scholarly journals Forced Vibration Testing and Analysis of Pre- and Post- Retrofit Buildings

2011 ◽  
Author(s):  
Erica Dawn Jacobsen
Keyword(s):  
Forced Vibration ◽  
Vibration Testing ◽  
Forced Vibration Testing

Modal identification of a bridge-abutment system using forced vibration testing

2012 ◽  
Vol 45 (4) ◽  
pp. 161-170
Author(s):  
L.S. Hogan ◽  
L.M. Wotherspoon ◽  
S. Beskhyroun ◽  
J.M. Ingham
Keyword(s):  
System Identification ◽  
Forced Vibration ◽  
Experimental Testing ◽  
Principal Direction ◽  
Lateral Spreading ◽  
Modal Identification ◽  
Vibration Testing ◽  
Longitudinal Response ◽  
Bridge Superstructure ◽  
Forced Vibration Testing

During the 2010 Mw7.1 Darfield earthquake, the single span Davis Road Bridge located 5 km southeast of Lincoln, New Zealand, sustained significant lateral spreading damage to the western approach. While lateral spreading resulted in up to 450 mm of approach settlement and evidence of damage to the pile foundations, the bridge superstructure sustained no significant damage. Prior to reinstating traffic, the bridge was used for full scale dynamic testing to characterise the influence of different substructure components on the lateral dynamic behaviour of the bridge superstructure. The bridge was characterised using an eccentric mass shaker and an array of accelerometers to perform lateral forced vibration testing in both the transverse and longitudinal directions. Modal properties were extracted from these tests using multiple system identification algorithms. The experimental testing and system identification methodology are described here. Forced vibration testing was able to detect one mode in each principal direction of the bridge, with the fundamental modes for the transverse and longitudinal direction occurring at a period of 0.118 s and 0.092 s respectively. The torsional response found during the transverse direction shaking was most likely due to the effect of gap opening around the piles on the western abutment, while the longitudinal response was dominated by the approach soil.

Dynamic response of a concrete dam impounding an ice-covered reservoir: Part I. Mathematical modelling

2004 ◽  
Vol 31 (6) ◽  
pp. 956-964 ◽  
Author(s):  
Najib Bouaanani ◽  
Patrick Paultre ◽  
Jean Proulx
Keyword(s):  
Dynamic Response ◽  
Forced Vibration ◽  
Seismic Analysis ◽  
Ice Cover ◽  
Complex Nature ◽  
Concrete Dams ◽  
Vibration Testing ◽  
Concrete Dam ◽  
Structure Interaction ◽  
Forced Vibration Testing

This paper examines the dynamic response of a concrete dam impounding an ice-covered reservoir and subjected to forced-vibration testing. The analytical research presented is a follow-up to an extensive dynamic testing program carried out on a 84-m high concrete gravity dam located in northeastern Quebec, Canada, under harsh winter conditions, including a 1.0- to 1.5-m-thick ice sheet covering the reservoir. One of the major challenges encountered when analyzing ice-dam-reservoir-foundation interaction is modelling the complex nature of the ice and the boundary conditions governing reservoir motion. The problem is further complicated because there are little or no appropriate experimental data and observational evidence relevant to ice-dam interaction processes. Some of these challenges are addressed herein using a two-dimensional analytical approach, which investigates the effects due to ice cover, water compressibility, and reservoir bottom absorption. A frequency-domain substructure method technique is used and a new boundary condition along the ice-cover-reservoir interface is proposed. The technique developed is implemented in a finite element code specialized in the seismic analysis of concrete dams. Numerical results are discussed in the companion paper in this issue. Key words: gravity dams, concrete dams, ice, reservoirs, mathematical models, ice-structure interaction, fluid-structure interaction, forced-vibration testing, finite elements modelling.

Forced Vibration Testing and Finite Element Modeling of a Nine-Story Reinforced Concrete Flat Plate-Wall Building

2015 ◽  
Vol 31 (2) ◽  
pp. 1069-1081 ◽  
Author(s):  
Ozan Cem Celik ◽  
Haluk Sucuoğlu ◽  
Ugurhan Akyuz
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Flat Plate ◽  
Forced Vibration ◽  
Structural Model ◽  
Dynamic Properties ◽  
Mode Shapes ◽  
Structural System ◽  
Vibration Testing ◽  
Forced Vibration Testing

Tunnel form buildings, owing to their higher construction speed and quality, lower cost, and superior earthquake resistance over that of conventional reinforced concrete buildings, have been widely used for mass housing, urban renewal, and post-earthquake reconstruction projects all over the world as well as in Turkey. However, there have been few dynamic tests performed on existing buildings with this structural system. This study investigates the dynamic structural properties of a typical nine-story reinforced concrete flat plate-wall building by forced vibration testing and develops its three-dimensional (3-D) linear elastic finite element structural model. The finite element model that uses the modulus of elasticity for concrete in ACI 318 predicts the natural vibration periods well. Mode shapes are also in good agreement with the test results. Door and window openings in the shear walls, and the basement with peripheral wall emerge as modeling considerations that have the most significant impact on structural system dynamic properties.

scholarly journals Field-Testing of Structure on Shallow Foundation to Evaluate Soil-Structure Interaction Effects

2015 ◽  
Vol 31 (4) ◽  
pp. 2511-2534 ◽  
Author(s):  
Lisa M. Star ◽  
Michael J. Givens ◽  
Robert L. Nigbor ◽  
Jonathan P. Stewart
Keyword(s):  
Forced Vibration ◽  
Field Testing ◽  
Shallow Foundation ◽  
Base Shear ◽  
Vibration Testing ◽  
Foundation Soil ◽  
Plan View ◽  
Steel Columns ◽  
Wide Range ◽  
Forced Vibration Testing

A simple test structure was designed and constructed to facilitate forced-vibration testing of a shallow foundation experiencing combined base shear and moment demands. The structure consists of a reinforced concrete foundation and top slab separated by steel columns that can be configured with braces. The slabs have a 2:1 aspect ratio in plan view to facilitate variable amount of overturning for shaking in orthogonal directions. The structure was transported to two field sites with representative shear-wave velocities of approximately V S = 95 m/s and 190 m/s. At each site, the foundation slab was cast-in-place. Forced vibration testing was conducted over a wide range of frequencies and load levels to enable the evaluation of foundation-soil stiffness and damping behavior for linear and nonlinear conditions. The data collected to facilitate such analyses include acceleration, displacement, and foundation pressure records (data can be accessed at DOI: 10.4231/D3NK3658M, DOI: 10.4231/D3HT2GC4G, DOI: 10.4231/D3D21RK0N).

Uniqueness in the Identification of Building Structures from Forced Vibration Tests

1985 ◽  
Vol 9 (1) ◽  
pp. 19-25
Author(s):  
F.E. Udwadia
Keyword(s):  
Forced Vibration ◽  
Structural Systems ◽  
Building Structures ◽  
Structural System ◽  
Vibration Testing ◽  
Forcing Function ◽  
Shear Beam ◽  
Vibration Tests ◽  
Forced Vibration Testing

This paper investigates the problem of uniqueness in the identification of building structural systems from data gathered during forced-vibration testing. Modelling the structure as an undamped discrete shear beam, it is shown that if the top floor response to a known forcing function which is also applied at the same location is available, then unique identification of the structural system is possible. Several useful results on the ability to uniquely identify some, but not all, of the stiffness constants of the system have also been obtained.

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