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• Wall-Frames are appropriate structural system for hospital buildings. • Yield strain limit state of rebar monitored for evaluating Occupiability performance. • Atleast overall 3% SPD should be provided in Wall – Special Moment Resisting Frame. • Minimum column-to-beam strength ratio of 2 is recommended for hospital buildings. In the aftermath of earthquakes, hospital buildings are expected to remain occupiable to treat the injured. For the purpose, firstly, an appropriate structural system that ensures no or limited structural damage should be provided in such buildings; wall-frames are the recommended structural systems in hospital buildings. Secondly, it is also essential to adequately design wall-frames to help meet the preferred Occupiability seismic performance. The work presented in this paper examines the contributing factors for failure of structural elements in hospital buildings and explores structural configuration and design strategies for mitigating these failures. Nonlinear analyses studies of a typical hospital building in high seismic region in India are carried out to help provide quantitative guidelines for: (a) Structural Plan Density (SPD) of structural walls, and (b) design parameters, for achieving the preferred performance. Displacement-based limit state of structural damage adopted from traditional displacement demand estimation rules is proposed. Lateral stiffness, strength, and ductility are evaluated of study buildings, and efficacy of results obtained from nonlinear static analyses confirmed by performing nonlinear time history analyses in commercial software PERFORM 3D. Results demonstrate inadequacy of moment frame structural system in hospital buildings under strong earthquake shaking, identifies optimum overall SPD of structural walls and relative column-to-beam strength ratio of frame members, required to achieve Occupiability. A minimum 3% SPD of structural walls in Wall – Special Moment Resisting Frame (WSMRF), 4% SPD in Wall – Ordinary moment resisting frame (WOMRF) hospital buildings, and a minimum column-to-beam strength ratio (CBSR) of 2 is required in hospital buildings to attain Occupiability performance. [ABSTRACT FROM AUTHOR]

Drilling and blasting have been the important methods of making underground tunnels for irrigation, subways, metro-lines, drainage and defense. Of late TBM (tunnel boring machine) is considered as the best positive alternative, in view of several advantages offered such as smooth profile, automated faster tunneling rates, easy to implement controls, safe and economic tunneling under favorable conditions. It is a gigantic high performing machine, with minimum hassles of operation if selected and operated judiciously. Thus, this equipment is the best possible choice to obtain a high penetration rate at minimum cost. TBM performs various operations such as rock cutting, discharge of muck, ring building and shifting of rail track (TBM movement). These operations are connected serially having a provision to function in parallel. Considering the high initial cost and import dependence, development of methodologies to establish the reliability of the system is mandatory. The reliability analysis using markov modelling was carried out for an EPBTBM (earth pressure balance tunnel boring machine), being used in an irrigation tunnel, considering its suitability to analyze a continuous production system. Accordingly, the failure and repair rates of the different subsystems were critically analyzed and variability was fixed. Maximum availability can be obtained by increasing reliability and maintainability of the equipment. This paper reports the study on the reliability, maintainability and availability of an EPBTBM deployed for excavating an irrigation tunnel located in Central India and the impacts of these parameters on the progress of tunnel. Availability of EPBTBM was found to be 61% which increased to 70% by proper maintenance and proper planning. • EPBTBM performance depends on its reliability, maintainability and availability. • Markov analysis concludes 40% decrease in reliability in 1.5 h of operation. • Maintainability, M(t) increases with time from M s (1) = 0.09 to M s (20) = 0.99. • Availability of EPBTBM is under study around 61%. • Preventive maintenance increases availability of the EPBTBM from 0.61 to 0.70. [ABSTRACT FROM AUTHOR]

Abstract Distribution transformer is a most important component of the distribution system to provide uninterrupted power supply to the consumers and it should be highly reliable. Distribution transformer failure affects the reliability and power quality of the supply system. This paper presents distribution transformer failure analysis to find out causes of failures responsible for very high rate of failure in a state owned electric utility Punjab State Power Corporation Limited (PSPCL) in India. Detailed failure analysis is conducted on 348 distribution transformers failed from 2010 to 2015 in a city based sub division area. Failure analysis is carried out in accordance with IEEE standards and summarized the results statistically in the first part. In second part, the failure modes, effect and criticality analysis (FMECA) is used to analyse distribution transformer failure modes, causes of failure and effects of failure. Further, criticality analysis is performed and a risk priority number is assigned based upon the severity classification, probability of occurrence and probability of detection to identify most critical parts of transformer. FMECA leads to identify preventive actions to be taken to reduce the risk of the transformer in future by eliminating the causes of failure, reducing severity and probability of occurrence. Highlights • Analysis of distribution transformer failure in conjunction with a real time data of failure in public sector utility. • Failed transformers are analysed for month wise, year wise, age wise, component wise failure and causes of failure. • Failure Modes, effect and criticality analysis (FMECA) to identify most critical components of transformer. • Compensatory provision are provided to save the distribution transformer from premature failure. [ABSTRACT FROM AUTHOR]

