Seismic Structural Analysis and Design of Building

(Last Updated On: December 6, 2017)
The principle aim of the structural design is to prepare necessary data for the construction of the structure, which shall possess adequate strength and stability during the action of all possible loads in its life span. The process consists of
integration of consideration of design regulation, local condition and functional need. The behaviors of the structure in terms of stresses and strength have to be determined closer to the reality when subjected to the possible actions The subject matter, such as, the properties and mechanics of the materials, analytical methods, design techniques and production of the construction documents, studied in isolation to address in an integral approach to arrive at the creation of the needful structure. This report summarizes structural analysis and design of a building. In general context of the country, Nepal, the building is located in seismic zone V, with the considerable medium denseness sand. According to the seismographs and risk zoning maps, the country lies in a very high seismically active zone. 
Thus, the seismic structural design of structures is found to be very essential for countries like Nepal. The structures
need to be designed and detailed so as to counteract, the internal forces induce due to the earth mass shaking in base of these structures. The design should ensure the structure against stability, strength and serviceability with acceptable levels of seismic safety. Both code basic seismic analysis, and performance based seismic analysis of the structure was made to ensure further building safety.
Code basic seismic analysis is prescriptive measure, which is based on design basic earthquakes [DBE levels]. In this method, assumption is based on: The maximum considered earthquake [MCE levels] occurrences are not so frequent; it would not be economically feasible to design the building so as to ensure that they remain elastic
and damage-free. Thus it is reliable to design the ductile structure and not to design damage free structure during the major earthquake. The building has been designed as earthquake resistant design, i.e. building should not be collapsed during major earthquake. The design shall ensure the structure against stability, strength and serviceability with acceptable levels of seismic safety.
In case of earthquake analysis and load to be considered with their appropriate load combination, the more stringent requirement among the listed codes ACSE based load combination and IS Earthquake in the structural design criteria for school buildings [SDC-SB] has been used. The analysis has been based on IS 1893-2002 and RCC design has been based on ACI 318-2008. Considering the requirements of service and seismic loading the structure is prone to, detail structural analysis and design is carried out.
Performance based seismic analysis gives a clear insight about the building response, and the targeted level of building performances, like, life-safety and Collapsepreventions using actual ground motion data’s [ In our instance Nepal April 25 and Electro Earthquake] for return period of 1000 years and 2000 years. The performance based analysis of the building was performed as per ASCE41 design standards. The Code basic ground motions, and April 25th 2015, Gurkha Earthquake ground motion are considered during this analysis. The actual data for April 25 Gurkha, its scaled data to target IS spectrum photos are attached in Annex of this report.
The purpose of this report is to summarize structural analysis and design of proposed school building to be constructed at Godavari inside Mahendra Aadarsha Ma vi premises. This project includes construction of two story with one additional extension floor [all together three floor] School building.
Basic structural system of the building is specially designed Reinforced Concrete Moment Frame. The floor diaphragms of the building is of reinforced concrete solid slab of 125 mm thick. The sizes of columns ranging from 400mm x 400mm to 600mm x 600mm, and the sizes of beams ranging from 300mm x 350mm to 350x550 mm. The
foundation system of the building is isolated/ combined foundation with two level of tie beams- one at the base of foundation and other at plinth. Sizes of plinth beams are ranging from 300x350 mm to 350mm x 550mm.
The building is designed to satisfy Indian code which is more stringent than Nepal Building code for design basic earthquake [DBE ] level and ACI 31-2008 for RCC design criteria for this school building. Both the Code basic and the performance based analysis of the building were made. ASCE41 designed criteria is used in performance based analysis- two basic step of analysis, Analysis-1 and Analysis-2 was as seismic ground motion during analysis.

Seismic Structural Analysis and Design of Building
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