Friday, March 31, 2017
Sunday, September 6, 2015
Wednesday, October 16, 2013
Structural load Live Loads Dead Loads
A structure stands by resisting its own load of beams, columns, foundations etc. The occupancy of Engineers often evaluate structural loads based upon published regulations, contracts, or specifications. Accepted technical standards are used for acceptance testing and inspection.eA
Building codes require that structures be designed and built to safely resist all actions that they are likely to face during their service life, while remaining fit for use.[4] Minimum loads or actions are specified in these building codes for types of structures, geographic locations, usage and materials of construction
To meet the requirement that design strength be higher than maximum loads, Building codes prescribe that, for structural design, loads are increased by load factors. These load factors are, roughly, a ratio of the theoretical design strength to the maximum load expected in service. They are developed to help achieve the desired level of reliability of a structure[6] based on probabilistic studies that take into account the load's originating cause, recurrence, distribution, and static or dynamic nature.[7]tr
ucture stands by resisting its own load of beams, columns, foundations etc. The occupancy of the struhttp://en.wikipedia.org/wiki/Structural_loadcture, soil pressure, temperature variation, rain or snow fall, earthquake, wind force also prov
Live loThe major difference between live loads and dead loads is:
ads are consists of occupancy loads in buildings and traffic loads on bridges. They may be fully or partially in place or not present at all and may change its location. Human, chair, table, computer, bed, furniture etc are live loads. Live loads may change its present location as they are not lifetime part of a structure. So, in structural design live loads are provided a larger safety factor than the others. All the structural loads are expressed in psf (per square feet). The minimum uniformly distributed live loads for a residential building is 40 psf and for a office 50 psf.ide loads. So a structure has to resist all the loads to stand strongly. A structural designer designs considering all the above loads. The acting loads on a structure are classified into three main categories according to their types.
structure, soil pressure, temperature variation, rain or snow fall, earthquake, wind force also A structure stands by resisting its own load of beams, columns, foundations etc. The occupancy of the structure, soil pressure, temperature variation, rain or snow fall, earthquake, wind force also provide loads. So a structure has to resist all the loads to stand strongly. A structural designer designs considering all the above loads. The acting loads on a structure are classified into three main categories according to their types.
provide loads. So a structure has to resist all the loads to stand strongly. A structural designer desigA structure stands by resisting its own load of beams, columns, foundations etc. The occupancy of the structure, soil pressure, temperature variation, rain or snow fall, earthquake, wind force also provide loads. So a structure has to resist all the loads to stand strongly. A structural designer designs considering all the above loads. The acting loads on a structure are classified into three main categories according to their types.
ns considering all the above loads. The acting loads on a structure are classified into three main categories according to their types.
Building codes require that structures be designed and built to safely resist all actions that they are likely to face during their service life, while remaining fit for use.[4] Minimum loads or actions are specified in these building codes for types of structures, geographic locations, usage and materials of construction
To meet the requirement that design strength be higher than maximum loads, Building codes prescribe that, for structural design, loads are increased by load factors. These load factors are, roughly, a ratio of the theoretical design strength to the maximum load expected in service. They are developed to help achieve the desired level of reliability of a structure[6] based on probabilistic studies that take into account the load's originating cause, recurrence, distribution, and static or dynamic nature.[7]tr
ucture stands by resisting its own load of beams, columns, foundations etc. The occupancy of the struhttp://en.wikipedia.org/wiki/Structural_loadcture, soil pressure, temperature variation, rain or snow fall, earthquake, wind force also prov
Live Loads Dead Loads Environmental Loads Cyclic loads
Dead loads are static forces that are relatively constant for an extended time. The dead load includes loads that are relatively constant over time, including the weight of the structure itself, and immovable fixtures such as walls,plasterboard or carpet. Roof is also a dead load. The designer can also be relatively sure of the magnitude of dead loads as they are closely linked to density and quantity of the construction materials. These have a low variance, and the designer is normally responsible for specifying these components.
Live loads are usually unstable or moving loads. Live loads, or imposed loads, are temporary, of short duration, or moving. Live loads, sometimes also referred to as probabilistic loads include all the forces that are variable within the object's normal operation cycle not including construction or environmental loads.
Roof and Floor live loads are produced
- during maintenance by workers, equipment and materials, and
- during the life of the structure by movable objects such as planters and by people.
Bridge live loads are produced by vehicles traveling over the deck of the bridge.
Cyclic loads
Environmental loads[edit]
These are loads that act as a result of weather, topography and other natural phenomena.
- Wind loads
- Snow, rain and ice loads
- Seismic loads
- Temperature changes leading to thermal expansion cause thermal loads
- Ponding loads
- Lateral pressure of soil, ground water or bulk materials
- Loads from fluids or floods
- Dust loads
Engineers must also be aware of other actions that may affect a structure, such as:
- Support settlement or displacement
- Fire
- Corrosion
- Explosion
- Creep or shrinkage
- Impact from vehicles or machinery vibration
- Loads during construction
U = 1
Load combinations[edit]
A load combination results when more than one load type acts on the structure. Design codes usually specify a variety of load combinations together with Load factors (weightings) for each load type in order to ensure the safety of the structure under different maximum expected loading scenarios. For example, in designing a staircase, a dead load factor may be 1.2 times the weight of the structure, and a live load factor may be 1.6 times the maximum expected live load. These two "factored loads" are combined (added) to determine the "required strength" of the staircase.
The reason for the disparity between factors for dead load and live load, and thus the reason the loads are initially categorized as dead or live is because while it is not unreasonable to expect a large number of people ascending the staircase at once, it is less likely that the structure will experience much change in its permanent load..2 D + 1.6 L
ads are consists of occupancy loads in buildings and traffic loads on bridges. They may be fully or partially in place or not present at all and may change its location. Human, chair, table, computer, bed, furniture etc are live loads. Live loads may change its present location as they are not lifetime part of a structure. So, in structural design live loads are provided a larger safety factor than the others. All the structural loads are expressed in psf (per square feet). The minimum uniformly distributed live loads for a residential building is 40 psf and for a office 50 psf.ide loads. So a structure has to resist all the loads to stand strongly. A structural designer designs considering all the above loads. The acting loads on a structure are classified into three main categories according to their types.
structure, soil pressure, temperature variation, rain or snow fall, earthquake, wind force also A structure stands by resisting its own load of beams, columns, foundations etc. The occupancy of the structure, soil pressure, temperature variation, rain or snow fall, earthquake, wind force also provide loads. So a structure has to resist all the loads to stand strongly. A structural designer designs considering all the above loads. The acting loads on a structure are classified into three main categories according to their types.
provide loads. So a structure has to resist all the loads to stand strongly. A structural designer desigA structure stands by resisting its own load of beams, columns, foundations etc. The occupancy of the structure, soil pressure, temperature variation, rain or snow fall, earthquake, wind force also provide loads. So a structure has to resist all the loads to stand strongly. A structural designer designs considering all the above loads. The acting loads on a structure are classified into three main categories according to their types.
ns considering all the above loads. The acting loads on a structure are classified into three main categories according to their types.
Sunday, March 24, 2013
Subscribe to:
Posts (Atom)