This paper analyzes the impact of extending a trolleybus line on urban public transport performance, using an integrated methodological framework that combines gravity-based accessibility modeling with before/after analysis of generalized travel cost. The proposed approach enables the simultaneous evaluation of both territorial and operational effects generated by infrastructure interventions.
This paper analyses the seismic response of four continuous precast prestressed concrete girder bridges, with total lengths ranging from 80 m to 200 m, representative of Romanian road infrastructure. The structures were initially designed with neoprene elastomeric bearings, in compliance with the Romanian code for seismic design P100-1/2006 [1]. The seismic performance of the bridges was assessed through nonlinear static (Pushover) analyses using the FEMA 440 [2] equivalent linearization procedure, for five seismic hazard levels (return periods of 100, 225, 475, 970 and 2475 years). Results highlighted a significant vulnerability of the conventional neoprene system at moderate seismic intensities, with displacement demands exceeding the nominal bearing capacity from a return period of 225 years onwards. As an alternative, a pot bearing system was investigated, allowing larger displacements and providing more controlled seismic behavior. The study demonstrates that pot bearings reduce spectral accelerations by up to 54%, but increase the behavior factors, while maintaining bearing integrity at higher seismic hazard levels.
This paper evaluates the technical efficiency of Romanian inland ports along the Danube River over the period 2020–2024 using a Stochastic Frontier Analysis (SFA) framework. A panel data model with time-invariant inefficiency is estimated based on a Cobb–Douglas production function, where total cargo throughput is the output and quay length, number of quay cranes, and storage area are specified as inputs. The analysis covers 16 ports administered under the Upper and Lower Danube authorities. Results indicate a low average technical efficiency and substantial heterogeneity across ports. Lower Danube ports generally outperform Upper Danube ports, although the difference is not statistically significant. The estimated production elasticities reveal decreasing returns to scale, suggesting that most ports operate beyond their optimal size. Cargo diversification shows no statistically significant association with technical efficiency. The findings challenge the assumption that larger or more diversified ports are inherently more efficient and support a shift toward efficiency-oriented port development policies. The results should be interpreted considering the relatively short five-year available panel, which captures recent operational conditions, including the market disruptions associated with the Russian invasion of Ukraine.
Road safety is a major global concern nowadays. Within the road infrastructure, bridge sectors are the most dangerous in terms of the incidence and severity of accidents. Engineering practice is to reduce their gravity by installing safety barriers with a very high level of protection, type H4b. There are however situations in which these protection systems actually and up reducing the level of safety for road users by limiting visibility.
In the construction of large-span tunnels, the degree of joint development within the surrounding rock demonstrates heightened sensitivity and exerts a critical influence on the stability of the rock mass. To gain deeper insight into the influence of non-persistent joints on the stability of surrounding rock in large-span tunnels, a reliable discrete element numerical model was established based on the referenced tunnel project. By adopting the area of shear slip zones as a stability criterion, the safety factor of the surrounding rock was evaluated, and the effects of joint trace length, rock bridge ratio, and relative rock bridge dip angle on surrounding rock stability were further analysed. The results indicate that the safety factor first increases and then decreases with increasing joint trace length. Variations in the rock bridge ratio lead to changes in crack propagation modes: when the rock bridge length is smaller than the joint spacing, the stability of the surrounding rock is only slightly affected. The influence of the relative rock bridge dip angle on tunnel stability is comparatively minor. These findings may provide valuable reference for the design and construction of large-span tunnels.
