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QLDEngineeringQuick questions
Unit 3: Civil structures
Quick questions on Dead, live and environmental loads on structures for QCE Engineering Unit 3
5short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What are dead loads?Show answer
The dead load is the permanent, unchanging weight of the structure itself plus everything fixed to it: the beams, columns, slabs, cladding, roofing, ceilings and built-in services. Because it does not move or vary, the dead load is the most predictable load and is calculated directly from the volume and density of the materials. The weight of any body is:
What are live loads?Show answer
Live loads, also called imposed loads, are the variable loads that come from using the structure: people walking on a floor, vehicles crossing a bridge, furniture, machinery and stored materials. They move and change over time, so codes specify conservative design values (for example a crowd loading per square metre). Live loads are inherently less certain than dead loads, which is one reason a factor of safety is applied later.
What are step 1. combine the distributed loads?Show answer
All three act along the full span, so add them:
What is step 2. total force on the beam?Show answer
Multiply the UDL by the span:
What is step 3. equivalent point load?Show answer
A symmetric UDL acts as a single point load at midspan. By symmetry each support carries half:
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