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81-558: The Lytle Tunnel is a vehicular tunnel that carries Interstate 71 (I-71) under the historic Lytle Park in Cincinnati , in the U.S. state of Ohio , connecting Fort Washington Way to the Northeast Expressway . It is a six-lane tunnel with three tubes. There is a two-lane southbound tube, a three lane-northbound tube, and a one-lane southbound tube that separates from the highway and serves as an exit ramp to

162-407: A commercial industry involved in the research and development , engineering , production, and servicing of military material, equipment, and facilities. Many industrialized countries have a domestic arms industry to supply their own military forces, and some also have a substantial trade in weapons for use by their citizens for self-defense, hunting, or sporting purposes. Contracts to supply

243-405: A given country's military are awarded by governments, making arms contracts of substantial political importance. The link between politics and the arms trade can result in the development of a " military–industrial complex ", where the armed forces, commerce, and politics become closely linked. According to research institute SIPRI, the volume of international transfers of major weapons in 2010–2014

324-449: A large factor in the decision making process. Civil engineers usually use project management techniques for developing a major structure. Understanding the amount of time the project requires, and the amount of labor and materials needed is a crucial part of project planning. The project duration must be identified using a work breakdown structure and critical path method . Also, the land needed for excavation and construction staging, and

405-858: A major driver of cultural evolution and human history up to today since weapons are a type of tool that is used to dominate and subdue autonomous agents such as animals and, by doing so, allow for an expansion of the cultural niche, while simultaneously other weapon users (i.e., agents such as humans, groups, and cultures) are able to adapt to the weapons of enemies by learning, triggering a continuous process of competitive technological, skill, and cognitive improvement ( arms race ). The use of objects as weapons has been observed among chimpanzees , leading to speculation that early hominids used weapons as early as five million years ago. However, this cannot be confirmed using physical evidence because wooden clubs, spears, and unshaped stones would have left an ambiguous record. The earliest unambiguous weapons to be found are

486-466: A number of issues around the potential ongoing risks from deployed weapons, the safe storage of weapons, and their eventual disposal when they are no longer effective or safe. Strange and exotic weapons are a recurring feature or theme in science fiction . In some cases, weapons first introduced in science fiction have now become a reality. Other science fiction weapons, such as force fields and stasis fields , remain purely fictional and are often beyond

567-564: A period between January 2001 and May 2003, the tunnel was notorious for many truck accidents in the tunnel. The two main reasons for this were: In May 2003, the Ohio Department of Transportation installed radar speed signs at the ends of the tunnel that would show the posted speed for trucks along with the actual speed of the vehicle. Hazmats and explosives are not allowed in the Lytle Tunnel. Immediately after construction of

648-467: A pipe jack, with the span of some box jacks in excess of 20 metres (66 ft). A cutting head is normally used at the front of the box being jacked, and spoil removal is normally by excavator from within the box. Recent developments of the Jacked Arch and Jacked deck have enabled longer and larger structures to be installed to close accuracy. There are also several approaches to underwater tunnels,

729-421: A specialized method called clay-kicking for digging tunnels in clay-based soils. The clay-kicker lies on a plank at a 45-degree angle away from the working face and rather than a mattock with his hands, inserts with his feet a tool with a cup-like rounded end, then turns the tool with his hands to extract a section of soil, which is then placed on the waste extract. Clay-kicking is a specialized method developed in

810-434: A tube can be sunk into a body of water, which is called an immersed tunnel. Cut-and-cover is a simple method of construction for shallow tunnels where a trench is excavated and roofed over with an overhead support system strong enough to carry the load of what is to be built above the tunnel. There are two basic forms of cut-and-cover tunnelling: Shallow tunnels are often of the cut-and-cover type (if under water, of

