Coastal Construction Research Articles

Status Quo and Analysis of Risk Management Based on the PPP Project of Coastal Construction Enterprises

Shan, S., 2019. Status quo and analysis of risk management based on the PPP project of coastal construction enterprises. In: Li, L.; Wan, X., and Huang, X. (eds.), Recent Developments in Practices and Research on Coastal Regions: Transportation, Environment and Economy. Journal of Coastal Research, Special Issue No. 98, pp. 263–266. Coconut Creek (Florida), ISSN 0749-0208.Over the past 30 years of reform and opening up, China's economy has achieved rapid growth, which has attracted worldwide attention and has developed a comprehensive well-off society. To maintain this speed of development, the government must strengthen the construction of coastal construction urban infrastructure, such as electricity, roads, and water supply, to adapt to the needs of social development and eliminate the bottleneck that constrains economic development, which requires a large investment of funds. However, China's domestic funds are insufficient. The traditional methods of attracting investment and existing financial institutions and financing channels cannot fully meet the capital needs of China's economic development and require more financing channels. At the same time, like most developing countries, China has the problems of inefficient departments and poor infrastructure management. As an emerging project financing method, public–private partnership was born in the 1980s. Because it can effectively alleviate the shortage of infrastructure construction funds for coastal construction enterprises, it can also promote the efficiency of state-owned departments.

Total Quality Management and Evaluation: A Study of the Coastal Highway System

Lu, W.; Li, Z., and Zhang, H., 2019. Total quality management and evaluation: a study of the coastal highway system. In: Li, L.; Wan, X.; and Huang, X. (eds.), Recent Developments in Practices and Research on Coastal Regions: Transportation, Environment and Economy. Journal of Coastal Research, Special Issue No. 98, pp. 407–413. Coconut Creek (Florida), ISSN 0749-0208.Investment in coastal highway construction not only promotes the development of the transportation industry in China's coastal areas but also affects the economic and social development of China. With the continuous increase of coastal highway projects, the mileage of highways has been increasing, and the task of total quality management has become increasingly arduous. How to objectively evaluate the total quality management level and solve various problems existing in the current evaluation work has become an urgent problem for the financial investment management department. The research in this paper builds a total quality management evaluation system and decision-making model and a total quality management platform for coastal highway projects. The research in this paper has innovated and perfected the methods of evaluation decision making, has improved the efficiency of evaluation decision making and realized the efficient use of quality management funds, and has promoted the process of quality management work of coastal highway projects to be scientific and standardized.

Maintenance Decision-Making Model for Coastal Highway Project

Xiao, P. and Zhou, A., 2019. Maintenance decision-making model for coastal highway project. In: Li, L.; Wan, X.; and Huang, X. (eds.), Recent Developments in Practices and Research on Coastal Regions: Transportation, Environment and Economy. Journal of Coastal Research Journal of Coastal Research, Special Issue No. 98, pp. 290–293. Coconut Creek (Florida), ISSN 0749-0208.Investment in coastal highway projects not only promotes the development of China's transportation industry, but also enhances China's economy and society. This paper presents a coastal highway-maintenance evaluation system (CHMES) during project life-cycles in coastal highway construction, and a decision-making model for coastal highway maintenance. The CHMES contains three parts, (1) the acceptance list of coastal highway safeguards, (2) the selection and evaluation of coastal highway security schemes, and (3) the analyses and evaluation of safeguard projects, which are based on the Analytic Hierarchy Process (AHP) method. Also, two grades of decision-making models of maintenance management were established, the project-grade and the network-level, through the estimation and benefit analysis of different management schemes. The results of case analysis show that the decision-making model can improve coastal highway maintenance effectively.

Analysis of Coastal Zone Data of Northern Yantai Collected by Remote Sensing from 1990 to 2018

