Earthquake Engineering Specialized 413a PDF

EARTHQUAKE ENGINEERING SPECIALIZED 413a  Earthquake Resistive Construction Earthquake Engineering the study of the behavior of buildings and structures subject to seismic loading It can be defined as the branch of engineering devoted to mitigating earthquake hazards. In this broad sense,...

EARTHQUAKE ENGINEERING SPECIALIZED 413a  Earthquake Resistive Construction Earthquake Engineering the study of the behavior of buildings and structures subject to seismic loading It can be defined as the branch of engineering devoted to mitigating earthquake hazards. In this broad sense, earthquake engineering covers the investigation and solution of the problems created by damaging earthquakes, and consequently the work involved in the practical application of these solutions, i.e. in planning, designing, constructing and managing earthquake-resistant structures and facilities. General Goals in Seismic-Resistant Design and Construction The philosophy of earthquake design for structures other than essential facilities has been well established and proposed as follows: a. To prevent non-structural damage in frequent minor ground shaking b. To prevent structural damage and minimize non-structural damage in occasional moderate ground shaking c. To avoid collapse or serious damage in rare major ground shaking  Earthquake Resistant Techniques  The technologies in earthquake engineering to protect buildings from damaging earthquake effects are: Earthquake SEISMIC VIBRATION CONTROL Resistant Techniques SEISMIC RETROFITTING  SEISMIC VIBRATION CONTROL When ground seismic waves reach up and Seismic vibration control start to penetrate a base of a building, their is a set of technical energy flow density, due to reflections, means aimed to mitigate reduces dramatically: usually, up to 90%. seismic impacts in However, the remaining portions of the building and nonbuilding incident waves during a major earthquake structures. still bear a huge devastating potential. All seismic vibration control devices may be classified as passive, active or hybrid where:  passive control devices have no feedback capability between them, structural elements and the ground (TMD, TLD, viscous fluid and friction, base isolation)  active control devices incorporate real-time recording instrumentation on the ground integrated with earthquake input processing equipment and actuators within the structure; (AMD)  hybrid control devices have combined features of active and passive control systems. (HMD)  SEISMIC VIBRATION CONTROL Base isolation, also known as seismic base isolation or base isolation system, is one of the most popular means of protecting a structure against earthquake Seismic Base forces. Isolation  SEISMIC VIBRATION CONTROL A base isolated structure is supported by a series of bearing pads, which are placed between the buildings and building foundation. Seismic Base It is a collection of structural elements which should Isolation substantially decouple a superstructure from its substructure resting on a shaking ground thus protecting a building or non- building structure's integrity.  SEISMIC VIBRATION CONTROL Seismic Base Isolation  SEISMIC VIBRATION CONTROL Seismic Base Isolation  SEISMIC VIBRATION CONTROL  Dry-stone walls control  Lead rubber bearing Seismic  Spherical sliding base isolation Vibration  Tuned mass damper  Friction pendulum bearing Control  Building elevation control  Simple roller bearing Technologies  Springs-with-damper base isolator  Hysteretic damper  SEISMIC VIBRATION CONTROL  Dry-stone walls control Seismic Vibration Control Technologies Dry-stone walls of Machu Picchu Temple of the Sun, Peru  SEISMIC VIBRATION CONTROL  Dry-stone walls control Seismic Vibration Control Technologies  SEISMIC VIBRATION CONTROL  Lead rubber bearing Seismic LRB is a type of base isolation employing a heavy damping. It was invented by Bill Robinson, a New Zealander. Vibration Control Lead-rubber bearings are the frequently-used types of base isolation bearings. A lead rubber bearing is made from layers Technologies of rubber sandwiched together with layers of steel.  SEISMIC VIBRATION CONTROL  Lead rubber bearing Seismic Vibration Control Technologies  SEISMIC VIBRATION CONTROL  Lead rubber bearing Seismic Vibration Control Technologies  SEISMIC VIBRATION CONTROL  Spherical sliding base isolation Seismic Spherical sliding isolation systems are another type of Vibration base isolation. The building Control is supported by bearing pads that have a curved surface Technologies and low friction.  