1. Parametric study on the overstrength capacity of bridge piers under earthquakes
Authors : Ammar A. Abdul Rahman, Ahmed Mohammed Abdullah
Pages : 329-344
DOI : http://dx.doi.org/10.21172/1.83.049
Keywords : eywords – Bridge piers, earthquakes, overstrength capacity of concrete, 3D FEA, ABAQUS. Abstract :Abstract- In the seismic analysis of reinforced concrete bridge piers, there is now a common awareness that excessive strength of the concrete is essential and required in the analysis up to failure of the pier. This means it is necessary to assess the overstrength capacity of pier columns subjected to earthquake after incorporating the concrete plastic damage parameter in the analysis. A three dimensional finite element model of the complete typical pier used in Iraqi bridges was developed using the computer software ABAQUS where concrete plasticity damage was incorporated. The model was used in studying the behavior of typical bridge piers used in Iraq up to failure under the action of actual earthquake took place and recorded in Iraq. The model didn’t fail due to reaching the concrete compressive strength at certain locations but rather continued following the formation of plastic hinges at the critical sections and making use of the overstrength capacity of the concrete due to its plastic damage strength. It was observed that such piers can sustain the actual earthquake took place and used only 17% of the concrete compressive damage capacity. To cover more cases, a parametric study was conducted where different columns’ diameters were studied with multiples of the original earthquake intensity. From the study it was observed that the 800 mm diameter columns used with typical piers can sustain the original earthquake but with using only 41% of the concrete plastic damage capacity. This column was unable to carry out 2.5 and 3 times of the original earthquake and it will be recommended for designers not to use this column diameter in bridge piers in zones with earthquake activity. Piers with 1200 mm diameter columns can sustain larger earthquake intensities but the tensile cracks will spread at the outer faces of the columns which will reduce its compressive overstrength capacity. Following the formation of plastic hinges in the compression zones of concrete under the effect of earthquake loading up to failure after reaching a mechanism gave clear picture on the true capacity of the typical piers used in Iraq under the action of earthquakes. The piers can sustain 8 times of their capacities measured using their maximum compressive strengths. There will be cracks, and plastic hinges but the pier will not fail until the structure reaches a mechanism of collapse.
Citing this Journal Article :Ammar A. Abdul Rahman, Ahmed Mohammed Abdullah, "Parametric study on the overstrength capacity of bridge piers under earthquakes", Volume 8 Issue 3 - May 2017, 329-344
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