Using remote sensing images of different time phases from 1990 to 2018, the surface coverage information of northern Yantai (coastline, 2 km from coastline to land) was extracted by means of average high tide line and visual interpretation. The end point change rate (EPR) and linear regression rate were used to study the coastline change rate, the fractal dimension of the coastline in the study area was analyzed, and the change of the type of coastal surface cover was analyzed by the transition matrix. The results show that: (1) Form 1990 to 2018, a significant trend of a continuous increase in the total length of coastline was observed with an increase of 181.08 km (43.18%). In the study area, the coastline of Laizhou had the greatest change rate with an EPR value of 33.67 m/a, whereas the coastline of Laishan had the smallest change rate with an EPR value of 0.30 m/a. (2) Over the past 30 years, with the rapid economic development of Yantai and the ensuant urbanization, the total surface area of the coastal zone in the study area has increased by 144.94 km2, mainly in the areas covered by structures and forests/grasses, by 112.96 km2 and 96.08 km2, respectively, while the areas of desert/bare land and water have decreased by 92.26 km2 and 12.32 km2, respectively. (3) The changes among different types in the study area were clear, mainly from desert/bare land, cultivated land, and building areas to forests/grasses cover and structures. The change areas were mainly concentrated in Laizhou, Longkou, Zhifu, and Penglai. Frequent human activities are an important factor affecting the continuous expansion of the coastal areas of Jiaodong Peninsula to the sea. Aquaculture, coastal construction, construction of artificial islands, and expansion of port terminals have seriously affected the sustainability of ecological resources in the coastal areas. At the same time, the changes in the ecological environment in the coastal zone will have a greater impact on the health of the coastal zone.

Issues in Underwater Cultural Heritage Impact Assessments in China

During the past decades, the number of coastal and marine construction projects has multiplied in China, posing a serious threat to underwater cultural heritage in its waters. In contrast, there are few rules dealing with underwater cultural heritage impact assessment which has not yet become a mandatory procedure in various coastal and marine construction projects. With China putting forward the Belt and Road Initiative, the conflicts between the protection of underwater cultural heritage and the need of various coastal and marine construction projects might become more frequent. Chinese legislation in this domain, undergoing important revision, intends to establish a mandatory procedure of proactive archeological investigation. This revision could have a great influence on the protection of underwater cultural heritage as well as the coastal and marine construction projects in China but the relevant provisions are still far from satisfactory. The present study will review the current Chinese legislation concerning the impact assessment of marine or coastal construction projects on underwater cultural heritage and explore the possibility for further improvement at the legislative level.

Applying FAHP Model to Access Coastal Road Construction Performance

Wang, F., 2019. Applying FAHP model to access coastal road construction performance. In: Gong, D.; Zhu, H., and Liu, R. (eds.), Selected Topics in Coastal Research: Engineering, Industry, Economy, and Sustainable Development. Journal of Coastal Research, Special Issue No. 94, pp. 181–185. Coconut Creek (Florida), ISSN 0749-0208.Based on the whole process management of coastal road construction projects, this thesis analyzes the performance evaluation of coastal road construction projects from economic factors, social factors and engineering elements. The Analytic Hierarchy Process (AHP) is used to determine the index weights and the Fuzzy Comprehensive Evaluation method (FCE) is used to evaluate the performance of coastal road construction projects in Shandong Province, as to establish an evaluation system, which provides a useful reference for effective performance evaluation and sustainable development of coastal road construction.

Modeling Study on the Hydrodynamic Environmental Impact Caused by the Sea for Regional Construction near the Yanwo Island in Zhoushan, China

Waves are one of the most important factors affecting offshore marine engineering. Accurate calculation of wave distribution is an important prerequisite to ensure the safety of coastal engineering construction. Due to the influence of complex topography, hydrological conditions, and marine structures on the propagation of waves offshore, slowly varying topography, refraction, diffraction, reflection, shallowness, and other phenomena may occur. This article combines the MIKE21 Spetral Waves (SW) wave model and the MIKE21 Boussinesq Waves (BW) wave model which are developed by Danish Hydraulic Institute (DHI) for a joint application (SW–BW nested model). It simulates the hydrodynamic environment of the Yanwo Island scenic area, located in Zhoushan, in both large and small ranges. In addition, wave height distribution and berthing stability of different breakwater planning schemes are calculated to optimize the layout of the breakwater. Through the analysis of simulation results, it is concluded that the hydraulic performance of Scheme 2 (the broken line section on the west side is 100 m long, and that on the east is 1200 m long, and the breakwater is rotated 8 degrees counterclockwise along the axis on the basis of Scheme 1) is better than that of Scheme 1 (the broken line section on the west side is 100 m long, and that on the east is 1100 m long), which can provide a more reliable construction reference for the construction of the Yanwo Island scenic area.

Экспериментальное исследование силовых нагрузок на опоры надводной конструкции на основе математической модели волновых процессов

The article is devoted to the research of the effects of wave processes on above-water constructions using a mathematical model of wave processes based on the system of Navier–Stokes equations, which includes three equations of motion in areas with dynamically changing geometry of the computational domain. The pressure correction method is used for the approximation of a hydrodynamic model. The difference schemes describing the mathematical model of the wave exit to the shore are constructed on the basis of the integro-interpolation method using the scheme with weights. An adaptive alternating-triangular iterative method is used to solve the system of grid equations. The practical significance of numerical algorithms and the complex of programs implementing them consists in the possibility of their application in the study of hydrophysical processes in coastal water systems, as well as for the construction of the velocity field and pressure of the aquatic environment, as well as the assessment of the hydrodynamic effect on coastal protection structures and riparian constructions in the presence of surface waves.

