In this paper, a semi-active structural control system, which incorporates a magnetorheological damper, is devised, built, and implemented in a two-degree-of-freedom shear frame model. First, parameters of the damper model are identified based on the Bouc-wen model using test data. Furthermore, two control systems, including the skyhook and PID, are implemented in the structure. The performance of the control systems is then evaluated via Shake table tests for a sample earthquake. Experimental results reveal that the skyhook control system can successfully mitigate the transmitted accelerations to the floors. As a result, the base shear is considerably decreased. Furthermore, it is shown that performance of the proposed PID control system is quite comparable with that of the ideal skyhook one, implying successful performance of the PID controller in tackling the seismic disturbance.

The design and implementation of a novel fuzzy supervisory control approach for the motion control of a seismic Shake table is addressed in this work. For this purpose, a single degree of freedom laboratory-scale electric Shake table was developed. The control scheme comprises two loops: a PI inner loop and a fuzzy outer loop as the supervisor. Three separate supervisory controllers are proposed and implemented in the Shake table and their performance in tracking two real earthquakes is assessed via extensive Shake table testing. The test results reveal the effectiveness of the fuzzy supervisory controller in reducing displacement and acceleration tracking errors.

This paper presents a qualitative evaluation of uni-axial Shake table test results for a halfscale reinforced concrete house designed by the Indonesia Aid Foundation (IAF). The building is intended to provide a quality-controlled design by being precast at a factory and delivered to the site for assembly, thus providing a living area for a family of approximately six people. In addition, the house is to be base isolated on used car tires filled with sand to approximate more technical rubber bearing base isolators available for use in construction and seismic retrofit today. The base isolation system was extremely effective and did not allow shear force to be transferred into the reinforced concrete walls, resulting in virtually no damage.

Background: Early treatment with exogenous surfactant is associated with better outcome in neonates with Hyaline membrane disease (HMD), but diagnosis may only become clear late in the course of the disease. In order to rapidly and reliably identify such neonates, we have evaluated the Gastric aspirate Shake test (GAST).Methods: Eighty one neonates with gestational age less than 34 weeks enrolled to this study (51 newborns without pulmonary diseases and 31 newborns with HMD). The clinical characteristics of HMD considered as the gold standard of diagnosis. About 1 ml mixture of normal saline (0.5ml) and stomach contents were collected within 30 minutes of birth (0.5ml) were shaking for 15 seconds into a glass test tube. Then 1 ml of 95% ethanol was injected into the test tube and the 2 ml mixture of gastric aspirate, saline and alcohol agitated for a further 15 seconds. After a waiting time of 15 min, the surface of fluid was examined for bubbles to decide the result of Shake test. If no bubbles were present then the test was NEGATIVE (very little surfactant). If bubbles were seen around the top of the fluid but not enough bubbles were present to completely cover the surface, then the test was INTERMEDIATE (only some surfactant). If bubbles were present right across the surface of the fluid, then the test was POSITIVE (adequate amounts of surfactant). Findings: All infants who developed HMD had negative or intermediate test results. The GAST had a specificity of 66%, sensitivity of 100%, positive predictive value of 64.5% and negative predictive value of 100% for developing HMD. The sensitivity and specificity of the GAST for prediction of surfactant requirement in HMD patients were 100% and 64.8%, respectively, with a positive and negative predictive value of 62.5% and 100%, respectively. Conclusion: We conclude that the GAST on gastric aspirates obtained within 0.5 hour of delivery is a rapid and simple procedure for rule out of HMD and surfactant requirement. 

Whilst the use of impact damper for single-degree-of-freedom (SDOF) systems has received a significant amount of attention, investigations into their interaction with SDOF systems is rare. In this paper, results of a series of experimental analysis of a horizontal particle impact damper under earthquake and sinusoidally excited primary system are investigated. Specific impact damping is determined for a SDOF. The influence of some system parameters such as clearance, stiffness and specific intensity of excitation are investigated experimentally. Driven by the experimental observation, it has been shown that a value of damping capacity was reached with a particle impact damper. The obtained results proved the efficiency of this process for achieving high structural damping; the results in some instances did not correspond with those found for control of SDOF systems in particular.One of the main contributions of this investigation involves studying the sensitivity to stiffness. Increased stiffness of the vibration system did not necessarily lead to an increase in damping for all modes. Also, the effect of clearance is unpredictable. In short, the achievements gained in the paper have revealed dynamic characteristics, bringing important engineering application. The paper raises these and other issues which require consideration if impact dampers are to be used to control the dynamic response of SDOF systems.

In this paper the dynamic soil-structure interaction effects on the seismic response of building structures with surface and embedded mat foundations have been studied using Shake table tests on scaled models. Results obtained from test and analysis is compared with buildings code requirements. For this purpose, four structural models with 5, 10, 15 and 20 floors as common representative buildings in an urban area are designed and constructed for dynamic tests. Both soft and relatively soft soil media are considered in this study. Different parameters have been studied in this research which includes: building aspect ratio, shear wave velocity, frequency content, damping and acceleration of structural models. Also, the results of finite element analysis of soil-structure system compared with Shake table results. The effects of soil-structure interaction is demonstrated as increasing the period of vibrations and damping ratio with a dominant rocking mode in higher buildings. However, these effects are reducing by increasing the embedment effects of foundation. Morever, the results of this research is important for developing of Soil-Structure-Interaction in national codes.

Control of seismic Shake table in order to track the predefined earthquake profile is a key concern in design of seismic Shake tables. This paper proposes a vision-based real time displacement measurement system using image processing techniques to control a laboratory-scale seismic Shake table. The Shake table is controlled via a fuzzy-supervisory controller, an inner PID loop and a Fuzzy outer one, whose feedback is provided by the vision-based measurement system. To minimize tracking errors, the fuzzy controller uses displacement and acceleration responses as its feedbacks. For this purpose, a camera and an image processing application are utilized to measure the motions directly in real time. Results are sent to a host PC through a network as the controller feedback. Proposed system performance is compared with an alternative system which utilizes a linear encoder as displacement sensor and controller feedback. test results prove effectiveness of the proposed fuzzy system in cutting back the tracking errors. In addition, the vision-based system uses a very low cost camera to measure the displacement directly. It has appropriate accuracy, works in real time, and doesn't need any contact with the table, comparing to the encoder version.

Buried pipeline response to earthquake induced landslide is one of the challenging problems in geotechnical earthquake engineering. In this study, two physical models were constructed to investigate the effect of burial angle of the pipes on their response to the landslide. Similitude laws for 1g Shake table tests were employed to construct the physical models. In each model, four aluminum pipes were installed at different positions but at identical depths from the model surface. All the properties in both models - except the pipes angles relative to the slope - are the same. The pipes were heavily instrumented with pair strain gauges to measure pure bending strain. Input shaking consisted of 25 sinusoidal cycles of loading with amplitude of 0.32 g and frequency of 5 Hz. The results showed that reduction of pipe burial angles from90 to 70 degrees in relative to the slope direction, decreased bending strain in the pipes. Therefore, reduction of burial angle of the pipes can be considered as one of the remediation methods against landslide. Also, in both models, the lower part of the slope was the most critical location for buried pipes