material_used klarabergsviadukten
The Romans constructed numerous aqueducts in order to bring ___MASK15___ from often distant sources into cities and towns , supplying public baths , latrines , fountains and private households . Aqueducts also provided ___MASK15___ for mining operations , milling , farms and gardens . ___MASK29___ is a ___MASK94___ composed of coarse aggregate bonded together with a fluid cement that hardens over time . Most concretes used are lime - based concretes such as Portland cement concrete or concretes made with other hydraulic cements , such as ciment fondu . However , asphalt concrete , which is frequently used for road surfaces , is also a type of concrete , where the cement material is bitumen , and polymer concretes are sometimes used where the cementing material is a polymer . ___MASK47___ is an alloy of iron and other elements , primarily carbon , that is widely used in construction and other applications because of its high tensile strength and low cost . ___MASK47___ ' s base metal is iron , which is able to take on two crystalline forms ( allotropic forms ), body centered cubic and face centered cubic ( FCC ), depending on its temperature . It is the interaction of those allotropes with the alloying elements , primarily carbon , that gives ___MASK47___ and cast iron their range of unique properties . In the body - centred cubic arrangement , there is an iron atom in the centre of each cube , and in the face - centred cubic , there is one at the center of each of the six faces of the cube . Carbon , other elements , and inclusions within iron act as hardening agents that prevent the movement of dislocations that otherwise occur in the crystal lattices of iron atoms . A viaduct is a bridge composed of several small spans for crossing a valley , gorge , marshland or forming a flyover . The term " viaduct " is derived from the Latin " via " for road and " ducere ", to ___MASK38___ . The ancient Romans did not use the term ; it is a modern derivation from an analogy with aqueduct . Like the Roman aqueducts , many early viaducts comprised a series of arches of roughly equal length . Viaducts may span land , ___MASK15___ or both . Stockholm ( or ) is the capital of Sweden and the most populous city in the Nordic countries ; 932 , 917 people live in the municipality , approximately 1 . 5 million in the urban area , and 2 . 3 million in the metropolitan area . The city is spread across 14 islands on the coast in the southeast of Sweden at the mouth of Lake Mälaren , by the Stockholm archipelago and the Baltic Sea . The area has been settled since the ___MASK50___ Age , in the 6th millennium BC , and was founded as a city in 1252 by a Swedish statesman Birger Jarl . It is also the capital of Stockholm County . The Baltic Sea ( ; ) is a sea of the Atlantic Ocean , enclosed by Scandinavia , Finland , the Baltic countries , and the North European Plain . It includes the Gulf of Bothnia , the Bay of Bothnia , the Gulf of Finland , the Gulf of Riga , and the Bay of Gdask . The sea stretches from 53 ° N to 66 ° N latitude and from 10 ° E to 30 ° E longitude . A mediterranean sea of the Atlantic , with limited ___MASK15___ exchange between the two bodies , the Baltic Sea drains through the Danish islands into the Kattegat by way of the straits of Øresund , the Great Belt , and the Little Belt . A polymer ( Greek " poly -", " many " + "- mer ", " parts ") is a large molecule , or macromolecule , composed of many repeated subunits . Because of their broad range of properties , both synthetic and natural polymers play an essential and ubiquitous role in everyday life . Polymers range from familiar synthetic ___MASK75___ such as polystyrene to natural biopolymers such as DNA and proteins that are fundamental to biological structure and function . Polymers , both natural and synthetic , are created via polymerization of many small molecules , known as monomers . Their consequently large molecular mass relative to small molecule compounds produces unique physical properties , including toughness , viscoelasticity , and a tendency to form glasses and semicrystalline structures rather than crystals . Klara Sjö ( Swedish for " Lake Klara ") is a canal in central Stockholm , Sweden . In materials science , ductility is a solid material ' s ability to deform under tensile stress ; this is often characterized by the material ' s ability to be stretched into a ___MASK37___ . Malleability , a similar property , is a material ' s ability to deform under compressive stress ; this is often characterized by the material ' s ability to form a thin sheet by hammering or rolling . Both of these mechanical properties are aspects of plasticity , the extent to which a solid material can be plastically deformed without fracture . Also , these material properties are dependent on temperature and pressure ( investigated by Percy Williams Bridgman as part of his Nobel Prize - winning work on high pressures ). An island or isle is any piece of sub - continental land that is surrounded by ___MASK15___ . Very small islands such as emergent land features on atolls can be called islets , skerries , cays or keys . An island in a river or a lake island may be called an eyot or ait , and a small island off the coast may be called a holm . A grouping of geographically or geologically related islands is called an archipelago , e . g . the Philippines . ___MASK88___ ( RC ) is a composite material in which concrete ' s relatively low tensile strength and ductility are counteracted by the inclusion of reinforcement having higher tensile strength or ductility . The reinforcement is usually , though not necessarily , ___MASK47___ reinforcing bars ( ___MASK86___ ) and is usually embedded passively in the concrete before the concrete sets . Reinforcing schemes are generally designed to resist tensile stresses in particular regions of the concrete that might cause unacceptable cracking and / or structural failure . Modern reinforced concrete can contain varied reinforcing materials made of ___MASK47___ , polymers or alternate composite material in conjunction with ___MASK86___ or not . ___MASK88___ may also be permanently stressed ( in compression ), so as to improve the behaviour of the final structure under working loads . In the United States , the most common methods of doing this are known as pre - tensioning and post - tensioning . For a strong , ductile and durable construction the reinforcement needs to have the following properties at least : Biography . Early life . It is known that Birger grew up and spent his adolescence in Bjälbo , Östergötland but the exact date of his birth remains uncertain and available historical