891-747: A tunnel than a sufficiently strong bridge). Some water crossings are a mixture of bridges and tunnels, such as the Denmark to Sweden link and the Chesapeake Bay Bridge-Tunnel in Virginia . There are particular hazards with tunnels, especially from vehicle fires when combustion gases can asphyxiate users, as happened at the Gotthard Road Tunnel in Switzerland in 2001. One of the worst railway disasters ever,

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972-917: A tunnel, though some recent tunnels have used immersed tube construction techniques rather than traditional tunnel boring methods. A tunnel may be for foot or vehicular road traffic , for rail traffic, or for a canal . The central portions of a rapid transit network are usually in the tunnel. Some tunnels are used as sewers or aqueducts to supply water for consumption or for hydroelectric stations. Utility tunnels are used for routing steam, chilled water, electrical power or telecommunication cables, as well as connecting buildings for convenient passage of people and equipment. Secret tunnels are built for military purposes, or by civilians for smuggling of weapons , contraband , or people . Special tunnels, such as wildlife crossings , are built to allow wildlife to cross human-made barriers safely. Tunnels can be connected together in tunnel networks . A tunnel

1053-432: A tunnel. Bridges usually require a larger footprint on each shore than tunnels. In areas with expensive real estate, such as Manhattan and urban Hong Kong , this is a strong factor in favor of a tunnel. Boston's Big Dig project replaced elevated roadways with a tunnel system to increase traffic capacity, hide traffic, reclaim land, redecorate, and reunite the city with the waterfront. The 1934 Queensway Tunnel under

1134-617: A worldwide crusade in the 1920s. Poison gas did not win battles, and the generals did not want it. The soldiers hated it far more intensely than bullets or explosive shells. By 1918, chemical shells made up 35 percent of French ammunition supplies, 25 percent of British, and 20 percent of American stock. The “Protocol for the Prohibition of the Use in War of Asphyxiating, Poisonous, or Other Gases and of Bacteriological Methods of Warfare”, also known as

1215-409: Is a stub . You can help Misplaced Pages by expanding it . Tunnel A tunnel is an underground or undersea passageway. It is dug through surrounding soil, earth or rock, or laid under water, and is usually completely enclosed except for the two portals common at each end, though there may be access and ventilation openings at various points along the length. A pipeline differs significantly from

1296-449: Is allowed in this tunnel tube, and motorcyclists are directed to the other tube. Each level was built with a three-lane roadway, but only two lanes per level are used – the third serves as a hard shoulder within the tunnel. The A86 Duplex is Europe's longest double-deck tunnel. Weapon While ordinary objects such as sticks , rocks , bottles , chairs , and vehicles can be used as weapons , many objects are expressly designed for

1377-505: Is intended to carry both the Istanbul metro and a two-level highway, over a length of 6.5 km (4.0 miles). The French A86 Duplex Tunnel  [ fr ] in west Paris consists of two bored tunnel tubes, the eastern one of which has two levels for light motorized vehicles, over a length of 10 km (6.2 miles). Although each level offers a physical height of 2.54 m (8.3 ft), only traffic up to 2 m (6.6 ft) tall

1458-494: Is relatively long and narrow; the length is often much greater than twice the diameter , although similar shorter excavations can be constructed, such as cross passages between tunnels. The definition of what constitutes a tunnel can vary widely from source to source. For example, in the United Kingdom, a road tunnel is defined as "a subsurface highway structure enclosed for a length of 150 metres (490 ft) or more." In

1539-401: Is sometimes necessary during the excavation of a tunnel. They are usually circular and go straight down until they reach the level at which the tunnel is going to be built. A shaft normally has concrete walls and is usually built to be permanent. Once the access shafts are complete, TBMs are lowered to the bottom and excavation can start. Shafts are the main entrance in and out of the tunnel until

1620-515: Is that the open building pit is muted after tunnel construction; no roof is placed. Some tunnels are double-deck, for example, the two major segments of the San Francisco–Oakland Bay Bridge (completed in 1936) are linked by a 160-metre (540 ft) double-deck tunnel section through Yerba Buena Island , the largest-diameter bored tunnel in the world. At construction this was a combination bidirectional rail and truck pathway on

