CHENGYU LI, P.E., S.E., Ph.D.
Assistant Professor
Structural Engineering
Department of Civil Engineering
University of Colorado at Denver
Campus Box 113
P.O. Box 173364
Office Phone: 303-796-4636
Email:
EDUCATION
Ph.D. in Structural Engineering, 1995, Arizona State University, Tempe, AZ 85287, USA
M.S. in Structural Engineering, 1986, Northeast Forestry University, Harbin, China
B.S. in Civil Engineering, 1983, Northeast Forestry University, Harbin, China
ACADEMIC EXPERIENCE
2009-Present Assistant Professor CCT, University of Colorado at Denver, CO 80217
Courses Taught:
Structural Dynamics
Structural Steel Design
2001-2009 Adjunct Professor, University of Colorado at Denver, CO 80217
Courses Taught:
Structural Steel Design
Structural Earthquake Engineering,
Structural Dynamics
Advanced Topics in Reinforced Concrete
Advanced Topics in Steel Design
Prestressed Concrete (at CU Boulder)
Committee member and advisor for master and Ph.D. programs.
1992-1995 Teaching and Research Assistant, Arizona State University, Tempe, AZ, USA
Performed research on fiber reinforced concrete sponsored by the national science foundation
Teaching assistant for classes of experimental stress analysis, reinforced concrete design, and mechanics of materials
1986-1991 Associate Professor, Department of Civil Engineering, Northeast Forestry University, Harbin, China
Taught undergraduate and graduate classes of structural analysis, concrete design, bridge engineering, and engineering economy
Performed research on bridge vibration, bridge condition evaluation, and bridge rehabilitation
1983-1986 Research and Teaching Assistant, Northeast Forestry University, Harbin, China
Performed research on bridge vibration and impact simulations
INDUSTRIAL EXPERIENCE
1998-Present Principal Bridge Engineer and Project Manager, URS Corporation, 8181 East Tufts Avenue, Denver, CO 80237, USA
Principal Bridge Engineer and Project Manager for transportation projects. Responsibilities include bridge concept development, design technical review and supervision, and project management. Projects included large design-build projects, complex steel bridge rehabilitations, and concrete and steel bridge design.
1995-1998 Project Structural Engineer, Vaughn and Melton Consulting Engineers, Asheville, NC, USA
Project structural engineer for bridge and building design projects. Work included analysis and design of reinforced concrete, prestressed concrete, and steel bridges, design of reinforced concrete arch and box culverts, design of residential and industrial buildings, and design of retaining structures and foundations.
1983-1991.1 Project Structural Engineer, Design Institute of Northeast Forestry University, Harbin, China
Project structural engineer for design of post-tensioned concrete box girder bridges, concrete arch bridges, and concrete and steel bridges.
MEMBERSHIP IN SCIENTIFIC AND PROFESSIONAL SOCIETIES
Member, American Concrete Institute
Associate Committee Member, ACI Fiber Reinforced Concrete Committee 544
Member, American Society of Civil Engineers
Member, American Institute of Steel Construction
PROFESSIONAL REGISTRATION
Professional Engineer: Colorado, Utah, New Mexico, North Carolina, Washington
Structural Engineer: Arizona, Washington, Utah
REVIEWER
ACI Materials Journal
AREAS OF TEACHING AND RESEARCH INTERESTS
Teaching: mechanics of materials, structural analysis, experimental stress analysis, reinforced concrete design, prestressed concrete design, steel design, structural dynamics, structural seismic design, bridge engineering
Research: Bridge vibration and seismic design, experimental structural evaluation, structural monitoring and non-destructive testing, structural system modeling and retrofit techniques, concrete composite materials
SPONSORED RESEARCH
Fiber Reinforced Concrete (1992-1995), Sponsored by the National Science Foundation
Bridge Expansion Joint Evaluations and Rehabilitation (1987-1989), Sponsored by the Harbin Department of Transportation
Bridge Dynamic and Live Load Impact Evaluations (1986-1988), Sponsored by the China Forestry Ministry
PROJECT EXPERIENCE
RTD FASTRACKS, North Metro Corridor, Denver, CO: Lead Structure Engineer responsible for the preliminary design of all structures on the RTD Fastracks North Metro Corridor project. The North Metro corridor provides 18 miles of commuter rail transit with 8 Park-n-Ride stations between Denver Union Station and 162nd Avenue. Major structures include 15 bridges, including one 6500 ft long bridge, 3 pedestrian underpasses and 35 major retaining walls.
TXDOT, SPUR-601 Design/Build, TX: Lead Project Bridge Engineer for the design of WN connector and the main viaduct on the project. The WN connector has 19 spans of prestressed concrete Type IV girders. The substructures include hammerhead and multi-column bents supported on drilled shafts. The main viaduct has 53 spans of prestressed concrete Type IV girders with a total length of 6500 ft.. The substructures include multi-column bents, post-tensioned hammerhead and straddle bents. All bents are supported on drilled shafts.
