Bridge Station Research Articles

A GIS-based spatiotemporal study of the variability of water quality in the Dubai Creek, UAE

This paper presents the outcomes of a study on the water quality of Dubai Creek which aimed to assess its eutrophication status. Field water quality data from stations along the creek collected in 2012 and 2013 were used. Ordinary least squares (OLS) and spatial autocorrelation analyses were used as part of geographic information system (GIS)-based exploratory regression analysis to study the relationship between chlorophyll-a and nutrients, specifically total nitrogen and phosphate. Multiple logistic regression analysis was used to study the vulnerability of the creek to eutrophication. Results showed unique trends of spatiotemporal variability of chlorophyll-a and nutrients. OLS modeling showed high correlation between field and modeled chlorophyll-a values between Al Garhoud Bridge and Sanctuary stations, located about 2 km upstream and downstream of the Sewage Treatment Plant (STP) Outfall station. Furthermore, results showed the lower half of the creek was more vulnerable to eutrophication than the upper, which was believed to be due to the location of the STP station, poor flushing, shallow water depth, and irregular circulation patterns in the creek. Accordingly, this study recommends development of a mitigation plan in order to control the levels of nutrients in the creek.

The quadripartite vaults at London Bridge station

In this winning essay from the Institution of Structural Engineers' Engineering Architecture Prize 2013, Michelle Hicks explains how a professional training placement working on the redevelopment of London Bridge station sparked her interest in the station’s historic quadripartite vaults. The Engineering Architecture Prize is a biennial essay competition open to sixth-form students and Student and Graduate members of the Institution. In the 2013 competition, entrants were asked to write an essay on their favourite structure. Michelle was a winner in the Student and Graduate category. For more details, see: www.istructe.org/engineering-architecture-prize

Prediction of dissolved oxygen in River Calder by noise elimination time series using wavelet transform

Prediction of dissolved oxygen (DO) plays an important role in water resources especially in surface waters such as rivers. The oxygen affects a vast number of other water indicators. In this study, the artificial neural network (ANN) and a hybrid wavelet-ANN (WANN) models were considered to predict thirty minutes dissolved oxygen in the River Calder at the Methley Bridge Station was located in the UK. For the proposed WANN model, the discrete wavelet transform (DWT) was linked to the ANN model for DO prediction. To achieve this aim, the original time series of thirty minutes DO and temperature (T) were decomposed in several sub-time series by DWT, and these new sub-series were imposed to the ANN model. The results were compared with single ANN model. The comparisons were done by some of the widely used relevant physical statistic indices. The Nash–Sutcliffe coefficient values were 0.998 and 0.740 for the WANN and ANN models, respectively. The model computed values of DO by the WANN model were in close agreement with respective measured values in the river water. Elimination noise by DWT model during pre-processing data is one of the abilities of the WANN model to better prediction. Since the results indicate closer approximation of the peak DO values by the WANN model, this model could be used for the simulation of cumulative DO data prediction in thirty minutes ahead.

Assessing the potential of harvesting rainfall runoff using pans to meet Marigat's water demand: an application of WEAP21 model

Water resources are vital to basic livelihoods and economic growth. Marigat division in Baringo County, Kenya experiences water scarcity during the dry periods, a situation that is further aggravated by droughts and erratic rains. During the rainy seasons, a lot of water is lost as surface runoff, which can be harvested and stored in water reservoirs and used for domestic and livestock throughout the dry seasons. Water Evaluation and Planning (WEAP21) system model was used to determine whether the water to be harvested from rainfall runoff was able to meet the Marigat community's water demand. This was achieved by building creation of proposed new water pans scenario from the reference scenario. The results of the reference scenario were validated using observed river flows at Marigat Bridge station, and WEAP21 was also used to develop a water supply network. The results show that with the creation of proposed new water pans for harvesting surface runoff in areas facing water scarcity, the unmet domestic and livestock water demand is met up to 2020.