1701-698: Is the Siloam Tunnel , built in Jerusalem by the kings of Judah around the 8th century BC. Another tunnel excavated from both ends, maybe the second known, is the Tunnel of Eupalinos , which is a tunnel aqueduct 1,036 m (3,400 ft) long running through Mount Kastro in Samos , Greece. It was built in the 6th century BC to serve as an aqueduct . In Ethiopia , the Siqurto foot tunnel , hand-hewn in

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1782-499: Is the trafficking of contraband weapons and ammunition . What constitutes legal trade in firearms varies widely, depending on local and national laws. In 2001, the United Nations had made a protocol against the manufacturing and trafficking of illicit arms. This protocol made governments dispose illegal arms, and to licence new firearms being produced, to ensure them being legitimate. It was signed by 122 parties. There are

1863-569: The Balvano train disaster , was caused by a train stalling in the Armi tunnel in Italy in 1944, killing 426 passengers. Designers try to reduce these risks by installing emergency ventilation systems or isolated emergency escape tunnels parallel to the main passage. Government funds are often required for the creation of tunnels. When a tunnel is being planned or constructed, economics and politics play

1944-467: The Geneva Protocol , was issued in 1925 and was accepted as policy by all major countries. In 1937, poison gas was manufactured in large quantities but not used except against nations that lacked modern weapons or gas masks. Many modern military weapons, particularly ground-based ones, are relatively minor improvements to weapon systems developed during World War II. World War II marked perhaps

2025-471: The Port Authority of New York and New Jersey was not aware of this bill and had not asked for a grant for such a project. Increased taxes to finance a large project may cause opposition. Tunnels are dug in types of materials varying from soft clay to hard rock. The method of tunnel construction depends on such factors as the ground conditions, the groundwater conditions, the length and diameter of

2106-848: The Queens-Midtown Tunnel between Manhattan and the borough of Queens on Long Island ; the Detroit-Windsor Tunnel between Michigan and Ontario ; and the Elizabeth River tunnels between Norfolk and Portsmouth, Virginia ; the 1934 River Mersey road Queensway Tunnel ; the Western Scheldt Tunnel , Zeeland, Netherlands; and the North Shore Connector tunnel in Pittsburgh, Pennsylvania . The Sydney Harbour Tunnel

2187-472: The River Mersey at Liverpool was chosen over a massively high bridge partly for defense reasons; it was feared that aircraft could destroy a bridge in times of war, not merely impairing road traffic but blocking the river to navigation. Maintenance costs of a massive bridge to allow the world's largest ships to navigate under were considered higher than for a tunnel. Similar conclusions were reached for

2268-548: The Schöningen spears , eight wooden throwing spears dating back more than 300,000 years. At the site of Nataruk in Turkana, Kenya, numerous human skeletons dating to 10,000 years ago may present evidence of traumatic injuries to the head, neck, ribs, knees, and hands, including obsidian projectiles embedded in the bones that might have been caused by arrows and clubs during conflict between two hunter-gatherer groups. But

2349-679: The United Kingdom of digging tunnels in strong clay-based soil structures. This method of cut and cover construction required relatively little disturbance of property during the renewal of the United Kingdom's then ancient sewerage systems. It was also used during the First World War by Royal Engineer tunnelling companies placing mines beneath German lines, because it was almost silent and so not susceptible to listening methods of detection. Tunnel boring machines (TBMs) and associated back-up systems are used to highly automate

2430-580: The arquebus were much more powerful than human-powered weapons. Firearms became increasingly important and effective during the 16th–19th centuries, with progressive improvements in ignition mechanisms followed by revolutionary changes in ammunition handling and propellant. During the American Civil War , new applications of firearms, including the machine gun and ironclad warship , emerged that would still be recognizable and useful military weapons today, particularly in limited conflicts . In

