Instrumentation and Long-Term Monitoring of the North Halawa Valley Viaduct

Aerial View of North Halawa Valley Viaduct during Construction

The newest member of Hawaii's highway system is the H-3 Freeway, connecting the Leeward and Windward sides of Oahu. The freeway spans approximately sixteen miles from Haiku Valley, through Koolau Mountain, to the North Halawa Valley. The freeway consists of two systems of highways and viaducts leading to two parallel Trans-Koolau Tunnels. The project is the largest ever undertaken by the State of Hawaii Department of Transportation (HDOT), the cost totaling nearly one billion dollars.

Viaduct Cross-section during Construction

One of the largest sections of the H-3 Freeway is the North Halawa Valley Viaduct. This Viaduct is a segmental cast-in-place post-tensioned concrete box-girder bridge. The bridge was built by the cantilever construction method. With the construction of the North Halawa Valley Viaduct, the State had an opportunity to evaluate the long term performance of an important bridge type and to advance the state of the art in the design of prestressed concrete bridges. The focus of this study was to instrument the North Halawa Valley Viaduct in order to monitor the creep and shrinkage strains in the structure. This information has been used to improve the constitutive models currently used in analysis and design programs for this type of structure, leading to improved prediction of performance in future structures. In addition, the study produced valuable knowledge for a better assessment of the remaining structural capacity and long-term performance of the viaduct.

Seven sections of the inbound Viaduct were selected for instrumentation to provide an adequate representation of the Viaduct behavior. The necessary measurements to achieve the project goals are concrete and reinforcing steel strain, tendon forces, concrete and ambient temperatures, span deflections, support rotations, span shortening, and concrete creep and shrinkage strains. The instrumentation system used to make the above measurements includes vibrating wire strain gages, electrical resistance strain gages, demec strain gages, load cells, thermocouples, a base-line system, tiltmeters, extensometers, and an automated monitoring system. During the construction of the bridge in 1994, all instrumentation was installed by personnel from the University of Hawaii (UH) and Construction Technology Laboratories (CTL). CTL, a Structural/Architectural Engineering, Consulting, and Material Technology company located in Skokie, Illinois, also performed concrete testing to determine the compressive strength, static modulus of elasticity, and coefficient of thermal expansion.

Instruments in Stem of Box-Girder

Automatic Datalogger

Standard creep and shrinkage tests were performed under laboratory conditions in accordance with the American Society for Testing and Materials (ASTM) and in atmospheric conditions similar to those of the structure. The laboratory testing was being conducted by CTL in Skokie, Illinois, while the on-site tests were located inside and outside of the box girder bridge in Halawa Valley.

Monitoring of the instrumentation continued for 10 years after construction, from 1994 to 2004.  The improved creep and shrinkage modeling techniques generated by this project were applied to the design of another long-span post-tensioned bridge structure over the Kealakaha Stream in the County of Hawaii (Big Island). 

Numerous reports, papers and presentations were used to disseminate the results of this study, including:

Research Reports

·         Lee, Andre, and Robertson, Ian N., Instrumentation and Long-Term Monitoring of the North Halawa Valley Viaduct, Civil Engineering Research Report UHM/CE/95-08, University of Hawaii, September 1995.

 

·         Robertson, Ian N., Vibrating Wire Strain Gage Instrumentation Report, University of Hawaii at Manoa, July 1995.

 

·         Durbin, Michael P., and Robertson, Ian N., Predictive Models for Creep and Shrinkage of Concrete Compared with test data from the North Halawa Valley Viaduct, Civil Engineering Research Report UHM/CE/98-04, University of Hawaii, June 1998.

 

·         Matsumoto, Eric, and Robertson, Ian N., Short-Term Deflections of the North Halawa Valley Viaduct, Civil Engineering Research Report, University of Hawaii, August 1998.

 

·         Dwight, Todd P., and Robertson, Ian N., Prediction of Long-Term Bridge Behavior Based on Short-Term Laboratory Creep and Shrinkage Tests, Civil Engineering Research Report UHM/CE/98-06, University of Hawaii, August 1998.

 

·         Shushkewitch, K., Vo, N., and Robertson, I. N., Instrumentation of the North Halawa Valley Viaduct, Oahu, Hawaii, Three-year Progress Report to HI-DOT and FHWA, September, 1998.

 

·         Dong, James, and Robertson, Ian N., Long-Term Structural Modeling of the North Halawa Valley Viaduct, Civil Engineering Research Report UHM/CE/99-04, University of Hawaii, April, 1999.

 

·         Ao, Weng, and Robertson, Ian N., Investigation of Thermal Effects and Truck Loading on the North Halawa Valley Viaduct, Civil Engineering Research Report UHM/CE/99-05, University of Hawaii, April, 1999.