SEISMIC VIBRATION CONTROL  Spherical sliding base isolation Seismic Vibration Control Technologies  SEISMIC VIBRATION CONTROL  Tuned mass damper Seismic Typically, the tuned mass dampers are huge concrete blocks mounted Vibration in skyscrapers or other structures and moved in opposition to the Control resonance frequency oscillations Technologies of the structures by means of some sort of spring mechanism.  SEISMIC VIBRATION CONTROL  Tuned mass damper Seismic Vibration Control Technologies Taipei 101 (Taipei, Taiwan)  SEISMIC VIBRATION CONTROL  Tuned mass damper Seismic Vibration Control Technologies  SEISMIC VIBRATION CONTROL  Friction pendulum bearing Seismic  articulated friction slider; Vibration  spherical concave sliding Control surface;  enclosing cylinder for Technologies lateral displacement restraint.  SEISMIC VIBRATION CONTROL  Friction pendulum bearing Seismic Vibration Control Technologies  SEISMIC VIBRATION CONTROL  Building elevation control Seismic Pyramid-shaped skyscrapers continue to attract the Vibration attention of architects and engineers because such Control structures promise a better Technologies stability against earthquakes and winds.  SEISMIC VIBRATION CONTROL  Springs-with-damper base isolator Seismic These base isolators move and stretch under Vibration pressure and absorb much of an earthquake's Control impact by reducing Technologies swaying and shaking during an earthquake.  SEISMIC VIBRATION CONTROL  Springs-with-damper base isolator Seismic Vibration Control Technologies  SEISMIC VIBRATION CONTROL  Hysteretic damper Seismic Hysteretic damper is intended to provide better and more reliable seismic performance than that of a conventional Vibration structure at the expense of the seismic input energy dissipation. Control Technologies  SEISMIC VIBRATION CONTROL  Hysteretic damper Seismic There are four major groups of hysteretic dampers used for the purpose, namely: Vibration  Fluid viscous dampers (FVDs) Control  Metallic yielding dampers (MYDs)  Viscoelastic dampers (VEDs) Technologies  Friction dampers (FDs)  SEISMIC VIBRATION CONTROL  Hysteretic damper Seismic  Fluid viscous dampers (FVDs) energy is absorbed by silicone-based fluid passing Vibration between piston cylinder arrangement. Control  Metallic yielding dampers (MYDs) Technologies energy is absorbed by metallic components that yield  SEISMIC VIBRATION CONTROL  Hysteretic damper Seismic  Fluid viscous dampers (FVDs) energy is absorbed by silicone-based fluid passing Vibration between piston cylinder arrangement. Control  Metallic yielding dampers (MYDs) Technologies energy is absorbed by metallic components that yield  SEISMIC VIBRATION CONTROL  Fluid viscous dampers (FVDs) Seismic Vibration Control Technologies  SEISMIC VIBRATION CONTROL  Hysteretic damper Seismic  Viscoelastic dampers (VEDs) energy is absorbed by utilizing the controlled shearing Vibration of solids. Control  Friction dampers (FDs) Technologies energy is absorbed by surfaces with friction between them rubbing against each other.  SEISMIC VIBRATION CONTROL  Hysteretic damper Seismic Vibration Control Technologies  SEISMIC VIBRATION CONTROL  Hysteretic damper Seismic Vibration Control Technologies The Yokohama Landmark Tower This building equips within itself a Hyb mass damper (a combination of tuned m damper and an active control actuator) well as something called “bandage pilla These are earthquake resisting pillars th are designed with the help of resin fibres th essentially may allow some chunks of t pillar to fall off but prevent it from collaps in case of an earthquake. Reinforce the Building’s Structure To withstand collapse, buildings must redistribute forces that travel through them during a seismic event. Shear walls, cross braces, diaphragms and moment-resisting frames are central to reinforcing a building. Shear walls are a useful building technology that can help transfer earthquake forces. Made of multiple panels, these walls help a building keep its shape during movement. Shear walls are often supported by diagonal cross braces made of steel. These beams can support compression and tension, helping to counteract pressure and push forces. Cross braces attach to a building’s frame by bracing stud to stud in an X pattern to increase load capacity. The use of cross-bracing keeps buildings stable against high winds and seismic activity. Diaphragms are also a central part of a building’s structure. Consisting of the building’s floors, roof and the decks placed over them, diaphragms help remove tension from the floor and push forces to the building’s vertical structures. Moment-resisting frames provide additional flexibility in a building’s design. These structures are placed among a building’s joints and allow columns and beams to bend while the joints remain rigid. Thus, the building can resist