2511-610: The canton of Glarus . The borehole has a diameter of 8.03 metres (26.3 ft). The four TBMs used for excavating the 57-kilometre (35 mi) Gotthard Base Tunnel , in Switzerland , had a diameter of about 9 metres (30 ft). A larger TBM was built to bore the Green Heart Tunnel (Dutch: Tunnel Groene Hart) as part of the HSL-Zuid in the Netherlands, with a diameter of 14.87 metres (48.8 ft). This in turn

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2592-498: The downtown area . The tunnel is ventilated by two grates in the northbound tube and the southbound exiting tube. It was completed in 1970. At 335 meters (1,099 feet), it is the longest vehicular tunnel in Ohio. It is also the only tunnel on I-71. During the construction of the Lytle Tunnel, many historic buildings were razed for the project. The old Lytle Park was similar to a town square, with many Greek Revival buildings surrounding

2673-585: The trireme , were in use by the 7th century BC. During the first First Punic War , the use of advanced warships contributed to a Roman victory over the Carthaginians. European warfare during post-classical history was dominated by elite groups of knights supported by massed infantry (both in combat and ranged roles). They were involved in mobile combat and sieges , which involved various siege weapons and tactics. Knights on horseback developed tactics for charging with lances , providing an impact on

2754-489: The water table . This pressurizes the ground ahead of the TBM cutter head to balance the water pressure. The operators work in normal air pressure behind the pressurized compartment, but may occasionally have to enter that compartment to renew or repair the cutters. This requires special precautions, such as local ground treatment or halting the TBM at a position free from water. Despite these difficulties, TBMs are now preferred over

2835-689: The 16th century as a metaphor for a narrow, confined space like the inside of a cask. Some of the earliest tunnels used by humans were paleoburrows excavated by prehistoric mammals. Much of the early technology of tunneling evolved from mining and military engineering . The etymology of the terms "mining" (for mineral extraction or for siege attacks ), " military engineering ", and " civil engineering " reveals these deep historic connections. Predecessors of modern tunnels were adits that transported water for irrigation , drinking, or sewerage . The first qanats are known from before 2000 BC. The earliest tunnel known to have been excavated from both ends

2916-638: The 1960s. The main idea of this method is to use the geological stress of the surrounding rock mass to stabilize the tunnel, by allowing a measured relaxation and stress reassignment into the surrounding rock to prevent full loads becoming imposed on the supports. Based on geotechnical measurements, an optimal cross section is computed. The excavation is protected by a layer of sprayed concrete, commonly referred to as shotcrete . Other support measures can include steel arches, rock bolts, and mesh. Technological developments in sprayed concrete technology have resulted in steel and polypropylene fibers being added to

2997-716: The 1971 Kingsway Tunnel under the Mersey. In Hampton Roads, Virginia , tunnels were chosen over bridges for strategic considerations; in the event of damage, bridges might prevent US Navy vessels from leaving Naval Station Norfolk . Water-crossing tunnels built instead of bridges include the Seikan Tunnel in Japan; the Holland Tunnel and Lincoln Tunnel between New Jersey and Manhattan in New York City ;

3078-409: The 19th century, warship propulsion changed from sail power to fossil fuel -powered steam engines . Since the mid-18th century North American French-Indian war through the beginning of the 20th century, human-powered weapons were reduced from the primary weaponry of the battlefield to yielding gunpowder-based weaponry. Sometimes referred to as the "Age of Rifles", this period was characterized by

3159-569: The 4th century BC. Cavalry developed once horses were bred to support the weight of a human. The horse extended the range and increased the speed of attacks. Alexander's conquest saw the increased use of spears and shields in the Middle East and Western Asia as a result Greek culture spread which saw many Greek and other European weapons be used in these regions and as a result many of these weapons were adapted to fit their new use in war In addition to land-based weaponry, warships , such as

