Civil Engineering

Several bridge crossings proposed for the Red River Floodway expansion project were recently constructed using vertical sand drains to accelerate excess pore-water pressure dissipation and settlement caused by embankment fill loading. With limited local data regarding the performance of sand drains, the calibrated model presented here addresses the need to optimize the design of sand drain configurations, maximize cost savings, and minimize construction delays for future structures. This study presents a coupled finite element embankment consolidation model calibrated against measured pore-water pressure and settlement data from the Salter Street Bridge embankment fill construction, which used vertical sand drains to dissipate excess pore-water pressures. A hydraulic conductivity modification procedure was used to simulate the axisymmetric flow conditions with a plane-strain model neglecting well resistance but incorporating the effects of a smear zone. A sensitivity analysis was pe...

In 1999, after a period of extensive rainfall, two shallow slope failures developed in the right-of-way of Provincial Road 259 near Virden, Manitoba. The rainfall caused dissipation of soil suction in the near-surface soil, thereby reducing shear resistance and triggering failure. A research project was initiated between the Geotechnical Group at the University of Manitoba and the Manitoba Department of Highways and Transportation to assess the mechanism of failure. The project included a field investigation program, laboratory testing program, and advanced numerical modeling to identify the cause of failure. The results demonstrate that the rainfall resulted in dissipation of the suction in the soil slope, resulting in a reduction in the soil shear strength that triggered shallow failures. The dissipation of the soil suction has been modeled using a time-dependent seepage model that accounts for the flux boundary condition that existed at the ground surface.Key words: slope stabili...

An approach to developing and using Bayesian networks to model watershed management decisions is presented with a case study application to phosphorus management in the East Canyon watershed in Northern Utah, USA. The Bayesian network analysis includes a graphical model of the key variables in the system and conditional and marginal probability distributions derived from a variety of data and information sources. The resulting model is used to 1) estimate the probability of meeting legal water quality requirements for phosphorus in East Canyon Creek under several management scenarios and 2) estimate the probability of increased recreational use of East Canyon Reservoir and subsequent revenue under these scenarios.

Federal funding for intercity bus programs is available to states under Section 5311 (f) of the Federal Transit Act. The act requires that 15% of all federal funding for public transportation in nonurbanized areas be expended for intercity bus transportation, unless the state governor certifies that the intercity bus service needs are adequately met. A demand-supply-deficiency analysis was undertaken to assess whether intercity bus needs are being met in Illinois. The analysis indicates that some larger city-to-city routes could use additional service. In addition, many smaller urban places have no access to rail or bus service, especially in southern Illinois, and many of these have no Section 5311(f) recipients. Without state support for intercity bus programs, it is unlikely that people in these places will have access to such service in the foreseeable future.

A methodology is developed to more accurately estimate the static response of bridges due to moving vehicles. The method can also be used to predict dynamic responses induced by moving vehicles using weigh-in-motion (WIM) techniques. Historically, WIM is a well-developed technology used in highway research, since it has the advantage of allowing for the stealthy automatic collection of weight data for heavy trucks. However, the lack of accuracy in determining the dynamic effect in bridges has limited the potential for its use in estimating the fatigue life of bridge structures and their components. The method developed herein amends the current WIM procedures by filtering the dynamic responses accurately using the Fast Fourier Transform (FFT). Example applications of the proposed method are shown by using computer-generated data. The method is fast and improves the predicted truck weight up to 5% of the actual weight, as compared to errors up to 10% using the current WIM methods.Key...

The continuous expansion of the Water Distribution Network (WDN) makes its design a dynamic process performed within many planning horizons. An appropriate planning horizon is important to save costs and avoid over-design. Typically, a master plan is practiced around every 20 years. The complexity of WDN and computational demands have prevented a full network study of the impact of planning horizons on system cost and efficiency. In this paper, a dynamic network model was employed to simulate the growth of WDN under different growth patterns (exponential and linear) and planning horizons to explore the optimum planning horizon under different interest rates. It is found that the choice of the optimum (i.e. least costly) planning horizon is sensitive to the interest rate. For both growth patterns, a shorter planning horizon is favored with higher annual interest rates while a longer planning horizon is favored with lower rates. With the same interest rate, exponential growth pattern ...

ABSTRACTThis article presents a climatology of total cloud cover (TCC) in the area of the three inland Eurasian seas (Black, Caspian, and Aral Sea). Analyses are performed on the basis of 20 years of data (1991–2010), collected from almost 200 ground stations. Average TCC is 49%, with broad spatial and seasonal variability: minimum TCC values are found in summer and to the southeast, whereas maximum values correspond to winter and to the northwest. For the whole area, linear trend analyses show that TCC did not vary during the study period. We only detected a statistically significant positive trend (+1.2% decade−1) in autumn. We obtained different results for the regions delimited by means of a principal component analysis: a clear decrease, both for the annual, spring, and summer series, was detected for the south of Black Sea, while increasing TCC was found for the annual, autumn, and winter series in the north Caucasus and the west and north of Black Sea. We also analysed the TC...

This paper presents from first principles methods of evaluating the seismic performance of a building using the method of inertial forces, method of maximum energy and method of maximum displacement. The introduction of these methods forms the main thrust of the paper. Importantly, the building can be deemed safe should this be indicated by any one of the three methods none of which requires the natural period of the building nor structural response factors to be estimated. Whilst these methods are verysimple and consume little time to apply, the accuracies of the results are comparable with those from response spectrum methods. It is noted that the fundamental basis of each of these methods is very consistent with the new response spectrum model stipulated by the new Australian standard for seismic actions. A succinct and insightful account of the development of the seismic hazard model for Australia is also provided followed by a commentary on the use of dynamic analysis methods i...

This paper indicates new microzonation maps of Perth, Western Australia, utilising microtremor spectral ratios. This metropolitan area has been developing in recent times on Perth Basin which is one of the most active seismic zones in the country. The authors carried out simultaneous measurings of microtremors over most of metropolitan Perth, using a 3 km grid as a basis and hard rock reference site throughout. They calculated spectral ratios of microtremors at deposit site to rock reference site and plotted and contoured on maps for 6 frequency bands from 0.2 to 5.0 Hz. Spectral ratio contours appeared to correlate well with various geological subsurface contours. They also showed that previously estimated earthquake risk estimates underestimated ground motions by up to a factor of two.