Types Of Loads On Structure


The loads are broadly classified as vertical loads, horizontal loads and longitudinal loads. The vertical loads consist of dead load, live load and impact load. The horizontal loads comprises of wind load and earthquake load. The longitudinal loads i.e. tractive and braking forces are considered in special case of design of bridges, gantry girders etc.

1. Dead load:

Dead loads are permanent or stationary loads which are transferred to structure throughout the life span. Dead load is primarily due to self weight of structural members, permanent partition walls, fixed permanent equipments and weight of different materials.

2. Imposed loads or live loads:

Live loads are either movable or moving loads with out any acceleration or impact. There are assumed to be produced by the intended use or occupancy of the building including weights of movable partitions or furniture etc. The floor slabs have to be designed to carry either uniformly distributed loads or concentrated loads whichever produce greater stresses in the part under consideration. Since it is unlikely that any one particular time all floors will not be simultaneously carrying maximum loading, the code permits some reduction in imposed loads in designing columns, load bearing walls, piers supports and foundations.

3. Impact loads:

Impact load is caused by vibration or impact or acceleration. Thus, impact load is equal to imposed load incremented by some percentage called impact factor or impact allowance depending upon the intensity of impact.

4. Wind loads:

Wind load is primarily horizontal load caused by the movement of air relative to earth. Wind load is required to be considered in design especially when the heath of the building exceeds two times the dimensions transverse to the exposed wind surface.

For low rise building say up to four to five storeys, the wind load is not critical because the moment of resistance provided by the continuity of floor system to column connection and walls provided between columns are sufficient to accommodate the effect of these forces. Further in limit state method the factor for design load is reduced to 1.2 (DL+LL+WL) when wind is considered as against the factor of 1.5(DL+LL) when wind is not considered. IS 1893 (part 3) code book is to be used for design purpose.

5. Earthquake load:


Earthquake loads are horizontal loads caused by the earthquake and shall be computed in accordance with IS 1893. For monolithic reinforced concrete structures located in the seismic zone 2, and 3 without more than 5 storey high and importance factor less than 1, the seismic forces are not critical.

Comments

Post a Comment

Popular posts from this blog

How To Calculate or Estimate Long-span Aluminium Roofing Sheets.

Image
Aluminium roofing sheets, they come in rolls of average of 600mm to 1300mm depends on the manufacture and specifications. As stated in previous articles, the aluminium sheets comes in rolls at the factory just like toilet rolls but with different widths and thickness based on specifications. Calculating the roof required could be done by calculating the surface area in square meters of the area covered by the aluminium and for some companies it could be calculated in meter lengths ,knowing the width which is 600mm above as constant. For a simple gable roof as shown in pic 1 with length of 25.2m. First you must know the height of roof from the section. For this sample we are taken the eight to be 3meters (10 feet)to know the length of leaf “x” or “y” Remember the pythagoras theorem x2=32 +6.12 x=6.8m Hence the area of roof is (6.8 i.e x)+6.8 i.e y) multiply by length 25.2m=342.72m2 If the width of the roof comes in 600mm or 0.6m, the length of the roof ...
Read more

Post Tension Slab – Advantages and Disadvantages of Post Tension Slab

Image
Post Tension Slab Although concrete is a strong material for construction, it is not resistant to breakdown especially where longer concrete slabs are required like in a bridge or a length of a beam. For this, the concrete slab is tensioned with a process called pre-stressing and the slab of concrete which comes out after this process is known as post tension slab. This slab is much stronger as well as more durable than the normal concrete slabs. In today’s world, where the modern engineering is finding new ways to build longer, more efficient and stronger structures, post tension slab becomes one of their chief requirements. There are many advantages and disadvantages of post tensioned slabs which we will discuss in this post. Advantages of Post Tension Slab Post tension slabs are advantageous in many ways. Some of the major benefits of post tension slabs are as follows. 1. Reduced cost: Post tension slabs are excellent ways to construct stronger structures at an affordable...
Read more

How to install POP (plaster of paris) ceilling

Image
Plaster of Paris is regarded as any type of plaster containing calcined gypsum (calcium sulfate dihydrate), sand and water. When these ingredients are combined, they result in the formation of a tough, dry product; however, plaster of Paris can be sanded to achieve a variety of looks. By following some basic guidelines, you can use plaster of Paris to mend cracks, fix dents,for ceiling, in walls and even to create artworks. However in this case our focus is on ceiling. POP popularly called plaster of Paris is used for a lot of purposes because it can easily be formed to any shape and it hardens quickly and is easy to operate. To do a pop ceiling in your home, getting it done is in two ways, you can buy the materials yourself which include pop cement , yarn(sponge-like material) etc then pay the installer based on per square meter of area of coverage, or you can give it out totally as a contract. But these are the basic steps in getting pop ceiling cast-on-site done. Get cemen...
Read more