The Philippines is known to be one of the most earthquake prone countries in the world. It is in the list of the ’10 Earthquake Prone Countries in The World’ (10 Earthquake Prone Countries In The World 2019) and is located within the area known as the ‘Pacific Ring of Fire’, which comprises of a string of sites of seismic activities around the Pacific Ocean. (Society 2019) Therefore, it is very much susceptible to earthquakes. The country has experienced numerous earthquakes over the years however the most notable earthquake was the Bohol earthquake of October 15, 2013 which reached a staggering magnitude of 7.2, ultimately causing a death toll of at least 185 residents. (Save the Children - Philippine Country Office 2013) Due to the earthquake, approximately 759,640,000.00 Filipino pesos worth of damages was totalled, which equates to £11,406,667.00. Also, there were approximately 36,645 houses damaged due to the 7.2 magnitude earthquake. From these damages, the report from Save the Children states that around 78,585 families were displaced. (Save the Children - Philippine Country Office 2013) These statistics on the number of deaths, families displaced and houses damaged indicates that there is a need for improvement in the design aspect of these buildings.
As of now, there is a lot of research and published books on the subject area. There are many books that give the importance of design however, the existing resources do not have in place the sustainability aspect of the designs which is very important when focusing the research on a third world country. Finance is a big factor when constructing in a third world country as the existing books give options which are not very sustainable in terms of economy – they disregard the costs of the earthquake resistant structures. From the number of buildings being completely demolished due to these earthquakes, it is evident that there is a vast room for improvement on the design of these buildings and structures to prevent absolute damage from earthquakes.
The importance of strong foundations is clearly stated by many different sources. Firstly, a widely used handbook in the Philippines named ‘Good Building Design and Construction in the Philippines’ briefly explores what makes a foundation suitable depending on the condition of the ground. The material and design of the foundation heavily depends on the state of the ground. (German Technical Cooperation et al. 2008) However, this handbook does not cover any technical information of how the foundation is to be designed and it has its’ limitations because the handbook exclusively looks at houses rather than big structures like a multi-storey building. Moreover, literature written by Rollo Reid generally communicates the importance of lateral loading when constructing foundations. It lacks detail on how the foundation is to be designed to resist lateral loading. (Reid, R.) Like the handbook by the German Technical Cooperation, it does not specifically give the details on the design of the foundation. Moreover, another type of foundation which is being used are isolated foundations – there are bearing pads fixed between the foundation and the building and the bearings are strong and stiff on the vertical direction and flexible in the horizontal. (Padmanabhan 2019). This will be further researched to decide whether the base isolation is a suitable technique to use in scenes such as the Philippines., The existing research done on the topic do not give a clear procedure on how to design these foundations and my project will consider in depth foundation design for an earthquake resistant structure.
Building materials have a huge impact on how the structure will withstand lateral loading caused by earthquakes. The book named ‘Earthquake-Resistant Structures: Design, Build and Retrofit’ by Mohiuddin Ali Khan describes how the modern and innovative materials that are being developed can help create a more earthquake resistant structure. For example, Mohiuddin Ali Khan states that ‘Perhaps the innovations with the greatest potential for earthquake resistance are advancements in dampening technology’ (Khan 2013) This book has a lot of information on how to produce an earthquake resistant structure however, it does not touch the realm of sustainability which is essential in a third world country like the Philippines. Another book called ‘Earthquake Resistant Design of Structures’ states that the quality of materials must satisfy minimum standards of quality and resistance. (Agarwal and Shrikhande 2008) The requirements are stated in the book – this can be used to compare different materials to see which is most sustainable also meeting the requirements. To summarise, it is important that the materials used to construct an earthquake resistant structure should meet a requirement which will help prevent collapse of the whole structure and the materials should be of good quality. For the project, I will utilize this information to determine the most suitable and sustainable materials to use for a house in the Philippines.
The main body of the project will consist of the structural design of the structure. Many of the books out there cover what is needed to minimise the damage on structures caused by the seismic waves. The book by David Dowrick implies that here are two main designs which are strength-based and displacement-based. The book states that there is currently a debate on which design would be more effective. (Dowrick 2009) Using this idea, extensive research can be done to determine which design is more sustainable and most suited for construction in the Philippines. Also from preliminary research, the book ‘Guidelines for Earthquake Resistant Non-Engineered Construction’ makes it evident that ductility is desired when looking to construct a building to minimise earthquake damages. (Arya 1986) The ductility of steel as a material is very important in this modern age as steel structures ‘have been less liable to collapse in earthquakes than traditionally designed concrete or masonry ones.’ (Dowrick 2009). The concept of a strong column – weak beam is well known and is discussed in the literature titled ‘INFLUENCE OF STRONG COLUMN & WEAK BEAM CONCEPT, SOIL TYPE AND SEISMIC ZONE ON SEISMIC PERFORMANCE OF R C FRAMES FROM PUSHOVER ANALYSIS’ it states that for multi-storey buildings, it is important to have weak beams as this what makes the structure more ductile – which is desired to minimise damage caused by lateral loading from the seismic waves. (Swamy 2015) This concept will be further researched to identify whether it would be the best to have weak beams and strong columns or whether other options should be considered better. To summarise, in terms of structure the information that can be gathered from many books can be used to produce an ideal design for a multi-storey building in the Philippines. The resources will aid in determining the importance of structural design for earthquake resistance.