Spatial and Temporal Streamflow Trends in Northern Taiwan

Streamflow is an important factor in the study of water resource management, floods, and droughts. Dramatic climate change has created extreme rainfall distributions, making the study of streamflow trends and variability even more crucial. In this study, the long-term streamflow data and trends recorded at gauging stations in Northern Taiwan are analyzed using the Mann-Kendall test. The data used for trend analysis are the average annual streamflow, the average seasonal streamflow, and the high and low flows. The slope trend is calculated using the Theil-Sen estimator. Finally, change point analysis is conducted using the Mann-Whitney-Pettit test and the cumulative deviation test to gain further information about the change points and to understand the changes in streamflow before and after the change points. The average annual streamflow of the 12 gauging stations in the study area is analyzed using the Mann-Kendall test. The results show that of the 12 gauging stations, only the Ximen Bridge Station in the Lanyang River basin show a significant downward streamflow trend. Results of the monthly and seasonal average streamflow analysis show that in the spring, 72.2% of the gauging stations showed upward streamflow trends, most of which were located in the Tamsui River and the Touqian River basins. The high and low flow data analysis shows that the Ximen Bridge Station was the only gauging station to feature a significant downward streamflow trend for both high and low flows. This distribution pattern provides valuable information for regional hydrological studies and water management.

Identification of sound sources in soundscape using acoustic, psychoacoustic, and music parameters

This paper explores the possibility of automatic identification/classification of environmental sounds, by analyzing sound with a number of acoustic, psychoacoustic, and music parameters, including loudness, pitch, timbre, and rhythm. The sound recordings of single sound sources labeled in four categories, i.e., water, wind, birdsongs, and urban sounds including street music, mechanical sounds and traffic noise, are automatically identified with machine learning and mathematic models, including artificial neural networks and discriminant functions, based on the results of the psychoacoustic/music measures. The accuracies of the identification are above 90% for all the four categories. Moreover, based on these techniques, identification of construction noise sources from general urban background noise is explored, using the large construction project of London Bridge Station redevelopment as a case study site.

The Characteristics of Temperature Field in the Cup-Shaped Frozen Soil Walls for Horizontal Reinforcement of Shield Tunneling

The variation of temperature distribution in the cup-shaped frozen soil wall is real-timely monitored during the whole process of the horizontal freezing reinforcement project in Yixian Bridge Station, the first phase in Line 2 of Nanjing Subway. The development characteristic of the temperature field at different depth is analyzed, and the formation time and developing speed of the frozen soil wall is further calculated. The monitoring results show that, the average growth rate of the temperature field at the interface between the frozen soil and the underground continuous wall is significantly faster than the one in the cylinder reinforced area.There is significant differences in the average growth rate of temperature field in the frozen soil wall at different area of the reinforcing plates.

Precipitation Characteristics and Trend in the Hsiao-Ching River Basin of Jinan City during the Past 50 Years

Monthly precipitation data from Huangtai Bridge Station were used to study seasonal and annual precipitation characteristics and trend. The covered time-period is from 1956 to 2007. Different methods including linear regression, 5-year moving average, anomalies in decadal scale and the Mann-Kendall test were applied in the study. Nearly two-thirds of the total rainfall amount is concentrated in summer, with autumn and spring months to follow, and only about 3% in winter. An increasing trend in spring months is found. It starts in 1978, becomes significant after 2002, and probably continues into the future. A decreasing trend is recorded in winter and begins in 1980. No significant trend is found in summer, autumn and yearly precipitation. The same fluctuations are observed between summer and annual precipitation indicating the dominant influence of the summer season.

Flood Frequency Analysis by Probability and Stochastic Method for Padma River, Bangladesh

In most of the practical cases, Flood frequency analysis is carried out due to the safe design of hydraulic structures. This paper represents the result of Flood frequency analysis for Padma River at Hardinge Bridge station. The Flood frequencies of 2, 5, 10, 20, 50, 100, 200, 300, 400, 500 and 1000 year Floods was analyzed by probability methods develop by Gumbel, Powell, Ven Te chow as well as Stochastic methods. The analysis was carried out for the duration of 13 years ranges from 2000 to 2012. This research aims to compare four methods of Flood frequency analysis to find the optimum method in terms of safe design of hydraulic structures. From the comparison between four methods the Gumbel and stochastic method may be recommended for designing and locating hydraulic structures.