3240-488: The Lytle Tunnel, the 550 E Fourth Street apartments (2 buildings) and were built on air rights over the tunnel along with the reconstruction of Lytle Park, which became the first park built over an interstate highway. 39°6′6″N 84°30′15″W  /  39.10167°N 84.50417°W  / 39.10167; -84.50417 This Ohio road or road transport-related article is a stub . You can help Misplaced Pages by expanding it . This United States tunnel–related article

3321-709: The Middle Ages, crosses a mountain ridge. In the Gaza Strip , the network of tunnels was used by Jewish strategists as rock-cut shelters, in first links to Judean resistance against Roman rule in the Bar Kokhba revolt during the 2nd century AD. A major tunnel project must start with a comprehensive investigation of ground conditions by collecting samples from boreholes and by other geophysical techniques. An informed choice can then be made of machinery and methods for excavation and ground support, which will reduce

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3402-599: The United States, the NFPA definition of a tunnel is "An underground structure with a design length greater than 23 m (75 ft) and a diameter greater than 1,800 millimetres (5.9 ft)." The word "tunnel" comes from the Middle English tonnelle , meaning "a net", derived from Old French tonnel , a diminutive of tonne ("cask"). The modern meaning, referring to an underground passageway, evolved in

3483-442: The beginning of the implementation of firearms in western warfare. Guns and rockets were introduced to the battlefield. Firearms are qualitatively different from earlier weapons because they release energy from combustible propellants , such as gunpowder , rather than from a counterweight or spring. This energy is released very rapidly and can be replicated without much effort by the user. Therefore, even early firearms such as

3564-400: The blocky nature of rocks, the exact location of fault zones, or the stand-up times of softer ground. This may be a particular concern in large-diameter tunnels. To give more information, a pilot tunnel (or "drift tunnel") may be driven ahead of the main excavation. This smaller tunnel is less likely to collapse catastrophically should unexpected conditions be met, and it can be incorporated into

3645-502: The concrete mix to improve lining strength. This creates a natural load-bearing ring, which minimizes the rock's deformation . By special monitoring the NATM method is flexible, even at surprising changes of the geomechanical rock consistency during the tunneling work. The measured rock properties lead to appropriate tools for tunnel strengthening . In pipe jacking , hydraulic jacks are used to push specially made pipes through

3726-498: The development of ancient weapons. It was not the introduction of early Iron Age swords , however, as they were not superior to their bronze predecessors, but rather the domestication of the horse and widespread use of spoked wheels by c.  2000 BC . This led to the creation of the light, horse-drawn chariot , whose improved mobility proved important during this era. Spoke-wheeled chariot usage peaked around 1300 BC and then declined, ceasing to be militarily relevant by

3807-426: The development of firearms for infantry and cannons for support, as well as the beginnings of mechanized weapons such as the machine gun . Artillery pieces such as howitzers were able to destroy masonry fortresses and other fortifications, and this single invention caused a revolution in military affairs , establishing tactics and doctrine that are still in use today. An important feature of industrial age warfare

3888-428: The development, production, stockpiling, proliferation, and usage of weapons, from small arms and heavy weapons to weapons of mass destruction . Arms control is typically exercised through the use of diplomacy, which seeks to impose such limitations upon consenting participants, although it may also comprise efforts by a nation or group of nations to enforce limitations upon a non-consenting country. Arms trafficking

3969-409: The end of this period revolutionized warfare. Formations of musketeers , protected by pikemen , came to dominate open battles, and the cannon replaced the trebuchet as the dominant siege weapon . The Ottoman used the cannon to destroy much of the fortifications at Constantinople which would change warfare as gunpowder became more available and technology improved The European Renaissance marked

