Cast and Steel Iron in Building Construction - Case Study Example

Building Construction 1 Cast and Steel Iron in Building Construction Building Construction 2 Construction has a long history, particularly in England construction had been a great business, where the United Kingdom remained and remains a pioneer for other countries. In the earlier days iron was used for construction, mainly cast and wrought iron was in use. So it could be realised visually that many of the buildings and bridges were built with cast iron frames structures. Iron was used as a basic as well as main structural material for many years. The first cast iron bridge was built at Coalbrookedale in Shropshire , in 1779 buy Darby [Chanakya Arya 1994] Iron was in priority in UK during the early times. . “Mass produced cast iron components such as classical columns, Gothic window-tracery, nave arcading and even roof trusses were used in an increasing growing number of buildings”[Faculty 2006]. One of the best example for building constructed of cast and wrought iron is Crystal Palace. While cast and wrought iron were utilised for construction, steel took its full accumulation in construction only during the later part of the 19th century, there are many buildings that are made of steel one among them is St.Mary Axe, at London. This is considered as one of the best illustrations that reflects the skills in construction field of today. The use of cast and wrought iron could be found in buildings of the earlier times, until the 19th century the system excited. However, at present cast and wrought iron are used in building bridges and dams. This is mainly due to the fact that the advent of steel has occupied the place of iron in residential as well as industrial buildings. Nevertheless, in some of the industrial constructions cast and wrought iron are used to set the roofing. Building Construction 3 Some of the cast iron and wrought iron buildings in UK are Tobacco Dock, Greenwich Hospital complex, South West Round Tower [Nantgylo] , Crystal Palace etc. In the beginning of 18th century cast iron was used a lot and the prefabricated construction technique was practised by using the above form of iron. The property of the cast iron is that it is obtained as a natural source and it has high quantity of carbon in it. Though why cast iron was used in spit of bring brittle is that it does get rust formation when exposed to water and other climatic changes. Wrought iron is strong when get compressed and ductile. In some of the ear4lier buildings, wrought iron was used for roofing. Crystal Palace is one such building, constructed with cast and wrought iron. The load bearing system determines the technological aspect of bearing the whole weight of the walls. As far as Crystal Palace is concerned, “vertical load bearing” had been constructed. This vertical load bearing was fixed with the aim of carrying the maximum load of the people as well as the walls of the building. This load bearing system is constructed with cast and wrought iron columns, with each column height ranging from 16’-7.5” to 18’-8” with taller versions on the ground surface and each column is formed of four-faced cylindrical surface [Chris H. Luebkeman and Donald Peting. 1995] The girders and trusses were also made of cast and wrought iron, with three feet depth. There were three types of girders and trusses used depending on the different strengths of cast and wrought iron .[Chris H. Luebkeman and Donald Peting. 1995]gives the information regarding the type of girder and trusses , he says “There are three Building Construction 4 different strengths of 24 foot cast iron girders (also used for its strength in compression). One strength of 24-foot wrought iron trusses (wrought iron is used for its tensile strength). One strength of 48-foot wrought iron trusses. Three strengths of 72 foot wrought iron trusses, and 24 foot wooden trusses.” The truss had been designed in such a way that its stiff bending would carry the load for the girder and the column finally carries this load. The Faculty of Architecture and Building Planning [2006] has to say on the girds and trusses of Crystal Palace “The main area covers 1848 feet by 408 feet, plus an additional 936 feet by 48 feet extended along the northern side. It would require 3,300 iron columns, 2,150 girders, 372 roof trusses and 205 miles of sash bars. The main building rose in 3 tiers, all covered with the "Paxton Gutter" and glass roof system”. Cast iron was used for building girders because cast iron would prevent torsion. The use of cast and wrought iron girders and trusses were intended for four main reasons 1.First thing was that steel was not popularly used for building construction until 19th century 2. cast iron was considered as a natural resource with more carbon, and remained good for compression and stress. And one ore reason would be that “Iron and glass, the main components of the Crystal Palace, stands out due to its ease of erection, adaptability and expressions that they offered. The wide spread of coke smelting during the 2nd half of the 18th century, and the increasing use of pudding process, also made iron and glass cheaper and even more readily available.”