of 1.61 m (5.3 ft) compared with the design camber after 18 years, and it collapsed in 1996 as a consequence of remedial prestressing, after a 3-month delay. Compared with three-dimensional analysis, the traditional beam-type analysis of box girder deflections is found to have errors up to 20%, although greater errors are likely for bridges with higher box-width-to-span ratios than the KB Bridge. However, even three-dimensional finite-element analysis with step-by-step time integration cannot explain the observed deflections when the current American Concrete Institute, Japan Society of Civil Engineers, Comité Euro-International du Béton (or Comité Euro-International du Béton—Fédération internationale de la précontrainte), and Gardner and Lockman prediction models for creep and shrinkage are used. These models give 18-year deflection estimates that are 50–77% lower than measured and yield unrealistic shapes of the deflection history. They also predict the 18-year prestress loss to be 46–56% lower than the measured mean prestress loss, which was 50%. Model B3, which is the only theoretically based model, underestimates the 18-year deflection by 42% and gives a prestress loss of 40% when the default parameter values are used. However, in Model B3, several input parameters are adjustable and if they are adjusted according to the long-time laboratory tests of Brooks, a close fit of all the measurements is obtained. For early deflections and their extrapolation, it is important that Model B3 can capture realistically the differences in the rates of shrinkage and drying creep caused by the differences in the thickness of the walls of the cross section. The differences in temperature and possible cracking of the top slab also need to be taken into account. Other paradigms on which data have recently been released are four bridges in Japan and one in the Czech Republic. Their excessive deflections can also be explained. The detailed method of analysis and the lessons learned are presented in Part II.
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References
ABAM Engineers Inc. (ABAM). (1993). “Koror-Babeldaob bridge repairs: Basis for design.” Bureau of Public Works Rep., ABAM, Koror, Republic of Palau.
American Concrete Institute (ACI). (1971). “Prediction of creep, shrinkage and temperature effects in concrete structures.” Designing for effects of creep, shrinkage and temperature in concrete structures, ACI, Detroit, 51–93.
American Concrete Institute Committee 209 (ACI). (2008a). “Guide for modeling and calculating shrinkage and creep in hardened concrete.” ACI Rep. 209.2R-08, ACI, Farmington Hills, MI.
American Concrete Institute Committee 318 (ACI). (2008b). Building code requirements for structural concrete (ACI 318-05) and commentary (ACI 318-05), ACI, Farmington Hills, MI.
Bažant, Z. P. (2000). “Criteria for rational prediction of creep and shrinkage of concrete.” Adam Neville symposium: Creep and shrinkage—structural design effects, Al-Manaseer, A., ed., ACI, Farmington Hills, MI, 237–260.
Bažant, Z. P. (2001). “Creep of concrete.” Encyclopedia of materials: Science and technology, et al. and Buschow, K. H. J., ed., Vol. 2C, Elsevier, Amsterdam, Netherlands, 1797–1800.
Bažant, Z. P., and Baweja, S. (1995). “Creep and shrinkage prediction model for analysis and design of concrete structures: Model B3.” Mater. Struct.MASTED, 28(6), 357–367.
Bažant, Z. P., and Baweja, S. (2000). “Creep and shrinkage prediction model for analysis and design of concrete structures: Model B3.” The Adam Neville symposium: Creep and shrinkage—Structural design effects, Al-Manaseer, A., ed., ACI, Farmington Hills, MI, 1–83.
Bažant, Z. P., Hauggaard, A. B., Baweja, S., and Ulm, F.-J. (1997). “Microprestress-solidification theory for concrete creep. I. Aging and drying effects.” J. Eng. Mech.JENMDT, 123(11), 1188–1194.
Bažant, Z. P., Hubler, M. H., and Yu, Q. (2011a). “Pervasiveness of excessive segmental bridge deflections: Wake-up call for creep.” ACI Struct. J.ASTJEG, 108(6), 766–774.
Bažant, Z. P., Hubler, M. H., and Yu, Q. (2011b). “Ubiquity of excessive multi-decade segmental bridge deflections: A revelation.” ACI Concrete International Rep., Northwestern Univ., Evanston, IL.
Bažant, Z. P., Hubler, M. H., Yu, Q., Křístek, V., and Bittnar, Z. (2011c). “Wake-up call for creep, myth about size effect and black holes in safety.” Proc., fib Congress, Prague, Czech Republic.