4050-652: The enemy formations, and then drawing more practical weapons (such as swords ) once they entered melee. By contrast, infantry, in the age before structured formations, relied on cheap, sturdy weapons such as spears and billhooks in close combat and bows from a distance. As armies became more professional, their equipment was standardized, and infantry transitioned to pikes . Pikes are normally seven to eight feet in length and used in conjunction with smaller sidearms (short swords). In Eastern and Middle Eastern warfare, similar tactics were developed independent of European influences. The introduction of gunpowder from Asia at

4131-409: The entire tunnelling process, reducing tunnelling costs. In certain predominantly urban applications, tunnel boring is viewed as a quick and cost-effective alternative to laying surface rails and roads. Expensive compulsory purchase of buildings and land, with potentially lengthy planning inquiries, is eliminated. Disadvantages of TBMs arise from their usually large size – the difficulty of transporting

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4212-441: The final tunnel or used as a backup or emergency escape passage. Alternatively, horizontal boreholes may sometimes be drilled ahead of the advancing tunnel face. Other key geotechnical factors: For water crossings, a tunnel is generally more costly to construct than a bridge. However, both navigational and traffic considerations may limit the use of high bridges or drawbridges intersecting with shipping channels, necessitating

4293-405: The ground behind a TBM or shield. This method is commonly used to create tunnels under existing structures, such as roads or railways. Tunnels constructed by pipe jacking are normally small diameter bores with a maximum size of around 3.2 metres (10 ft). Box jacking is similar to pipe jacking, but instead of jacking tubes, a box-shaped tunnel is used. Jacked boxes can be a much larger span than

4374-640: The immersed-tube type), while deep tunnels are excavated, often using a tunnelling shield . For intermediate levels, both methods are possible. Large cut-and-cover boxes are often used for underground metro stations, such as Canary Wharf tube station in London. This construction form generally has two levels, which allows economical arrangements for ticket hall, station platforms, passenger access and emergency egress, ventilation and smoke control, staff rooms, and equipment rooms. The interior of Canary Wharf station has been likened to an underground cathedral, owing to

4455-435: The inevitable smoke and steam. A major disadvantage of cut-and-cover is the widespread disruption generated at the surface level during construction. This, and the availability of electric traction, brought about London Underground's switch to bored tunnels at a deeper level towards the end of the 19th century. Prior to the replacement of manual excavation by the use of boring machines, Victorian tunnel excavators developed

4536-470: The interpretation of warfare at Nataruk has been challenged due to conflicting evidence. The earliest ancient weapons were evolutionary improvements of late Neolithic implements, but significant improvements in materials and crafting techniques led to a series of revolutions in military technology . The development of metal tools began with copper during the Copper Age (about 3,300 BC) and

4617-476: The interwar period (between WWI and WWII) with the continuous evolution of weapon systems by all major industrial powers. The major armament firms were Schneider-Creusot (based in France), Škoda Works (Czechoslovakia), and Vickers (Great Britain). The 1920s were committed to disarmament and the outlawing of war and poison gas, but rearmament picked up rapidly in the 1930s. The munitions makers responded nimbly to

4698-468: The large TBM to the site of tunnel construction, or (alternatively) the high cost of assembling the TBM on-site, often within the confines of the tunnel being constructed. There are a variety of TBM designs that can operate in a variety of conditions, from hard rock to soft water-bearing ground. Some TBMs, the bentonite slurry and earth-pressure balance types, have pressurized compartments at the front end, allowing them to be used in difficult conditions below

4779-629: The lower deck with automobiles above, now converted to one-way road vehicle traffic on each deck. In Turkey, the Eurasia Tunnel under the Bosphorus , opened in 2016, has at its core a 5.4 km (3.4 miles) two-deck road tunnel with two lanes on each deck. Additionally, in 2015 the Turkish government announced that it will build three -level tunnel, also under the Bosporus. The tunnel