[Faculty 2006] Building Construction 5 3. wrought iron was fragile, so they could get any king of shape for constructing a desired design. 4. the innovative method of prefabricated structural frame was introduced from the construction of Crystal Palace. This structural frame type gained lot of reception later in many modern steel buildings also. The prefabricated structure design determines the buildability features of the respective buildings. Crystal Palace’s prefabricated building structure helps in assembling and dissembling the frame work, there remains the characterictics of the building technology. The Crystal Palace was designed in such a way that all its parts could be factory-made and 33.assembled on the site. Like the railway buildings, to which it was related, it was a highly flexible 34.kit of parts, the first ever example of prefabrication and large-scale industrialized building” argues[Uniric.it 2006]. On the other side of this argument 30, St.Mary Axe had been considered for studying the feature of building construction constructed with modern steel. St.Mary Axe is one of the skyscrapers at UK. It is made constructed with a diagonal steel structure. The gird is also diagird in structure similar to that of the diagonal frame. This structure is used to form the frame of the spiral light wells. The steel is used in the form of nodes or connections to connect the spiral structure of this 40 storied building. There are totally 360 steel girds used in the construction od St.Mary Axe, to support the interior load bearing structure of the building. The nodes are the key technological features of the building, all the diagirds are built in the tapering Building Construction 6 form the frame. “The nodes consist of three steel plates welded together at different angles. Each connection is up to 2m high and links the 2500 tonnes of steel that make up the diagrid.”[Swiss Re 2001] . A 360 degree view of London could be seen from the top of the tower. The buildability features for construction a steel diagird are that it gives more advantages for remaining spacious, at the bottom level the tapers leave more ground space and allowing a new public oriented living space [which could occupy more number of people] , the circular towers at the top ends up in less down draft. However, the tapering at the top helps in resisting the wind travelling down ward further. There remains one of its buildability features. A 55km of steel parts, with 1500 diagonal loading column with an average depth of the pile foundations have been used for this 40 storied building. “The diagrid itself consists of intersecting tubular steel sections that provide vertical support to the floor and an additional benefit of this is column-free office space. As well as structural support, the diagrid gives excellent performance under wind loading.” Says [Arup.com.2006]. Further several research reports say that the 3-D computerised modelling was used to design the steel frame. This further was given to the architect for further suggestions in fabrication works. The building weighs 70,000 tonnes, contains 333 piles in the foundations, 35 kilometres of structural steel at 11,000 tonnes, and 24,000 square metres of glass cladding. [skyscrapers news.com 2006]. The diagonal gird technology used in this steel building stands a pioneer in high tech vision and sharp edged skyscrapers. Building Construction 7 The reason behind choosing a diagird is that “We developed the concept for the node to simplify the construction of the diagrid and it was adopted by the contractor. The nodes consist of three steel plates welded together at different angles. Each connection is up to 2m high and links the 2500 tonnes of steel that make up the diagrid.” Says Arup.com.2006]. the shape in the form of a cone is selected with the intension that it would reduce the wind turbulence. The triangulated perimeter structure helps the building from other external reinforcements. This would probably also help while needed for reconstruction or maintenance purposes. The shape acts as the most advantageous factor for this building, the tapers at the bottom and at the top serves the purpose of required air circulation. Apart form steel 24, 000 square meters of glass cladding have also been used. This is also on e of the innovative techniques followed form the earlier building construction types. The similarity that could be seen between the two buildings are that both contains glass works at large. Steel has been in use for construction purpose because, steel is stronger, harder and lighter than iron, and it is made up of combining carbon and iron [this gives more strength for steel rather than iron]. More over the growth of multi-storied buildings are increasing, steel structural frame helps in construction a building in a small space leaving maximum living space inside, where as the cast iron buildings were built in larger space. Steel if found out to be cost effective and fits well for the environmental conditions, whereas cast or wrought iron needs, maintenance. Building Construction 8 “Steel structures can withstand