Bažant, Z. P., and Kim, J.-K. (1989). “Segmental box girder: Deflection probability and Bayesian updating.” J. Struct. Eng.JSENDH, 115(10), 2528–2547.
Bažant, Z. P., and Kim, J.-K. (1991a). “Segmental box girder: Effect of spatial random variability of material on deflections.” J. Struct. Eng.JSENDH, 117(8), 2542–2547.
Bažant, Z. P., and Kim, J.-K. (1991b). “Improved prediction model for time-dependent deformations of concrete: Part 2—Basic creep.” Mater. Struct.MASTED, 24(6), 409–421.
Bažant, Z. P., and Kim, J.-K. (1992a). “Improved prediction model for time-dependent deformations of concrete: Part 3—Creep at drying.” Mater. Struct.MASTED, 25(1), 21–28.
Bažant, Z. P., and Kim, J.-K. (1992b). “Improved prediction model for time-dependent deformations of concrete: Part 4—Temperature effects.” Mater. Struct.MASTED, 25(2), 84–94.
Bažant, Z. P., and Kim, J.-K. (1992c). “Improved prediction model for time-dependent deformations of concrete: Part 5—Cyclic load and cyclic humidty.” Mater. Struct.MASTED, 25(3), 163–169.
Bažant, Z. P., Kim, J.-K., and Jeon, S.-E. (2003). “Cohesive fracturing and stresses caused by hydration heat in massive concrete wall.” J. Eng. Mech.JENMDT, 129(1), 21–30.
Bažant, Z. P., Kim, J.-K., and Panula, L. (1991). “Improved prediction model for time-dependent deformations of concrete: Part 1—Shrinkage.” Mater. Struct.MASTED, 24(5), 327–345.
Bažant, Z. P., Křístek, V., and Vítek, J. L. (1992). “Drying and cracking effects in box-girder bridge segment.” J. Struct. Eng.JSENDH, 118(1), 305–321.
Bažant, Z. P., and Li, G.-H. (2008a). “Comprehensive database on concrete creep and shrinkage.” ACI Mater. J.AMAJEF, 105(6), 635–639.
Bažant, Z. P., and Li, G.-H. (2008b). “Unbiased statistical comparison of creep and shrinkage prediction models.” ACI Mater. J.AMAJEF, 105(6), 610–621.
Bažant, Z. P., Li, G.-H., and Yu, Q. (2009). “Prediction of creep and shrinkage and their effects in concrete structures: Critical appraisal.” Proc., 8th Int. Conf. on Creep, Shrinkage and Durability of Concrete and Concrete Structures, Vol. 2, Tanabe, T., Sakata, K., Mihashi, H., Sato, R., Maekawa, K. and Nakamura, H., eds., CRC, Boca Raton, FL, 1275–1289.
Bažant, Z. P., Li, G.-H., Yu, Q., Klein, G., and Křístek, V. (2008). “Explanation of excessive long-time deflections of collapsed record-span box girder bridge in Palau.” Preliminary Structural Engineering Rep. 08-09/A222e, Infrastructure Technology Institute, Northwestern Univ., Evanston, IL.
Bažant, Z. P., and Liu, K.-L. (1985). “Random creep and shrinkage in structures: Sampling.” J. Struct. Eng.JSENDH, 111(5), 1113–1134.
Bažant, Z. P., and Panula, L. (1978a). “Practical prediction of time-dependent deformations of concrete. Part I: Shrinkage.” Mater. Struct.MASTED, 11(65), 307–316.
Bažant, Z. P., and Panula, L. (1978b). “Practical prediction of time-dependent deformations of concrete. Part II: Basic creep.” Mater. Struct.MASTED, 11(65), 317–328.
Bažant, Z. P., and Panula, L. (1978c). “Practical prediction of time-dependent deformations of concrete. Part III: Drying creep.” Mater. Struct.MASTED, 11(66), 415–424.
Bažant, Z. P., and Panula, L. (1978d). “Practical prediction of time-dependent deformations of concrete. Part IV: Temperature effect on basic creep.” Mater. Struct.MASTED, 11(66), 424–434.
Bažant, Z. P., and Panula, L. (1979a). “Practical prediction of time-dependent deformations of concrete. Part V: Temperature effect on drying creep.” Mater. Struct.MASTED, 12(69), 169–174.
