Infrastructure Engineering - Research Publications
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ItemIndentation into an aluminium panel by the impact of a rigid spherical object(Elsevier BV, 2022-11)This paper introduces algebraic expressions for determining the amount of permanent indentation caused to an aluminium panel when impacted by a rigid spherical object. The magnitude of indentation is observed to vary significantly with the position of impact within the panel when the impactor and the velocity of impact are kept the same. This spatial variation of indentation is caused by the changes in the combinational mass (which is in turn function of the participating mass of the plate) and the Coefficient of Restitution COR. Both parameters are shown to correlate with the position of impact. The proposed algebraic expression featuring the combinational mass and COR as input parameters, allows potential damage to the panel to be predicted conveniently in day-to-day engineering practices. The original contribution of this article is in illustrating this phenomenon analytically, and have the analytical predictions verified by impact experimentation which has been conducted by the authors on panels of varying dimensions.
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ItemNo Preview AvailableThe synthesis of soft rocks based on physical and mechanical properties of red mudstone(PERGAMON-ELSEVIER SCIENCE LTD, 2022-03-01)
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ItemNo Preview AvailableApplication of New Polymer Composite Materials in Rock Slope Ecological(IOP Publishing, 2021-10-27)
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ItemEarly Risk Warning of Highway Soft Rock Slope Group Using Fuzzy-Based Machine Learning(MDPI, 2022-03-01)Maintaining the stability of highway soft rock slopes is of critical importance for ensuring the safety of road networks. Although much research has been carried out to assess the stability of individual soft rock slope, the goal of efficient and effective risk management focusing on multiple highway soft rock slopes has not been fully achieved due to the many complex factors involved and the interactions among these factors. In the present study, a machine learning algorithm based on a fuzzy neural network (FNN) and a comprehensive evaluation method based on the FNN is developed, in order to identify and issue early warnings regarding the risks induced by soft rock slopes along highways, in an efficient and effective way. Using a large amount of collected soft rock slope information as training and validation data, an FNN-based risk identification model is first developed to identify the risk level of individual soft rock slope based on the meteorological conditions, topographical and geomorphological factors, geotechnical properties, and the measured horizontal displacement. An FNN-based comprehensive evaluation method is then developed, in order to quantify the risk level of a soft rock slope group according to the slope, road and external factors. The results show that the risk level identification accuracy obtained based on validation of the FNN model was higher than 90%, and the model showed a good training effect. On this basis, we further made early warnings of the risks of soft rock slope groups. The proposed early-warning model can quickly and accurately evaluate the risk posed by multiple soft rock slopes to a highway, thereby ensuring the safety of the highway.
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ItemEvaluating uncertainties to deliver enhanced service performance in education PPPs: a hierarchical reliability framework(EMERALD GROUP PUBLISHING LTD, 2022-06-20)Purpose This study aims to develop a hierarchical reliability framework to evaluate the service delivery performance of education public–private partnerships (PPPs) effectively and efficiently during long-term operations. Design/methodology/approach The research design included development and test phases. In the development phase, three performance layers, i.e. indicator, component and system, in the education service delivery system were identified. Then, service component reliability was computed through first order reliability method (FORM). Finally, the reliability of the service system was obtained using dynamic component weightings. A PPP school example in Australia was set up in the test phase, where performance indicators were collected from relevant contract documents and performance data were simulated under three assumptive scenarios. Findings The example in the test phase yielded good results for the developed framework in evaluating uncertainties of service delivery performance for education PPPs. Potentially underperforming services from the component to the system level at dynamic timepoints were identified, and effective preventative maintenance strategies were developed. Research limitations/implications This research enriches reliability theory and performance evaluation research on education PPPs. First, a series of performance evaluation indicators are constructed for assessing the performance of the service delivery of the education PPP operations. Then, a reliability-based framework for service components and system is developed to predict service performance of the PPP school operations with consideration of a range of uncertainties during project delivery. Practical implications The developed framework was illustrated with a real-world case study. It demonstrates that the developed reliability-based framework could potentially provide the practitioners of the public sector with a basis for developing effective preventative maintenance strategies with the aim of prolonging the service life of the PPP schools. Originality/value Evaluating education PPPs is challenging as it involves long-term measurement of various service components under uncertainty. The developed reliability-based framework is a valuable tool to ensure that reliability is maintained throughout the service life of education PPPs in the presence of uncertainty.
