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Abstract

This study aims to find the potential of Bus Rapid Transit (BRT) to attract the vehicle owners from their personal vehicles i.e., motorcars and motorcycles. Stated preference survey (questionnaires) and interviews were conducted at BRT (Metro Bus) Stations for the prediction of the individuals shifting from their private vehicles to BRT. Questions were designed critically as per the requirements of the research related to numerous aspects of BRT use i.e., vehicle ownership of the travelers, driving license holder, demographic characteristics, choice to use BRT if the fare increases, trip purpose and their prior mode of transportation for the same trip. A total of 374 responses, as per the population of the study area (Islamabad-Rawalpindi, Pakistan), were collected. The Multinomial Logistic Regression (MNL) model has been employed for four categories of vehicle ownerships i.e., “Car owners using BRT”, “Bike owners using BRT”, “Both Car and Bike owners using BRT” and the last one which has been taken as reference category is “BRT users with no vehicle ownership”. The analysis indicated that BRT has attracted considerably private vehicle users specially the bike owners. Some socio-economic factors like income and residence location (accessibility) additionally have a major effect on the selection of BRT. In addition, it has been observed that fare increase can alter the mode choice of the BRT users and they will again prefer their own vehicles. The Travel choice model developed in the study can be very useful for policy makers and transport planners to enhance the BRT service and attraction, to mitigate traffic congestion and car ownership.

Abstract

The purpose of the current paper is to raise awareness on the behaviour of rectangular reinforced concrete columns with disproportionate cross-section dimensions subjected to compression and biaxial bending, considering the fact that in the current structural design process, the design of columns is usually done with respect to each of the two principal directions without considering their combined effect.

The paper is based on a case study regarding a building that is currently in the design phase, in which to obtain a correct seismic behaviour, rectangular columns with disproportionate cross-section dimensions were used.

The design of both the building and the columns follows the Romanian seismic design codes (“P100-1/2013 - Seismic design code - Part 1 - Design provisions for buildings” and “SR-EN 1998/2004 - Design of structures for earthquake resistance”).

Results were compared and conclusions were drawn based on the interaction curves and interaction surfaces computed with expressions from specialized literature and sectional analysis software.

Abstract

The study provided economic justification for private sector investment in developing, revitalizing and making operable, the rail-freight-corridors between hub-seaports and inland container depots in Nigeria. It estimated the operator-benefits and profitability potentials of investment in each of the ten rail-freight-corridors consisting of existing but inoperable and proposed rail routes from the major seaports to the Inland container depots in different geopolitical regions of Nigeria. Secondary data on the import and export (cargo generation) capacities of each of the ICD regions to and from the respectively connected hub-seaport were obtained from the Nigerian ports authority statistical report covering a period of two years (2018 – 2019) based upon which the annual expected revenue earnings of the operators were estimated. The cost of investment was also obtained. Benefit-Cost-Ratio (BCR) and Net Present Value (NPV) were used to estimate the operator-benefits and profitability potentials of each rail route. It was found that six of the rail routes have BCR > 1; and NPV>0; implying higher operator-benefits over costs within the period while four of the rail-routes have BCR <1; and NPV <0; implying higher operator-costs over benefits.

Abstract

The current paper studies the effect of superior eigen-modes on the seismic response for a series of reinforced concrete structures having eigen-periods near code control periods. Although the structural design is based on Romanian seismic design codes (“P100-1/2013 - Seismic design code - Part 1 - Design provisions for buildings” and “SR-EN 1998/2004 - Design of structures for earthquake resistance”), it carries some importance for other countries with similar seismic design spectra.

A total of twenty-four models for structures were considered by varying their location (through control period values), three-dimensional regularity, overall dimensions and height regime.

Results were compared and conclusions were drawn based on percentage values of relative displacements (storey drifts) and base shear forces.