4860-572: The manufacture, sale, transfer, possession, modification, and use of small arms by civilians. Countries that regulate access to firearms will typically restrict access to certain categories of firearms and then restrict the categories of persons who may be granted a license for access to such firearms. There may be separate licenses for hunting, sport shooting (a.k.a. target shooting), self-defense, collecting, and concealed carry, with different sets of requirements, permissions, and responsibilities. International treaties and agreements place restrictions on

4941-453: The most frantic period of weapon development in the history of humanity. Massive numbers of new designs and concepts were fielded, and all existing technologies were improved between 1939 and 1945. The most powerful weapon invented during this period was the nuclear bomb ; however, many other weapons influenced the world, such as jet aircraft and radar , but were overshadowed by the visibility of nuclear weapons and long-range rockets. Since

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5022-483: The older method of tunnelling in compressed air, with an airlock/decompression chamber some way back from the TBM, which required operators to work in high pressure and go through decompression procedures at the end of their shifts, much like deep-sea divers . In February 2010, Aker Wirth delivered a TBM to Switzerland, for the expansion of the Linth–Limmern Power Stations located south of Linthal in

5103-540: The operation of empty and loaded trains at the same time. The temporary way is replaced by the permanent way at completion, thus explaining the term " Perway ". The vehicles or traffic using a tunnel can outgrow it, requiring replacement or enlargement: An open building pit consists of a horizontal and a vertical boundary that keeps groundwater and soil out of the pit. There are several potential alternatives and combinations for (horizontal and vertical) building pit boundaries. The most important difference with cut-and-cover

5184-662: The park. On the park's east side is the Taft Museum of Art . A few of the original buildings remain, including the Literary Club of Cincinnati , the Anna Louise Inn , Guilford School building , and the Phelps Apartments. A CB radio broadcast on channel 19, the most commonly used commercial trucking frequency, loops a warning about this turn and its hazards 24 hours a day, seven days a week. During

5265-465: The point of being able to ensure the destruction of the Earth by 100 fold, a new tactic had to be developed. With this realization, armaments development funding shifted back to primarily sponsoring the development of conventional arms technologies for support of limited wars rather than total war . The arms industry is a global industry that involves the sale and manufacture of weaponry. It consists of

5346-522: The project is completed. If a tunnel is going to be long, multiple shafts at various locations may be bored so that entrance to the tunnel is closer to the unexcavated area. Once construction is complete, construction access shafts are often used as ventilation shafts , and may also be used as emergency exits. The New Austrian Tunnelling method (NATM)—also referred to as the Sequential Excavation Method (SEM) —was developed in

5427-490: The proper machinery must be selected. Large infrastructure projects require millions or even billions of dollars, involving long-term financing, usually through issuance of bonds . The costs and benefits for an infrastructure such as a tunnel must be identified. Political disputes can occur, as in 2005 when the US House of Representatives approved a $ 100 million federal grant to build a tunnel under New York Harbor. However,

5508-412: The purpose; these range from simple implements such as clubs , axes , spears , and swords to complicated modern firearms , tanks , intercontinental ballistic missiles , biological weapons , and cyberweapons . Something that has been repurposed, converted, or enhanced to become a weapon of war is termed weaponized , such as a weaponized virus or weaponized laser . The use of weapons has been

5589-529: The rapidly shifting strategic and economic landscape. The main purchasers of munitions from the big three companies were Romania, Yugoslavia, Greece, and Turkey – and, to a lesser extent, Poland, Finland, the Baltic States, and the Soviet Union. Realistic critics understood that war could not really be outlawed, but its worst excesses might be banned. Poison gas became the focus of

5670-490: The realization of mutual assured destruction (MAD), the nuclear option of all-out war is no longer considered a survivable scenario. During the Cold War in the years following World War II, both the United States and the Soviet Union engaged in a nuclear arms race . Each country and their allies continually attempted to out-develop each other in the field of nuclear armaments. Once the joint technological capabilities reached

