The network arch bridge (NAB) is a new structural form of arch bridge that was devised 60 years ago by the Norwegian engineer Per Tveit, who is now prof. dr. docent emeritus at the University of Agder, Norway. The network arch is a tied-arch (also known as a bowstring-arch) bridge that combines the benefits of tied-arch bridges and trusses in a single system. While in a classical tied arch, the hangers are vertical, in a network arch, the suspension of the deck to the arch is ensured through a network of inclined hangers that intersect each other at least twice. Thus, the core of the NAB is the hanger arrangement that minimizes the bending moment in the arch to very small values, leading to compression in the arch. Compression with only small bending leads to very slender cross-sections for the elements of the bridge, and deep reductions in terms of materials used and economic and environmental costs. This paper reviews the research into the structural form proposed by Per Tveit and extended by researchers and engineers worldwide. The research methodology included bibliometric literature research, obtained by interrogating the ISI Web of Science (WoS) database and the cited references from the articles on WoS. While the first structural form of a network arch is still in use today and it has proven to be a good idea for spans around 100–120 m, engineers worldwide devised new bridge cross-sections. A brief view of the types of bridge cross-section in use today is given, with details about the bridges chosen as representative. Using analysis of Prof. Tveit’s map, Structurae database and literature review, a database of the network arches around the world was created, emphasizing the development of network arches from the perspectives of continental distribution, opening year, number of structures in different structural forms, and bridge purposes. The structural form was assessed from the perspective of materials used for the arch and the tie, span, purpose and number of lanes, the presence/absence of upper wind-bracings and arch disposition in the vertical plane. In the last part of this review, the newest research into the development of the network arch is discussed. In the past 15 years we have seen an acceleration in network arch development from multiple perspectives: new materials used, such as glulam for the arch or carbon fiber-reinforced plastic for the hangers; span lengths of 250 m and 380 m for large bridge widths; architectural constraints that lead to the outward inclination of the arch, that is pleasing to the eye, but difficult to address from an engineering perspective; the most slender arch bridge in the world, with very slender cross-sections for the arch and the tie.

This paper’s aim is to assess the rail wear evolution of railway tracks under mixed traffic conditions for sharp curves. Field investigations were conducted over a period of five years, at 800 points on a rail track, for two curves that underwent maintenance interventions: sleeper and rail replacements during measurements. Lateral and vertical wear measurements were monitored with mechanical instruments, and Prokon and Sap simulations were performed in order to determine the bearing capacity of the rail at different stages of wear. The results obtained after five years of investigation show wear speed propagation on the outer rail of small-radius curves as well as the bending moments and admissible stress variation. At more than 18% of the studied points, lateral wear exceeded the maximum admissible limit, showing a faster propagation speed on the outer rail compared to the vertical wear rate.

This paper aims to study the on-going problem of traffic generated noise pollution, focusing on the influence of speed breakers on specific areas of the noise spectrum. We studied different types of speed breakers around the metropolitan area of Cluj-Napoca, measuring a sound spectrum from 20 Hz to 20 kHz. Speed breakers have an extensive use all over the world as safety measures near parks, schools, residential areas, but the question to answer is whether they also contribute to the increase in noise pollution and to what measure this contribution is. The study considers the different types of speed breakers used in the metropolitan area and the degree of usage the speed breakers have.

The connections with end plates and bolts can be used in steel bridge structures, or joining the decking beams, which can lead to very simple and economical constructive solutions. The paper presents some theoretical aspects concerning the behavior and calculation of the end plate connections which is partially pre-tensioned by high-strength bolts, and supplementary a welded cover plate is added to the tensioned flange of the plate girder. In the case of connections subjected to tension forces, it is not recommended to prestress the bolts as much as is the case when the joints are subjected only to shear because live loads can lead to the overloading of the bolts; the overload is a function of the relative stiffness of the end plate and of the bolts. The additional welded splice at the tension flange contributes to the transfer of the large tension stresses from the extreme bolts to the welded cover plate, resulting in a significantly reduced joint assembly loading and an increased load-bearing capacity. The paper includes a numerical example highlighting the influence of the stiffness of the joint elements and of the welded splice-plate on the joint loading, considering its pre-tensioning effect from the cooling contraction of the longitudinal welding fillets.