Challenges of High-Rise Structures - Essay Example

Running Head: High-rise Structures Structural and Regulatory Challenges of High-Rise Structures: A Case Study of 30 St Mary Axe Building [Client’s Name] [Affiliation] Generally speaking, the major challenges in putting up a building design are classified into two – the regulatory requirement of the locale or region where the bulding must be erected and the structural requirements that need to be met in order to erect the building. Structural engineering requirements change in building designs for high rise structures. Part of the changes is the regulatory requirements that must be satisfied before, during, and actual building construction process is performed. Another part of the change is the structural challenges that must be met in order to erect the building and make it withstand the stress, strains, and pressures without collapsing in the process. The regulatory and structural challenges could be great and immense but the rewards derived from such process are so great that the building usually becomes a wonder. One of this modern structural wonders is the 40 storey building found on 30 St. Mary Axe, the Swiss Re Tower. Regulatory Challenges in High Rise Buildings Putting together the Swiss Re Tower took a lot of painstaking efforts and ingenious engineering feats. Engineers and architects have to deal with the construction constraints in a densely populated area, particularly the logistics involved as well as the issues concerning the load bearing capacities of the supporting lateral beams at higher levels. The Swiss Re Tower is situated at the heart of London, exactly where the Baltic Exchange Building used to stand and is very close to Lloyd’s Building. Other nearby prominent structures includes Tower 42, Bishop’s Gate, Mitre Square, Bevis Marks Synagogue, and St Helen’s. This means that the area where the tower has to be built has very limited space that project management team headed by the architects and engineers of Forster and Partners struggled with the issue of building a 179.8m tall building in a 0.57 hectares piece of land right across busy streets. Moreover, the architectural design of the building is everything but conventional. The façade of the building is built with over 8000 pieces of steel and more than 5 football fields of glass and the overall look of the building is that of a bullet which was an unprecedented structure in London (Archinomy, 2010). This means that getting the required approval to perform a massive construction in a heavily populated area would require a lot of skill and effort. The first issues that have to be resolved by the architects are how to integrate a historically old building (designed in 1903) in the design of a new building and how to get an approval from the city authorities. The 590-foot building is supposed to rise in the site of the Baltic Exchange building which was a casualty to the IRA bombing in 1992. Various architectural agencies in London wanted to preserve what is left of the Baltic Exchange building since it is among the very first exchange floors in London (Archinomy, 2010). The City of London Corporation as well as the English government’s statutory conservation adviser, the English Heritage, demands that any renovation done on the site should also include massive restoration of the Exchange building. The ownership of the building was later transferred to Trafalgar House sometime in 1995 due to the inability of the Baltic Exchange to afford such expensive restoration (BBC, 2000). Baltic Exchange could not afford to spend the amount required to renovate or preserve the building. This regulatory requirement imposed by the City of London Corporation pushes architectural plans and development away from the site. This is because such effort only befits the very rich and wealthy where they can restore the dilapidated building to its original form for no or insignificant returns in both the short and the long run. A consideration of this magnitude is hard to dismiss particularly if the site is located in a commercial district. Moreover, construction projects need to conform to the existing laws and regulations of the locale in order to have a smooth and well-coordinated implementation of the project. Swiss Reinsurance Company is aware of this implication and so it did not made any drastic moves until 1998. Upon closer inspection, the English Heritage found out that the damage to the building was so severe that any hopes for restoration would be impossible. In 1998, planning Minister John Prescott issues an order for it to be demolished despite numerous oppositions from architectural preservation movements. In 2000, John Prescott allowed the construction of a new building on the same site and needs no further convincing after seeing the design presented by Foster & Partners (BBC, 2000). Swiss Reinsurance Company as well as other companies vying for the development of the site took advantage of this new regulatory provision. The release of this new regulation that allows construction on the site is just half of the success story for Swiss Reinsurance Company. The company must compete with other companies for the design of the building that must be erected. True enough, with an architectural design suitable and complementary to the physical environment of its location, the relevance placed of the design on the local wind environment, and the promise of significant reduction of energy consumption using smart building control systems, integrated natural ventilation, and low façade heat gain among other things, it is very difficult to dismiss the design over the conventional, four-sided rectangular buildings