A comparative study of water quality in the peripheral rivers of Dhaka city

This study examined the present status of surface water pollution and a comparison of the quality of water in different seasons at different locations of the major river, around the Dhaka City. Field investigation was started from January, 2011 and sample collection was conducted six times at an interval of two months up to December, 2011. The observed value of different water quality parameters such as pH, DO, BOD, COD and TDS were compared with the standards recommended by Department of Environment (DoE), Bangladesh and United States Environmental Protection Agency (USEPA). A simple ANOVA and Box-Cox study was also conducted to detect the variation of water quality in the major rivers. The study revealed that during the dry season especially in the months of December to February (winter), the higher values of parameters with respect to the acceptable limits of DoE and USEPA standard indicate the pollution of the river water samples and make the water unsuitable for various uses. Comparisons of abundance values demonstrated high significant difference (p < 0.05) between the mean concentrations of respective parameters except pH at different locations in water source types. Water quality in Hagaribagh of Buriganga river and the Tongi railway bridge stations of Tongi khal was significantly more common polluted area than any other sites of selected water sources as the largest amounts of toxic chemicals are released here by the tannery and dyeing industries without any treatment.
 Dhaka Univ. J. Biol. Sci. 22(2): 145-154, 2013 (July)

Wavelet kernel support vector machines forecasting techniques: Case study on water-level predictions during typhoons

This paper presents a novel algorithm, wavelet support vector machines (wavelet SVMs), for forecasting the hourly water levels at gauging stations. These stations are under strong precipitations and affected by tidal effects during typhoons. An admissible wavelet kernel SVMs implements the combination of wavelet technique with SVMs. The wavelet is a multi-dimension wavelet function that can approximate arbitrary nonlinear functions. Using both classical Gaussian and wavelet SVMs, this study constructed the channel level models for forecasting downstream water levels. The developed models were then applied to the Tanshui River Basin in Taiwan and the water levels at various lag times predicted by both Gaussian and wavelet SVMs were compared. Analysis results showed that the optimal situation occurred at the lag time of 3 h with relative mean square errors (RMSEs) of 0.205 and 0.160 m obtained by the Gaussian and wavelet SVMs, respectively at Taipei Bridge station and RMSEs of 0.154 and 0.092 m at Tudigong station, respectively. As seen in the comparison, wavelet SVMs yielded more accurate predictions than Gaussian SVMs and offered a practical solution to the problem of water-level predictions during typhoon attacks.

Study on the Deformation Characteristics of Supporting System of Deep Foundation Pit in Subway Station Construction

Taking Jiyu Bridge Station of Wuhan Metro Project as example, the deformation characteristics of supporting system of deep foundation pit was studied by means of numerical simulation (FLAC3D) in consideration of construction order. The deformation fields of different excavation depths of diaphram wall were obtained and analyzed in order to gain the maximum horizontal displacement value and settlement value. By comparison with the monitoring data, the simulation results can basically reflect the deformation characteristics. Moreover, the simulation results showed that the application of diaphram wall was feasible for foundation pit supporting in Jiyu Bridge Station, meanwhile, the results can be based on to guide the construction.

The Model Test Study on Frost Heaving and Melting Sedimentation of Subway Tunnel Construction with Manual Level Freezing Method

With the aim of solving technical problems existing in the rehabilitation construction of butt-joint sect works with manual level freezing undermining method, under Huangpu River of Shanghai Underground Subway 4# between Nanpu Bridge station and Pudong South Road Station, Group of large-scaled physical model tests had been performed adopting the Manual Level Freezing Undermining Method (MLFM in brief) in constructing double track tunnel. Firstly, the model design and test system integration were made; afterward, through model tests, the paper systematically studied the laws of stratum frost heaving, melting sedimentation rule and stratum displacement variations etc, during the undermining construction of tunnel being frozen. The results indicate: the Maximum displacement of frost heaving measured at the top of freezing wall during up line freezing process was 1.36mm, which is equivalent to actual work quantity of 29.92mm; the strata melting sedimentation displacement during forceful thawing is 54% less than what was during natural thawing, which illuminates that adopting forcing thawing can reduce melting sedimentation of soil blocks.

