Infrastructure Engineering - Research Publications
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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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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)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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ItemAutomation in structural health monitoring of transport infrastructure(Springer Singapore, 2021-01-01)Roads are among the most important assets in the world. Road structure improvements make a crucial contribution to economic development and growth and bring important social benefits. Automation in structural health monitoring allow the accurate prediction of ongoing damage caused by long-term traffic loading. This permits optimal road structure management and ensures the longevity and safety of road structures. This chapter discusses a variety of advanced automation techniques in structural health monitoring of road structures, such as data acquisition, data processing, and life-cycle assessment. It demonstrates that the implementation of automation in road asset management can increase the productivity and extend the service life of road structures, and enhance the durability of crucial road structures and increase transport infrastructure sustainability.
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ItemA Simplified Methodology for Condition Assessment of Bridge Bearings Using Vibration Based Structural Health Monitoring Techniques(WORLD SCIENTIFIC PUBL CO PTE LTD, 2021-09-01)The mechanical properties of bridge bearings gradually deteriorate over time resulting from daily traffic loading and harsh environmental conditions. However, structural health monitoring of in-service bridge bearings is rather challenging. This study presents a bridge bearing condition assessment framework which integrates the vibration data from a non-contact interferometric radar (i.e. IBIS-S) and a simplified analytical model. Using two existing concrete bridges in Australia as a case study, it demonstrates that the developed framework has the capability of detecting the structural condition of the bridge bearings in real-time. In addition, the results from a series of parametric studies show that the effectiveness of the developed framework is largely determined by the stiffness ratio between bridge bearing and girder ([Formula: see text], i.e. the structural condition of the bearings can only be effectively captured when the value of [Formula: see text] ranges from 1/100 and 100.
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ItemDegradation of Alkali-Activated Slag and Fly Ash Mortars under Different Aggressive Acid Conditions(ASCE-AMER SOC CIVIL ENGINEERS, 2021-07-01)Acidic environments constitute serious chemical threats to concrete-like cementitious materials. The purpose of this study is to experimentally investigate the degradation of alkali-activated slag/fly ash mortars with different slag/fly ash ratios: 80/20, 60/40, and 40/60 in acidic environments. Mortar samples were exposed to three different types of aggressive acidic solutions: phosphoric acid, sulfuric acid, and a mixture of phosphoric acid and sulfuric acid maintained at a constant pH value of 2.5±0.5 for a period of 150 days. Results showed that, for all mortar samples, the aggressivity of the phosphoric acid is greater compared to the other acids. Moreover, samples with a slag/fly ash ratio of 60/40 demonstrate the highest resistance against the three types of acidic environments. In addition, it shows that the degradation process of alkali-activated mortars can be divided into two degradation stages: an early stage and a subsequent stage. The chemical-reaction dominated early degradation stage is described by using Hill function, whereas a diffusion process-dominated subsequent stage is simulated with Fick's second law. Finally, the results of theoretical analysis predicted that the degradation depth of alkali-activated slag/fly ash mortars exposed to sulfuric acid environment (pH=2.0) for 50 years could be reduced by about 52%-60% compared to that of an ordinary Portland cement (OPC)-based mortar.
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ItemNo Preview AvailableReliability assessment of concrete under external sulfate attack(ELSEVIER, 2021-12)
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ItemCalculation model and bearing capacity optimization method for the soil settlement between piles in geosynthetic-reinforced pile-supported embankments based on the membrane effect(PUBLIC LIBRARY SCIENCE, 2021)The geosynthetic-reinforced pile-supported embankment (GRPSE) system has been widely used in road construction on soft soil. However, the application of the GRPSE system is often restricted by its high-cost. The reason is that they are designed for bearing control as defined in the past. During the construction process, the pile spacing is reduced to meet the requirements for the embankment bearing capacity and settlement. These factors cause the membrane effect to not be exploited. As a result, the utilization efficiency of the bearing capacity of the soil between the piles is low and the project cost is high. Therefore, in order to solve the problem of insufficient bearing capacity of soil between piles, we established a settlement calculation model of soil between piles based on membrane effect. The model considers the relationship between the geosynthetic reinforcement (GR) and the pile spacing. Based on the obtained model, a method for optimizing the soil bearing capacity of GRPSEs is proposed. By controlling the settlement of soil between piles, the bearing capacity of soil between piles and the membrane effect of embankment can be fully utilized. Therefore, the project cost can be reduced. Finally, the method is applied to field tests for comparison. The results show that the method is reasonable and applicable. This method can effectively exploit the membrane effect and improve the utilization efficiency of the bearing capacity of the soil between piles. An economical and reasonable arrangement scheme for the piles and GR was obtained. This scheme can not only ensure the safety of the project, but also fully utilize the bearing capacity of the soil between the piles and provide a new method for engineering design.
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ItemNo Preview AvailableAnalysis of microstructure and spatially dependent permeability of soft soil during consolidation deformation(JAPANESE GEOTECHNICAL SOC, 2021-06)
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ItemNumerical prediction of the optimal shield tunneling strategy for tunnel construction in karst regions(PUBLIC LIBRARY SCIENCE, 2021-06-04)Shield tunneling in karst areas poses significant challenges, as vibration caused by the shield machine can disturb the stability of the karst caves, ultimately resulting in the collapse of a tunnel. In the present study, a numerical model involving an iteration process was developed based on the Mindlin solution scheme to identify the optimal shield tunneling speed for minimizing the disturbance to karst cave stability. The developed model was then implemented to investigate an underground tunnel constructed in a karst region with different shield tunneling strategies. By using the variation in the energy density of a karst cave as a performance index, the model predicts that when approaching the affected zone of a karst carve (e.g., approximately 5 m from the carve), the shield tunneling machine should be controlled within a certain speed (i.e., < 30 mm/min). Once the shield tunneling machine moves into the affected zone of the cave, the speed of the machine needs to be decelerated to 11 mm/min, and the speed of 30 mm/min can be restored when the shield machine moves out of the affected zone. This finding demonstrates that the developed model could potentially be used to identify the optimal shield tunneling speed to minimize the disturbance to karst cave stability and ensure the safety of tunnel construction in karst regions.
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ItemModeling Riverbank Slope Reinforcement Using Anti-Slide Piles with Geocells(MDPI, 2021-04)Geocells are increasingly used in engineering applications, but the design of riverbank slope reinforcements that use only geocells limits reinforcement performance. Moreover, the design and use of anti-slide piles with geocells are mainly based on experiences that are unsupported by theoretical models. In this paper, by combining the confinement effect and vertical action mechanism of geocells, the horizontal friction mechanism of the geocell layer and the vertical support mechanism of piles, a theoretical model of riverbank slope reinforced by anti-slide piles with geocells was constructed. In addition, to describe the mechanical behavior of a riverbank slope reinforced by anti-slide piles with geocells, the slip-resisting mechanism of the anti-slide pile with interaction between geocells and their internal filler is considered in the model. Furthermore, to investigate the influence of changes in water level on riverbank slope stability, the developed model takes into account settlement, lateral displacement, pile bending moment and pile axial force. The model predications were validated by the field measurement data. The results from a series of parametric studies show that the use of anti-slide pile and geocells can effectively reduce the settlement and the lateral displacement of a riverbank slope. The developed model could contribute to an optimal design of anti-slide pile with geocells for enhancing the stability of a riverbank slope.