like the one proposed by GMW architects for the same site (GMW, 2007). Moreover, the design presented by Forster & Partners shows a not too imposing design at ground level, allowing the pedestrians to traverse the narrow streets where the Baltic Exchange was once located. The previous discussion highlights the importance of regulatory requirements in high-rise building construction. In some locations, regulatory requirements would not allow the construction of buildings bordering the high-rise level due to issues with the immediate community. Moreover, construction plans, project management schemes, and architectural designs of buildings depend largely on the regulatory requirements of the locale where the building must be erected. As was seen in Swiss Re Tower, such regulatory difficulties must first be overcome in order for the actual construction development to occur. Otherwise, all the plans laid for the project will have to remain in black and white, as what occurred to the plans submitted by GMW Architect. Structural Challenges in High-Rise Buildings Forster & Partners realized that creating a high-rise building in a very compact location surrounded by busy streets would be very difficult. The architects realized that it takes a lot of experience in project management as well as a certain maturity in project implementation to be able to construct the Swiss Re Tower from ground upwards without losing the identity and the aesthetics of the design. According to Don Neff of La Jolla Pacific, high-rise buildings are prone to three major issues that include water intrusion, foundations and structural framing (Johnson, 2006). Taller buildings need to have wider bases in order for the structure to support the weight imposed by the building as it gets higher. In principle, wider base ensures stability of the building and thus allowing the building to get to higher levels. Dealing with potential issues in base structures is important for various reasons: first, base outline will determine the possible maximum height of the building without toppling over (Wong et al, 1996); second, the structures and the materials used in the foundation of the building determines its ability to resist seismic activities (Azab, 2010); lastly, a good and comprehensive design for building foundations minimizes the risk of integrity loss of the interactions between structural components (Kang & Kren, 2006). This simply means that a good high rise building must be built on strong, reliable and sound foundations in order to optimize its design functions as well as keep the rest of the building intact and standing. As the building construction progresses upwards, other issues become more apparent. Theory suggests that lateral loads for high-rise buildings must be able to withstand the loads exerted by winds and seismic activities (Hasan, 2006). At higher altitudes, different wind speeds manifest. The variation of wind speed at high altitudes becomes very important in high-rise structures since the natural frequency of buildings, regardless of their flexibility limits, are significantly less compared to the damping oscillation introduced by wind velocities (Thanh et al, 2005). As the structure of the building leaves the foundation, it is less likely to resist the induced motion (Hasan, 2006). This means that the aero-elastic response of the structure becomes significant at greater heights. For this reason, it becomes necessary for the building design to take into consideration the effects of the wind speeds on the structural integrity of high rise buildings. Wind serviceability criteria of a lateral load must be within the limits of the building code-defined horizontal sway limit and the top floor acceleration as it has been noted in various researcher that the horizontal sway limit of high rise buildings increases logarithmically as the height increases (Ukhov, 2004). From a purely theoretical perspective, the stress induced by wind pressure on the structure will, at some point, break the natural elastic limit of the structure which could yield disastrous results (Thanh et al, 2005) (although this issue has been well accounted for in various building designs). Thus said, building designs must be strong enough to withstand the seismic activity from the ground and at the same time must be flexible enough to dampen the effects of strong wind velocities at higher levels. In other words, a building that is flexible enough to withstand the wind pressure at a higher altitude must also be able to be solid enough to support the frame of the structure. The typical rectangular buildings with square foundations are chosen for high-rise building designs not only because of their functionality but for the strength of support it provides the structure (Roesset et al, 1973). The fear of losing structural integrity at higher levels made architects and engineers stick with the conventional building designs with little or no modifications. But Foster & Partners ignored this structural convention and confidently created a building design that is not only symbolic but also represents the historic gravity of the Baltic Exchange that once stood in the location. Swiss Re Tower looks like a gherkin or a bullet with a 330 piles of 750mm thick foundation capable of supporting 117,000 tones of weight (Archinomy, 2010). In order to solve the issue of space, Foster & Partners created a building design whose maximum width is not at the base but at 16 floors above the ground. The floor plan of the building is shaped like a flower having a circular perimeter surrounded by six triangular light courts. As the building rises, the area of the surrounding light courts remains