Earthquake Prediction

Among the countless natural disasters, earthquakes are capable to inflict vast devastation to a large number of buildings and constructions at the blink of an eye. Lack of knowledge and awareness on earthquake as well as its comeback is conspicuous and results in disaster; leading to bitter memories. Therefore, earthquake forecast has been a polemical study theme that has defied even the most intelligent of minds. In this chapter, an attempt was made to do an extensive overview in the area of the earthquake prediction as well as classifying them into the main strategies comprising short‐, immediate‐, and long‐term prediction. An example of each strategy was carried out by mentioning their corresponding approaches/algorithms, such as ΔCFS, CN, MSc, M8, ANN, FFBPANN, KNN, GRNN, RBF, and LMBP; depending on the importance of each strategy. Based on these, it was concluded that, after the Tohoku‐Oki earthquake with M9.0, the current orientation of the Headquarters for earthquake Research Promotion of MEXT in Japan declare that, their mission would be long‐term statistical forecast of seismicity. Even, it is claimed that they do not emphasize on short‐term forecasting. Besides, intermediate‐term estimations are not capable to be used for prevention of all damages and protect all human life, but they may be utilized to undertake certain affordable activities to decrease damage, losses, and modify postdisaster relief. And, despite the long‐term prediction is more concerned by researchers, there is no certain satisfactory level to content them. De facto, the made covenant of 1970 that investigators will be capable to forecast/predict ground excitations within a decade, still remains unmet

Corrosion Assessment of Pre-corrosion Concrete Specimens using Acoustic Emission Technique

The acoustic emission (AE) technique is known as a non-destructive testing (NDT) method, which is effective for assessing corrosion in concrete structures. This study aims to utilize the AE technique, for the assessment of pre-corroded concrete specimens, which are under load testing. Experiments were carried out on small-scale pre-corroded specimens, which were subjected to monotonic loading. The results showed that the majority of the beam specimens failed with shear cracks. Three AE parameters, namely acoustic emission hits, as well as the RA and AF values, were also used, in order to assess the flexure behaviour of the pre-corroded beam specimens. These experiments helped to understand the flexural behaviour of pre-corroded specimens, which were under a loading test, via the use of the AE technique

Urban conservation : A framework for community involvement in Malaysia.

Whilst interest in conservation planning in Malaysia is growing, there is evidence that it contains several deficiencies, including the commitment and resources to support effective community involvement. This research investigates the underlying factors that contribute to these deficiencies in the system and aims to develop principles to be taken forward for application in a practice-oriented framework, drawn from a critical analysis of the relationships between best practice, as identified through the literature and contemporary practice in Malaysia, as identified through the empirical work.The research examines various examples of community involvement practice from selected developed countries, including the United Kingdom. This suggested a framework of community involvement best practice, which would achieve sustainable conservation results. The current community involvement approach practice in Malaysia (using the Case Study of Historical City of Malacca) was compared to this suggested framework. This comparison to best practice with Malaysia's present practice demonstrates, quite clearly, the vital need for an involvement framework in Malaysia to be improved to make the current practice and provisions more effective.The findings proved that the present process is inefficient. It lacks systematic techniques, adequate communication and awareness. Additionally, there is an imbalance of power and control which requires better coordination and collaboration between both stakeholder organisations (all levels of government, i.e. federal, state and local, as well as private and NGOs) and the communities. The summary of findings from both the authorities and communities was compared and arranged towards a concluding reconciliation of perspectives. This led to the proposed framework for community involvement based on the lessons of best practices explored for the improvement to the present conservation system.The recommended practice-oriented framework comprises of its key principles to guide the reform process and highlights on six main elements, i.e. the emphasis on community focus; policy and approach; involvement and consultation stages; process and procedures; consultation methods; and evaluation and monitoring. The implementation of the framework requires investment in terms of resources, as well as related education and awareness programmes to help secure its success

Invited Review: Recent developments in vibration control of building and bridge structures