the larger forces of an earthquake while still allowing designers the freedom to arrange building elements. Shield Buildings from Vibrations Rather than just counteracting forces, researchers are experimenting with ways buildings can deflect and reroute the energy from earthquakes altogether. Dubbed the “seismic invisibility cloak,” this innovation involves creating a cloak of 100 concentric plastic and concrete rings and burying it at least 3 feet beneath the foundation of the building. As seismic waves enter the rings, ease of travel forces them to move through to the outer rings. As a result, they are essentially channeled away from the building and dissipated into the ground. Taipei 101 has a secret weapon to keep it safe – a Taipei 101 (Taipei, Taiwan) giant steel ball that sways like a pendulum to counterbalance earthquakes and typhoons. Suspended from the upper floors of the pagoda- inspired skyscraper, the 660 metric-ton, 5.5- meter-wide ball is a “tuned mass damper”. Its design limits the movement of the 508-meter- high tower near a fault line. Dozens of steel columns, as well as eight concrete-filled mega columns inside Taipei 101 create a sturdy frame, bolstered by outrigger trusses. Engineers reinforced its foundations by driving hundreds of piles driven deep into the bedrock below. Taipei 101 is perhaps one of the most mesmerizing supertall skyscrapers in the world. The exterior design (by C.Y. Lee) was inspired by the phrase, “we climb in order to see further.” Putting aside the architecture, the mind-blowing fact about Taipei 101 is that it houses the world’s most significant tuned mass damper (TMD)! It’s a giant metal ball that counteracts significant transient loadings like wind and earthquakes to reduce the sway of the supertall tower. The TMD is supported by hydraulic damper arms and bumper systems, which function in the same way as a car’s shock absorber. When large forces act upon the tower, the TMD sways in the opposite direction, bringing the entire building into equilibrium by damping the transient forces using the ball’s mass. This earthquake damper system is located between the 87th floor and 92nd floors. TORRE REFORMA, MEXICO CITY Ensuring new skyscrapers are quake-resistant is critical in Mexico City, whose foundation by the Aztecs on a wobbly lake bed makes it vulnerable to tremors. Set on the city’s main artery, the triangular Torre Reforma is an “open book” shaped tower, with two walls of reinforced shear concrete and a glass façade. It’s designed to move. Flexible hinges feature on the glass front which has “crumple zones” allowing it to shift in a quake. Irregular gaps punched in the concrete outer walls of the 246-meter tower allow them to bend instead of crack while coupling beams help to dissipate energy. Additionally, the concrete walls sink 60 meters below ground to give stability to architect L. Benjamin Romano’s design. Engineers say simulated tests show Torre Reforma could withstand any earthquake over the next couple of millennia. Ranked as the world’s biggest earthquake-resistant building, Istanbul’s Sabiha Gokcen airport terminal stretches over 400,000 square meters. It can withstand a tremor reaching up to 8 on the Richter scale. Located in a seismically active zone – where the 1999 Izmit earthquake killed over 17,000 people – the terminal is on top of hundreds of energy-absorbing isolators. These separate it from the ground and reduce potentially devastating lateral forces by up to 80 percent. Engineered by Arup, it moves from side-to-side as a single unit to limit damage and protect passengers. The terminal’s engineers tested the design to make sure it would stand up to 14 earthquake scenarios. SABIHA GOKCEN TERMINAL, ISTANBUL One of the major airports to serve the historical city of Istanbul, it also happens to be one of the world’s most earthquake-proof buildings. Sabiha Gökçen is one of the two international airports in Istanbul, Turkey, which is located near the North Anatolian fault. It was designed by the engineering firm Ove Arup to have 300 base isolator systems that can withstand an earthquake of up to a maximum of 8.0 Mw (moment magnitude). The base isolators can reduce lateral seismic loadings by 80%, which makes it one of the largest seismically isolated structures in the world. One of the airport’s major features that makes it earthquake-resistant is its so-called “triple friction pendulum device.” Architects Journal explains that “the whole terminal building sits on a platform that is, to a high degree, isolated from the ground below. This enabled the team to design the terminal as though it were situated in a non- seismic location and to include features such as [structures