constant although the space between them gradually diminishes relative to the height. The design was able to nullify the effects of wind speed at higher altitude by streamlining the path of the winds from any direction though its aerodynamically stable exterior design. Moreover, the light wells of the building allow light to penetrate the depths of the building which saves energy consumption by up to 50% (Arhcinomy, 2010). Swiss Re Building was able to achieve stability from seismic activities by having a firm foundation deeply embedded on the soils of London. It is also able to achieve structural integrity through its rigid core and by the steel beams that encloses the exterior of the building. With the ability of the building to address the minimum structural requirements imposed for high-rise buildings, it is clear that the rest are just details. Conclusion The case analysis of Swiss Re Building has offered various insights on how high-rise building design and construction development must commence. First and foremost, it is necessary to obtain the regulatory approval for the building design since not all locations would allow the construction of high-rise buildings. Obtaining the approval of the government agency responsible for building review also means that important regulatory requirements in the design such as fire fighting and evacuation plans are addressed in the design stage. The second most important learning from the case study is the need to conform to and address the structural requirements of buildings. Building designs are not approved based on their peculiarity or for their beauty but on the integrity of the building to support habitation. It would be impossible for Swiss Re Tower to be constructed had it failed in any of the structural calculations done and shown in the design stage even if the tower is very beautiful. With everything planned carefully to its last details, the rest is just manual labor. References Archinomy. 2010. 30 St Mary Axe (The Gherkin), London. Retrieved online from http://www.archinomy.com/case-studies/669/30-st-mary-axe-the-gherkin-london Azab, M. (2010). Structural Sustainability Techniques for RC High Rise Buildings. World Academy of Science, Engineering and Technology. 61; 294-298 BBC. (23 August, 2000). ‘Erotic Gherkin’ for London Skyline. Retrieved online from http://news.bbc.co.uk/2/hi/uk_news/893161.stm GMW Architects. (2007). Issues. Retrieved online from http://www.gmw-architects.com/publications/GMW%20Issues%20spring%2007.pdf Hasan, A. (2006). High Rise Structures – The Challenges is in the Design. Concrete. Retrieved online from http://www.allbusiness.com/concrete/41712-1.html Johnson, B. (27 Jan, 2006). High-rise Construction Presents a New Set of Risks and Challenges. Daily Record and the Kansas City Daily News-Press. Retrieved online from http://findarticles.com/p/articles/mi_qn4181/is_20060127/ai_n16038992/pg_3/?tag=content;col1 Kang, G. & Kren, A. (2006)., “Structural engineering strategies towards sustainable design”, Structural Engineers Association of California, SEAOC proceedings, pp. 473-490 Korista, S., Sarkisian, M. & Abdelrazaq, A. (1998). Unique Structural Engineering Solutions for China’s Tallest Building. Long Span and High Rise Structure. IABSE Symposium. 79; p.619-624 Thanh, T., Yamada, H. & Katsuchi, H. (2005). Motion-dependent Forces in High-Rise Buildings. Conference Proceeding. Metropolis & Beyond. Roesset, J., Harmon, T., Efimba, E. & Hansen, R. (1973). Some Structural Problems – Standard Oil of Indiana Building. Journal of the Structural Division. 99(4). 637-654. Stanley, H. (2002). Structural Design of High-Rise Building Structures. Concrete. Retrieved online from http://www.allbusiness.com/manufacturing/nonmetallic-mineral-product-manufacturing/958313-1.html Ukhov, S. (2004). Beds and Foundations of High-Rise Buildings. Soil Mechanics and Foundation Engineering. 40(5). 173-175. Wong, I., Ooi, K. & Broms, B. (1996). Performance of raft foundations for high-rise buildings on the Bouldery Clay in Singapore. Canadian Geotech Journal. 33(2): 219–236 Description of the building process (10% of total course mark).Written and diagrammatic analysis of the structural system (10% of total course mark) Rationale for selecting a case study high rise project (10% of total course mark) Professional report (10% of total course mark) Understand the techniques used in high-rise construction and how they are incorporated into the building process. 4.1.3 Assignment brief You are employed in a Project Management role within a major Architectural practice. The practice has significant experience in residential and commercial design and project management work, but only within the context of low-medium rise buildings. However, the Directors are interested in tendering for High-Rise design and construction projects throughout Australia, but initially in Sydney’s CBD. As part of the feasibility study you are required to initially investigate the structural implications and building process of high-rise construction. Taking a case study approach, which focuses on an existing high-rise building, provide: Understand the application of the materials, products and components used in the construction of high-rise buildings. 4 Course Assessment 4.1 Assignment 1 – Structural and Building Process Analysis Due date: Friday 16 April by 11.59pm Assessment weighting: 40% of total Course mark 4.1.1 Assignment aim The aim is for the students to demonstrate an understanding of the issues associated with structural systems and the building process for a high-rise building. 4.1.2 Assignment objectives On completion of this assignment the student should be able to: Read More