Abstract

Study of feasible usage of waste plastic in addition with Nitrile butadiene rubber to enhance the engineering and rheological properties of bitumen binder. Rheological properties impact the performance and service life of bitumen greatly. Different percentages of Nitrile butadiene rubber were introduced as an additive in base bitumen binder along with Low density polyethylene. Nanoclay was used as compatibility agent. Waste plastic percentage was restricted to 3% where as NBR was used by 14 % by weight of bitumen. The nano-composite yielded softening value increased by 34% and recovery percentage was improved by 7.3 %.

Abstract

The importance of mastering the temperatures of laying and compacting the bituminous layers is addressed by a multitude of researches in the field, but the treatment of their control possibilities throughout the work surface is less addressed. Checking the temperatures through classical methods (usually point measurements with a manual thermometer or on the direction of the thermometer attached to the beam of the spreading-finishing machine) can outline an image of the working temperatures, but cannot certify that the entire surface of the layer is at the same temperature.

This article presents a new method for monitoring bituminous layers during execution, on an experimental road sector, with the help of a UAV (UAV - Unmanned Aerial Vehicle), equipped with two image capture cameras (for the visible area and for the infrared field). Following the qualitative analysis of the thermal images, information is obtained regarding the place where there are anomalies of the temperature uniformity, on the surface of the freshly laid bituminous layer.

Abstract

A characteristic feature of bridges made using cantilever concreting technology is their excessive deflections, which are a result of rheological processes in concrete and prestressing steel. These deflections can be caused by the destruction of the material, e.g. concrete cracking, as well as the changing of the static scheme of the bridge structure, such as the subsidence of supports. The final result of a structure’s operation is changes in its grade line, which in this paper are considered as the deflection line of a bridge’s span.

The purpose of the paper is to determine the participation of a structure’s rotation over supports in the deformation of the span with the largest length. The authors proposed an algorithm for determining the deflection function and rotation angles, which were obtained on the basis of changes in the curvature of the beam. It is characterised by an accurate mapping of the rheological processes that occur in the bridge, which is calculated on the basis of the changes of the grade line obtained from geodetic measurements on site.

The paper proposes a general geometric indicator of the box cross-section cantilever, which is calculated for the construction phase, and a different indicator for the operation phase. They can be used for comparative analyses of various bridges. The analysis of deflections in cantilever bridges during the operation phase of their longest spans indicates that there is a significant influence of the angles of rotation over the supports. In the paper, such a group of bridges is qualified as unstable, in which the static scheme changes from a determinate cantilever state (the construction phase) into a multi-span system with different span lengths (the operation phase).

Abstract

The paper presents aspects of the design and execution of the Turdas tunnel located on the local variant (route), on the Coşlariu - Simeria section, from the rehabilitation project of Brasov – Simeria railway line, component part of Pan European Railway Corridor IV, for train circulation with maximum speed of 160km/h. The tunnel crosses through alluvial deposits with silt and clay with locally sand layers at the upper part, sand and gravel with water in the middle part and marly silty clay and neogenic marl, with swelling phenomena, at the lower part. The overburden is between 2.00m and 13.00m. The initial project provided execution in underground, on 510.00m in the central area and from surface at both ends, 225.00m at the entrance and 45.00m at the exit. The new optimized project, based on new geological and geotechnical studies, proposed an execution from surface for the entire length of the tunnel. To establish the optimal solution two methods of surface execution and structural solutions were analyzed comparatively: “Cut and Cover” and “Cover and Cut”. The adopted method was “Cut and Cover”, with a structural solution composed of a temporary retaining structure – diaphragm walls with a special internal lining. This has been divided in six sections with different behavioral types, taking into account the ground configuration in longitudinal profile and the geological and geotechnical data. The technological execution phases are presented in detail. To investigate the behavior of this type of structure under soil and swelling actions, three-dimensional finite element analyses were carried out, taking into account the execution phases for each cross section. A monitoring system was provided to verify the stresses in the temporary retaining structure and the internal lining and also to calibrate future calculations.

Abstract

In this paper some aspects regarding the dynamic behavior of footbridge structures under traffic actions correlated with the people’s comfort are presented. The comfort criterion during footbridge passing depends of the frequencies and accelerations of the structure which must be situated between certain limits. If the frequencies and accelerations of the structure are in the critical domains, some measures to modify them must be taken.