1 / 19

Analysis Model and Displacement Measurement

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.). Korean group. Analysis model and displacement measurement Seoul National University (SNU)

levana
Download Presentation

Analysis Model and Displacement Measurement

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 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.)

  2. 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

  3. 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.)

  4. 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.

  5. FE modeling Plate elementfor flange Plate elementfor web * 8 node 3D solid element (Isometric formulation with incompatible modes) **3 or 4 node 3D plate element (Kirchhoff Plate Theory) • RC Slab :*solid element • Girder • Web & flange : ** plate element

  6. FE modeling Bracing Diaphragm Bracing, diaphragm : 2 node space frame elements

  7. 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

  8. Boundary conditions Fixed bearings Movable bearings P1W P2W y x • 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

  9. 3D full modeling

  10. Measurement of displacement • Direct measuring with LVDT • Reconstruction from ACCELEROMETER • Identification from images of CAMCORDER

  11. 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

  12. Dynamic displacement • Measured Displacement • The static displacements are included in measured displacements. • To eliminate the static components from the measurements, a moving average technique is employed.

  13. Reconstructed displacements • Results • LVDT • ACC Reconstruction

  14. Displacement from camcorder images • Digital Image Processing Algorithm Image Arrangement Grid Generation ( Target Image ) Correlation Size Selection ( ROI ) Sum Table Calculation NCC Computation ROI ROI ROI Target Target Target Searching for the position where the maximum value of Normalized Cross Correlation Coefficient is obtained Initial coordinate Coordinates of best Coordinates of best ( x , y ) match ( x , y ) match ( x , y ) 1 1 2 2 3 3 Frame 1 ( t ) Frame 2 ( t ) Frame 3 ( t ) 0 1 2 Enhancing the resolution of displacement responses by using the 2nd Order Polynomial Transform Function Sub - pixel Estimation Displacement Response

  15. Identification of displacement from camcorder images • Measurement conditions Target Span Span-2 Target(L/2) Span-2 Camera Image Camcorder SAMSUNG VM HMX10A Sampling Rate LVDT : 100Hz Camcorder : 60fps Resolution 1280 x 720 pixels (Full High Definition) 50mm/101pixel s= 0.495mm/pixel Target (2L/3) Target (L/2) Target

  16. Identified displacements • Comparison of Responses on LVDT Vertical Vertical

  17. Time plan and future test-bed in Korea • 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 2013. • Reliability-based approaches will be examined. • A typical concrete bridge and a steel bridge will be selected and tested in 2012 and 2013. • The bridges will be open for testing to international society. • Typical sensors will be installed by Korean side.

  18. Time plan and future test-bed in Korea • Equations for Load Rating • AASHTO LRFR • CHBDC Live Load Capacity Factor Mean Load Method RC-T Beam PSC Beam

  19. Korean group and IBS supporters Many thanks to Jeff and Prof. Aktan for their sincere assistance.

More Related