Earthquake Resisting Techniques on A G+10 Storey Building with the Help of Shear Walls & Bracings, using Software

From the beginning of life on Earth it is evident that natural catastrophes cause a lot of destruction to human life and property. One of the major natural phenomena is the Earthquake. Sudden shaking of ground is a difficult challenge to any structure standing on earth. Due to Improper design of the structure without seismic resistance many buildings have collapsed and lives have lost during earthquakes. Different shapes & materials of buildings have been used to achieve the strength required to withstand the earthquake. In modern era, lots of seismic force resisting techniques are being used to make a structure/building earthquake resistant. These techniques include introducing Shear walls, Bracings, base isolation, column jacketing etc. to enhance the structure. In this paper, I present a Comparative analysis of earthquake resisting techniques on a G+10 story building with the help of different types of Shear walls & Bracings, using software. The comparison is done between: an un-Resisting structure, parallel shear walls, L-shaped shear wall, diagonal bracings, X-shaped bracings & Vshaped bracings. The use of shear walls and bracings helps to strengthen then structure to make it more Earthquake resistant. The analysis in done on a G+10 building for seismic zone III as per IS 1893:2002 codal provisions. The software that I have used to carry out this analysis is Staad pro v8. It is found out that shear walls and bracing contribute largely in reducing the deflection by increasing the strength and stiffness of the building. The results of this project can further be used to enhance the seismic strength of buildings using combination of seismic resistance techniques.

Condition Assessment of Existing Concrete Building Using Non-Destructive Testing Methods for Effective Repair and Restoration-A Case Study

Buildings constructed during early 70’s & late 80’s of the last century in India are found to be in distressed conditions due to inadequate specifications and poor construction practices. The continuous monitoring of concrete structures using suitable NDT (Non Destructive Testing) methods and use of possible restoration methods help in a considerable reduction of the rate of deterioration of concrete structures thereby increasing the life span of structures. NDT methods have greater advantage in evaluating the uniformity, homogeneity, approximate compressive strength, durability, the extent of corrosion of rebars in concrete etc. of damaged structures. The objective of the present study is to enhance the life of 50 year old existing hospital building (Partly RC and Brick masonry) in Kurnool, Andhra Pradesh. Condition assessments are carried out through a visual, field and laboratory evaluation of samples collected from the structure and results are presented in this paper. The paper also highlights the assessment of strength and durability of concrete to evaluate the extent of distress and damage in the building. Besides visual inspection, the Non Destructive Evaluation covering UPV & Rebound Hammer values and Half Cell Potential with respect to the status of corrosion of reinforcing bars and chemical tests on selected un-distressed RC columns, beams, and slabs are also presented and discussed. The repair and strengthening techniques using the latest materials and possible restoration works such as column jacketing, shotcreting, anticorrosive coatings, etc. have been suggested to enhance the life of the structure.

Seismic Retrofit of a Typical School Building Using Column Jacketing and Supplement Beams

To ensure the safety of students during earthquakes, the Department of Education in Taiwan has been conducting a seismic evaluation and rehabilitation project on elementary and high-school buildings in recent years. In this project, column-jacketing is one of the most frequently used retrofit techniques due to its compatibility with existing building configurations. However, the seismic performance of column-jacketing often falls behind other retrofit techniques such as addition of shear walls. In order to enhance the seismic performance of column-jacketing, the addition of supplemental beams is proposed in this study. Analysis conducted on a typical school building based on nonlinear push-over analysis indicates that such addition could improve the seismic performance of column-jacketing for 38%, which would provide a great enhancement on the seismic safety of the retrofitted building.

PARALLEL STEEL FRAME TECHNIQUE FOR SEISMIC STRENGTHENING OF RC STRUCTURES: CASE STUDY

To strengthen reinforced concrete (RC) structures against possible future earthquakes, several techniques are used in practice such as adding new RC shear walls, column jacketing using steel or RC or carbon fibers, adding steel bracing, and using seismic isolation and dampers. To apply these techniques, the whole building or part of it should be evacuated for several months and if this building is a school or a factory it means that the building will lose its function for several months during the strengthening construction. In this paper, parallel braced steel frame strengthening technique is proposed to strengthen the low or middle raise RC structures in which all the construction works are applied from outside of the building and do not affect the building function. The main features of this technique are ensuring the view, ventilation, and sunlight from windows after the retrofitting work is done. Furthermore, using the construction steel members lead to shortening the construction term, improve in quality, and reduce costs. The idea of this technique is to reduce the earthquake displacement demand on the nonductile existing RC structures by attaching steel frames to the building floors. These frames are parallel to the structural system of the building and their foundations are connected to the existing building's foundation. In doing so, it is expected that during an earthquake the building's interstory drifts will reduce in half and prevent building collapse. The parallel steel frames can be designed to the desired limit states using performance-based design method in FEMA or Turkish earthquake code. A study case of a factory building in Turkey is presented. The seismic performance of the building before and after the strengthening was evaluated according to the Turkish earthquake code TERDC-2007. Analysis results indicate the effectiveness of the proposed technique.