The City of London Corporation as well as the English government’s statutory conservation adviser, the English Heritage, demands that any renovation done on the site should also include massive restoration of the Exchange building. The ownership of the building was later transferred to Trafalgar House sometime in 1995 due to the inability of the Baltic Exchange to afford such expensive restoration (BBC, 2000). Baltic Exchange could not afford to spend the amount required to renovate or preserve the building.

This regulatory requirement imposed by the City of London Corporation pushes architectural plans and development away from the site. This is because such effort only befits the very rich and wealthy where they can restore the dilapidated building to its original form for no or insignificant returns in both the short and the long run. A consideration of this magnitude is hard to dismiss particularly if the site is located in a commercial district. Moreover, construction projects need to conform to the existing laws and regulations of the locale in order to have a smooth and well-coordinated implementation of the project.

Swiss Reinsurance Company is aware of this implication and so it did not made any drastic moves until 1998. Upon closer inspection, the English Heritage found out that the damage to the building was so severe that any hopes for restoration would be impossible. In 1998, planning Minister John Prescott issues an order for it to be demolished despite numerous oppositions from architectural preservation movements. In 2000, John Prescott allowed the construction of a new building on the same site and needs no further convincing after seeing the design presented by Foster & Partners (BBC, 2000).

Swiss Reinsurance Company as well as other companies vying for the development of the site took advantage of this new regulatory provision. The release of this new regulation that allows construction on the site is just half of the success story for Swiss Reinsurance Company. The company must compete with other companies for the design of the building that must be erected. True enough, with an architectural design suitable and complementary to the physical environment of its location, the relevance placed of the design on the local wind environment, and the promise of significant reduction of energy consumption using smart building control systems, integrated natural ventilation, and low façade heat gain among other things, it is very difficult to dismiss the design over the conventional, four-sided rectangular buildings like the one proposed by GMW architects for the same site (GMW, 2007).

Moreover, the design presented by Forster & Partners shows a not too imposing design at ground level, allowing the pedestrians to traverse the narrow streets where the Baltic Exchange was once located. The previous discussion highlights the importance of regulatory requirements in high-rise building construction. In some locations, regulatory requirements would not allow the construction of buildings bordering the high-rise level due to issues with the immediate community. Moreover, construction plans, project management schemes, and architectural designs of buildings depend largely on the regulatory requirements of the locale where the building must be erected.

As was seen in Swiss Re Tower, such regulatory difficulties must first be overcome in order for the actual construction development to occur. Otherwise, all the plans laid for the project will have to remain in black and white, as what occurred to the plans submitted by GMW Architect. Structural Challenges in High-Rise Buildings Forster & Partners realized that creating a high-rise building in a very compact location surrounded by busy streets would be very difficult. The architects realized that it takes a lot of experience in project management as well as a certain maturity in project implementation to be able to construct the Swiss Re Tower from ground upwards without losing the identity and the aesthetics of the design.

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