Analysis Model and Displacement Measurement Prof. Ho-Kyung Kim (Seoul Nat’l Univ.) Prof. HaeSung Lee (Seoul Nat’l Univ.) Prof. Nam-Sik Kim (Pusan Nat’l Univ.)

IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University Korean group  Analysis model and displacement measurement Seoul National University (SNU)  Visual inspection and condition assessment PEC (Pyunghwa Engineering Consultants) KCQR (Korea Construction Quality Research Center) Inha Univ.  Model updating for the SMART load rating KEC (Korea Expressway Corporation) Sejong Univ.  Application of NDT techniques for online monitoring KAIST  4 universities and 3 companies

IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University Target span  Southbound of Span 2 Severe vibrations have been observed. The longest span length Deteriorations on bearings, bracings and cracks on pier cap Controlled loading test data is available (tested by Drexel Univ.)

IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University FEA Software  MIDAS Civil 2006 Database including live load models in the design specification of Korea, U.S., etc. Sectional properties of structural members (such as bracing, diaphragm) are easily obtained using in-built database.

IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University FE modeling  RC Slab : * solid element  Girder Web & flange : ** plate element Plate element for web Plate element for flange * 8 node 3D solid element (Isometric formulation with incompatible modes) ** 3 or 4 node 3D plate element (Kirchhoff Plate Theory)

IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University FE modeling  Bracing, diaphragm : 2 node space frame elements Diaphragm Bracing

IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University FE modeling  Variation of flange thickness Top flange with two thicknesses Bottom flange with three different thicknesses Sectional properties are varied according to flange details

IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University Boundary conditions  Fixed bearing Between girders and pier 1 Rotation in y direction is released  Movable bearing Between girders and pier 2 Rotation in y direction, translation in x direction are released P1W P2W xy Movable bearings Fixed bearings

IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University 3D full modeling

IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University Measurement of displacement 1.Direct measuring with LVDT 2.Reconstruction from ACCELEROMETER 3.Identification from images of CAMCORDER

IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University Reconstruction of displacement from measured acceleration  Variational Statement for the Minimization Problem  Integration by Parts Twice  Governing Equation and Boundary Conditions The same governing equation for a beam on elastic foundation Discretization of governing equation yields FFIR type filter for reconstruction

IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University  Measured Displacement The static displacements are included in measured displacements. To eliminate the static components from the measurements, a moving average technique is employed. Dynamic displacement

IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University  Results Reconstructed displacements LVDTACC Reconstruction

IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University Displacement from camcorder images  Digital Image Processing Algorithm Image Arrangement Grid Generation(Target Image) Sum Table Calculation Sub-pixel Estimation Displacement Response Correlation Size Selection(ROI) NCC Computation Target Initial coordinate (x 1,y 1 ) Frame1(t 0 ) ROI Coordinates of best match(x 3,y 3 ) Frame3(t 2 ) Target ROI Coordinates of best match(x 2,y 2 ) Frame2(t 1 ) Target ROI Enhancing the resolution of displacement responses by using the 2 nd Order Polynomial Transform Function Searching for the position where the maximum value of Normalized Cross Correlation Coefficient is obtained

IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University  Measurement conditions Target(L/2) Span-2 Target Span Camera Image Target (L/2) Target (2L/3) Span-2 Target Camcorder SAMSUNG VM HMX10A Sampling Rate LVDT : 100Hz Camcorder : 60fps Resolution 1280 x 720 pixels (Full High Definition) 50mm/101pixel s= 0.495mm/pixel Identification of displacement from camcorder images

IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University  Comparison of Responses on LVDT Identified displacements Vertical

IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University Time plan and future test-bed in Korea Field testingJune 6~10, 2011 Preliminary reportJuly 15, 2011 Final reportJuly 30, 2011  Time plan  Future test-bed in Korea  A new KEC project for evaluating the load carrying capacity of bridges will start from July 2011 to December  Reliability-based approaches will be examined.  A typical concrete bridge and a steel bridge will be selected and tested in 2012 and  The bridges will be open for testing to international society.  Typical sensors will be installed by Korean side.

IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University Time plan and future test-bed in Korea  Equations for Load Rating  AASHTO LRFR  CHBDC RC-T Beam PSC Beam Live Load Capacity Factor Mean Load Method

IBS Workshop, CAIT at Rutgers, June 14-15, 2011Seoul National University Korean group and IBS supporters Many thanks to Jeff and Prof. Aktan for their sincere assistance.