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ItemExperiments on an ice ball impacting onto a rigid target(PERGAMON-ELSEVIER SCIENCE LTD, 2022-09-01)This paper is concerned with the peak force (Fp) and time of occurrence (Tp) generated by the spherical ice specimen impacting onto a rigid target. The ice specimens had diameter ranging from 31.8 to 50.8 mm, and were prepared at temperature of -10°C and -30°C, respectively. The key original contribution of the article is the derivation of a correlation relationship for providing accurate predictions of Fp and Tp, for given hail size, velocity and temperature. A total of 149 Hopkinson bar tests were conducted, with impact velocity varying from 13 to 105 m/s for measuring the impact force. The tensile strength of ice, which is a term in the predictive expressions (and is measurable by the Brazilian tests), can be adjusted to take into account changes in temperature of the ice specimen. Experimental results showed that as the size of the ice specimen and its impact velocity increases, Fp increases significantly whereas Tp only increases slightly. Lowering of the temperature resulted in an increase in Fp, and decrease in Tp. Dimensional analysis was employed for processing the experimental data. Empirical relationships expressed as functions of impact velocity, specimen radius, tensile strength of ice, ice density and elastic wave speed of ice were derived. The ratio of the measured impulse to the momentum generated by the impact has also been checked, and was found to be within the range of 0.8 to 1.12. The derived empirical relationships will serve as a guide for further investigations into the structural responses to impact of an ice ball.
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ItemImproving Design by Partnering in Engineering-Procurement-Construction (EPC) Hydropower Projects: A Case Study of a Large-Scale Hydropower Project in China(MDPI, 2021-12-01)Hydropower, as a renewable energy resource, has become an important way to fit for Chinese long-term energy policy of energy transformation. Engineering–procurement–construction (EPC) has been increasingly adopted for improving hydropower project delivery efficiency in the utilization of water resources and generation of clean energy, where design plays a critical role in project success. Existing studies advocate the need to use partnering for better solutions to designs in EPC hydropower projects. However, there is a lack of a theoretical framework to systematically address design-related issues considering different participants’ interactions. This study coherently examined the causal relationships among partnering, design management, design capability, and EPC hydropower project performance by establishing and validating a conceptual model, with the support of data collected from a large-scale EPC hydropower project. Path analysis reveals that partnering can directly promote design management and design capability and exert an effect on design capability through enhancing design management, thereby achieving better hydropower project outcomes. This study’s contribution lies in that it theoretically builds the links between intra- and inter-organizational design-related activities by systematically mapping EPC hydropower project performance on partnering, design management, and design capability. These findings also suggest broad practical strategies for participants to optimally integrate their complementary resources into designs to achieve superior hydropower project performance.
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ItemA Comparative Study on the Degradation of Alkali-Activated Slag/Fly Ash and Cement-Based Mortars in Phosphoric Acid(FRONTIERS MEDIA SA, 2022-03-09)This study compares the degradation behavior of the alkali-activated slag/fly ash (AASF) and ordinary Portland cement (OPC) mortars exposed to phosphoric acid with different pH values. The experimental results show that AASF mortars exhibit better resistance than OPC mortars against surface damage, although both systems get white deposits on the surface in phosphoric acid with a relatively high pH level. AASF mortars obtained lower mass loss than OPC mortars in phosphoric acid with pH at 2 and 3. The strength reduction in AASF mortars after immersion in phosphoric acid is more significant than that in OPC mortars. However, total degradation depth of AASF was smaller than that of OPC regardless of the pH of the acid solutions. Based on the experimental data, linear relationships were identified between the slope of degradation depth–mass loss curves and the Al/Si and Ca/Si ratios of the binders. This may indicate a new way to assess the degradation behavior of AASF and OPC based on their chemical compositions.
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ItemHOW TO GET INTERNATIONAL CONSTRUCTION PROJECTS DELIVERED ON TIME: FROM CHINESE CONTRACTORS' PERSPECTIVE(VILNIUS GEDIMINAS TECH UNIV, 2022-01-01)67.9% of Chinese international construction projects are seriously delayed, which creates the potential for instability in its rapidly growing share of global contracting markets. A greater understanding of the reasons behind the challenges confronting international contractors is urgently required such that improvements can be developed that ultimately will benefit many countries. This study aims to investigate the time performance of international projects in developing countries and to explore the root causes of time overrun. Based on both quantitative and qualitative analysis of 112 case study projects, collected from 12 of the largest Chinse state-owned enterprises (SOEs), this study identifies the distinctive characteristics of three types of projects (late, acceptable, early) classified based on their time performances. It is established that time performance is significantly related to the contractor’s adaptability and project complexity. The results reveal the root causes of construction delays in international project delivery, which provides a structured and in-depth understanding of both internal and external time performance influential factors. The above findings provide sound basis for guiding practitioners in choosing appropriate strategies to improve project time performance, such as encouraging cross-cultural dialogues, integrating global resources and establishing long-term global partnerships with stakeholders.