Bažant, Z. P., and Panula, L. (1979b). “Practical prediction of time-dependent deformations of concrete. Part VI: Cyclic creep, nonlinearity and statistical scatter.” Mater. Struct.MASTED, 12(69), 175–183.
Bažant, Z. P., Panula, L., Kim, J.-K., and Xi, Y. (1992). “Improved prediction model for time-dependent deformations of concrete: Part 6—Simplified code-type formulation.” Mater. Struct.MASTED, 25(4), 219–223.
Bažant, Z. P., and Prasannan, S. (1988). “Solidification theory for aging creep.” Cem. Concr. Res.CCNRAI, 18(6), 923–932.
Bažant, Z. P., and Prasannan, S. (1989a). “Solidification theory for concrete creep: I. Formulation.” J. Eng. Mech.JENMDT, 115(8), 1691–1703.
Bažant, Z. P., and Prasannan, S. (1989b). “Solidification theory for concrete creep: II. Verification and application.” J. Eng. Mech.JENMDT, 115(8), 1704–1725.
Bažant, Z. P., and Yu, Q. (2006). “Reliability, brittleness and fringe formulas in concrete design codes.” J. Struct. Eng.JSENDH, 132(1), 3–12.
Bažant, Z. P., and Yu, Q. (2011). “Viscoplastic constitutive law for prestressing steel relaxation at varying strain.” Structural Engineering Rep. 11-03/ITIv, Northwestern Univ., Evanston, IL.
Bažant, Z. P., Yu, Q., and Li, G.-H. (2012). “Excessive long-time deflections of prestressed box girders. II: Numerical analysis and lessons learned.” J. Struct. Eng.JSENDH, 138(6), 687–696.
Bažant, Z. P., Yu, Q., Li, G.-H., Klein, G., and Křístek, V. (2010). “Excessive deflections of record-span prestressed box girder: Lessons learned from the collapse of the Koror-Babeldaob Bridge in Palau.” Concr. Int.CNCIEH, 32(6), 44–52.
Berger/ABAM Engineers, Inc. (Berger/ABAM). (1995a). Koror-Babeldaob Bridge modifications and repairs.
Berger/ABAM Engineers, Inc. (Berger/ABAM). (1995b). Koror-Babeldaob Bridge Repaire Project Report on Evaluation of VECP, presented by Black Construction Corporation.
Brooks, J. J. (1984). “Accuracy of estimating long-term strains in concrete.” Mag. Concr. Res.MCORAV, 36(128), 131–145.
Brooks, J. J. (2000). “Elasticity, creep, and shrinkage of concrete containing admixtures.” Proc., Adam Neville Symp. on Creep and Shrinkage—Structural Design Effects, ACI SP-194, Al-Manaseer, A., American Concrete Institute, Farmington Hills, MI, 283–360.
Brooks, J. J. (2005). “30-year creep and shrinkage of concrete.” Mag. Concr. Res.MCORAV, 57(9), 545–556.
Buckler, J. D., and Scribner, C. F. (1985). “Relaxation characteristics of prestressing strand.” Engineering Studies Rep. No. UILU-ENG-85-2011, Univ. of Illinois, Urbana, IL.
Burgoyne, C., and Scantlebury, R. (2006). “Why did Palau bridge collapse?” Struct. Eng.SRUEAN, 84, 30–37.
Comité Euro-International du Béton (CEB). (1972). Recommandations internationales pour le calcul et l’exécution des ouvrages en betón: Principes et recommandations, CEB, Paris.
Comité Euro-International du Béton–Fédération International de la Précontrainte (CEB-FIP). (1990). CEB-FIP model code for concrete structures, Thomas Telford, London.
Cottrell, A. H. (1964). The mechanical properties of matter, Wiley, New York.
DRC Consultants, Inc. (DRC). (1996). Koror-Babelthuap Bridge: Force distribution in bar tendons.
Fédération internationale de béton (fib). (1999). Structural concrete: Textbook on behaviour, design and performance, updated knowledge of the of the CEB/FIP model code 1990, Vol. 1, FIB, Lausanne, Switzerland, 35–52.
Fédération internationale de béton (fib). (2010). Draft of FIB model code, FIB, Lausanne, Switzerland.