• The mechanism of face instability and associated spalling was studied. • The critical strain limit of face instability was proposed. • A design criteria was proposed for three-dimensional quantification of face spalling. • Pertinent rock mechanics indicators of face spalling were comprehensively discussed. The majority of the longwall panels in India have been worked underneath massive sandstone main roof with soft coal/shale immediate roof. As the mining goes deeper, ensuring stability and consistent production from such workings is a great challenge for their safety and sustainable performance. In this scenario, understanding the face instability mechanism and its rock mechanics precursors have evolved as a significant design challenge for obtaining an optimal longwall geometry in complex geo-mining conditions. Research to date mostly focused on the failure mechanism and, in some part, displacement characteristics of the coal wall. In contrast, minimal work has been performed to address the critical research gap from the face failure to spalling with the associated rock mechanics parameters and its three-dimensional quantification. This paper considered the longwall panel of 250 m face length and 3.5 m working height in the Godavari Valley Coalfield, which was worked underneath 23.5 m massive sandstone roof at a cover depth of 323 m. The finite difference software FLAC3D was employed to investigate stress redistribution, failure characteristics, strain dynamics, and horizontal displacement of the coal wall until the occurrence of the main weighting. Accordingly, a set of criteria, namely, Percentage of Critically Strained Zone (PCSZ) and Percentage of Spalling Zones (PSZ), were proposed based on the critical limits of the lateral strain and the horizontal displacement of the face. The formation of these critical zones around the face was further correlated with the failure and caving characteristics of the massive sandstone roof. The study revealed that within 0–3 m distance ahead in the central region of the face, the extent of PCSZ in the Peak stress period was 46, which further enhanced and contributed in PSZ of 78 as noted during the weighting period. It is indicated that the impact of spalling dominated in the middle and the middle to the top portions of the face, covering 53% of total face length within 0–3 m regions ahead of the face. The relative influence of the failure and caving characteristics of the key roof positively correlated with the PCSZ and PSZ at the face. The critical limits of lateral strain (0.58%) and horizontal displacement (−15.40 mm), as projected in this study for evaluation of face instability, provided closer agreement with field observed extent of face spalling. The findings of the study supplements the existing knowledge about the mechanism of face spalling and its quantification in the Indian geo-mining conditions. The approach developed in this paper can be employed to analyze the extent of face instability during weighting periods. [ABSTRACT FROM AUTHOR]

• This research paper analysed a 2010 disaster due to explosion that occurred at an underground coal mine in India. • Old mine fire, accumulation of flammable gas and deposition of coal dust caused the explosion as a result 14 persons were killed and 5 persons were seriously injured. • Thrust is given in this article for identification of root causes like organizational factors, task conditions, task environment etc. which resulted in human error or an unsafe act leading to failure of the defenses and thereby causing the accident/incident. • Gaps in the existing accident investigation system of the Indian mining industry were also highlighted. Workplace accidents are mostly the result of a combined effect of unsafe acts and unsafe conditions which cause ultimate failure of the existing defenses in the system. The unsafe act or unsafe conditions, task environment and task conditions are the product of some dormant, passive and latent causes generated from the organizational factors. But in accident prevention strategy at the workplace, the major thrust is often put on human behavior behind the unsafe acts. In this paper, an in-depth analysis of a mining disaster in India, as to "Why" and "How" the accident did happen has been carried out and the sequence of events was shown by an Event Sequence Diagram. In this article, efforts have been made to identify the root causes of this accident using an accident causation model like the Accident Causation Tree (ACT) and the Swiss Cheese Model, thereby improving the understanding of the mechanism of the accident. The most important aspect of accident analysis, i.e. the key lessons learned from this accident, has also been identified for the benefit of the industry. [ABSTRACT FROM AUTHOR]