5751-613: The realms of known physical possibility. At its most prosaic, science fiction features an endless variety of sidearms , mostly variations on real weapons such as guns and swords . Among the best-known of these are the phaser used in the Star Trek television series, films, and novels, and the lightsaber and blaster featured in the Star Wars movies, comics, novels, and TV series. In addition to adding action and entertainment value, weaponry in science fiction sometimes becomes

5832-482: The risk of encountering unforeseen ground conditions. In planning the route, the horizontal and vertical alignments can be selected to make use of the best ground and water conditions. It is common practice to locate a tunnel deeper than otherwise would be required, in order to excavate through solid rock or other material that is easier to support during construction. Conventional desk and preliminary site studies may yield insufficient information to assess such factors as

5913-542: The sheer size of the excavation. This contrasts with many traditional stations on London Underground , where bored tunnels were used for stations and passenger access. Nevertheless, the original parts of the London Underground network, the Metropolitan and District Railways, were constructed using cut-and-cover. These lines pre-dated electric traction and the proximity to the surface was useful to ventilate

5994-400: The tunnel drive, the depth of the tunnel, the logistics of supporting the tunnel excavation, the final use and the shape of the tunnel and appropriate risk management. There are three basic types of tunnel construction in common use. Cut-and-cover tunnels are constructed in a shallow trench and then covered over. Bored tunnels are constructed in situ, without removing the ground above. Finally,

6075-428: The two most common being bored tunnels or immersed tubes , examples are Bjørvika Tunnel and Marmaray . Submerged floating tunnels are a novel approach under consideration; however, no such tunnels have been constructed to date. During construction of a tunnel it is often convenient to install a temporary railway, particularly to remove excavated spoil , often narrow gauge so that it can be double track to allow

6156-461: The wide introduction of aircraft into warfare and naval warfare with the introduction of aircraft carriers . Above all, it promised the military commanders independence from horses and a resurgence in maneuver warfare through the extensive use of motor vehicles. The changes that these military technologies underwent were evolutionary but defined their development for the rest of the century. This period of innovation in weapon design continued in

6237-410: Was technological escalation – innovations were rapidly matched through replication or countered by another innovation. World War I marked the entry of fully industrialized warfare as well as weapons of mass destruction ( e.g. , chemical and biological weapons ), and new weapons were developed quickly to meet wartime needs. The technological escalation during World War I was profound, including

6318-434: Was 16 percent higher than in 2005–2009, and the arms sales of the world's 100 largest private arms-producing and military services companies totaled $ 420 billion in 2018. The production, possession, trade, and use of many weapons are controlled. This may be at a local or central government level or by international treaty. Examples of such controls include: All countries have laws and policies regulating aspects such as

6399-575: Was constructed to provide a second harbour crossing and to alleviate traffic congestion on the Sydney Harbour Bridge , without spoiling the iconic view. Other reasons for choosing a tunnel instead of a bridge include avoiding difficulties with tides, weather, and shipping during construction (as in the 51.5-kilometre or 32.0-mile Channel Tunnel ), aesthetic reasons (preserving the above-ground view, landscape, and scenery), and also for weight capacity reasons (it may be more feasible to build

6480-632: Was followed by the Bronze Age , leading to the creation of the Bronze Age sword and similar weapons. During the Bronze Age, the first defensive structures and fortifications appeared as well, indicating an increased need for security. Weapons designed to breach fortifications followed soon after, such as the battering ram , which was in use by 2500 BC. The development of ironworking around 1300 BC in Greece had an important impact on

6561-732: Was superseded by the Madrid M30 ringroad , Spain, and the Chong Ming tunnels in Shanghai , China. All of these machines were built at least partly by Herrenknecht . As of August 2013 , the world's largest TBM was " Big Bertha ", a 17.5-metre (57.5 ft) diameter machine built by Hitachi Zosen Corporation , which dug the Alaskan Way Viaduct replacement tunnel in Seattle, Washington (US). A temporary access shaft

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