with] large spans because the platform and pendulum devices mean that violent lateral ground movements will scarcely affect it.” The airport’s triple friction pendulum bearing was manufactured by Earthquake Protection Systems (EPS). They use the principle of a basic pendulum to prolong a structure’s isolation during serious earthquake events. When an earthquake hits the structure, the airport’s earthquake-proofing structures move with small pendulum motions. Earthquake-induced displacements occur primarily in the bearings, so lateral loads and movements transmitted to the structure are significantly reduced. THE TRANSAMERICA PYRAMID, SAN FRANCISCO The devastating Loma Prieta earthquake of 1989 was a test to the tremor-resistant design of the 48-floor landmark. It shook and swayed for a minute, and emerged intact. Designed as pyramid to allow natural light to filter down to the streets below, the structure’s wide base gives it stability. Looking to limit the degree by which would twist and shake in a quake, engineers used a unique truss system. Below ground, its steel and concrete foundations lay 15 meters into the rocks below and move with the horizontal earthquake forces. On the outside, steel rods on each floor of the building reinforce the precast quartz-coated exterior. The Transamerica Pyramid is an iconic 1970s structure in the Californian city of San Francisco, which sits closely beside the San Andreas and Hayward faults. In 1989, the Loma Prieta earthquake struck the area at a magnitude of 6.9 Mw which caused the top story of the structure to sway by almost one foot (30 cm) from side to side for more than a minute, but the building stood tall and undamaged. This earthquake resistance feat can be attributed to the 52- foot-deep steel and concrete foundation designed to move with seismic loadings. Vertical and horizontal loadings are supported by a unique truss system above the first level, with interior frames extending up to the 45th level. The complex combination of these structural systems makes the building resistant to torsional movements and allows the absorption of sizeable horizontal base shear forces. FA-BO, NOMI CITY Enveloped by a web of cables, Japan’s Fa-Bo building might look as if it’s been attacked by Spider-Man, but the high-tech system withstands quakes and tsunamis. Architect Kengo Kuma‘s design inverts many earthquake-resistant plans by relying on support from the outside rather than a strengthened internal core. The thermoplastic carbon fiber composite cables anchoring the three-story concrete building are much stronger and lighter than steel, and angled to cope with lateral loads. It’s the first time carbon fiber has been used for earthquake-resistant designs. In a country facing 1,500 tremors a year, it’s going to need to stand the test. Burj Khalifa This skyscraper doesn’t require any introduction. The Burj Khalifa is simply one of the most iconic supertall structures in the world. It also happens to be an earthquake-proof building! The structure comprises mechanical floors where outrigger walls connect the perimeter columns to the interior walling. By doing this, the perimeter columns can support the lateral resistance of the structure. The verticality of the columns also helps with carrying the gravitational loads. As a result, the Burj Khalifa is exceptionally stiff in both lateral and torsional directions. A complex base and foundation design system was derived by conducting extensive seismic and geotechnical studies. The Mori Tower finished construction in 2003 and features some of the most advanced earthquake resistant technology. The Mori Tower also uses internal damper systems, but what differs is they have chosen to use 192 fluid-filled shock absorbers. These absorbers are filled with thick oil and when the tower begins to sway due to weather, the oil moves in the other direction of the wind to minimize swaying. Mori Tower (Tokyo, Japan)  The Philippine Arena is the world’s largest domed Philippine Arena arena and is a fantastic earthquake-proof structure. It is owned by the Christian group Iglesia Ni Cristo (INC), which commissioned this 55,000 seating capacity arena for its 100th anniversary three years ago on July 27, 2014. It is also the centerpiece of the Ciudad De Victoria tourism enterprise zone in Bulacan, Philippines. The Australian architecture firm Populous and the elite engineering firm Buro Happold designed the arena. The Philippine plate sits along the Pacific Ring of Fire, home to the world’s most notorious and active chain of earthquake fault lines. Previous earthquakes in the country have reached as much as 8.2 Mw and have claimed thousands of lives. Seismic activities have also