Topic: Bridges and Tunnels
The Band-e Kaisar (Persian: بند قیصر, "Caesar's dam"), Pol-e Kaisar ("Caesar's bridge"), Bridge of Valerian or Shadirwan was an ancient arch bridge in Shushtar, Iran, and the first in the country to combine it with a dam. Built by the Sassanids, using Roman prisoners of war as workforce, in the 3rd century AD on Sassanid order, it was also the most eastern example of Roman bridge design and Roman dam, lying deep in Persian territory. Its dual-purpose design exerted a profound influence on Iranian civil engineering and was instrumental in developing Sassanid water management techniques.
The approximately 500 m long overflow dam over the Karun, Iran's most effluent river, was the core structure of the Shushtar Historical Hydraulic System (سازههای آبی شوشتر) from which the city derived its agricultural productivity, and which has been designated by the UNESCO as Iran's 10th World Heritage Site in 2009. The arched superstructure carried across the important road between Pasargadae and the Sassanid capital Ctesiphon. Many times repaired in the Islamic period, the dam bridge remained in use until the late 19th century.
- "Band-e Kaisar – “Caesar's dam”" | 2016-01-03 | 16 Upvotes 2 Comments
The Gotthard Base Tunnel (GBT; German: Gotthard-Basistunnel, Italian: Galleria di base del San Gottardo, Romansh: Tunnel da basa dal Son Gottard) is a railway tunnel through the Alps in Switzerland. It opened on 1 June 2016, and full service began on 11 December 2016. With a route length of 57.09 km (35.5 mi), it is the world's longest railway and deepest traffic tunnel and the first flat, low-level route through the Alps. It lies at the heart of the Gotthard axis and constitutes the third tunnel connecting the cantons of Uri and Ticino, after the Gotthard Tunnel and the Gotthard Road Tunnel.
The link consists of two single-track tunnels connecting Erstfeld (Uri) with Bodio (Ticino) and passing below Sedrun (Graubünden). It is part of the New Railway Link through the Alps (NRLA) project, which also includes the Ceneri Base Tunnel further south (scheduled to open late 2020) and the Lötschberg Base Tunnel on the other main north–south axis. It is referred to as a "base tunnel" since it bypasses most of the existing Gotthard railway line, a winding mountain route opened in 1882 across the Saint-Gotthard Massif, which was operating at its capacity before the opening of the GBT. The new base tunnel establishes a direct route usable by high-speed rail and heavy freight trains.
The main purpose of the Gotthard Base Tunnel is to increase local transport capacity through the Alpine barrier, especially for freight, notably on the Rotterdam–Basel–Genoa corridor, and more specifically to shift freight volumes from trucks to freight trains. This both significantly reduces the danger of fatal road crashes involving trucks, and reduces the environmental damage caused by heavy trucks. The tunnel provides a faster connection between the canton of Ticino and the rest of Switzerland, as well as between northern and southern Europe, cutting the Basel/Zürich–Lugano–Milan journey time for passenger trains by one hour (and from Lucerne to Bellinzona by 45 minutes).
After 64 percent of Swiss voters accepted the NRLA project in a 1992 referendum, first preparatory and exploratory work began in 1996. The official start of construction began on 4 November 1999 at Amsteg. Drilling operations in the eastern tunnel were completed on 15 October 2010 in a breakthrough ceremony broadcast live on Swiss TV, and in the western tunnel on 23 March 2011. The tunnel's constructor, AlpTransit Gotthard AG, originally planned to hand over the tunnel to Swiss Federal Railways (SBB CFF FFS) in operating condition in December 2016 but, on 4 February 2014, the handover date was changed to 5 June 2016 with the start of an 850-day opening countdown calendar on the AlpTransit homepage. As of 1998, the total projected cost of the project was CHF 6.323 billion; as of December 2015, the final cost is projected as CHF 9.560 billion. Nine people died during construction.
- "Gotthard Base Tunnel" | 2015-10-28 | 97 Upvotes 48 Comments
The Magdeburg Water Bridge (German: Kanalbrücke Magdeburg) is a large navigable aqueduct in central Germany, located near Magdeburg. The largest canal underbridge in Europe, it spans the river Elbe and directly connects the Mittellandkanal to the west and Elbe-Havel Canal to the east of the river, allowing large commercial ships to pass between the Rhineland and Berlin without having to descend into and then climb out of the Elbe itself.
- "Magdeburg Water Bridge" | 2019-11-21 | 52 Upvotes 41 Comments
Hobby tunneling (or tunnelling) is tunnel construction as a diversion. Usually, hobby tunnelers dig their tunnels by hand, using little equipment, and some can spend years or even decades to achieve any degree of completion. In some cases tunnels have been dug secretly, and only discovered by chance.