Pushover Analysis: A New Procedure to Include Torsional Effects in Buildings | Chapter 3 | Theory and Applications of Engineering Research Vol. 7

Non-linear Static analysis or Pushover analysis is a very practical method fit for day-to-day use in the structural design field when compared to Non-linear Time History analysis due to its computational intensity and experienced judgement required. However, it is found that Non-linear Time History analysis is more accurate than Pushover analysis, the disadvantage being more pronounced in the case of irregular and torsional buildings. Here a new PoA method by which the eigenvectors naturally translate to force/moment vectors is proposed and investigated to find whether it predicts the responses of a torsional structure closer to NL-THA than the conventional PoA. The proposed procedure was applied to structures with different configurations, including a non-torsional one, and the results obtained were compared with those of NL-THA. The analyses were done using the structural analysis package of SAP2000 which has inbuilt functions for PoA based on both the Capacity Spectrum Method and the Displacement Coefficient Method. With conventional PoA, the torsional effects are mostly pronounced in the elastic range and early stages of plastic behaviour and tend to decrease with an increase in plastic deformations, thus failing to capture the effects of torsion in buildings. The obvious answer is the inclusion of torsional elements in the lateral load pattern, a new method by which the eigenvectors are translated to their corresponding lateral load vectors with the torsional aspect included is proposed. On investigation, it is found to overcome the above drawback and gives results closer to that of Non-linear Time History analysis, especially for irregular torsional buildings. Results obtained from the Proposed PoA method show that for torsional buildings responses are closer than the Conventional PoA method to the Time History results, while for non-torsional buildings, both methods have been found to give more or less the same result, suggesting that the proposed method can be applied to torsional buildings to get more accurate results.

Author(s) Details:

Rahul Leslie,
Buildings Design, DRIQ, Kerala Public Works Department, Trivandrum, India.

Abhilash R.,
Department of Civil Engineering, College of Engineering and Management, Punnapra, Alappuzha, India.

Saraswathy B.,
Department of Civil Engineering, T.K.M. College of Engineering, Kollam, India.

Please see the link here: https://stm.bookpi.org/TAER-V7/article/view/13682

Study on Seismic Capacity Assessment of Existing RC Building by Using Pushover Analysis | Chapter 6 | Recent Developments in Engineering Research Vol. 7

 For the most part, the infrastructure existing in Sudan is not structured or planned to withstand seismic forces. The study investigated the seismic damage in Khartoum , Sudan, to an existing 5-storey reinforced concrete structure. In the report , three performance standards were considered, which included immediate occupancy, life protection, and prevention of collapse. Using the force control approach and lateral push with displacement control, the gravity push was performed using SAP2000. The push curve, consisting of capacity spectrum, demand spectrum, and performance point, is generated by Pushover analysis. In addition to maximum base shear carrying power, it showed the performance level of building components. The demand curve has been observed to intersect the capability curve between points B and C in the X direction, which is the level of life protection, and between points B and C in the Y direction, which is the level of life safety and collapse prevention. Therefore, to be reinforced, some building elements are required. Due to its simplicity, the study concluded that pushover analysis is preferably used for static nonlinear procedures. The position of plastic hinges has been shown to suggest weak zones in a structure, which is helpful in re-strengthening existing buildings. It has been studied that by modifying member properties and re-running the study, the building can easily be stiffened or strengthened.

Author(s) Details

Dr. Mohammed Ismaeil
Department of Civil Engineering, College of Engineering, University of Prince Mugrin, Saudi Arabia and Sudan University for Science and Technology, Khartoum, 79371, Sudan

View Book :- https://bp.bookpi.org/index.php/bpi/catalog/book/299

Study on Seismic Capacity Assessment of Existing RC Building by Using Pushover Analysis| Chapter 6 | Recent Developments in Engineering Research Vol. 7

 

For the most part, the infrastructure existing in Sudan is not structured or planned to withstand seismic forces. The study investigated the seismic damage in Khartoum , Sudan, to an existing 5-storey reinforced concrete structure. In the report , three performance standards were considered, which included immediate occupancy, life protection, and prevention of collapse. Using the force control approach and lateral push with displacement control, the gravity push was performed using SAP2000. The push curve, consisting of capacity spectrum, demand spectrum, and performance point, is generated by Pushover analysis. In addition to maximum base shear carrying power, it showed the performance level of building components. The demand curve was found to overlap the capability curve between points B and C in the X direction, which is the degree of life protection, and between points B and C in the Y direction. That is the degree of life security and collapse prevention. Therefore, to be reinforced, some building elements are required. Due to its simplicity, the study concluded that pushover analysis is preferably used for static nonlinear procedures. The position of plastic hinges has been shown to suggest weak zones in a structure, which is helpful in re-strengthening existing buildings. It has been studied that by modifying member properties and re-running the study, the building can easily be stiffened or strengthened.

Author(s) Details

Dr. Mohammed Ismaeil
Department of Civil Engineering, College of Engineering, University of Prince Mugrin, Saudi Arabia and Sudan University for Science and Technology, Khartoum, 79371, Sudan.

View Book :- https://bp.bookpi.org/index.php/bpi/catalog/book/299