# Forces on Structures

Forces on Structures

1. A.) Shear – This is where forces are pulling apart the two pieces which are being held together by welding or a bolted connection. An example of shear force is when the wind blows the top of a peaked roof, the side walls will experience a force pushing at the top, towards the direction of the wind, whereas the bottom of the walls will be going in the opposite direction from the ground.

B.) Tension – This is where forces cause a beam to “pull” apart. A tensile force usually occurs on the “bottom” of a beam, “stretching” the structure.

C.) Compression – This is when a vertical force pushes down on a structure. Forces within the structure then push back with equal force. A compressive force would happen if you were to put a beam into a building and then place something on top of it (e.g. another floor).

D.) Stress – This occurs when a structure transmits the force load from section to section within a structure. Stress occurs when pressure is put on to a structure (e.g. when a heavy load is placed on top of the structure).

E.) Strain – This is when a piece of a structure is loaded by a force and placed under some measure of stress causing a slight change in a structure. This happens on a load bearing beam as it slightly shrinks when more pressure is but upon it.

2. A.) If a portal frame is overloaded at the bolted joint with the column, I would expect for the bolts to experience shear force and the opening will then become compressed out of its alignment. The worst case scenario would be that the whole structure fails and results in collapse.

B.) If a concrete lintel only has an end bearing of 50mm above a window at each end, it would be put under a lot of pressure if there are floors above. This will cause the concrete, over time, to crack and deteriorate which eventually would lead to collapse. To avoid this happening, you should use a lintel three to four times this measurement as this will spread the weight more...