been responsible for volcanic eruptions and tsunamis in the region. Philippine Arena’s vast stadium roof, spanning 170m, was engineered to withstand severe transient loadings such as earthquakes, winds, and typhoons. During an earthquake, the lateral loads generated throughout the structure can reach up to 40% of its mass. This allows the base and foundation system to move freely with the earthquake’s force while the top structure remains stationary. This is genuinely a fantastic earthquake engineering feat! Buro Happold cleverly responded with an independent base design for the entire structure, meaning that the arena’s main structural body is isolated from its base and foundation. The gap between the main structure and base foundation system is composed of lead rubber bearings (LRB), a flexible arrangement of materials with high energy dissipation properties Petronas Twin Tower, Malaysia Architect: César Pelli Year of completion: 1999 This iconic structure remained the tallest skyscraper in the world well until the year 2004. This still, however, remains the tallest twin tower in the world at a whopping height of 452m. The two glass towers are connected with a centralized 2 storey bridge. This feature is not only aesthetic addition but also is designed to slide in and out of the building every time there seem to be substantial lateral loads acting upon the building. One Rincon Hill South Tower, USA The rather unique feature about this high-end residential tower is the tuned liquid mass damper atop the 60 storey structure. It is essentially a 5 feet tall tank filled with 50,000 gallons of water that flows the opposite side of the sway to decrease the impact on the inhabitants.  In the early 1920s, Roque Ruaño was chosen to craft the blueprints for the University of Santo Tomas: Dubbed as the First University of Santo Tomas (UST) Main earthquake-resistant building in the Philippines Building, which was to be established on the Sulucan property of the Dominican Order. By 1922-23, the drafts were complete, which marked a significant milestone for the project. During this time, there was a growing consciousness in the architectural community regarding the importance of factoring in earthquake- resistance measures in building design. This crucial consideration led to the decision to revise the blueprints in light of what had been learned from the Great Kanto earthquake of September 1, 1923. This devastating seismic event levelled the cities of Tokyo and Yokohama. Still, its lessons would help ensure that the UST Main Building was built to withstand seismic activity in the region. After incorporating these design adjustments, construction of the Main Building finally began in 1924. Is Your House Earthquake Proof? How Can I Earthquake-proof my House in the Philippines? Last June 15th, a 6.3 magnitude earthquake shook the lands of Calatagan, Batangas that awakened a large portion of the country in a sudden jolt. According to a report by Rappler, the powerful shake has a depth of 1.3 kilometers. The Philippine Institute of Volcanology and Seismology (PHIVOLCS) warned the public of aftershocks reaching up to Intensity IV in Metro Manila and nearby cities. In the event of a major earthquake, not only the lives of people are at risk, but the safety and strength of buildings and establishements as well. Earthquakes are nature’s way of displaying its formidable force, with the potential to wreak havoc in communities, leaving behind a trail of destruction of structures. As the Philippines sit within the Pacific Ring of Fire, it is prone to experiencing seismic activities with varying magnitudes and intensities that may cause destruction to properties. As the Philippines continue to face the threat of earthquakes, safeguarding homes against these tremors becomes an essential priority for homeowners. Which then leads us to the question, “Is my House Earthquake Resilient?” In this article, we will take a look at the features of earthquake resistant buildings as well as how you can integrate them into your home. How Can I earthquake-proof my House in the Philippines? Build a flexible foundation BigRentz shares some insights on how earthquake resistant structures are designed. And one of the crucial components is the flexible foundation of the establishment. When the plates beneath the arth move, they send tremors that may cause a building or establishment to crumble down. That’s why a sound and flexible foundation is extremely crucial. Big Rentz states that one of the ways to withstand earthquakes is to ‘lift the building’s foundation above the earth through a method called base isolation.’ The building is constructed on top of flexible pads that are usually made of steel, rubber, and lead. These systems of padded cylinders and ball bearings serve as shock absorbers that absorb seismic waves when an earthquake occurs. Taking this context in home construction, Civil + Structural Engineer suggests to ‘place a solid foundation slab made of reinforced concrete and crisscrossing strips atop an intermediate cushion of sand.’ A house built with a foundation made with reinforced concrete slabs can withstand the shaking during earthquakes. Not to forget, earthquake proof buildings should be built on a stable and strong soil. Reinforce the building’s structure To prevent the collapse of the property, the force of the earthquake should be evenly distributed. There are several essential elements to achieve this: Diaphragms – The best examples of diaphragms are floors and roofs. They are beams built with their own decks that distribute the earthquake force to the vertical elements of the building, minimizing the earthquake damage. Shear walls – Shear walls prevent the swaying of the building by stiffening the structure’s frame. These panels are usually supported by diagonal cross braces made of steel. Moment-resisting frames – When it comes to flexibility, the moment-resisting frames get the job done. Optimum Seismic describes these as ‘an assembly of beams and columns in which those beams are flexible, but are rigidly connected to the columns.’ The way it is constructed allows the beams to sway while the joint remains steady and rigid. Trusses – Trusses are diagonal structures that give additional strength to the diaphragm’s weak points. Cross-bracing – This diagonal intersecting system aims to revert the seismic waves back to the ground. Shore up your windows Building earthquake resistant structures also takes windows into consideration, too. Glass windows may shatter that can cause injury to your family. That’s why it’s important to shore up your windows to hold the glass in place in case it shatters. Install light roofing It is a rule of thumb that building earthquake proof homes means installing light roofing. Check out our article about choosing the right roofing for your home in the Philippines. Integrate innovative materials When building earthquake proof houses, the quality and type of materials should also be taken into consideration aside from the construction. Reinforced concrete and wood are some of the favored earthquake resistant materials used in building houses within an earthquake zone as they remain intact under strong forces of seismic activity. Big Rentz further states that innovative materials such as memory alloy are taken into consideration as they can also withstand seismic activity while maintaining their shape. A fiber-reinforced plastic made up of a variety of polymers provides 38% added strength and stability when wrapped around a column. Moreover, a research conducted by Indian Institute of Technology Roorkee shows that thermocol– Expanded Polystyrene (EPS) can be used as a material to build earthquake resistant homes. Aside from that, their test revealed that this unconventional material also provides excellent thermal insulation and performs well at energy conservation in construction. In addition, scientists and engineers are also tapping into nature to counter the force of nature itself through bamboo, mussels, and spider silk. If your house is made-up of materials like stucco or brick that are usually less earthquake resistant, you may have to conduct a seismic retrofitting to reinforce your house and withstand earthquake forces. What is Seismic Retrofitting? The concept of earthquake-proofing, also known as seismic retrofitting, has emerged as a critical approach to mitigating the devastating impacts of seismic events on residential structures. Earthquake-proofing entails implementing structural modifications and engineering strategies that enhance a building’s ability to withstand the forces unleashed during an earthquake. From reinforcing foundations and strengthening load-bearing walls to securing fixtures and utilities, the process involves a comprehensive evaluation and implementation of measures tailored to the specific needs of each home. Check your house’s earthquake resiliency through the Phivolcs app The Philippine Institute of Volcanology and Seismology (Phivolcs) has launched a self-check app that will aid homeowners in evaluating the resiliency and structural integrity of their house against natural disasters like earthquakes. The app ‘How Safe Is My House?’ answer 12-point questions which are as follows: 1. Who built or designed my house? 2. How old is my house? 3. Has my house been damaged by past earthquakes or disasters? 4. What is the shape of my house? 