sources are contradictory . Examinations of his mortal remains indicate that he was probably about 50 upon his death in 1266 which would indicate a birth around 1216 . However , his father Magnus Minnesköld is assumed to have died no later than 1210 , which would ___MASK38___ to an assumed birth a few years earlier . Under any circumstance , he was the son of Ingrid Ylva , who according to Olaus Petri was a daughter of Sune Sik and granddaughter of King Sverker I of Sweden , which would make Birger a matrilineal member of the House of Sverker . His brothers or half - brothers  Eskil , Karl , and Bengt  were all born long before 1200 , and it can therefore be assumed that they had another mother . He was also a nephew of the jarl Birger Brosa from the House of Bjelbo . The combination of this background proved to be of vital importance . A body of ___MASK15___ or waterbody ( often spelled ___MASK15___ body ) is any significant accumulation of ___MASK15___ , generally on a planet ' s surface . The term most often refers to oceans , seas , and lakes , but it includes smaller pools of ___MASK15___ such as ponds , wetlands , or more rarely , puddles . A body of ___MASK15___ does not have to be still or contained ; Rivers , streams , canals , and other geographical features where ___MASK15___ moves from one place to another are also considered bodies of ___MASK15___ . The ___MASK50___ Age was a broad prehistoric period during which ___MASK50___ was widely used to make implements with an edge , a point , or a percussion surface . The period lasted roughly 3 . 4 million years , and ended between 8700 BCE and 2000 BCE with the advent of metalworking . ___MASK86___ ( short for reinforcing bar ), collectively known as reinforcing ___MASK47___ and reinforcement ___MASK47___ , is a ___MASK47___ bar or mesh of ___MASK47___ wires used as a tension device in reinforced concrete and reinforced masonry structures to strengthen and hold the concrete in tension . ___MASK86___ ' s surface is often patterned to form a better bond with the concrete . A ___MASK94___ ( also called a composition material or shortened to composite , which is the common name ) is a material made from two or more constituent materials with significantly different physical or chemical properties that , when combined , produce a material with characteristics different from the individual components . The individual components remain separate and distinct within the finished structure . The new material may be preferred for many reasons : common examples include materials which are stronger , lighter , or less expensive when compared to traditional materials . More recently , researchers have also begun to actively include sensing , actuation , computation and communication into composites , which are known as Robotic Materials . Canals and navigations are human - made channels for ___MASK15___ conveyance ( supply ), or to service ___MASK15___ transport vehicles . In the vernacular , both are referred to as ' canals ', and in most cases , the engineered works will have a series of dams and locks that create areas of low speed current flow . These areas are referred to as " ' slack ___MASK15___ levels '," often just called ' levels '. The main difference between them is that a navigation parallels a river and shares part of its waters , its drainage basin and leverages its resources by building dams and locks to increase and lengthen its long stretches of " deep enough " slack ___MASK15___ levels while staying in its valley . In contrast , a canal cuts across a drainage divide atop a ridge ( however humble ), generally requiring an external ___MASK15___ source above the highest elevation . Many canals have been built at elevations towering over valleys and others ___MASK15___ ways crossing far below . Cities need a lot of fresh ___MASK15___ and many canals with sources of ___MASK15___ at a higher level can deliver ___MASK15___ to a destination where there is a lack of ___MASK15___ . The Roman Empire ' s Aqueducts were such ___MASK15___ supply canals . Klarabergsviadukten ( Swedish : `` The Viaduct of Hill of St Clare '' ) is a ___MASK88___ bridge and a viaduct in central Stockholm , Sweden . Stretching over Klara Sjö , it connects Norrmalm to Kungsholmen . Where in English viaduct generally signify a bridge composed of several small spans , in Swedish it is also used for other bridges , generally railway or motorway bridges , of one span or more , spanning only land or , for example a street . The ( not particularly small ) spans of Klarabergsviadukten stretches over both a railway yard and Klara sjö ( `` Lake Klara '' ) , and was originally intended to form part of a traffic route , Klarabergsleden , connecting central Stockholm to the western suburbs , plans cancelled in 1974 . Though not obviously a viaduct even in the Swedish sense , it still retains its name . First brought up in a proposal in 1928 , a traffic route bridging the central railway yard in Stockholm and Klara sjö was planned to continue through the Seraphim Hospital area over Norr Mälarstrand along the southern shore of Kungsholmen to reach Drottningsholmsvägen , the road leaving Stockholm for the western suburbs . Over the years , the expected development of the traffic system in Stockholm made the planned route wider and wider , from the planned 18 metres in 1932 to 31 metres when the viaduct and bridge were finally built in 1961 . Klarabergsviadukten is composed of several sections . It stretches 106 metres with a maximum span of 32 metres over Vasagatan ; 136 metres over the railway yard with spans varying from 12 to 17 metres ; and the bridge over Klara sjö having a maximum span of 41 metres . Because the bridge never was used as part of a motorway , its dimensions are out of proportion , and it is therefore partly being used for parking . A bridge is a structure built to span physical obstacles without closing the way underneath such as a body of ___MASK15___ , valley , or road , for the purpose of providing passage over the obstacle . There are many different designs that each serve a particular purpose and apply to different situations . Designs of bridges vary depending on the function of the bridge , the nature of the terrain where the bridge is constructed and anchored , the material used to make it , and the funds available to build it . A ___MASK26___ is a binder , a substance used in construction that sets and hardens and can bind other materials together . The most important types of ___MASK26___ are used as a component in the production of mortar in masonry , and of concrete , which is a combination of ___MASK26___ and an aggregate to form a strong building material .