This paper presents a state-of-the-art review of recent articles published on active, passive, semi-active and hybrid vibration control systems for structures under dynamic loadings primarily since 2013. Active control systems include active mass dampers, active tuned mass dampers, distributed mass dampers, and active tendon control. Passive systems include tuned mass dampers (TMD), particle TMD, tuned liquid particle damper, tuned liquid column damper (TLCD), eddy-current TMD, tuned mass generator, tuned-inerter dampers, magnetic negative stiffness device, resetting passive stiffness damper, re-entering shape memory alloy damper, viscous wall dampers, viscoelastic dampers, and friction dampers. Semi-active systems include tuned liquid damper with floating roof, resettable variable stiffness TMD, variable friction dampers, semi-active TMD, magnetorheological dampers, leverage-type stiffness controllable mass damper, semi-active friction tendon. Hybrid systems include shape memory alloys-liquid column damper, shape memory alloy-based damper, and TMD-high damping rubber

Data Mining Technology for Structural Control Systems: Concept, Development, and Comparison

Structural control systems are classified into four categories, that is, passive, active, semi-active, and hybrid systems. These systems must be designed in the best way to control harmonic motions imposed to structures. Therefore, a precise powerful computer-based technology is required to increase the damping characteristics of structures. In this direction, data mining has provided numerous solutions to structural damped system problems as an all-inclusive technology due to its computational ability. This chapter provides a broad, yet in-depth, overview in data mining including knowledge view (i.e., concept, functions, and techniques) as well as application view in damped systems, shock absorbers, and harmonic oscillators. To aid the aim, various data mining techniques are classified in three groups, that is, classification-, prediction-, and optimization-based data mining methods, in order to present the development of this technology. According to this categorization, the applications of statistical, machine learning, and artificial intelligence techniques with respect to vibration control system research area are compared. Then, some related examples are detailed in order to indicate the efficiency of data mining algorithms. Last but not least, capabilities and limitations of the most applicable data mining-based methods in structural control systems are presented. To the best of our knowledge, the current research is the first attempt to illustrate the data mining applications in this domain

Effect of incremental static damage on modal frequencies of reinforced concrete beams

The modelling and the failure mechanisms of RC structures is a complex phenomenon because the constituent materials’ strengths are combined to overcome their weaknesses. Therefore, the failure mechanisms have not been understood completely. Modelling concrete beams using plasticity approaches has gained a lot of attention because of its versatility. This research incorporates the plasticity model with continuum damage model to evaluate the modal frequency deterioration of the reinforced beams. These beams were incrementally damaged in flexure using finite element modelling. It was observed that the model represents the damage mechanism of RC beams quite reasonably. The dynamic response of the beams is also in line with the experimental results. Based on the dynamic response, it was observed that the modal frequencies are sensitive to damage at initial stages and there is not significant reduction in the natural frequencies at complete damage

Nondestructive test methods for concrete bridges: A review

NDT methods applicable to concrete bridges are reviewed. The methodology, advantages and disadvantages along with up to date research on NDT methods are presented. Different damage levels, having less dependence on inspector judgment, are suggested. Moreover, a flow chart based on damage level along with NDT methods and potential remedial measures are proposed for periodic health monitoring of structures

Dynamic Behavior of Connected Structures

The effect of connected structure on SMK Bukit Tinggi building was investigated based on their dynamic behaviour. The structure was constructed with four main buildings are interconnected. Ambient vibration testing (AVT) was used to predict the dynamic response and characteristics by using triaxial 1Hz seismometer and CityShark data logger. The AVT signals were analysed using GEOPSY software for Fourier Amplitude Spectral (FAS). All predominant frequencies (fo) and mode shapes were identified and verified with previous research finding using similar testing approach on the same building, but with different instrument of accelerometer sensor and ARTeMIS software processing tool. Five modes of fo were found from the FAS curves from this research, but only four fo were obtained from ARTeMIS analysis. The highest deviation percentage was indicated at the 5th mode of building frequency at 9.5 %, but 0 to 2.5% to the rest frequencies mode (1st to 4th frequencies mode). Ununiformed buildings response behaviour was believed to contribute, and initiate active progressive shear cracking on the slab panels, columns, beam and at the reentrant corners between laboratory and academic buildings of Building C. It worst when the buildings were struck by several earthquakes’ series. The unsynchronised oscillation between adjacent buildings to Building C had induced couple lateral and torsional deformations. The structural and non-structural damages mostly concentrated at the reentrant corners and mid-span of the building, which identical to the location of maximum deflection amplitudes. In conclusion, strict attention must be emphasized on the fo and mode shapes based on their dynamic response and characteristics analyses, which could be altered by the presence of connected structures