도시유역의 Fwl-D-F 곡선 산정 및 활용에 관한 연구

Abstract There have been performed many researched for flood magnitude analysis, for example, the Flood- Duration-Frequency relations in the west. Because flood water stage data are more available rather than flood amount data at flood gauge stations of Korea, this study developed Flood water level-Duration-Frequency (Fwl-D-F) curves using rainfall Intensity-Duration-Frequency(I-D-F) curves for the quantitative flood risk assessment in urban watersheds. Fwl-D-F curve is made from water level data for 18 years at Joongrayng bridge station of Joongrayng River basin in Han River drainage area. Fwl-D-F curve can estimate the occurrence frequency for a certain flood elevation, which can be used for urban flood forecasting. It is expected that the flood elevation can be estimated from the forecasted rainfall data using both Fwl-D-F and I-D-F curves. Key Words : Flood water level, I-D-F curve, Fwl-D-F curve, Flood forecasting 본 연구는 국토해양부가 출연하고 한국건설교통기술평가원에서 위탁시행한 건설기술혁신사업 (08기술혁신F01)에 의한 차세대홍수방어기술개발연구단의 연구비 지원에 의해 수행되었습니다.

소양호 원생생물과 동물플랑크톤간의 먹이망 동태

To clarify the role of protozoans in the microbial food web of Lake Soyang ecosystem, the clearance rate(CR) and carbon flux(C-flux) of zooplankton assemblage were investigated. Zooplankton were divided into two size groups(microzooplankton (MICZ): 60～200 μm, macrozooplankton (MACZ): >200μm). Conducted were both quantitative trophic linkage between protist and zooplankton community structure at two sites with different trophic status from April to December, 2006. In carbon flux from protist to zooplankton, and annual range of food contribution to microzooplankton were between 0.0003 in June and 0.0087 μgC․L—1․h—1 in September, whereas they contributed to macrozooplankton between 0.0423 in December and 1.0823 μgC․L—1․h—1 in September, respectively. In highlight of sampling time and station, carbon fluxes of protist to macrozooplankton was higher than microzooplankton in both two stations, the front of Dan and Yanggu bridge station. The magnitude of carbon flux between protist and zooplankton in the front of Dam station was relatively high in spring and summer, while that in Yanggu bridge was high in autumn and winter, respectively. Comparing the carbon flux between phytoplankton and protist to their same predator, micro- and macrozooplankton, four times(April, May, October and November) of total seven samplings carried out in the front of Dam station and four times(April, May, October and November) of total eight samplings were relatively high in protist. Therefore, these results indicated that protist was important prey of zooplankton(micro- and macrozooplankton) in Soyang lake.

Parameter estimation of an ARMA model for river flow forecasting using goal programming

River flow forecasting constitutes one of the most important applications in hydrology. Several methods have been developed for this purpose and one of the most famous techniques is the Auto regressive moving average (ARMA) model. In the research reported here, the goal was to minimize the error for a specific season of the year as well as for the complete series. Goal programming (GP) was used to estimate the ARMA model parameters. Shaloo Bridge station on the Karun River with 68 years of observed stream flow data was selected to evaluate the performance of the proposed method. The results when compared with the usual method of maximum likelihood estimation were favorable with respect to the new proposed algorithm.

Study on intelligent method of prediction by small samples for ground settlement in shield tunnelling