MODOT, I-64 Design/Build, MO: Project Bridge Engineer for the seismic analysis and design of five bridges on the project. Three-dimensional models with soil-structure interaction were used to determine the seismic forces and displacements. Response spectrum analysis was carried out with SAP2000 program. The columns, connections, and foundations were designed for the seismic forces and displacements.
CALTRANS, SR-22 Design/Build, CA: Project Structural Engineer responsible for design of various types of retaining walls, moment slab barriers and major drainage structures. Retaining walls include cantilever walls with footing and pile foundations, MSE walls and tieback walls. Drainage structures include two complex headwalls, a 3-sided open channel confluence structure and various other non-standard drainage structures.
MNDOT, Roc 52 Design/Build, MN: Lead Bridge Engineer for the design of three bridges on the project. Precast/prestressed concrete girders were used for the superstructures. The abutments were tall walls supported on steel H-piles with pilasters and the piers consisted of concrete caps and columns supported on steel H-piles. Form liner was used on all exposed surfaces.
St. Louis Bay Bridge, MS, Mississippi Department of Transportation. Provided design oversight, review of plans, and checked design calculations.
E-470 Public Highway Authority, Denver, CO: Project Engineer for the widening design of two bridges. The precast/prestressed concrete girders were used for superstructure and the substructures included integral abutments on H-pile and concrete columns founded on shafts.
E-470 Public Highway Design/Build E-470/I-70 Interchange, Denver, CO: Design overview of the E-470/I-70 interchange for E-470 Public Highway Design/build project. The main structure is an 11-span precast concrete Tub girder bridge. The superstructure is curved and consists of three continuous units with post-tensioning. The concrete piers are supported on caissons and abutments are founded on steel piles.
CDOT, US 287, Loveland, CO: Lead Bridge Engineer responsible for the design of four precast/prestressed Bulb Tee GIRDER bridges. The substructures included integral abutments on H-pile and concrete column piers founded on caissons.
CDOT, 120th Avenue Bridges, CO: Lead Structural Engineer for the design of three bridges, including a 5-span bridge and two single-span bridges. Precast/prestressed concrete Bulb-Tee girders were used for the superstructures. The end bents were concrete caps on stele HP piles and the interior bents were concrete columns on drilled concrete shafts. Architectural form liner and stone accent columns were used on the bridge for aesthetic effects.
CDOT, Crews Gulch Bridge on SH 85, Colorado Spring, CO: Project Structural Engineer for a single span precast/pretressed Bulb-Tee girder superstructure with span length of 38 meters and integral abutments on steel piles. The bridge was located in an urban area and designed with raised median and sidewalk and a bike path underneath the bridge.
City and County of Denver, Central Park Blvd Extension, Denver, CO: Lead Structural Engineer for the design of three bridges, including a 2-span bridge over I-70 and two bridges over ramps. Precast/prestressed concrete Bulb-Tee girders were used for the superstructures. The end bents were concrete caps on stele H piles and the interior bents were concrete columns on drilled concrete shafts. Architectural form liner and special railings were used on the bridges for aesthetic effects.
City and County of Denver, 56th Avenue Reconstruction, Denver, CO: Lead Structural Engineer for the design of three highway bridges and one pedestrian bridge for the project. The WB bridge over Haulroad is a new structure with precast prestressed concrete girders. The existing Haulroad bridge is used for the EB traffic and rehabilitation was designed to strengthen the abutments, replace the sidewalk and curbs, and replace the expansion joints.
City and County of Denver, 6th Avenue Viaduct Condition Evaluation and Retrofit Design, Denver, CO: Principal Investigator and Project Manager for this viaduct built in 1960’s and modified in 1990’s. The structure consists of 18 spans of composite steel girders with a total length of 1430 feet. The viaduct showed extensive deterioration. Field investigation was conducted to determine the bearing and other structural element conditions and bridge movements. Stresses due to temperature fluctuation were measured on steel columns using strain gages. Critical fatigue details were tested using ultrasonic and dye penetrant techniques to detect potential cracks. A three-dimensional frame model using SAP2000 was used to study the superstructure and substructure under thermal and other loading conditions. Structural deficiency was identified with concrete deck, steel girders, bearings, piers, and foundations. The retrofit involves replacing bearings and columns and strengthening the foundations.
City and County of Denver, 8th Avenue Viaduct Thermal Analysis and Condition Assessment, Denver, CO: Principal Investigator and Project Manager for this viaduct built in 1980’s. The structure consisted of 20 spans of twin continuous steel box girders with a total length of 2361 feet. The bridge was on three horizontal compound curves and two vertical curves. The original guide system failed and extensive cracks were present on all concrete piers. Field investigations were conducted to assess the bearing movements and crack extension. A three-dimensional finite element model using ANSYS was developed to study the structural movement and stresses due to thermal variation and other design loads. The cracks on the pier were studied for structural strength and integrity.
City and County of Denver, West Evans Avenue Bridge over South Santa Fe Drive, Denver, CO: Principal Investigator and Project Manager for this project to assess the structural conditions. The bridge consists of 9 spans of steel composite girders with a total length of 765 feet. Field investigation was conducted to evaluate the bridge existing conditions. Displacement measurement system was installed on the bridge to monitor the bridge movement due to temperature fluctuation. Non-destructive testing was performed on the steel girders and concrete piers to determine the steel corrosion and concrete cracking. The bridge was studied for the structural capacity and retrofit recommendations were provided for the steel girders, bearings, and concrete piers.
