University of Nebraska at Lincoln
Behrouz Shafeishafei@iastate.edu email >
Structural Engineer, BEC
Brent Pharesbphares@iastate.edu email >
Bridge Research Engineer, BEC
About the research
Concrete barriers (CBs) are widely used to direct vehicular traffic in construction work zones. For bridge applications, CBs have a critical role to prevent vehicles from departing the travelway until permanent barriers can be installed. For roadway applications, they not only provide the flexibility of guiding the flow of traffic, but also protect the construction personnel and equipment from potential accidents. A critical aspect to ensure the proper performance of CBs is to leave ample empty space behind the barrier. This space is essential to accommodate the lateral deflection of the barrier when it is subjected to vehicle impact loads. While a “less than sufficient” space may magnify the consequences of accidents for motorists and construction workers, a “more than sufficient” space will take away the much needed work area for construction activities. To avoid the listed issues, the required space is determined based on the design of the barrier and how it is connected to the supporting structures/surfaces. One category of design is free-standing temporary barriers, which can be conveniently installed, repositioned, and removed. While the issue of connection to the ground surface is completely eliminated in such barriers, they suffer from the excessive impact-induced lateral deflections that cannot be accommodated in the most of practical cases. To limit the lateral deflection of barriers, especially where limited space is available, anchoring, pinning, or bolting techniques must be used to restraint the barrier to the underlying ground. This, however, may cause significant damage to the bridge deck or pavement (1) at the time of installation, (2) when an accident occurs, and (3) at the time of removal. This is one of the main motivations of the project, which aims at identifying the potential CBs that do not require, or significantly reduce, anchoring to the supporting structures/surfaces.