Piles have been used as a deep foundation for both inland and offshore structures. After installation, pile capacity may increase with time. This time dependent capacity increase is known as setup, and was first mentioned in the literature in 1900 by Wendel. When accounted for accurately during the design stages, the integration of pile setup can lead to more cost-effective pile design as it will reduce pile length, pile section, and size of driving equipment. In this paper, Both Multiple Linear Regression (MLR) and Artificial Neural Networks (ANN) models were developed for predicting pile setup for three pile types (pipe, concrete, and H-pile) using 169 dynamic load tests obtained from the published literature and the authors’ files. In addition, the paper discusses the choice of variables that were examined to obtain the optimum model. Furthermore, the paper compares the predictions obtained by the developed MLR and the ANN models with those given by four traditional empirical formulae. It is concluded that the ANN model outperforms both the MLR model and the examined empirical formulae in predicting the measured pile setup. Finally, static load test data was used to further verify the developed models. It’s noted that the optimal ANN model overestimated pile capacity by 17% to 21% for the H-piles, and underestimated pile capacity by 12% to 17% for the pipe piles.
15 April 2021 in Innovative Infrastructure Solutions
Purpose: The purpose of this paper is to develop new predictive models using gene expression programming in order to estimate the compressive strength of green concrete, as accurate models that can predict the compressive strength of green concrete are still lacking. Design/methodology/approach: To estimate the compressive strength of plain concrete, fly ash concrete, silica fume concrete and concrete with silica fume and fly ash, four predictive GEP models are developed. The GEP models are developed using a large and reliable database that is collected from the literature. The GEP models are validated using the collected experimental database. Findings: The R2 is used to statistically evaluate the performance of the GEP models wherein the R2 values for the GEP models including all data are 85, 95, 80 and 95.3 percent for the models that predict the compressive strength of plain concrete, fly ash concrete, silica fume concrete and concrete with silica fume and fly ash, respectively. Originality/value: The GEP models have high R2 values and low RMSE and MAE, which indicates that they are capable of predicting the compressive strength of green concrete with a reasonable accuracy.
1 January 2020 in Journal of Public Transportation
Being able to provide high-quality, metro-like transit service at a fraction of the cost of other options, bus rapid transit (BRT) has been viewed as one of the most cost-effective public mass transport systems suitable for urban areas. Considering significant amounts of greenhouse gas (GHG) and air pollutant emissions are attributed to the transport sector, deploying low carbon buses for BRT systems should be of high priority. With a view to promoting low carbon buses instead of diesel buses for a BRT system currently being planned in Amman, Jordan, this paper evaluates several low carbon bus options – hybrid, plug-in hybrid, opportunity charging, trolleybus, and battery electric bus options – against the baseline case of diesel buses. While low carbon buses reduce GHG and air pollutant emissions often considerably, they usually require higher upfront capital costs and additional infrastructure investments. On the other hand, they tend to incur lower energy and maintenance costs and have a longer lifetime particularly for battery electric buses. All these advantages and disadvantages are included in the assessment of low carbon bus options relative to diesel buses. For the trunk routes of the Amman BRT, the analysis shows that the opportunity charging bus can be the most appealing option having a positive internal rate of return (IRR) for the incremental investment costs. For the feeder routes, both low carbon bus options considered, hybrid and battery electric, do not result in a positive IRR. Nevertheless, the battery electric bus is found to be a comparatively better option than the hybrid bus. In consideration of variability in several parameters used in the analysis such as capital expenditures, electricity price, and diesel price, a sensitivity analysis is conducted for both trunk and feeder routes. The results show that IRR could increase favorably under certain conditions.
The use of roundabouts is well recognized for sustaining an efficient and safe intersection. However, the safety results may vary based on the prevailing conditions. Therefore, this study assesses the safety performance of roundabouts in Jordan. This study developed a predictive model by collecting and analyzing all accident records of 12 major urban roundabouts in the country over 3 years. For developing the model, this study employed an accident frequency analysis. The model calculated the rate of accidents and incorporated the geometric and operational characteristics of roundabouts. This was followed by ranking the safety performance of the roundabouts. It was concluded that driver behavior of violating the traffic rules, lack of clear lane markings in the circulating area and inadequate signage at the roundabouts entries are the main causes of roundabout accidents. The research recommends including the developed predictive model in future traffic control and planning studies, for identifying hazardous locations, or for prioritizing roundabout improvements based on safety performance.