Search

Eccentrically Braced Frames (EBFs) are the structural systems that are recommended to be constructed in Earthquake Hazard Areas. This system combines good characteristics in withstanding the seismic load, i.e., stiffness, ductility, and dissipation energy. Link is a component in EBFs that play the role of the seismic energy dissipator. As far, several studies have been conducted to enhance the link performance, but the information is still limited. This study observed the structural performance of the IWF flexural link, where this link will experience failure at the flange due to seismic energy dissipation. The investigation was conducted by establishing three Finite Element (FE) models of flexural link. Each link was designed with the same length, i.e. 1000 mm. Three-link models were distinguished by the differences in web stiffener configuration, i.e., non-stiffener link, 250 mmstiffener spacing link, and 100 mm-stiffener spacing link, respectively. All models were examined under cyclic loading with yield displacement controlled. The research discovered that adding the web stiffener on the IWF flexural link significantly escalated the EBFs’ seismic performance, i.e., strength, stiffness, ductility, and dissipation energy. The best seismic performance was presented by a 100 mm-stiffener spacing link. Accordingly, it is indicated that arranging the web stiffeners at the narrow space in the IWF link can be suggested to improve the seismic performance of EBFs.

Equity premium is a vital number to consider in finance when making fund allocations and investment decisions. This study explores the relationship between (controllable) determinants of firm-level equity premiums in the context of the Pakistan stock market. It uses a sample of 306 firms’ annual data, from January 2001 to December 2015, using a two-stage least-squares method to estimate our panel data model (Jeffrey M. Wooldridge 2005; Manuel Arellano 2016). During the selected sample period, the average market premium of the Pakistan stock exchange (100 Index) was 20%. The average equity premium of individual firms was only 8%. Company fundamentals are considered determinants of firm-level equity premiums. Panel data econometrics techniques were used to estimate the modified version of the multi-factor model for the Pakistan Stock Exchange. It is found that the market premium, return on equity, dividend payout ratio, accounts receivable and firm size significantly and positively affect the firm-level equity premium. However, increase in the debt-to-equity and quick ratio negatively affect that premium. The company fundamental variables are controllable for the firms and can be improved by company management to encourage investors and maximize shareholder wealth.

The processing area of offshore platform has high probability of leakage of hydrocarbons. Liquefied Natural Gas (LNG) is one of the most common hydrocarbon produced in offshore platforms. Leakage of LNG can cause pool fire, jet fire, flash fire or fire ball. Thermal radiations due to fire is the major source of damage to workers on board. But due to fire, various combustion product toxic gases are also produced that have both acute and chronic health effects. These toxic gases can cause incapacitation, increased heart rate, vomiting and even death. Predicting the human injury due to thermal radiations and concentration of toxic gases are the key issues. A risk based approach takes in to consideration the duration a worker spent on different location of offshore platform and also it has the additive ability to evaluate overall risk due to fire radiation and toxic gases. Grid based approach helps in better visualization of risk posed by fire radiation and combustion product toxic gases at different locations of platform. The current study proposed an integrated consequence modelling approach for fire and combustion product toxic gases using risk based and grid based approaches. The integrated accident is modelled using Computational Fluid Dynamics (CFD) code Fire Dynamics Simulator (FDS). The results showed that risk posed by thermal radiation is confined on sub cellar deck (lower deck) but estimated risk due to combustion product gas (carbon monoxide) on cellar deck (upper deck) has significant value that needs to be considered. The current approach would be useful for emergency preparedness plans and safety measures designs for offshore platforms.

One of the potential applications of bored piles is the construction of a retaining wall where the piles are closely installed and the spacing between them is often grouted to build a waterproof retaining wall. Based on previous experience, it is observed that the selection of an appropriate retaining structure is crucial to the strength and stability of a structure, provided that the design of retaining structure is adequate and it satisfies the structural requirements. This study considers a Malaysian slope, Bukit Antarabangsa, to perform the probabilistic stability analysis of bored piles. Statistical tools of FORM and Monte Carlo are used to demonstrate the influence of soil parameters on the reliability levels of structure. This paper also presents the load and resistance factors which are developed to counter the rotational and flexural failure modes of a bored pile wall. It is expected that this study will provide a support to the Malaysian geotechnical industry to integrate a reliability-based design for slope construction.

The processing area of an offshore platform consists of various equipment for handling, separation and transferring of crude oil and natural gas. Consequently, the chances of an accidental release are quite high as compared to other areas. Among the major hazard posed on an offshore platform, Vapor Cloud Explosion (VCE) is the fatal one. Among the various factors that impact the resulting overpressure developed due to VCE: leak rates, wind speeds, and wind directions are the important ones. The current paper investigates the effect of these factors (leak rates, wind speeds and wind directions) on explosion strength on an offshore platform. The release, dispersion and resulting VCE are modelled by utilizing Computational Fluid Dynamics (CFD) software Flame Acceleration Simulator (FLACS). Furthermore, risk estimation for human injury/fatality (risk of eardrum rupture, head impact, and whole-body displacement) has been done considering these factors using probit models. The results showed that these factors (leak rates, wind speeds, and wind directions) have a major impact on resulting explosion strength and consequently, on the risk of human injury/fatality. Risk of head impact is quite high while risk of eardrum rupture and whole-body displacement is low. The current study can be useful in designing effective safety measures to reduce the impact of such accidents.

Offshore and onshore structures continuously experience hydrocarbon fire accidents almost every year. To secured structure against extreme fire conditions, passive fire protection (PFP) is applied. However, PFP is a costly material which is applied only on critical structural members. Any unprotected surface can cause major structural damages during fire incidence if the behaviour of an unprotected surface is unknown. Usually, PFP applied easily around the column, but for beams, the application varies with the beam locations. In this paper the behaviours of steel beam compared with three different common scenarios such as fully protected, unprotected and partially protected under hydrocarbon fire. Fully protected beam has tremendous fire resisting capability compared to partially protected beams or unprotected beams. The study revealed that temperature of the top flange in partially protected beam exceeds more 600°C in less than 10 minutes which caused rapid failure in less than 30 minutes. Under extreme fire conditions the strength and stiffness of a beam affected which cause instability of structure during fire accident.

Slope stability is one of the focal areas of curiosity to geotechnical designers and also appears logical for the application of probabilistic approaches since the analysis lead to a “probability of failure”. Assessment of the existing slopes in relation with risks seems to be more meaningful when concerning with landslides. Probabilistic slope stability analysis (PSSA) is the best option in covering the landslides events. The intent here is to bid a probabilistic framework for quantified risk analysis with human uncertainties. In this regard, Fault Tree Analysis is utilized and for prediction of risk levels, consequences of the failures of the reference landslides have been taken. It is concluded that logics of fault trees is best fit, to clinch additional categories of uncertainty; like human, organizational, and knowledge related. In actual, the approach has been used in bringing together engineering and management performances and personnel, to produce reliability in slope engineering practices.