City and County of Denver, Lower Colfax Bridge, Denver, CO: Project Structural Engineer provided structural selection, preliminary design, and final superstructure design. The replaced structure consisted of three spans of precast/prestressed concrete box girders. Integral piers and abutments with drilled caisson foundation were used.
Foundation Coal, SH 14/16 Relocation, Wyoming: Lead Bridge Engineer for a three-span composite steel plate girder bridge. The bridge was located over a reclaimed section of the Eagle Butte Mine that was backfilled with up to 275 feet of mining backfill material. The potential consolidation settlement is the major concern for the design of the roadway and bridge. The foundation utilized over-excavation with re-compaction to a depth of approximately 10 feet below the bottom of the footings and geopiers to a depth of approximately 20 feet below the bottom of the over-excavation beneath. Special steel settlement plates were installed under the bearings so they can be removed in the future to adjust the deck profile for the uneven settlements between the abutments and the piers.
WVDOT, Bridge on US 52, near Huntington, WV: Project Structural Engineer for the design of a dual mainline bridge on US 52. The bridge was a three-span AASHTO Type IV girders with deck slab continuity at interior bents. Integral end bents and solid wall piers were supported on steel HP piles.
NCDOT, Truelight Church Bridge Over Charlotte Outer Loop, Charlotte, NC: Project Structural Engineer for this two-span steel plate composite bridge with span lengths of 44 m and 43 m. The bridge was on a 51-degree skew and located on a curved section of the roadway. The substructure was steel HP pile end bents and intermediate concrete column bent with steel HP pile foundation.
NCDOT, New Land Bridge, New Land, NC: Project Structural Engineer for the design of a single span bridge with AASHTO Type IV girders and integral abutments on steel HP piles.
NCDOT, Bridges on Charlotte Outer Loop over CRX, Charlotte, NC: Structural Project Engineer for the design of a four-span AASHTO Type IV girder bridge and a two-span steel plate girder bridge. The first bridge was 110 meters long and located on both horizontal and vertical curves. The second bridge was 68 meters long. The substructure included end bents of concrete caps on steel piles and interior bents of concrete columns on concrete footings founded on steel piles.
PUBLICATIONS
"Fatigue of Concrete Beams Strengthened with Advanced Glass-Fiber Composite under Flexure," in review, ACI Materials Journal.
"Performance of Polymer Modified Asphalt Bridge Expansion Joints in Low Temperature Regions," ASCE Performance of Constructed Facilities, Vol. 23, Number 4, pp. 227-233.
"Finite Element Simulations of Fiber Pullout Toughening in Fiber Reinforced Cement Based Composites," Advanced Cement Based Materials, 7, 1998, pp. 123-132.
"Effect of Interfacial Properties on the Crack Propagation in Cementitious Composites," Advanced Cement Based Materials, 4, 1996, pp. 93-105.
"Mechanical Properties of Hybrid Cement Based Composites," ACI Materials Journal, May-June, 1996, pp. 284-292.
"Modeling of Stiffness Degradation of the Interfacial Zone During Fiber Debonding," Composites Engineering, Vol. 5, No. 10-11, 1995, pp. 1349-1365.
"Experimental R-Curve for Assessment of Toughening in Micro-Fiber Reinforced Hybrid Composites," American Concrete Institute, SP-155, 1995, pp. 93-114.
"Bridge Vibration and Impact under Moving Vehicles," Proc. 1996 Engineering Systems Design and Analysis Conference, Volume 9, Structural Dynamics, Vibration, and Buckling, ASME 1996, pp. 17-23.
"Processing Techniques for Manufacturing High Volume Fraction Cement Based Composites," Proc., First International Conference on Composites in Infrastructure, January 15-17, 1996, pp. 123-136.
"Effect of Bridge Deck Roughness on Bridge Dynamic Response," Proc., 7th International Conference on Computational Methods and Experimental Measurements, VII, May 1995, pp. 485-492.
"Modeling of Fiber Pullout in Cement Based Composites Using an R-Curve Approach," Proc. of the Third Materials Eng. Conference, Infrastructure: New Materials and Methods for Repair, 1994, pp. 559-566.
"Tensile Fracture of Carbon Whisker Reinforced Cement Based Composites," Proc. of the Third Materials Engineering Conference, Infrastructure: New Materials and Methods for Repair, ASCE 1994, pp. 551-558.
"Fracture of Whisker Reinforced Cement Based Composites," Proc., International Symposium, Brittle Matrix Composites 4, 1994, pp. 116-124.
"Effect of Interfacial Properties on the Strength of Cementitious Composites," Proc., The First International Conference on Composites Engineering (ICCE/1), 1994, pp. 351-352.
"Finite Element Simulations of Toughening in Cement Based Composites," MRS 1996 Fall Meeting, Symposium HH: Structure-Property Relationships in Hardened Cement pastes and Composites, Boston, Mass.