Design Load Combinations - Design and drawing of Steel Structure | Summary and Q&A

TL;DR

This video discusses design load combinations and their various types, including dead load plus live load, dead load plus wind load, and dead load plus imposed load. It also explains the use of partial safety factors to increase certain loads.

Key Insights

• 👨‍💻 The IS code 1893 2002 provides guidelines for design load combinations and is available for download as a PDF.
• 🧑‍🏭 Partial safety factors, such as 1.5 and 1.2, are used to increase certain loads in the design process.
• 💀 Different combinations, such as dead load plus live load and dead load plus wind load, have their own factors for calculation.
• 🍉 Creep, which refers to long-term deflection, is not considered in load combinations for design.
• 😒 The use of partial safety factors is essential in the design of reinforced concrete and prestressed concrete structures.
• ❓ Overturning stability criteria should be considered when assessing certain load combinations.
• 🥡 Positive and negative directions of earthquake loads are taken into account in load combinations.

Transcript

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Questions & Answers

Q: What are design load combinations?

Design load combinations refer to the different types of load combinations that need to be considered in structural design. They include combinations such as dead load plus live load, dead load plus wind load, and dead load plus imposed load.

Q: Why do we use partial safety factors in load combinations?

Partial safety factors are used in load combinations to account for uncertainties and ensure a higher level of safety in structural design. These factors increase certain loads to prevent potential failures.

Q: How are load combinations calculated?

Load combinations are calculated by multiplying the respective loads by their corresponding factors. For example, in the first combination of dead load plus live load, the live load is multiplied by 1.5, and the sum of both loads is taken.

Q: How is the critical load determined for design?

The critical load is determined by comparing the results of different load combinations. The combination that produces the highest load value is considered the critical load, and the structure is designed accordingly.

Summary & Key Takeaways

• The video explains the concept of design load combinations, which are taken from the IS code 1893 2002, and emphasizes the use of partial safety factors to increase loads.

• It provides examples of the first combination, which is 1.5 times the sum of dead load and live load, and explains the calculation process using specific load values.

• The second combination mentioned is one times dead load plus 1.5 times wind load, and the third and final combination is 1.2 times the sum of dead load, live load, and wind load. The critical load for design is determined based on these combinations.