• Extensive geotechnical characterization of the soil from landslide slip surface helps evaluate the failure mechanism of landslide. • High-intensity rainfall, unplanned vertical cuts and slopes have witnessed the loss of lives and substantial monetary losses during the southwest monsoon in Kerala, India, in 2018. • Importance of locally available sustainable green martial uses in engineering practices. • The numerical analysis confirmed that the vertical cut stabilization with coir geotextiles is safe during high-intensity rainfall. This paper presents laboratory and numerical analysis of vertical cut failure due to rainfall-induced landslide resulting in building failure that led to the death of nine people in Kerala, India, on August 15, 2018. The residual shear strength parameters are evaluated by the ring shear test. The soil water characteristics curve (SWCC) is developed by unsaturated soil strength parameters. The slope stability and infiltration analysis are carried out with limit equilibrium and finite element methods, respectively. The infiltration analysis is carried out by considering three different rainfall patterns on the slope as low, medium, and high intensities. The study includes a two-stage numerical analysis of vertical cut. Firstly, vertical cut analysis with and without rainfall effects and second, the analysis of vertical cut using coir geotextile as reinforcement with rainfall effects. The study emphasized the utilization of locally available coir geotextiles as a reinforcement for slope stabilization. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents different types of premature failures observed during full-scale testing of Transmission line towers at Tower Testing and Research Station, Structural Engineering Research Centre, Chennai. Failures that have been observed during testing are studied and the reasons are discussed in detail. The effect of non-triangulated hip bracing pattern and isolated hip bracings connected to elevation redundants in ‘K’ and ‘X’ braced panels, on tower behaviour are studied. The tower members are modeled using beam-column and plate elements. Different types of failures are modeled using finite element software and the analytical results and the test results are compared with various codal provisions. The non-linear finite element analysis program NE-NASTRAN has been used to model the elasto-plastic behaviour of towers. Importance of secondary member design and connection detail in overall performance of the tower was studied. Non-linear finite element analysis is useful in understanding the system behaviour and for prediction of failure pattern and ultimate load. Based on the test results the importance of studying the failures is highlighted. The need for testing of transmission line towers is emphasized. [Copyright &y& Elsevier]

Abstract: An on-line structural safety evaluation system (BOSSES) has been developed over the years at Bhabha Atomic Research Centre (BARC), India, which is capable of assessing the damage due to creep and fatigue in critical plant components. The system acquires plant transients in real time and processes them to evaluate the stress, temperature and damage distribution in the components and provides information through a visual module. The aim of the paper is to briefly describe the details of the damage assessment methodology adopted by BOSSES with some case studies of real life plant components. [Copyright &y& Elsevier]

Rear axle shafts of 575 DI tractors manufactured by Mahindra and Mahindra Ltd, Tractor Division, Mumbai, failed before completion of warranty period. Most of the shaft failures (nearly 80–85%) occur during puddeling operations. Rear axle shafts fail in the spline portion. Cracks were found at the root of the splines. The causes of failure and remedies have been discussed in this paper. The work is summarized by a comparative statement of the modifications suggested with respect to life and cost. [Copyright &y& Elsevier]

• The coordinated condition motoring approach is reported in the present study. • Vibration analysis, Noise analysis, wear debris analysis and ultrasonic monitoring methods are employed. • The root causes of hydraulic coupling bearing failures are identified. • The catastrophic failure of an Induced Draft Fan 2-A is avoided. Early detection of the fault is not only essential to ensure the current health of the critical equipment but also to diagnose the fault before any catastrophic failure. In order to improve the capability for early fault detection and diagnosis of critical equipment, an improved form of generalized coordinated condition monitoring approach has been developed and adopted in this paper. The effectiveness of an integrated approach has been realized by concurrently using selected condition monitoring techniques viz. vibration analysis, noise measurement, wear debris analysis, ultrasonic monitoring in terms of increased fault diagnosis accuracy. A case study on failure analysis of Induced Draft (ID) fan 2A from 250 × 2 MW thermal power plant located in the western region of India is carried out. The vibration trend of acceleration parameter of hydraulic coupling input bearing found to be on the higher side and reached to 4.2 (g) level, sound level meter recorded an increased noise level of 99.8 dB, and high-frequency sound of 18 dB ultrasound was observed by the ultrasonic meter. In addition, medium alloy bearing particles of size 68 µm were found in the test oil sample, which confirmed that hydraulic coupling input bearing deterioration, has occurred. The vibration parameter provides sufficient insights into the earliest failures, and the fault location, severity, its effect on other process parameters are monitored by noise, wear, and ultrasound level. Furthermore, the secondary damages related to motor and fan were avoided. Simultaneous use of these techniques not only detects the earlier fault but can be diagnosed before any catastrophic failure. The result obtained in this study assisted the maintenance engineer of the plant for scheduling the maintenance activity well in advance. [ABSTRACT FROM AUTHOR]