University of Illinois Contribution

1. Seismic Simulation and Design of Bridge Columns under Combined Actions, and Implications on System Response University of Illinois Contribution Amr S. Elnashai Sung Jig Kim Curtis Holub Narutoshi Nakata Oh Sung Kwon

2. Research Focus Existing methodologies Analysis tools Bidirectional loading Torsion UIUC Vertical Motion Vertical Motion • Performance assessment of bridge system using PSD tests • Determination of the impact of varying vertical force on behavior of reinforced concrete bridge columns • Evaluation of the effect of shear-axial-flexure interaction • Consideration of soil-structure interaction • Investigation of the effect of early arrival of vertical motion on the periods of flexural vibrations under horizontal motion for RC bridge structures • Derivation of design guidance for reduced shear capacity in the presence of high vertical motion NEES-R Performance assessment of the bridge columns under complex loading

3. Analysis and Design • Analysis of a series of bridge structures subject to different levels of earthquake excitations • OpenSees, Zeus-NL- the MAE Center advanced analysis platform • This process will be conducted using UI-SIMCOR as a simulation coordinator • Analytical work will provide the modeling of PSD conditions to zoom on parameters resulting in high levels of simultaneous transverse and vertical accelerations. • Study the seismic response of the bridge systems, including foundations and surrounding soils • Appropriate multidirectional loading and boundary conditions for columns can be obtained • Determination of the appropriate input loading for the specimens tested in the subsequent phases of the project

4. Experiment Test at UIUC Large Scale Test Small Scale Test Test with UMR NEES-R • MISST test (previous multi-site test at UIUC) will provide the test bed for the loading protocols • Tests of 3 large scale and 4 small scale bridge columns with different aspect ratios and seismic design details using MUST-SIM Facility • Column test with UMR under different loading conditions • Verify local and global analytical part of the hybrid simulation • Provide an opportunity for researchers outside of a NEES facility • Detailed design of UIUC and UNR experiments will be guided by bridge system analysis

5. Parametric Study for Effect of Vertical Motion on Bridge Pier Start Select Records Ms >5.5, D <25 km V/H > 0.6 Choose Model Structure and Parameters Parametric Study Span length, ratio and column height Complex Structure V/H ratio, Time Interval Bridge Dynamic Time History Analysis Zeus-NL Evaluate Resuts Dx, Fy, Mz and strains Calculate Shear Demand and Capacity Estimate the effect of VGM End

6. Summary of Parametric Study VGM HGM Axial force variation Increasing ratio of V due to VGM Axial force • Axial force is mainly affected by vertical ground motion • Especially, as span ratio increase, the effect of vertical seismic motion to axial force increase significantly only when vertical record is considered • Shear capacity is reduced by vertical ground motion • Span length is longer • Span ratio is close to 1 • Column height is shorter • In case of seismic assessment for the structure with above geometric configurations, vertical ground motion should be considered • Future parameter study • Various connection type between deck and piers, Number of spans, Various deck stiffness, Type of abutment, Curved bridge

7. Small-Scale Testing • Current testing • Several 1/16 scaled piers are currently being tested • Used to evaluate system and material/pier design Test Setup After Test

8. Multi-Site Soil-Structure-Foundation Interaction Test (MISST) – Pre-NEESR Project Three Site Distributed Hybrid Bridge System Test Setup - UIUC After Test - UIUC