Analysis and Design of High Rise Buildings using ETABS and Foundation Design using SAFE for Seismic Loads

Earthquakes generate a seismic load that can be destructive to structures. Seismic design is essential in ensuring that buildings remain functional even after earthquakes. It is important for learners to understand the effects of earthquakes on structures, and the design considerations that go into the development of a high-rise building.

This week will cover

• Seismic design philosophy and limit states
• Earthquake and their geotechnical and structural effects
• Capacity design philosophy

Earthquakes are considered dynamic loads as their force varies overtime. Structural dynamics focuses on the response of structures that experience these dynamic loads. When designing high-rise buildings, structural dynamics and earthquake engineering assess how a structure responds under seismic loads. In order to design high-rise buildings to be earthquake resistant, it is important for learners to understand concepts related to structural dynamics and earthquake engineering.

This week will cover

• Force displacement system
• Damping Force
• Equation of motion – external force
• Equation of motion – earthquake excitation
• Undamped free vibration systems
• Viscously damped free damping
• Earthquake response of linear systems

• Response spectrum concept
• Deformation, pseudo-velocity and pseudo-acceleration response spectra
• Peak structural response from the response spectrum

Civil engineers consider the forces buildings are subjected to during an earthquake in order to reduce associated damage. The system of forces can be represented as a continuous system with partial differential equations. It is important to understand the mathematical models behind the forces acting on buildings during an earthquake to predict their behavior, and effectively design them to withstand these forces.

This week will cover

• Multi degree of freedom systems
• Discretization of structural systems
• Elastic, damping & inertia forces
• Damping force
• Equation of motion
• Free vibration – Systems without damping
• Modal response spectrum analysis

• Equivalent lateral force method

Buildings are commonly made with concrete because of its ability to absorb strong impacts and withstand large forces. Concrete buildings specifically undergo a seismic design process that makes them resilient to earthquakes. It is important for learners to understand the theory behind the design of concrete buildings in terms of earthquake resistance.

This week will cover

• General principles of conceptual seismic design
• Regularity and irregularity of building structures

The tensile strength of buildings can be improved by using reinforced concrete (RC) that has metal bars or wires integrated within. This increases the structure’s stiffness, ductility, and strength to make it earthquake resistant. RC frame systems have columns and beams connected together to make the skeleton of a building. These systems are used for their global ductility and deformation capacity that improves their resistance to earthquakes. It is important for learners to understand the RC systems and their properties in the design of earthquake resistant structures.

This week will cover

• Essentials of structural system for seismic resistance - RC frame systems, wall systems, and dual systems
• The Capacity Design philosophy
• The role of a stiff and strong vertical spine in the building
• Ductility as an alternative to strength

IS 13920 elaborates on the ductile detailing of RC structures that experience seismic forces. This code focuses on ensuring that buildings are designed to withstand large shocks from earthquakes without collapsing. It is important for learners to understand how RC beams are designed in accordance with IS 13920.

This week will cover

• Design of beams with reference to IS 13920

IS 13920 is also applied to the design of RC columns. It is important for learners to understand how both RC columns and beams are designed in accordance with IS 13920.

This week will cover

• Design of columns and beam - column joints with reference to IS 13920

IS 13920 is also applied to the design of shear walls. It is important for learners to understand how shear walls are designed in accordance with IS 13920.

This week will cover

• Design of shear walls with reference to IS 13920

ETABS is a software tool used to design, analyze, and model whole structures, specifically multistory structures, and their individual parts. By using ETABS, engineers can understand how different buildings respond to varying loads. It is important for learners to understand how to use ETABS in the modeling and analysis of structures.

This week will cover

• Architectural drawings - a cost efficient load path carved out using ETABS 2016.
• From identifying loads, to creating an ETABS model
• Complete analysis and design of RCC building in zone 5 will be demonstrated

The foundation of all buildings is essential in supporting and stabilizing the superstructure by transferring its load to the earth. As high-rise buildings are large structures, their foundation is designed to support heavy loads. Pile foundations are commonly used in high-rise buildings as they offer a deep foundation that strongly anchors the structure. It is important for learners how the foundations of high-rise buildings are designed to maximize the safety of the structure.

This week will cover

• Foundation structures for frames and structural walls
• Footing & pile design using Excel spreadsheet

Liquefaction happens when the stiffness and strength of soil decreases by sudden loading or intense shaking. This is common in the case of earthquakes. When liquefaction happens, the foundation may sink into the ground and collapse. Raft foundations are resistant to liquefaction, and can be designed by SAFE software. This tool is used in the drawing and design of concrete foundations and floors. It is important for learners to understand what liquefaction is, and how foundations are designed to resist this phenomenon.

This week will cover

• Check for liquefaction
• Design of raft foundation using SAFE