Seawater Icicles of the Adriatic Sea

AbstractThe marine icicles that form on coastal constructions (e.g., piers and railings) are very common in polar and subpolar areas. The occasional formation of icicles in the coastal zones of the Mediterranean Sea occurs in relation to cold-air outbreaks from the polar region, such as the one presented in this paper in February 2018. The air temperatures over the northern Adriatic Sea, the northernmost part of the Mediterranean, dropped below –2.1°C, a necessary condition for seawater to freeze, with salinity between 38.0 and 38.5 PSU. The formation of icicles on the coastal structures was further enabled by the bora wind and related high seas along the coast. Measurements presented in this paper confirm that the icicles in the Bay of Piran in the Gulf of Trieste (45.55°N) were formed from the seawater. The measured salinity level of the melted icicles, around 9 PSU, is a typical value reported for marine icicles in polar regions.

PREDICTING THE RESHAPING OF TEMPORARILY EXPOSED BUNDS WITH XBEACH-G

During coastal construction works, damages often occur to temporary constructions consisting of fine and often wide graded rock material due to exposure to waves. Examples of vulnerable structures are the bunds that are constructed to serve as the core for a breakwater before placement of the filter and armour layers, or as temporary defense during reclamation works. Such structures – mostly built in bulk – are temporarily exposed to wave conditions, and will reshape depending on the duration of exposure and the prevailing hydraulic conditions. For the exposed breakwater core, it is important to have an idea on how much of the placed material will be moved outside the perimeter, and thus how much material needs to be rehandled before the cover layers can be constructed. For temporary defense works, it is important to know how much material needs to be placed initially in order to offer sufficient protection for a certain period. For both cases, an accurate prediction of the reshaping of such structures is necessary.

RESEARCH ON NEARSHORE WAVE CONDITIONS AT NHAT LE COASTAL AREA (QUANG BINH PROVINCE) BY USING MIKE21-SW

Research on marine dynamics, including coastal wave motions, is a concern of countries in the world in general and Vietnam in particular. Coastal wave dynamics has a direct impact on human activities including coastal construction, shipping, irrigation, aquatic resources exploitation, etc. The coastal area of Nhat Le, Quang Binh is one of the areas strongly influenced by the coastal wave regime which increases the risk of coastal erosion, estuarine sedimentation, destroys the economic life, affects marine fishing and directly affects the tourist beach area. This article aims to introduce some research results based on the application of MIKE21-SW model of the Danish Hydraulic Institute (DHI) to simulate coastal wave regime in Nhat Le coastal zone, Quang Binh province. The model results are verified by real-time wave data in long-term from the WaMoS® II Radar System at Quang Binh station. The results show that there are many similarities in wave height and direction between the computational model and the actual observation data from the radar system. This result will be an important basis for research and application for coastal protection, reduction in river mouth sedimentation, clearing and flood drainage in the study area.

Phytoplankton Community Response to Coastal Engineering Construction in the Caofeidian Sea, China

ABSTRACT Li, Z.-W. and Cui, L.T., 2018. Phytoplankton community response to coastal engineering construction in the Caofeidian Sea, China. In: Ashraf, M.A. and Chowdhury, A.J.K. (eds.), Coastal Eco...

A numerical study on the effect of tidal flat’s slope on tidal dynamics in the Xiangshan Bay, China

The Xiangshan Bay is a semi-enclosed and narrow bay, which is characterized by large scale tidal flats and has been historically utilized through coastal construction and aquaculture engineering. The hydrodynamic model using the Finite Volume Coastal Ocean Model (FVCOM) was constructed to examine the changes of tidal dynamics due to the variation of tidal flat slopes. According to the model results, a decreased slope of a tidal flat would amplify the M2 tidal amplitude and delay the M2 tidal phase in the inner harbor, due to an increased tidal prism, and vice versa. The amplitude of the main shallow-water tide M4 would be amplified/dampened in the entire bay due to the changed bottom friction, if the tidal flat’s slope were reduced/increased at the Tie inlet. The phase was advanced. The change of a tidal flat’s slope at the Tie inlet had greater impacts on tidal amplitude, phase and duration asymmetry, than that at the Xihu inlet. The impact of changes of the tidal flat slope at the Xihu inlet was small and was constrained locally. Changes in the tidal flats’ slopes at the Tie and Xihu inlets changed the tidal duration asymmetry, residual current and tidal energy via modulating tides. The ebb dominance decreased when the tidal flat’s slope at the Tie inlet was changed. Decreased/increased ebb dominance occurred when the tidal flat’s slope was reduced/increased at the Xihu inlet. The residual current and tidal energy density was amplified/dampened and more/less tidal energy was dissipated, with reduced/increased slope at both of the inlets. The findings in this study are instructive to coastal engineering and estuarine management.