unfavourable weather conditions such as hurricanes, high winds, heavy snow, and even earth quakes. Steel is also resistant to termites, creeping cracks,. Splitting and rotting: thus increasing in durability.”argues [Commercial Property.com 2006]. One of the basic requirement for steel based modern buildings is that the strategies put forward by the Steel Construction Sectors , British Steel Work Association, and the UK Government. These building sectors have combined to give a set of development objectives with the aim of monitoring the growth , employment, economic growth, social progress and prudent of resources. According to them steel constructions are efficient, and contributes to the nation’s economy, and steel based construction system provides flexible spaces, which was not required during the earlier days. Says [SCSSC 2006 ] The concept of energy consumption is also under consideration for using steel in majority of industrial as well as building construction. On the other hand, the facts that both cast and wrought iron was not easily obtained form the earth. Even though, architects used them as dependable resources, in spite of its cost and extraction. The time consumed for constructing the Crystal Palace was nine months. It should be realized that the mastery of the architectural skills behind the work, with major difficulties to get the metals had been meted out sucessfyully. Though cast iron and wrought iron is susceptible to the climatic changes, as far as the Crystal Palace structural frame work is concerned the architects have planned for a prefabricated structure to make it liable for further renovations at varying time intervals. Building Construction 9 In the case of St.Mary Axe, the structural pattern has been implemented in such a way that the steel could withstand the climatic changes. The nature of the modern buildings are planned to get constructed in small and flexibility of space has become an expected form of building construction type by the sectors as well as people. This method of flexibility is followed even in residential buildings. Where as wrought and cast iron was considered mainly for the acceptability of compression. Indeed it should be realised that the advantages of steel was not popularly known until 1890’s. Crystal Palace’s buidability remains in its prefabricated structure, where as St.Mary Axe,s remains in its triangular structure, which in turn helps for flexibility of space and wind circulation techniques. The load bearing structure of Crystal Palace depended particularly on its columns, because the building is just a 4 stories building, where as in the St.Mary Axe interior load bearing column is used, because the columns have to bear the interior building structure. In earlier days iron was used in majority, as constructors depend mainly on the labours, who carried the work of shaping, later the technological developments have given place for more industries and factories for shaping the steel structures. But while analysing the two types of buildings, the steel buildings are found to be best suitable for the present living condition. As building space is becoming less day-by-day due to increae in population. 30 St. Mary 30 St Mary Axe Structural frame used in crystal palace   PHOTOS OF CRYSTAL PALACE Erotic Gherkin (aka Swiss Re building), London Apologies to those on slow modems, but here are eight of the photographs of the Gherkin. Above, the shimmering Thames at sunset. St Paul’s Cathedral is clearly visible, as is the BT Tower (long closed to the public, after an IRA bomb went off) on the right. Like a set from James Bond. Tower bridge spanning the Thames, the Castle in front of it, and then the ancient City of London. Above - what can I say? Triangles are great. In the distance Canary Wharf, where London’s tallest buildings reside. But on the outskirts, most of us feel they are just pretenders. Tower 42 on the right, and St Paul’s in the centre. Sustainable Steel Construction, Building a better future .A Sustainability Strategy for the UK Steel Construction sector Developed by the Steel Construction Sector Sustainability Committee. Online available from. http://scinews.steel-sci.org/articles/pdf/SSC.pdf Chris H. Luebkeman and Donald Peting. 1995 The Crystal Palace of Hyde Park., London. England. Joseph Paxton.,The Architect http://darkwing.uoregon.edu/~struct/resources/case_studies/case_studies_simplebeams/case_studies_simplebeams.html Industrial Architecture and the Crystal Palace. Online available form http://www.unirc.it/ateneo/clarec/documenti/esercitazioni/examination_level_II.doc?PHPSESSID=2hqbj9oebfgqf6kfb4sb25ncs6 University of Melbourne , Faculty of Architecture Building and Planning , 702-231 Modern Architecture A online available from. http://www.geocities.com/soho/workshop/5220/history/Crystal/crystal_palace.html Chanakya Arya 1994 Design of Structural Elements :Concrete, Steel Work, Masonry, and Timber Design to British Standards and Eurocodes. Spon Press 29, West 35th Street New York 10001. COMMERCIAL PROPERTY 2006]. COMMERCIAL PROPERTY –STEEL PRE-FABRICATED BUILDING. HN http://www.propertyforsaleguide.com/Articles/Article_57.asp Read More