Another aspect to this project will be the components of the building. The structural components are not the only hazards but also architectural. The issue is often pushed aside when designing for an earthquake resistant multi-storey building. Shooshtari et al. states that a lot of the injuries come from architectural components, electrical components and building contents. (Shooshtari et al. 2010) This includes cladding and stairways which can be considered in the project to widen the detail on the importance of earthquake resistant design. The argument of safety from these components can be brought in and new ways to minimise hazards can be researched and put in place. Another aspect in which causes deaths during earthquakes is the use of glass. Glass tends to shatter when an earthquake occurs and glass falling from heights causes deaths. The online article titled ‘Seismic Behaviour of Point Supported Glass Panels’ informs us on how hazardous and dangerous these pieces of glass are. The article also gives a brief explanation on what can be done to minimise these risks such as researching what tests have been done to ensure the best type of glass and construction to use. (Martins et al. 2013) This will help the project give out more detail on what factors which should be considered to ensure a safer design to a multi-storey building. To summarise the subject of non-structural components as hazards, it is evident that many professionals believe that there is a lack of consideration when designing a building. Although ultimately the framing of the structure is what causes stability, even earthquakes of lower magnitude can trigger a hazard from one of the components in the building – as mentioned before, glass tends to shatter when being subjected to the seismic waves so appropriate designs can be researched in order to prevent injuries or possibly even death from the broken shards of glass.
The motivation behind this project is based on the fact that the Philippines is one of the most earthquake prone countries and that the need for sustainable earthquake building design is essential to saving lives. The main aim is to design a specialised sustainable earthquake resistant multi-storey building specifically for the Philippines. Because the construction in the Philippines is not as well regulated as more developed countries, research on earthquake resistance will help prevent maximum damage to buildings and ultimately save lives. This will consider the ground conditions, economy aspect and overall stability. This research project will help to aim the weaknesses of the design of the structures, specifically multi-storey buildings, in the Philippines so that action can be taken to minimise the damages caused by these mass earthquakes.
The objectives of this project comprise of gathering data to further improve existing research on the topic of earthquake resistant building design and to find the best design for a multi-storey building which will minimise the structural damage caused by the earthquakes. This can be broken down into smaller objectives such as:
• Locate information on foundations for earthquake resistance.
• Locate information on innovative earthquake resistant construction techniques.
• Email professional on this topic.
The objectives can be broken down so that it is clear on what needs to be done to complete the project.
Another objective is to look at the existing guideline for the design of buildings in the Philippines to identify what needs improving – From the information gathered on Philippines current designs against earthquakes, we can find the improvements needed. Finally, sustainability will be strongly accounted for as it is a third world country, the economical aspects of construction must be considered in order to achieve realistic solutions to the problem.
Qualitative analysis will be used during this project as the effects from these earthquakes on the design of structures can not be easily obtained and therefore the opinions of professionals in the field will be needed. Since the project will be based in the Philippines, I would need to contact these professionals via email. They can give information on the basic construction of multi-storey buildings in the Philippines. Once that data is collected, I can revise what has been given to me and identify what needs improving in order to get a sustainable seismic resistant structure design.
Experiments in the university laboratory will not be conducted as the results we would obtain by imitating a scaled down earthquake scenario will not give accurate and usable results. For this project, my main research method will be reviewing case studies and books. Most of the case studies will be found on the internet. After collecting many different resources from the library and internet, they can be compared to see the most viable option to achieving the best affordable and sustainable multi-storey building. As this project theme has already been researched previously, it will be ideal to gather different resources to identify a gap within the research of this theme. This means that the majority of this project will be the collection of secondary data. A lot of secondary data must be collected so that the project is not biased and takes the ideas of other sources, not just one or two.
Another method I will incorporate into my project is a literature analysis. This will be analysing the research collected and making it relevant to my project. This will ultimately bring my project together.
There are many resources which can be used for research. A number of books have been written in this subject area and there are many sources on the internet which specifically discuss the topic of earthquake resistant building design. The Coventry University library is filled with books on this subject so attaining adequate information will be of ease. Another resource could be the opinions from the professionals.
However, this project will have its limitations and the maths involved will be based on assumptions. The accuracy of the mathematics will be imprecise as this is due to the fact that the shear size of the structures and earthquakes can not be scaled down to be done in a laboratory giving accurate results and data. Equations which are gathered from different sources will be used instead as no actual personally collected data will be present.
Since the research conducted will collect secondary data, another limitation to this project will be the idea that documents and data collected may lack authenticity as it may not be possible to verify the authenticity and credibility of the authors. Another limitation is that if an email was sent to a professional civil engineer in the Philippines, it may consume time as the reliability of getting a reply would be questionable.