Gardner, N. J. (2000). “Design provisions of shrinkage and creep of concrete.” Proc., Adam Neville Symp.: Creep and Shrinkage—Structural Design Effects, ACI SP-194, Al-Manaseer, A., ed., American Concrete Institute, Farmington Hills, MI, 101–104.
Gardner, N. J., and Lockman, M. J. (2001). “Design provisions for drying shrinkage and creep of normal strength concrete.” ACI Mater. J.AMAJEF, 98(2), 159–167.
Japan International Cooperation Agency (JICA). (1990). Present condition survey of the Koror-Babelthuap Bridge, JICA, Tokyo.
Japan Society of Civil Engineers (JSCE). (1991). Standard specification for design and construction of concrete structure, JSCE, Tokyo (in Japanese).
Jirásek, M., and Bažant, Z. P. (2002). Inelastic analysis of structures, Wiley, New York.
Křístek, V., and Bažant, Z. P. (1987). “Shear lag effect and uncertainty in concrete box girder creep.” J. Struct. Eng.JSENDH, 113(3), 557–574.
Křístek, V., Bažant, Z. P., Zich, M., and Kohoutková, A. (2005). “Why is the initial trend of deflections of box girder bridges deceptive?” Proc., 7th Int. Conf. on Creep, Shrinkage and Durability of Concrete and Concrete Structures (CONCREEP 7), Nantes, France, Pijaudier-Cabot, G., Gérard, B. and Acker, P., eds., Hermes Science, London, 293–298.
Křístek, V., Bažant, Z. P., Zich, M., and Kohoutková, A. (2006). “Box girder deflections: Why is the initial trend deceptive?” ACI Concr. Int.CNCIEH, 28(1), 55–63.
Křístek, V., Vráblík, L., Bažant, Z. P., Li, G.-H., and Yu, Q. (2008). “Misprediction of long-time deflections of prestressed box girders: Causes, remedies and tendon lay-out effect.” Proc., 8th Int. Conf. Creep, Shrinkage and Durability Mechanics of Concrete and Concrete Structures (CONCREEP-8), Ise-Shima, Japan, Sato, R., Maekawa, K., Tanabe, T., Sakata, K., Nakamura, H. and Mihashi, H., eds., Taylor & Francis, London, 1291–1295.
Magura, D. D., Sozen, M. A., and Siess, C. P. (1964). “A study of stress relaxation in prestressing reinforcement.” PCI J.PCIJEE, 9(2), 13–57.
McDonald, B., Saraf, V., and Ross, B. (2003). “A spectacular collapse: The Koro-Babeldaob (Palau) balanced cantilever prestressed, post-tensioned bridge.” Indian Concr. J.ICJOAL, 77(3), 955–962.
Nawy, E. G. (2006). Prestressed concrete: A fundamental approach, 5th Ed., Section 3.3, Pearson Prentice Hall, Upper Saddle River, NJ.
Nilson, A. H. (1987). Design of prestressed concrete, 2nd Ed., Wiley, New York.
Parker, D. (1996). “Tropical overload.” New Civ. Eng., December, 18–21.
Pilz, M. (1997). “The collapse of the KB bridge in 1996.” Master’s degree thesis, Imperial College, London.
Pilz, M. (1999). “Untersuchungen zum einsturzter KB Brücke in Palau.” Beton- und StahlbetonbauBESTAI, 94(5), 229–232.
SSFM Engineers, Inc. (SSFM). (1996). “Preliminary assessment of Korror-Babeldaob Bridge failure.” Prepared for U.S. Army Corps of Engineers, Washington, DC.
T.Y. Lin International (TYLI). (1996). “Collapse of the Koror-Babelthuap Bridge.” Rep., T.Y. Lin International, San Francisco.
Yee, A. A. (1979). “Record span box girder bridge connects Pacific islands.” ACI Concr. Int., 1(6), 22–25.
Yu, Q., Bažant, Z. P., and Wendner, R. (2012). “Improved algorithm for efficient and realistic creep analysis of large creep-sensitive concrete structures.” ACI Struct. J.ASTJEG, in press.
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Published In
Journal of Structural Engineering
Volume 138 • Issue 6 • June 2012
Pages: 676 - 686
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© 2012. American Society of Civil Engineers.
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Received: Feb 1, 2010
Accepted: Aug 1, 2011
Published online: May 15, 2012
Published in print: Jun 1, 2012
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