The shield tunnelling in shallow soft ground would bring a risk of damage to the structures or pipelines in dense populated urban areas. The prediction of the ground settlement could reduce the risk and maintain normal tunnelling by effectively controlling parameters in the construction. The criteria need to be studied for all kinds of buildings and underground pipelines, one of that is normally limited to be from -3 to 1 cm in the ground settlement in Shanghai. The neural networks have the strong ability of non-linear mapping, which make it possible to establish a model directly from the observations. It is also convenient in practice to consider synthetic effects of both soil indexes and construction parameters. For the ground settlement could be regarded as a synthetic parameter reflecting the construction process and strata information, the inputs and outputs could only simplify to be sequential settlement. The inputs are detailed as S(N-2), S(N-1) and S(N), those are the observations of settlement in two days before, one day before and current day. The output parameter is only the settlement in the next day (S(N+1)). Currently, the structure design of existing neural networks for predicting settlement has not been solved well. In this paper, an intelligent evolutionary neural network (ENN) is proposed for predicting the ground settlement. The mechanism allows all aspects of the network structure, including the number of hidden nodes (N1 and N2) and learning parameters, to be evolved through genetic algorithms. Meanwhile, the pre-processing method of samples is improved. After the ENN is obtained, the ground settlement in the next advance step could be predicted. The observations are compared to the predictions, and standard deviation d is got. If the d is greater than a preset limit in processing, the primary sampling set is refined and a new ENN is achieved then. Otherwise, the prediction is continued while d is in limits. The ability to learn from relatively few training examples is important because training examples are often hard to find or expensive to collect. Thus, it is important for a learning system to be able to extract useful generalizations from a small set of examples. The ENN model also showed good ability in prediction trained by small samples. A primary use is made to the cross-over tunnel in down line zone near Nanpu Bridge Station of the Second phase of Shanghai Metro Pearl Line. The testing results showed a good predicting performance by using actual collected data from the project, with maximal average error 2.08% for training samples and -5.27% for testing samples. The hogging or sagging curves in the longitudinal direction are also drawn for analysis. The method would be especially valuable to the tunnelling by DOT (double-O-tunnelling) method under condition of large span and thin cover of earth, which may result in greater impacts to the structures or pipelines nearby. (A) Reprinted with permission from Elsevier. For the covering abstract see ITRD E124500.

The refurbishment of Putney Railway Bridge

Putney Railway Bridge is one of seven railway bridges crossing the River Thames in the Greater London Area and is one of only four providing a cross-London route. This paper covers the history of the bridge, the problems that developed in the bridge, the solutions developed to resolve those problems and the refurbishment works to the bridge. The bridge was built in 1888 and is an eight-span, half through, ‘four system’ lattice truss bridge carried on cast-iron caisson piers. It carries London Underground Limited's (LUL) District Line approximately seven metres above the Thames just south of Putney Bridge Station. Although intended to have excess capacity, war damage, corrosion, design errors and finally a major ship impact caused the line over the bridge to be closed temporarily. The repair and strengthening works incorporated the most up to date analysis techniques and a Quantified Risk Assessment. They addressed fundamental design omissions as well as deterioration and damage. The works were planned and executed to cause the minimum disruption to rail traffic and included the construction of mass sprung fenders, repair of a fractured caisson, replacement of the bearings, and extensive strengthening including the addition of cross girders.

The refurbishment of Putney Railway Bridge

Putney Railway Bridge is one of seven railway bridges crossing the River Thames in the Greater London Area and is one of only four providing a cross-London route. This paper covers the history of the bridge, the problems that developed in the bridge, the solutions developed to resolve those problems and the refurbishment works to the bridge. The bridge was built in 1888 and is an eight-span, half through, ‘four system’ lattice truss bridge carried on cast-iron caisson piers. It carries London Underground Limited's (LUL) District Line approximately seven metres above the Thames just south of Putney Bridge Station. Although intended to have excess capacity, war damage, corrosion, design errors and finally a major ship impact caused the line over the bridge to be closed temporarily. The repair and strengthening works incorporated the most up to date analysis techniques and a Quantified Risk Assessment. They addressed fundamental design omissions as well as deterioration and damage. The works were planned and executed to cause the minimum disruption to rail traffic and included the construction of mass sprung fenders, repair of a fractured caisson, replacement of the bearings, and extensive strengthening including the addition of cross girders.

Impact of climate change on water resources in southern Taiwan

This study investigates the impact of climate change on water resources in southern Taiwan. The upstream catchment of Shin-Fa Bridge station in the Kao-Pen Creek basin was the study area chosen herein. The historical trends of meteorological variables, such as mean daily temperature, mean daily precipitation on wet days, monthly wet days, and the transition probabilities of daily precipitation occurrence in each month, at the Kao-Hsiung meteorological station, near the catchments were detected using a non-parametric statistical test. The trends of these meteorological variables were then employed to generate runoff in future climatic conditions using a continuous rainfall–runoff model. The analytical results indicate that the transition probabilities of daily precipitation occurrence significantly influence precipitation generation, and generated runoff for future climatic conditions in southern Taiwan was found to rise during the wet season and decline during the dry season.