Development of a Control System and User Interface for the Quanser Shake Table II

Shake tables are often used to simulate earthquakes to test the performance of structures under seismic loads. This project focuses on implementing the Quanser Shake Table II, which is a valuable tool for conducting small-scale experimental vibration tests. This research project focused on the development of a control system and user interface for the shake table. With the aim of making the shake table easier to control, a proportional-integral-derivative (PID) controller and an intuitive graphical user interface (GUI) were developed. MATLAB was used to simulate the control system, while the graphical programming environment NI LabVIEW was used to develop the GUI. In this presentation, an overview of a closed-loop control system, the designed GUI, and the implementation results are discussed.Ope

Development of a fidelity structural model based on a shake table test for an innovative seismic resisting system

The research project is to produce a fidelity three-dimensional (3D) structural model based on a shake table test, which is used to demonstrate performances of an innovative seismic resisting system for reducing damages to building structures under earthquakes

Seismic qualification of directional valve

Seismic qualification tests on pneumatically operated directional valve were carried out in the shake table facility in Structural Integrity Division. Determination of the fundamental frequency for directional valve was carried out through exploratory vibration test as per ANSI B 16.41 Annexure E (Para E-3) to ascertain extent of flexibility as defined in the standard. Seismic (static) load test on same directional valve was also carried out to ascertain its capabilities to withstand the expected dynamic, seismic stresses and to ensure that the valves will not be subjected to performance degradation or malfunction under seismic conditions. This report describes the final seismic qualification documentation for directional valve manufactured by M/s Vijay Fire Protection Systems Ltd, Mumbai

Seismic Retrofitting of RC Buildings Using CFRP and Post-Tensioned Metal Straps: Shake Table Tests

This article examines the effectiveness of two innovative retrofitting solutions at enhancing the seismic behaviour of a substandard reinforced concrete building tested on a shake table as part of the Pan-European funded project BANDIT. To simulate typical substandard construction, the reinforcement of columns and beam-column joints of the full-scale structure had inadequate detailing. An initial series of shake table tests were carried out to assess the seismic behaviour of the bare building and the effectiveness of a first retrofitting intervention using Post-Tensioned Metal Straps. After these tests, columns and joints were repaired and subsequently retrofitted using a retrofitting solution consisting of Carbon Fibre Reinforced Polymers and Post-Tensioned Metal Straps applied on opposite frames of the building. The building was then subjected to unidirectional and three-dimensional incremental seismic excitations to assess the effectiveness of the two retrofitting solutions at improving the global and local building performance. The article provides details of the above shake table testing programme and retrofitting solutions, and discusses the test results in terms of the observed damage, global damage indexes, performance levels and local strains. It is shown that whilst the original bare building was significantly damaged at a peak ground acceleration (PGA) of 0.15g, the retrofitted building resisted severe three-dimensional shake table tests up to PGA=0.60g without failure. Moreover, the retrofitting intervention enhanced the interstorey drift ratio capacity of the 1st and 2nd floors by 160% and 110%, respectively. Therefore, the proposed dual retrofitting system is proven to be very effective for improving the seismic performance of substandard buildings

Large-Scale Shake Table Test Verification of Bridge Condition Assessment Methods

Methods that identify structural component stiffness degradation by pre- and postevent low amplitude vibration measurements, based on a linear time-invariant (LTI) system model, are conceptually justified by examining the hysteresis loops the structural components experience in such vibrations. Two large-scale shake table experiments, one on a two-column reinforced concrete (RC) bridge bent specimen, and the other on a two-span three-bent RC bridge specimen were performed, in which specimens were subjected to earthquake ground motions with increasing amplitude and progressively damaged. In each of the damaged stages between two strong motions, low amplitude vibrations of the specimens were aroused, and the postevent component stiffness coefficients were identified by optimizing the parameters in a LTI model. The stiffness degradation identified is consistent with the experimental hysteresis, and could be quantitatively related to the capacity residual of the components

A shake table test of typical mediterranean reinforced concrete structures

This research investigates the ultimate earthquake resistance of typical RC moment resisting frames designed accordingly to current standards, in terms of ultimate energy absorption/dissipation capacity. Shake table test of a 2/5 scale model, under several intensities of ground motion, are carried out. The loading effect of the earthquake is expressed as the total energy that the quake inputs to the structure, and the seismic resistance is interpreted as the amount of energy that the structure dissipates in terms of cumulative inelastic strain energy

Analysis and Testing of the FBA-11 Force [Balance] Accelerometer

The FBA-11 is a feedback-controlled accelerometer widely used to measure and record accelerations arising from earthquakes. It has found application both for structural response and for ground motion studies. The design intent of the FBA-11 was to provide electronic control of the natural frequency, damping, and output voltage. Included in this paper are (1) a circuit analysis yielding the complete closed-loop transfer function, and (2) the corroborative test results from shake table evaluations. The transfer function can be used to correct recorded accelerations for instrument response

A study into the earthquake resistance of circular adobe buildings

University Technology of Sydney. Faculty of Design Architecture and Building.Unreinforced adobe or mud-brick structures have in the past suffered severe damage from seismic forces and have caused a vast number of deaths. However, a number of adobe buildings located in seismic regions have performed well under several seismic events. Most of these traditional buildings are symmetrical in shapes which have significant bearing on the performance of the buildings during strong earthquakes. Most existing circular adobe houses have performed well in withstanding earthquakes even though some did not have any additional ductile reinforcements. This thesis presents a series of tilt table tests conducted to study the performance of unreinforced circular adobe buildings subjected to earthquake forces. Nine small-scale models (1:3 scale) of adobe structures were built with a variety of configurations and roof loads. The adobe house models were subjected to a constant acceleration when tilted on a tilt-up table. The lateral component of the models weight was used as a parameter to quantify the maximum seismic force for each model. The results then developed a methodology for designing circular adobe buildings to resist earthquakes in specific seismic zones and for specific site conditions. A static pushover test and two shake table tests were also conducted in order to evaluate the reliability of the predictive model from the tilt table tests. The research outcomes give simple and effective solutions for construction of new adobe buildings located in seismic hazard areas. It can also be applied to evaluate existing circular adobe buildings for their seismic resistance which can assist in predicting the likely outcome in the event of an earthquake. Keywords: Adobe construction, mud-brick, earthquake resistance, circular building, tilt table test, static pushover test, shake table test

Shake table testing of a tuned mass damper inerter (Tmdi)-equipped structure and nonlinear dynamic modeling under harmonic excitations

This paper presents preliminary experimental results from a novel shaking table testing campaign investigating the dynamic response of a two-degree-of-freedom (2DOF) physical specimen with a grounded inerter under harmonic base excitation and contributes a nonlinear dynamic model capturing the behavior of the test specimen. The latter consists of a primary mass connected to the ground through a high damping rubber isolator (HDRI) and a secondary mass connected to the primary mass through a second HDRI. Further, a flywheel-based rack-and-pinion inerter prototype device is used to connect the secondary mass to the ground. The resulting specimen resembles the tuned mass damper inerter (TMDI) configuration with grounded inerter analytically defined and numerically assessed by the authors in a number of previous publications. Physical specimens with three different inerter coefficients are tested on the shake table under sine-sweep excitation with three different amplitudes. Experimental frequency response functions (FRFs) are derived manifesting a softening nonlinear behavior of the specimens and enhanced vibration suppression with increased inerter coefficient. Further, a 2DOF parametric nonlinear model of the specimen is established accounting for non-ideal inerter device behavior and its potential to characterize experimental response time-histories, FRFs, and force-displacement relationships of the HDRIs and of the inerter is verified