Determining the Threshold Pressure of Clay-Cutting by a Mobile Jet for Coastal Construction

ABSTRACT Gu, L.; Ni, F.; Xu, L., and Li, Z., 2018. Determining the threshold pressure of clay-cutting by a mobile jet for coastal construction. Trailing suction hopper dredgers (THSD) are widely used in channel excavation and coastal construction projects. In such projects, clay is a common soil that is difficult for the drag head of THSDs to dredge. Jet-cutting using a mobile jet is often adopted to improve the efficiency of the drag head, since it can create grooves into the clay surface and reduce cutting forces for the drag head. The jet pressure is an important factor for jet-cutting, so it is necessary to accurately grasp the threshold pressure of clay-cutting by the mobile jet. In this paper, clay samples with three different strengths (undrained shear strength Su = 16 kPa, 35 kPa, and 51 kPa) were prepared, and clay-cutting experiments using a mobile jet were conducted. The effects of parameters such as the nozzle diameter, the moving speed, and the jet pressure on the cutting results were investi...

Recreational boating degrades vegetation important for fish recruitment

Recreational boating increases globally and associated moorings are often placed in vegetated habitats important for fish recruitment. Meanwhile, assessments of the effects of boating on vegetation, and potential effects on associated fish assemblages are rare. Here, we analysed (i) the effect of small-boat marinas on vegetation structure, and (ii) juvenile fish abundance in relation to vegetation cover in shallow wave-sheltered coastal inlets. We found marinas to have lower vegetation cover and height, and a different species composition, compared to control inlets. This effect became stronger with increasing berth density. Moreover, there was a clear positive relationship between vegetation cover and fish abundance. We conclude that recreational boating and related moorings are associated with reduced cover of aquatic vegetation constituting important habitats for juvenile fish. We therefore recommend that coastal constructions and associated boating should be allocated to more disturbance tolerant environments (e.g. naturally wave-exposed shores), thereby minimizing negative environmental impacts.

Estimating extreme sea levels in Yangtze Estuary by quadrature Joint Probability Optimal Sampling Method

Effective estimation of extreme sea levels is of primary importance for coastal construction and coastal hazard mitigation. To predict 100-year and 200-year Annual Maximum Water Levels in Yangtze Estuary, simulation studies using the Quadrature Joint Probability Method-Optimal Sampling (JPMOSQ) to generate a set of optimal synthetic typhoons and river discharges combined with numerical hydrodynamic models capable of accurately simulating sea levels were conducted. During the synthetic simulation combination generation process, astronomical tide was also taken into account based on the Monte Carlo method. After a series of model validations, which showed that this model performed well to reflect the characteristics of the typhoon field, wave height, and sea level in the studied region, this model was implemented to predict extreme sea levels. Through simulation, 100-year and 200-year Annual Maximum Water Levels at Wusong station were predicted to be +6.08 m (Wusong Datum, WD) and +6.28 m WD, respectively, while these two values for Baozhen station were predicted to be +6.12 m WD and +6.33 m WD, respectively. Also, the 100-year and 200-year Annual Maximum Water Levels at Hengsha station were predicted to be +5.99 m WD and +6.13 m WD, respectively. Comparisons with former studies showed that the JPMOSQ method can be used to forecast extreme sea levels during typhoons in Yangtze Estuary. Estimating results from this study would be conducive to risk assessment in coastal areas as a reference.