 

·         Li, Xianping, and Robertson, Ian, Long-Term Performance Predictions of the North Halawa Valley Viaduct. Civil Engineering Research Report UHM/CEE/03-04, University of Hawaii, 2003.

 

·         Robertson, Ian N. and Yoshimura, Ryan K., North Halawa Valley Viaduct Load Test.  Civil Engineering Research Report  UHM/CEE/04-02 , University of Hawaii, 2004

 

·         Johnson, Gaur P. and Robertson, Ian N., Structural Health Monitoring Systems for Civil and Architectural Structures: Lvdt-Taut-Wire Baselines, Crack Monitoring Devices, & Strain Based Deflection Monitoring Algorithms. Civil Engineering Research Report UHM/CEE/07-02, University of Hawaii, 2007

 

Journal papers

 

·         Robertson, Ian N., Correlation of Creep and Shrinkage Models with Field Observations, The Adam Neville Symposium: Creep and Shrinkage – Structural Design Effects, American Concrete Institute, SP-194, Editor: Akthem Al-Manaseer, Farmington Hills, Michigan, 2000, pp. 261-282.

 

·         Robertson, Ian N., and Li, Xianping, Shrinkage and Creep Predictions Evaluated using 10-year Monitoring of the North Halawa Valley Viaduct, ACI SP-227 Shrinkage and Creep of Concrete, Editors: N.J. Gardner and Jason Weiss, American Concrete Institute, April 2005, pp. 143-162

 

·         Robertson, Ian N., Prediction of vertical deflections for a long-span prestressed concrete bridge structure, Engineering Structures, Vol. 27, 2005, pp. 1820-1827.

 

Conference and Invited Presentations

 

·         Creep and Shrinkage: Comparison of Field and Laboratory Tests, Ian N. Robertson and Michael P. Durbin, American Concrete Institute Spring Convention, Denver, CO, March 1996.

 

·         Instrumentation for Long-Term Bridge Structure Monitoring: A Case Study, Ian N. Robertson, 2^nd RILEM International Conference on DIAGNOSIS OF CONCRETE STRUCTURES, ExpertCentrum, Bratislava, Slovakia, October 1996 (Published in conference proceedings).

 

·         Instrumentation and Monitoring of the North Halawa Valley Viaduct, Ian N. Robertson, Presentation at the Transportation Research Board Annual Meeting, Washington, DC, January 1997.

 

·         Creep and Shrinkage Prediction Models: a Case Study, Ian N. Robertson and Michael P. Durbin, American Concrete Institute Spring Convention, Seattle, WA, April 1997.

 

·         Instrumentation and Monitoring of the H3 North Halawa Valley Viaduct, Ian N. Robertson, American Society of Civil Engineers Hawaii Chapter, Dinner Meeting, July 1997.

 

·         Correlation of Laboratory Creep and Shrinkage Tests with Response of a Long-Span Bridge Structure, Ian N. Robertson, American Concrete Institute Fall Convention, Atlanta, GA, November 1997 (to be included in an ACI Special Publication).

 

·         Instantaneous and Long-Term Deflection of the North Halawa Valley Viaduct, Ian N. Robertson, Sixth Asia-Pacific Conference on Structural Engineering and Construction, EASEC-6, Taipei, Taiwan, January 1998 (to be included in published proceedings).

 

·         Long-Term Monitoring of the North Halawa Valley Viaduct, Ian N. Robertson, Structural Engineers World Congress (SEWC), San Francisco, July 1998.

 

·         Load Test on the North Halawa Valley Viaduct, Ian N. Robertson and Ryan Yoshimura, American Concrete Institute Fall Convention, Los Angeles, CA, October 1998.

 

·         Instrumentation and Long-term Monitoring of the North Halawa Valley Viaduct, Graduate Seminar Presentation, University of Hawaii, March 1999.

 

·         Creep and Shrinkage Predictions for the North Halawa Valley Viaduct, Structural Engineers Association of Hawaii (SEAOH) General Meeting, Honolulu, Hawaii, March 1999.

 

·         Robertson, Ian, Field Instrumentation for Long-Term and Seismic Monitoring, Applied Concrete Technology Conference, Midrand, South Africa, June 2004.

 

·         Robertson, Ian, Shrinkage and Creep Predictions Evaluated using 10-Year Monitoring of the North Halawa Valley Viaduct, American Concrete Institute Spring Convention, New York, April, 2005.

 

·         Robertson, I.N., Shrinkage and Creep Predictions Evaluated Using 10-year Monitoring of the North Halawa Valley Viaduct, Politecnico di Torino, Turin, Italy, July 4, 2007.

 

·         Robertson, I.N., Field Instrumentation for Concrete Creep and Shrinkage Bridge Monitoring, Invited Lecture, Saitama University, Saitama, Japan, July 29, 2009.