5. Has my house been extended or expanded? 6. Are the external walls of my house 6inch (150mm) thick CHB? 7. Are steel bars of standard size and spacing used in walls? 8. Are there unsupported walls more than 3 meters wide? 9. What is the gable of my house made of? 10. What is the foundation of my house? 11. What is the soil condition under my house? 12. What is the overall condition of the house? The app also has a website version that can be accessed here. Final Takeaway Earthquakes can have devastating consequences, causing loss of life, destruction of property, and long-term economic and social impacts. However, through careful planning, engineering expertise, and the incorporation of innovative technologies, it is possible to construct homes that can withstand the unpredictable shake with minimal damage. By implementing seismic design principles, such as reinforced foundations, flexible building materials, and strategic bracing systems, homeowners can significantly increase the structural integrity of their homes. These measures help dissipate the energy generated during an earthquake and prevent it from causing catastrophic damage. Additionally, advanced construction techniques and materials, such as base isolation and damping systems, can further enhance the resilience of buildings against seismic events. An earthquake-resilient home not only protects the lives of its occupants but also helps communities recover more swiftly after a disaster. By minimizing structural damage, the need for extensive repairs or even reconstruction can be reduced, saving valuable time and resources. This is particularly crucial in regions prone to frequent seismic activity, where the ability to bounce back quickly is essential for social and economic stability. Building an earthquake-resistant home is a proactive and necessary measure to protect lives, preserve property, and promote the overall resilience of communities. It is a collective effort that requires collaboration between various stakeholders to create a safer and more sustainable built environment. By investing in earthquake-resistant housing, we can mitigate the impacts of earthquakes and ensure a safer future for generations to come. Taishin, the minimum requirement, mandates that walls, beams, and pillars have a minimum thickness to cope with shaking. Seishin, recommended for high-rise buildings, uses dampers that absorb much of the energy of an earthquake. Menshin, the most advanced and expensive form, isolates the building structure from the ground using layers of lead, steel, and rubber, allowing the building to move little during severe quakes. In addition to these standards, Japanese buildings incorporate innovative features such as steel frames, diagonal dampers, pendulums, mesh structures, and connections to the country’s early warning system. These features help reduce the impact of earthquakes and increase the survivability of the buildings. Case studies of earthquake-resistant buildings in Japan Article continues after this advertisement The Tokyo Skytree and the Shinjuku Mitsui Building are prime examples of Japan’s earthquake-resistant design principles. The Tokyo Skytree, one of the tallest buildings in the world, uses seismic dampers on its base connected to a central pillar that absorbs an earthquake’s shock. The Shinjuku Mitsui Building, meanwhile, has several 300-ton pendulums retrofitted on its roof to counteract the building’s side-to-side movement during a quake. Lessons for the Philippines The Philippines can draw several lessons from Japan’s approach to earthquake-resistant architecture. Read more: https://business.inquirer.net/406091/adopting-japans-earthquake-ready- architecture#ixzz8kKhobjwb Follow us: @inquirerdotnet on Twitter | inquirerdotnet on Facebook First, adopting and enforcing strict building codes like Japan’s standards can ensure that all new buildings can withstand earthquakes. Incorporating earthquake-resistant features such as dampers, steel frames, and pendulums can likewise significantly reduce the damage caused by earthquakes. Investing in early warning systems can provide valuable time for people to take cover before an earthquake hits, while retrofitting existing buildings with earthquake-resistant features can help reduce the damage caused by future earthquakes. Read more: https://business.inquirer.net/406091/adopting-japans-earthquake-ready-architecture#ixzz8kKhv2dWC Follow us: @inquirerdotnet on Twitter | inquirerdotnet on Facebook  SEISMIC RETROFITTING Even as current practice of seismic retrofitting is Modification of existing predominantly concerned with structural improvements to reduce the seismic hazard of using the structures, it is structures to make them similarly essential to reduce the hazards and losses more resistant to from non-structural elements. It is also important to seismic activity, ground keep in mind that there is no such thing as an motion, or soil failure earthquake-proof structure, although seismic performance can be greatly enhanced through proper due to earthquakes. initial design or subsequent modifications.  