Mohd Shahir Liew

Decommissioning of offshore platform: A sustainable framework

The decommissioning activities for fixed offshore platforms in Malaysia are expected to rise significantly. For many of the approximate 300 oil platforms, their service life is approaching the end. Thus far, only a handful of offshore platforms in Malaysian waters have been decommissioned mainly due to lack of regulatory framework and weak decommissioning plans. The shortage of decommissioning yards provides another major challenge in managing onshore disposal. With a number of options viable in decommissioning our used platforms, a review of these possibilities is timely. The scope of this paper entails the decommissioning methods particularly in the Gulf of Mexico, where conditions are similar to Malaysian waters. Evaluations of methodology as well as sustainability implications are discussed. The usual methods of decommissioning involve any of these options: complete removal, partial removal, reefing or re-using. Employing the aspects of sustainability as a pillar of the study, a conceptual framework of a viable decommissioning scheme is drawn. It was conceptually found that refurbishing the whole of the structure as a livable hub has its own unique potentials. Given the calm conditions of Malaysian waters and the sturdy design of the platforms, the restored structures hold possibilities either as ocean townships or futuristic cities such as a ‘sea-stead’. This novel idea of decommissioning is presented and further discussed in the paper.

Shear Failure of RC Dapped-End Beams

Reinforced concrete dapped-end beams (RC-DEBs) are mainly used for precast element construction. RC-DEBs generally are recessed at their end parts and supported by columns, cantilevers, inverted T-beams, or corbels. The geometric discontinuity of dapped-end beams evokes a severe stress concentration at reentrant corners that may lead to shear failure. Therefore, stress analysis is required at the reentrant vicinity for design requirement of these beams. Four large-scale RC-DEBs specimens were prepared, cast, and tested up to failure. Three parameters were investigated: amount of nib reinforcements, main flexural reinforcements, and concrete type at the dapped-end area. Finite element analysis using Vec2 was also conducted to predict the behavior of RC-DEBs. It has been found that highest stresses concentration factors occur at the reentrant corners and its vicinity. By using engineered cementitious composite (ECC) in the dapped-end area, the failure load has increased by 51.9%, while the increment in the failure load was 62.2% and 46.7% as the amount of nib reinforcement and main flexural reinforcement increased, respectively. In addition, Vec2 analysis has been found to provide better accuracy for predicting the failure load of RC-DEBs compared to other analysis approaches.

The characteristics of coordination process in construction projects

Modern construction projects are no longer confined to a single discipline but are generally multidisciplinary. An independency relationship between a large number of stakeholders required to be managed in construction projects procurement and execution that need continuous coordination. Coordination function is to harmonize the different activities, so that the determined objectives can be reached effectively. However, the study of coordination characteristics are the way to assess the status of coordination in construction projects. Through the literatures, the most important characteristics of coordination process were identified. Quantitative approach was used to investigate them through questionnaire. The data were analyzed by means of statistical analysis and Chi-square test. The analysis showed that, 45.5 % of the respondents mentioned to a moderate level of knowledge about coordination, however 44.6 % were commonly applied coordination culture. Nevertheless, about 60% believed that, ability and willingness are the main obstacle of coordination application. At the same time, 75% considered coordination effect as significantly improve the project performance. In the future, 70 % of the respondents will always apply coordination consideration from their personal motivation. The results of Chi-square show a significant dependent relationship between the position and organization function variables and the eight coordination characteristics.

Tractability method for ontology development of Semantic Web

Ontology is an explicit representation of a particular domain of interest. This paper focuses on the inherent problem of intractability (data complexity) due to data capturing for heterogeneous sources. We proposed to follow the tradition of knowledge representation and reasoning processes to develop a Semantic Web. Building query systems is the ultimate goal for this study. Conjunctive queries were adopted over ontology methods to address the data complexity. The Conjunctive queries are the form of queries in first-order logic that deal with conjunction (Λ) and existential quantification (∃) in database atomic formulae. State of the art meteorological and oceanographic domain provides the motivation for this work. We found that the querying method facilitates the tractability in reasoning and logical systems.

Effect of crumb rubber and nano silica on the fatigue performance of roller compacted concrete pavement

Abstract Roller compacted concrete (RCC) pavement is subjected to continues traffic loading from vehicular activities which can results to fatigue cracking. Fatigue is one of the commonest defects affecting pavement which affect the cost of maintenance, and shortens pavement design life. To carter for these factors, higher deformation resistant pavements with longer design life need to be designed. Therefore, in this study, crumb rubber was used as a partial replacement to fine aggregate in RCC pavement to improve its fatigue life. Five mixtures were considered; one control mixture, two mixtures with fine aggregate replaced using crumb rubber at 10 and 20% by volume; one mixture containing 20% crumb rubber as partial replacement to fine aggregate 1% nano silica added by weight of cementitious materials. Lastly, one high volumefly ash (HVFA) RCC pavement mixture where 50% cement was replaced with fly ash, and 20% fine aggregate replaced with crumb rubber. The results showed that both crumb rubber and nano silica increases the bending resistance and fatigue life of RCC pavement. While HVFA decreases both flexural strength and fatigue performance of RCC pavement. The double logarithmic-equation can best be used to determine the stress level–number of cycles (S–N) fatigue behavior and relation for RCC pavement mixtures.

