Seismic Behavior and Design of Segmental Precast Post-Tensioned Concrete Piers

Final technical report.PDFTech ReportTNW2011-17DTRT07-G-0010Earthquake resistant designEarthquakesEarthquake engineeringEarthquake resistant structuresBridge piersPosttensioningTensioningSmart structuresConcreteWashingtonTransportation Northwest (Organization)Dawood, HaithamElGawady, MohamedCofer, WilliamTransportation Northwest (Organization)United States. Dept. of Transportation. Office of the SecretaryUniversity Transportation Centers Program (U.S.)NTL-ENERGY AND ENVIRONMENT-Environment ImpactsNTL-HIGHWAY/ROAD TRANSPORTATION-Bridges and StructuresUS Transportation CollectionSegmental precast column construction is an economic environmental friendly solution to accelerate bridge construction in the UnitedStates. Also, concrete-filled fiber reinforced polymer tubes (CFFT) represents a potential economic solution for durability issues inbridge industry. Combining the segmental precast and CFFT will result in rapid durable construction system. The proposed researchwill build on recent work by the PI where he experimentally investigated the seismic behavior of tens single-column and two-columnbents constructed using precast post-tensioned CFFT. The columns were constructed by stacking precast CFFT segments one on top ofthe other and then post-tensioned using unbonded tendons. Two specimens had external energy dissipation devices and another twospecimens had neoprene in the joints between the CFFT segments. The neoprene significantly reduced the seismic displacementdemand. The columns re-centered upon the conclusion of the test resulting in minimal residual displacement which represents, in thecase of a real strong earthquake, a huge advantage since the post-earthquake repair measures will be minimal. A 3-D finite elementmodels were developed by the PI to predict the performance of the single-column under monotonic lateral loads. The main objective ofthis proposal is to improve and expand the capabilities of these finite element models to produce design recommendations. Inparticular, the models will be expanded to include dynamic loading, two-column bents, and the neoprene in the joints. Includingdynamic loading in the model is essential to quantify the energy dissipation due to rocking of the columns segments. The output of thisresearch will be recommendations on the optimum construction characteristics of the system including the segment height/columndiameter ratio, neoprene thickness and hardness, external energy dissipater requirements, and post-tensioning force level. The proposedresearch will develop a durable environmental friendly rapid construction bridge system, which has low life-cycle costs, constructionwaste, noise, traffic disruption, and initial construction cost. In addition, the developed system will has high work zone safety, efficientuse of construction material, a short construction time, and improved constructability. The proposed construction system will not havea leakage of wet concrete into waterways leading to pollution of water and harm migrating fish. Finally, when the proposedconstruction system fully developed and implemented in construction, it will reduce the expense of bridge replacement, repair, andcontinuous operation interruption after earthquakes