103b: Building Loads and Forces

Question 1

2 structural loads? Full stop.

Answer 1

1) static
2) dynamic

Question 2

Why isn’t snow a dead load?

Answer 2

Snow comes and goes, building components are permanent

Question 3

Are people in a structure ever considered dynamic loads?

Answer 3

No. Structures are engineered to account for the movement of people.

Question 4

Is there anything in building materials or manufactured building structures such as footings that is NOT a dead load?

Answer 4

No. All the components of a building are a dead load.

Question 5

Would you consider a Christmas tree to be a live load?

Answer 5

Yes. It’s moved around the house during the year, and can put pressure on different areas of a floor

Question 6

If you need to build a second bed one weekend a month to house your friend. Are they and the bed live or dead loads?

Answer 6

Bed is live as it isn’t permanent.
Friend is live as structure is built to account for them.

Question 7

Can a static load ever be dynamic?

Answer 7

Wind CAN be dynamic if it is sudden enough. But wind is engineered for, and is therefore static live load.

Question 8

Why is a vibrating tamper in a backyard not considered a live load?

Answer 8

1) not putting pressure on house directly, so environmental
2) can potentially be vibrating soil that house sits on

Question 9

What kind of load buckles vinyl siding?

Answer 9

Environmental. Heat can cause expansion/contraction

Question 10

Even if my 50lb fish tank has been in my house for a year, is it still a live load if my dog knocked it over?

Answer 10

No. It’s dynamic because hitting the floor puts sudden pressure on the floor system.

Question 11

Oliver stood on your stomach. Is his paw a concentrated or distributed load?

Answer 11

Concentrated

Question 12

Why use teleports in a basement?

Answer 12

You add living space without building a supporting wall.

Question 13

I want to build a deck with storage room underneath. Should I build a supporting wall around the edge or something more “focused”?

Answer 13

Use posts at the corners. Concentrate the weight. Leave room for storage access.

Question 14

Do we ever put teleports under each joist?

Answer 14

No. Floor systems need loads distributed across them

Question 15

Does soil have a force?

Answer 15

Yes. Compressing it with the house weight also causes it to “press back”. It’s part of the dead loads on a house

Question 16

If I run across the house, which way does my “load” go?

Answer 16

Always down the structure. Floor systems move pressure to exterior walls and down to footings

Question 17

What kind of FORCE occurs in the physical earth during an earthquake?

Answer 17

Shearing force across tectonic plates

Question 18

I helped my uncle tear up his shit floor boards, and they were an inch narrower than the ones at work. Did the environment change them?

Answer 18

The environmental load on the old boards caused them to shrink from moisture loss over time.

Question 19

Why is it important for soil to evenly carry loads over time?

Answer 19

All buildings settle and uneven settlement over time can cause foundation issues

Question 20

Why do we pour a slab in a basement even if we never plan to use it?

Answer 20

It helps hold the foundation walls in place as the soil puts lateral load pressures on it

Question 21

When I pulled on my rope, it got nice and tight then suddenly snapped. What did my pulling force do?

Answer 21

Put tension on the rope until failure

Question 22

My couch cushion is half the height of when I originally bought it years ago. WhT gives?

Answer 22

My fat ass loaded it up over time and compressed it

Question 23

I put a mark on the foundation wall at grade before we started building our high rise. Now we’re up 20 floors up and when I checked on my lunch break I couldn’t find it. How come? foundation wall, and now it has shrunk a couple inches

Answer 23

Each floor added more compressive force to the f

Question 24

I tore a piece of paper by pulling on the bottom corners, but when it ripped at the bottom it left a bunch of wrinkles at the top. How come?

Answer 24

The paper had tension at the bottom, and compression at the top when the bottom corners were pulled apart.

Question 25

I forgot to drill a hole to run my new Reno’s pot light. Can I remove a little ceiling drywall and drill a little hole in the bottom of the joist? Just one?

Answer 25

No. The bottom of the joist exhibits the most tensile force, drillling there makes it weaker and prone to breaking.

Question 26

My pocket door is caught on the frame and I can only move it inches at a time….like I have to force it

Answer 26

Your pushing load is causing a shear force between the door and frame

Question 27

My mattress is perfect! But when I sit on it the edges poke off the bed frame. Is it me?

Answer 27

No. The mattress exhibits horizontal shear with the frame when you put pressure in the middle.

Question 28

Got down and dirty last night and my bed snapped RIGHT where the corner leg meets the frame…

Answer 28

Your body weight on top caused vertical shear at the frame/leg joint

Question 29

What is a carpenter’s main goal regarding loads and forces?

Answer 29

Transfer the load/force TO THE GROUND