Postseismic Uplift Along the Pacific Coast of Tohoku and Kanto Districts Associated with the 2011 off the Pacific Coast of Tohoku Earthquake

The 2011 off the Pacific coast of Tohoku earthquake (M9.0) produced up to 1.2 m subsidence along the Pacific coast in northeastern Japan. Based on Global Positioning System (GPS) observations, continuing postseismic coastal uplift has been detected in the past six years after the main shock. By applying a 3D spherical Earth viscoelastic finite element model using the postseismic seafloor and terrestrial GPS observations as constraints, I demonstrate that this uplift is mainly caused by the postseismic viscoelastic relaxation of the asthenosphere. Although the model was constrained only based on horizontal crustal deformation, the vertical displacements predicted for six years after the 2011 Tohoku earthquake agree reasonably well with the time series of the observed uplift at sites along the Pacific coast including the southern Sanriku coast and Kanto district. I estimated the time at which the cumulative postseismic uplift will fully compensate the coseismic subsidence. The results show that large coseismic coastal subsidence on the southern Sanriku coast will be fully offset by the postseismic uplift within several decades. To the immediate north, the model underpredicts the postseismic uplift and possibly indicates unaccounted postseismic fault creep. Farther south, the postseismic uplift of the coast of the Kanto district has already exceeded the small amount of coseismic subsidence over the past six years, as predicted by the model. To prepare for future earthquakes, especially with respect to the coastal construction at fishery ports, it is important to construct a comprehensive rheological structure model based on geophysical observations including GNSS positioning.

Development of New Coastal Erosion Countermeasure Using Wave Energy Control Method

Kang, Y.K. and An, S.H., 2018. Development of New Coastal Erosion Countermeasure Using Wave Energy Control Method. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 1516–1520. Coconut Creek (Florida), ISSN 0749-0208.Coastal erosion has become a social issue around the world, including Korea. A Considerable number of coastal erosions have occurred along the East Sea in Korea, primarily caused by port and harbor developments. Countermeasures have generally utilized wave breaks with wide–low–crest submerged breakwater (so-called artificial reefs), which are coastal constructions emulating the wave absorbing effect of natural reefs with good wave–protection performance. However, these result in secondary damages such as scouring near openings and erosion towards the rear because of strong currents generated by wave setups. This study suggests a new countermeasure for coastal erosion by controlling wave energy differentiated by incident wave, i.e., wave direction control method (WDCM) to prevent the critical coastal erosion expected from a massive harbor expansion project planned along the east coast of Korea. The WDCM attempts to balance disparities in wave energy caused by harbor expansion to restrain imbalanced wave energies that result in imbalanced littoral drift. To accomplish this purpose, low crest structures are obliquely deployed at 250–300 m from the coastline to manipulate the wave energy by modulating incident wave direction. This new deployment method avoids excessive interference with the incident waves, and prevents resilience by leaving cross-shore sediment transport unhindered. In order to determine the effectiveness of the proposed WDCM, numerical computations were conducted evaluating its performance regarding coastal erosion prevention.

New service limit state criteria for reinforced concrete in chloride environments

Abstract In chloride environments, reinforcement stress limits, intended to control flexural cracking, are one of the most important requirements for service limit state (SLS) design. However, concrete damage at the steel-concrete interface between bending cracks, so called cover-controlled cracking, is always correlated to areas of severe steel reinforcement corrosion. Based on the assumption that cover-controlled cracking should be limited, a model has been developed to provide alternative reinforcement stress limits in marine exposure conditions such as concrete in sea water, including permanently submerged, spray zone and tidal/splash zone, as well as coastal constructions located within 1 km of the shoreline. In this paper, the new reinforcement stress limitation is compared to the Australian Standards AS3600 concrete building code and AS5100.5 concrete bridge code provisions. Analysis shows that the new model is very sensitive to the reinforcement percentage of the cross-section. As a result, the existing AS3600 and AS5100.5 code provisions are more conservative than the new limitation for lightly to normally reinforced concrete cross-section. In this case, crack width control governs the SLS design. However, for normally to heavily reinforced concrete cross-section, the new model provides more conservative results suggesting that cover-controlled cracking governs the SLS design.

Analisis Perencanaan Break Water Dalam Penanganan Sedimentasi Pantai Di Desa Botubarani

Botubarani Beach is a coastal tourist attraction that has activities that can stimulate economic growth for people who are on the coast. Research and identification of the handling of natural phenomena in the shoreline is needed to provide the right handling solution in order to avoid increasing the level of more severe damage. The purpose of this study is to analyze and plan the types and dimensions of the right coastal protection building at Botubarani Beach. Beach buildings are used to protect the coast against damage caused by wave and current attacks. Coastal buildings are classified into three groups according to their function, ie construction constructed on shore and parallel to the shoreline (revetment), constructed on a straight coastal and coastal (groin and jetty) constructions constructed offshore and approximately parallel to the coastline (breakwater). The results of data analysis and calculation found that the building that will be used to handle sedimentation in Botubarani Beach is a break water building with the type of building that is rubble mount. Plate water level elevation is 1,694 m and for selected tetrapod protected layer.