Link to Latest Report: March 2023 Progress Report
Background:
The Federal Highway Administration (FHWA) and state departments of transportation (DOTs) are actively promoting accelerated bridge construction (ABC) to minimize construction costs and time and to also enhance work-zone safety. While several techniques are available to accelerate bridge superstructure construction, limited techniques are available to accelerate bridge substructure construction.
Hollow-core FRP-concrete-steel (HC-FCS) columns – a concrete core sandwiched between an outer FRP tube and an inner steel tube – provide a potential solution for accelerating bridge substructure construction and offer the following advantages over traditional construction materials and systems:
- Enhanced ductility and energy absorption
- Improved axial and flexural strength
- Enhanced durability and corrosion resistance
- Simplified construction techniques
- Decreased overall column weight
- Reduced material and labor costs
- Longer life
Because of their significantly enhanced ductility compared to existing bridge columns, HC-FCS columns also provide a column system better able to resist multiple hazards such as earthquakes, vehicular impact, blast, overload, excessive thermal stresses, progressive collapse, and fire.
Previous research combined with the results of this proposed study and a companion Oklahoma Department of Transportation (ODOT) study will provide the necessary performance data and recommendations to move HC‑FCS columns into practice.
Objective:
The overarching goal of this research study is to implement hollow-core FRP-concrete-steel (HC-FCS) columns for accelerated bridge construction. The objectives necessary to achieve that goal include:
- Determining the benefits of using high-strength SCC and UHPC for the concrete core of HC-FCS columns
- Developing design procedures and recommendations for steel, concrete, and FRP wall thicknesses, concrete type (SCC or UHPC), and nominal flexural and shear strengths of HC-FCS columns
Scope:
The project activities consist of static cyclic testing of half-scale columns and a parametric finite element analysis. The half-scale column tests will investigate the effects of steel, concrete, and FRP wall thicknesses, concrete type (SCC or UHPC), and column aspect ratios (slender, intermediate, and squat). The finite element analysis will investigate the effects of different parameters on embedment depths and column strengths. The results of the experimental testing and finite element analyses will form the basis for developing a set of design procedures and recommendations for HC-FCS columns.
- Task 1 – Design and Construct Half-Scale HC-FCS Columns
- Three (3) half-scale HC-FCS columns will be designed and constructed having different steel, concrete, and FRP wall thicknesses, concrete type (SCC or UHPC), and column aspect ratio These three (3) specimens will augment the eight (8) specimens that are part of the companion ODOT-sponsored HC-FCS research project mentioned previously.
- Task 2 – Test Half-Scale HC-FCS Columns Under Cyclic Lateral Load and Constant Axial Load
- The half-scale column specimens will be tested under cyclic lateral loading and a constant axial compressive load, as shown in Figure 1. The cyclic loading will be applied in a displacement-controlled manner using two hydraulic actuators connected to the column loading stub. The loading protocol is based on FEMA Publication FEMA P-2082-1 (2020), which recommends increasing each subsequent displacement amplitude by 40%. The protocol includes two cycles for each specified increment of displacement.
- Task 3 – Perform Parametric Finite Element Study of HC-FCS Columns
- The results from Task 2 combined with the results from the ODOT sponsored HC-FCS research project will be used to validate finite element models of the half-scale testing program. Once validated, the finite element models will be used to perform a series of parametric studies to investigate HC-FCS columns having different steel, concrete, and FRP wall thicknesses, concrete type (SCC or UHPC), footing and girder embedment depths, and column aspect ratios.
- Task 4 – Develop Design Procedures and Recommendations for HC-FCS Columns
- The results of Tasks 1 through 3 combined with the results from the ODOT-sponsored HC-FCS research project will form the basis for developing a set of design procedures and recommendations for HC-FCS columns.
- Task 5 – Document Progress, Results, Recommendations, and Design Guidelines of the Study Through Quarterly Progress Reports, a Final Report, and an ABC-UTC Guide
- This task involves documenting, reporting, disseminating, and promoting the results of the research and will include quarterly progress reports, a final report, and an ABC-UTC Guide on HC-FCS columns.
Research Team:
Principal Investigator: Dr. Jeffery S. Volz
Co-Principal Investigator: Dr. Royce W. Floyd
Research Assistant: Jackson Milner
Previous Progress Reports: