PRESENTED AT THE XII WORLD CONFERENCE ON SEISMIC ISOLATION ENERGY DISSIPATION, AND ACTIVE VIBRATION CONTROL OF STRUCTURES
Cathedral of our Lady of the Angels,
Due to the complexity of today’s architecture, the architect must incorporate the numerous scientific and technological advances such as base isolation in order to integrate a creative, imaginative and safe synthesis. The use of base isolation has an influence on structural behavior as well as on other architectural variables such as morphology, functionality, aesthetics and economy, being able to reach innovative design limits in seismic prones. This research tries to contribute to the integration of Architecture and Seismic Engineering, analyzing the architectural implications involved in the use of seismic base isolation. The theoretical conceptual knowledge of structural architecture is essential to develop more efficient and adequate architectural models.
Almost two thirds of the earth’s crust is seismically active. Every year, more than 150,000 seismic movements strong enough to be perceived by round about one billion people who live in these regions subject to earthquakes occur.
Among the different dangers that threaten the human beings, earthquakes are causes completely out of people’s control. They cannot avoid them. They can just take preventive measures against them to diminish their effects.
The architect conceives and designs the building configuration (Arnold and Reitherman 1999 – Charleson 2008) and therefore influences on the seismic behavior of buildings.
As a risky discipline, the Theory of Architecture must take into consideration the principles of seismic-resistant structural design and be updated with regard to the advances in the seismic protection technologies in the same way it does with regard to sustainability, resources consumption, recycling and others.
Seismic base isolation is a great advance for engineering to diminish the effects produced by earthquakes in architectural works. But no many architects have a thorough knowledge about the possibilities offered by this technology, nor an adequate integration between both disciplines allowing new projects to take advantage of this technology.
In the design of most of the new buildings with base isolation, architecture is restricted to solving detail problems, such as facilities, stairs, elevators, and the elements which may obstruct the free move of the building in the gap.
Conventional architectural design takes into account “an acceptable seismic risk” that may diminish the damage level in the building. It does not avoid damage.
This means a conceptual, an attitude and a decision change at facing the problem. One change consists in controlling the damages by designing them though they are not eliminated. The other change pursues the drastic reduction by the use of new devices. The solution is very different and it requires an adjustment to changes, which enables a new conception of the damage reduction in the buildings when a seism occurs.
In this way, new technologies of seismic protection have new applications creating a new architectural concept of Architecture.
The methodology of seismic protection is recent, but the idea dates back a long time ago, although it was not possible to bring it to fruition. There have been precedents of different preventive measures, not all of them being equally effective in the light of the present knowledge. As a general rule they have been the result of any sad event of catastrophic magnitude.
The Temple of Diana in Ephesus, described by Pliny The Elder (23 AD – 79 AD), confirms the human beings concerns about protecting their constructions by placing an interface between the foundations and the building. Fifty years ago, new materials helped to develop elements and the idea became true. The first building with base isolation was the school Pestalozzi in the ´60 in Skopje, Macedonia (Naheim and Kelly, 1999) and since then, the development and evolution of the concept have not stopped.
Base isolation technology has been applied worldwide in numerous earthquakes, showing a structural performance that had never been reached before.
2.1. Seismic Architecture
Man is the cause and purpose of Architecture. Human being is unique. He needs to protect himself from natural and social threats. In older times he made it in caves till now that he has created skyscrapers. (Salvadori 1979)
Architecture must be a protection system for the different elements which may put his life at risk. It must shelter the human being abandonment during his life.
Seismic Engineering stands as an interdisciplinary branch of civil engineering and earth sciences, mainly aimed at mitigating the effects of the seismic threat. The complex requirements of seismic engineering directly influence architectural composition and concepts (Parducci 2007).
Seismic Architecture is the combination of principles related to architectural design and seismic resistant engineering. It combines the necessary elements from both fields and establishes new conceptual interlinks in the field of architecture.
Earthquake resistant construction requirements are often seen as a pressure on artistic freedom and a restriction on the architectural ideas coming from non-seismic areas in the world.
Nevertheless, the main problem is not the restrictions but the lack of knowledge to develop seismic resistant structural designs according to an adequate, creative, innovative, audacious, safe and sustainable architecture.
2.1.1. Architectural Variables
Architecture is a science, enhanced by many other disciplines and knowledge. It is Theory and Practice. From the area of Architecture Theory, the starting point for analyzing the Architecture Variables, the ones defined as principals (Utilitas, Firmitas and Venustas by Marcus Vitruvius Pollio -Roman architect, writer, engineer and treatise writer from s1 b. C.), shall be taken. Over time, these variables evolved from the complexity acquired by the architecture.
Venustas refers to beauty as an aesthetic element, the meaning and communication of a message. Utilitas means the function the work will be used for, the organization and distribution of the architectural areas and Firmitas represents the concepts of durability, firmness, stability, permanence, resistance and configuration, among others. Safety mentioned by Vitruvio refers to material and technical aspects of Architecture.
With Engineering, it shares the “Firmitas” variable and thus there is a contact area where Architecture and Construcion join. Then, it is necessary to identify the common components so as to have a wider and more complex view of the architectural and structural design, which is critical in seismic areas. Figure 1
|Figure 1: Integration of Seismic Architecture Disciplines|
2.1.2. Seismic Architecture Variables
Firmitas variable is the one representing the possibility to design in an appropriate way an Architecture that is suitable for seismic high risk areas, which adds base seismic isolation as a strategy of damage reduction. It becomes very important and must be present from the conception itself of the architectural design.