Communication, coordination and cooperation in construction projects: business environment and human behaviours

The accomplishment of construction projects is extremely dependent on the integration of several stakeholders; therefore none of them has the control or the ability to accomplish the project alone. Each of them may influence and be influenced by the project management approach. There is no comprehensive theoretical platform for defining Communication, Coordination and Cooperation (3Cs) in the management of construction project. This paper deliberates the function of the 3Cs different theoretical perceptions. Through an analysis of selected articles from reputable academic journals in construction management, the business environment and human behaviour were identified as two main parts. A little has been done so far about the 3Cs, and how they are correlated with construction projects performance. Therefore, the objective of this paper is to explain the definitions and the association between the 3Cs. There is a significant link between communication and coordination. Coordination alternatively, is trust-based a logic of mutual and exchange. Consequently, cooperation is much more sophisticated, which needing more time and attempts.

Delphi Technique Procedures: A New Perspective in Construction Management Research

The Delphi technique is a methodology seeks to achieve a consensus among panel of experts. The consensus is gained through a sequence of rounds. The feedback information passed to panelists by questionnaires. The technique applications being progressively involved in construction management (CM) researches and it has been applied widely in many disciplines. This popularity meant that reasonable and accurate results have been gained using Delphi technique. The aim of this study is to analysis monetary Delphi technique as a robust and systematic data collection tool in CM. Discussion and review focused on the procedures of application, cons and pros and the technique key aspects. These key aspects included experts’ selection, anonymity, rounds and feedback; have been investigated through ten published articles in CM. Delphi technique has significant opportunity to be used widely in gaining consensus within CM research. This article provides rigorous guidelines for the technique application in CM to ensure bias elimination and the outcomes validity and reliability.

Single-Degree-of-Freedom Based Pressure-Impulse Diagrams for Blast Damage Assessment

Pressure-impulse (P-I) diagrams, which relates damage with both impulse and pressure, are widely used in the design and damage assessment of structural elements under blast loading. Among many methods of deriving P-I diagrams, single degree of freedom (SDOF) models are widely used to develop P-I diagrams for damage assessment of structural members exposed to blast loading. The popularity of the SDOF method in structural response calculation in its simplicity and cost-effective approach that requires limited input data and less computational effort. The SDOF model gives reasonably good results if the response mode shape is representative of the real behaviour. Pressure-impulse diagrams based on SDOF models are derived based on idealised structural resistance functions and the effect of few of the parameters related to structural response and blast loading are ignored. Effects of idealisation of resistance function, inclusion of damping and load rise time on P-I diagrams constructed from SDOF models have been investigated in this study. In idealisation of load, the negative phase of the blast pressure pulse is ignored in SDOF analysis. The effect of this simplification has also been explored. Matrix Laboratory (MATLAB) codes were developed for response calculation of the SDOF system and for repeated analyses of the SDOF models to construct the P-I diagrams. Resistance functions were found to have significant effect on the P-I diagrams were observed. Inclusion of negative phase was found to have notable impact of the shape of P-I diagrams in the dynamic zone.

A Conceptual Review of Tsunami Models Based on Sumatera-Andaman Tsunami Event

Sumatra-Andaman tsunami was categorized as the third worst tsunami by the United State Geology Survey (USGS). The tsunami was triggered at 00:58:53 UTC by a massive earthquake with recorded moment magnitude of 9.1 at the west coast of North Sumatera. Malaysia is one of the countries affected by the 26th December 2004 tsunami. Others countries also affected by this event include Indonesia, Sri Lanka, Thailand, India, Maldives, Myanmar, Bangladesh, Somalia, Tanzania, Kenya and Yemen. The earthquake epicenter is located where the Indian Plate subducted under the Burma Plate. This tsunami event has raised the awareness of many people. Today, several tsunami numerical models have been developed to model and forecast tsunami events in the future. This paper reviews five tsunami numerical models namely TUNA, TUNAMI, COMCOT, MOST and ANN Tsunami Forecast. Most of these models have been used by other researchers to perform tsunami simulation based on Sumatera-Andaman tsunami event. Each model have their own similarities, differences and limitations. A non-mathematically intensive approach is employed to choose a suitable tsunami numerical model for the case study in Malaysian offshore areas. Future studies will be conducted using one of the tsunami numerical models.

Tsunami Forecasting Due to Seismic Activity in Manila Trench of Malaysia Offshore Oil Blocks

Manila Trench is a potential generation source of tsunami in the South China Sea. Manila Trench is formed when Eurasian Plate is subducted under the Philippine Sea Plate. It has been classified as the most hazardous tsunami sources in USGS Tsunami Sources Workshop, 2006. The location of the trench begins at the north of Palawan, Philippines, continuing to the north along the west of Luzon, Philippine, and ends at Taiwan. The potential tsunami generated from Manila Trench affects Philippines and countries located in the vicinity of South China Sea including Malaysia. This chapter focuses on simulation of tsunami generation and tsunami wave propagation due to seismic activity in the Manila Trench. TUNA-M2 model is used to produce simulation results in terms of tsunami wave height and time of arrival of the first wave. The study area is Malaysian offshore reserves and operation where oil and gas platforms are located. There are three simulations performed at different moment magnitudes (M w: 7.0, 7.5, and 8.0). The result shows the range of wave heights at the Malay basin to be between 0.002 and 0.122 m, the range of wave heights at Sabah basin to be between 0.004 and 0.168 m, and the range of wave heights at Sarawak basin to be between 0.004 and 0.230 m. These results are useful in the future design of offshore platform structure and operation