SEISMIC RETROFITTING  Increasing the global capacity (strengthening) This is typically done by the addition of cross braces or new structural walls.  Reduction of the seismic demand Strategies by means of supplementary damping and/or use of base isolation systems.  Allowing sliding connections such as passageway bridges to accommodate additional movement between seismically independent structures  SEISMIC RETROFITTING  Increasing the local capacity of structural elements This strategy recognizes the inherent capacity within the existing structures, and therefore adopts a more cost-effective approach to selectively upgrade local capacity of individual structural components. Strategies  Selective weakening retrofit This is a counter intuitive strategy to change the inelastic mechanism of the structure, whilst recognizing the inherent capacity of the structure.  SEISMIC RETROFITTING Common seismic retrofitting techniques fall into several categories: External post-tensioning Strategies Supplementary dampers Slosh tank Active control system Ad hoc-addition of structural support/reinforcement  SEISMIC RETROFITTING  External post-tensioning Strategies  SEISMIC RETROFITTING  External post-tensioning Strategies  SEISMIC RETROFITTING  Supplementary dampers Strategies  SEISMIC RETROFITTING  Slosh tank Strategies  SEISMIC RETROFITTING  Active control system include at some upper story a large mass, constrained, but free to move within a limited range, and moving on some sort of bearing system such as an air cushion or Strategies hydraulic film.  SEISMIC RETROFITTING  Ad hoc-addition of structural support/reinforcement The most common form of seismic retrofit to lower buildings is adding strength to the existing structure to resist seismic forces. The strengthening may be limited Strategies to connections between existing building elements or it may involve adding primary resisting elements such as walls or frames, particularly in the lower stories.  SEISMIC RETROFITTING  Infill Shear Trusses Strategies  SEISMIC RETROFITTING  Massive Exterior Structure Strategies SEISMIC RETROFITTING  LA City Hall, retrofitted with base isolation In 1998 the building was closed during a total $135 million refurbishment which also included upgrading it so it could withstand a magnitude 8.2 earthquake including permitting it to sway in a quake.  Pasadena City Hall San Francisco City Hall The Loma Prieta earthquake of 1989 damaged the To help ensure it would withstand future earthquake structure, and twisted the dome four inches (102 mm) activity, the building was lifted off its foundation, on its base. Afterward, under the leadership of the San equipped with structural base isolators and given a new Francisco Bureau of Architecture in collaboration with foundation. Carey & Co. preservation architects, and Forell/Elsesser Engineers, work was completed to render the building The renovation has been among the costliest public earthquake resistant through a base isolation works projects in Pasadena, totaling $117 million, city system,[notes 1] which would likely prevent total officials decided that they couldn't risk losing the collapse of the building landmark in another quake Salt Lake City and County Building This was done in concert with a seismic upgrade called base isolation that placed the weak sandstone structure on a foundation of steel and rubber to better protect it from earthquake damage. Utah State Capitol building, USA Architect: Richard K. A. Kletting Year of completion: 1916 (with later seismic upgrades in 2004) This neoclassical Corinthian-styled classic colonnaded façade of a structure resembles the strength and repose a government building was once intended to. However, there were quite a few later innovations that were introduced to the structure’s foundation to deal with the earthquake situation in the region. It was designed to withstand up to 7.3 magnitude earthquakes while keeping the classical aura of the building intact. This base isolation system bears 281 lead-rubber laminated base isolators attached to the building foundation with the help of steel plates. In the event of an earthquake, every hard impact is absorbed by the rubber isolators while also gently shaking the building back and forth, so there is no damage or collapse.