From this approach, architecture, when it is inserted in its seismic context, receives external actions such as the earthquake, and must respond by means of internal actions.
Then, the architectural work must have the architectural performance and the structural performance that are appropriate to support said work. Figure 2
|Figure 2: Interdependence of the Architectural Design with its Context|
The analysis is performed by means of an interrelation between the three variables of the Seismic Architecture, which uses the Base Seismic Isolation, which will enable to evidence how the architectural design is optimized and enhanced.
2.2. Analysis of buildings with Base Seismic Isolation
The methodology which is applied for the analysis of buildings consisted of performing an identification of the more outstanding architectural implications of the works so as to discover the architectural potentialities arising as a consequence of the use of base seismic isolation in the architectural design
The selection criterion of the building typology is regarding the use, either because the buildings have great people concentrations, or because their survival is vital to act upon emergency situations caused by the seismic movements. Typologies of Hospitals, which may be operative after an earthquake so as to help victims and of Temples, which may be used as both a shelter for people who are homeless or as emergency centers are important.
Then, business buildings were analyzed for its potential avant-garde architectural design, which exceeds the traditional design limitations.
2.2.1. Analysis of the Seismic Architecture variables and the architectural implications when using Seismic Isolation
22.214.171.124. Hospital Typology
126.96.36.199. Hospital Typology
188.8.131.52. Temple Typology
184.108.40.206. Commercial Building Typology
3. PARTIAL CONCLUSIONS
After performing the analysis of the typologies that are selected, the following conclusions of the variables of Seismic Architecture are obtained, and then, the importance of the economic variable arises.
3.1. UTILITAS: Benefits regarding the functions increased by the use of ASB
. The optimization of the area of use is achieved, since it enables a better architectural exploitation. The degree of incidence or interference of the structure from the point of view of the use and distribution of the architectural space is lower.
. The functions of the buildings after a severe seismic movement are kept operative.
. The physical and psychological protection of the users by means of damage reduction is optimized.
. The psychological trauma generated by the perception of an important seismic movement and the devastating experiences that are caused by the deadly effects of the earthquakes is reduced
3.2. FIRMITAS: Benefits regarding the structure, increased by the use of ASB
. It enables complex configurations which respond to the project needs.
. The efforts and distortions in the structures with an optimal structural performance in case of severe seismic movements are reduced.
. Damages of a building during a severe seismic movement are drastically reduced, both from structural and non structural elements, by means of the isolation interface.
. The damage of the building contents is avoided (high-technology equipment, machinery, etc.)
. Life and Architecture Protection are optimized
. A better adaptation to the seismic determining factor with a demonstrated efficacy is reached.
. It is possible to preserve the cultural patrimony, the meaning and identity which witness periods in time.
3.3. VENUSTAS: Benefits regarding beauty, increased by the use of ASB
. It enables configuration freedom that was not previously recommended for the traditional seismic-resistant design.
. Potentiality of creative freedom in the aesthetic design of the works increases more and more.
3.4. ECONOMY: Benefits regarding investment and maintenance of capital
. A reduction of the initial cost of the work is achieved, if the structural design is taken into account from the beginning.
. The investment is maintained in time. Costs which would entail a structural rehabilitation as a consequence of an earthquake would be decreased in an important way.
. It also reduces the economic risks of the affected areas, since people keep their way of living and support.
. Decrease of economic losses due to activity standstill in the event of a seismic movement.
. The sustainable development in seismic areas is increased
. The application of technology of seismic protection in real estate projects may come to be only 1 % of the total cost, when it is previously planned (De La Llera 2011).
. Some benefits are difficult to translate into monetary values or are not always tangible, such as the mental ease.
4. FINAL CONCLUSIONS
Buildings, besides of being more efficient, safe, functional and economical, may achieve new design prospects in seismic regions. The architectural-structural theoretical conceptual knowledge of the architectural implications of Seismic Architecture is essential to develop efficient and adequate architectural models.
Seismic Architecture can thus provide a means of Passive Protection against a potential earthquake. For such purpose, it has to incorporate new technologies like base isolation, within its conceptual-theoretical knowledge and then use them as design tools in a vital, comprehensive protection system which will drastically reduce damages and human losses caused by an earthquake.
Environment is protected thanks to the work preservation, a greater possibility of applying strategies for the development of Sustainable Architecture and the use of new materials that are not recommended for seismic regions, such as prefabricate materials.
The use of this technology from the conception of architectural design will enable more savings than the ones obtained until now, and thus it optimizes the result of the public and private investment.
Solving an architectural work which not only contributes to decrease the seismic vulnerability and the environmental problem, but also provides benefits gives the possibility of living together with our planet, of living a promising future.
To my engineer friends for sharing their knowledge, in particular to engineers Juan Carlos de la Llera (Chile), José Inaudi (Cordoba, Argentina), Eng. Agustín Reboredo (Mendoza, Argentina) and to my e-mail consultant Andrew Charleson (New Zealand).
To my colleagues, Miguel Tornello and Daniel Moisset de Espanés, who support me in this branch of architectural discipline
To my friends Luis Matons Cañomeras, Juan José Marino and Julio Diaz Valentín who were a party to the knowledge adventure of the structural design.
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