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NOVEMBER 2018 DARBANDIKAN EARTHQUAKE OBSERVATIONS

Understand earthquakes, Elastic Rebound Theory, impacts, and building structures' reinforcement from Dr. Ahmet Öztaş, highlighting economic and societal consequences.

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NOVEMBER 2018 DARBANDIKAN EARTHQUAKE OBSERVATIONS

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  1. NOVEMBER 2018 DARBANDIKAN EARTHQUAKE OBSERVATIONS PROF. DR. AHMET ÖZTAŞ ISHIK UNIVERSITY

  2. What are Earthquakes? • The shaking or trembling caused by the sudden release of energy • Usually associated with faulting or breaking of rocks • Continuing adjustment of position results in aftershocks

  3. What is the Elastic Rebound Theory? • Explains how energy is stored in rocks • Rocks bend until the strength of the rock is exceeded • Rupture occurs and the rocks quickly rebound to an undeformed shape • Energy is released in waves that radiate outward from the fault

  4. The point within Earth where faulting begins is the focus, or hypocenter • The point directly above the focus on the surface is the epicenter The Focus and Epicenter of an Earthquake

  5. Seismographs record earthquake events At convergent boundaries, focal depth increases along a dipping seismic zone called a Benioff zone

  6. Where Do Earthquakes Occur and How Often? ~80% of all earthquakes occur in the circum-Pacific belt • most of these result from convergent margin activity • ~15% occur in the Mediterranean-Asiatic belt • remaining 5% occur in the interiors of plates and on spreading ridge centers • more than 150,000 quakes strong enough to be felt are recorded each year.

  7. The Economics and Societal Impacts of EQs Damage in Golcuk/Marmara 1999 • Building collapse • Fire • Tsunami • Ground failure

  8. Experiences • Adana/Ceyhan Eartquake, 1998, Turkey • Marmara Earhquake, 1999, Turkey • Bingol Earthquake, 2003, Turkey • Dibra Earthquake, 2008, Albania • L’Aquila Earthquake, 2009, Italy • Darbandikan Erathquake, 2017, KRG/Iraq

  9. REINFORCED CONCRETE STRUCTURE • Load Bearing Material: - Concrete + Reinforcement • Required Specifications: - Strength - Durability - Adherence (aderans) • Strength – Durability - Adherence: • W/C • Min. Cement content • Placement: Procesability Maks. Aggregate dimension Dr. Ahmet Öztaş

  10. C B A Dr. Ahmet Öztaş

  11. GRANULOMETRY • TS 706, A, B, C Curves • Between A-B ---> Most relevant • Between B-C ---> Thin • Water content • Below A Curve ---> More thick • Placement Dr. Ahmet Öztaş

  12. MAKSİMUM AGGREGATE DIMENTION b h Dmaks < b/5 Dmaks < h/3 e t Dmaks < t-5 Dmaks < 3/4e Dr. Ahmet Öztaş

  13. Elek Analizi-grafik Dr. Ahmet Öztaş

  14. How Earthquake makes Quality Check? If no relevant Design according to procedures,No quality material used,and wrong application of project on site, Either by demolishing the structures or giving damages in different levels. • Here are some Examples Dr. Ahmet Öztaş

  15. Dr. Ahmet Öztaş

  16. Dr. Ahmet ÖZTAŞ

  17. Insufficient tie Figure 2.1 insufficient of ties in contact with beam Dr. Ahmet Öztaş

  18. Demolished Building Figure 2.3 Overturned of four storeys Figure 2.4 Overturned of 2 storeys building residential building Dr. Ahmet Öztaş

  19. Confinement and Short Columns Failures mechanism Dr. Ahmet Öztaş

  20. Soft Story Two storeys building suffering from soft storey mechanism Dr. Ahmet Öztaş

  21. Wrong construction – Bingöl 2003 Y. Doç. Dr. Ahmet ÖZTAŞ

  22. General Evaluations • Poor construction quality both in terms of materials and seismic design, even in structures of recent construction which did not conform to the ACI 318 seismic design code. • Many unconfined and unreinforced masonry buildings, and reinforced concrete confined masonry buildings were in irregular geometries, poor materials and inadequate detailing. This results in low safety margins with brittle modes of failure. • The wide use of solid concrete blocks for the construction of infill walls and non-structural elements, which due to their large weight, result in an increase of the lateral forces induced by the earthquake. • Use of large openings at the ground floors to accommodate shops, commercial activities, parking and circulation of people, leading to the formation of soft-story mechanisms. Dr. Ahmet Öztaş

  23. Some Recommendations-1 • The seismic hazard of the affected area should be revised according to the current ACI 318 seismic design code, acknowledging the higher earthquake ground motions recorded during the earthquake. • The seismic provisions of the current ACI 318 seismic design code should be strictly enforced during the reconstruction phase and beyond, by means of adequate checking of the design, as well as by proper field inspection during construction. • Unconfined and unreinforced masonryconcrete block should no longer be adopted for the construction of building structures in high seismicity areas. • In construction of unreinforced and unconfined buildings, light tie beams (Rebat) and lintels should be used to protect the walls from crack formations. Dr. Ahmet Öztaş

  24. Some Recommendations-2 • In the construction of new reinforced concrete frames for the moment resisting purposes, capacity design principles should be strictly enforced, together with adequate detailing, confinement and shear resistance of joints and potential plastic hinge regions; particular attention should also be devoted to prevent short column failure modes and to ensure a proper transmission of inertial forces to the foundation. • Proper action should be taken to avoid future soft-story collapses, by acknowledging the actual stiffness contribution of infill walls in reinforced concrete frames and by recognizing the added demands induced in weak storys by the in- height irregular distribution of infill walls. Where possible, irregularities in-plan and in-height should be avoided, and use of lightweight infill walls should be encouraged. Dr. Ahmet Öztaş

  25. Some Recommendations-3 • The use of solid brick masonry for non-structural elements should be limited as much as possible and should be replaced by lighter materials, especially for the construction of parapets and facades, including those of prefabricated reinforced concrete in industrial buildings. • A coordinated programme of evaluating the vulnerability and associated risk of the existing building stock should be carefully implemented, adopting up-to-date methodologies and techniques for upgrading and retrofitting. • Civil engineers should be updated in the philosophy of Lifelong learning principles. Based on this, engineering syndicate may organize training courses and seminars for the purpose of updating engineers’ knowledge and information in parallel with new developments in engineering and science. Dr. Ahmet Öztaş

  26. Conclusion • The region is prone to EQ, • In Darbandikan/KRG/Iraq, as well as the other EQ prone countries, future EQs have high level of risk to deficient structures, • In the light of the observed damages; • Decision makers should be aware of the catastrophic nature of non-ductile structural systems, • Review the existing buildings stock • THE REMEDIAL ACTIONS MUST BE TAKEN SERIOUSLY !!!

  27. THANK YOU! Prof. Dr. Ahmet Oztas

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