The basis of structural design begins with the type of structure to be designed. Usually, there are specific data and requirements for any structural construction to commence. This structural data form an essential element in structural analysis in that it guides construction of structures that can withstand the different type of loads within their lifespan. It’s these loads that will determine the level of mechanism to be applied to various structures.
The different type of loads that act on structures are classified as horizontal loads, vertical loads, and longitudinal loads. How these loads affect a structure will depend on the design, location, use and the construction materials. In addition, civil engineering structural design process defines multiple design loads for different structures. Here are four main design loads that can act on various development structures.
Dead Load
Dead loads are the first vertical load also referred to as permanent loads. They are the mainly caused by the actual weight of the structure throughout their existence. Besides that, dead loads can also be associated with elements such as immovable fixtures and fixed non-structural partitions. In fact, any permanent part of a structure like roofing, partition walls, and column translates to dead loads.
With a good degree of accuracy, it is possible to calculate dead loads on structures. But how is this done? Dead loads are computed by factoring in the volume and weight of construction materials. However, getting the right estimates to calculate dead loads can be a bit of a challenge, making a huge discrepancy between the actual dead loads and those experienced in practice.
Live Loads
Live loads or imposed loads are the second vertical load and are either movable or moving loads with or without any impact or acceleration. Usually, these loads are caused by movable partitions, furniture, vehicle traffics or occupancy of the building. Depending on the time of day, the intensity of live loads may greatly differ. For instance, a residential building may experience increased imposed loads during the night or at weekends as compared to weekdays. Since live loads involve structural mobility, it may include elements such as vibration, impact or acceleration.
Wind Loads
One typical horizontal load are the wind loads that often emerge from the movement of air relative to a structure. In structural design, it’s crucial to understand the aerodynamics involved in designing structures especially the very tall ones. When it comes to construction of low-level building or structures, wind loads may not be significant because the moment of resistance provided by dead weight is enough to support the structure. However, when wind loads are extremely high than the dead weight of a structure, additional fixtures may be required to increase stability and counter the potential catastrophic wind loads. In complex structural design projects especially in places with strong winds, it may be necessary that a civil engineering company conducts a wind test to measure the speed and change in air flows. This is important because the findings can be used to develop a wind resistance structure that is safe and secure for occupancy or any other use.
Snow and Earthquake Load
These two loads are a type of environmental loads that widely vary on geographic regions. Snow loads are dominant in areas where snowfall are frequent. Constant accumulation of snow on the roof can significantly add the overall weight of a structure. That’s why construction codes in snow regions state the importance of having steeper roofs that discourage the accumulation of snow. Earthquake loads, on the other hand, can affect a structure during an earthquake. Therefore, before constructing a building in seismic regions, a proper land analysis must be done to fully understand the ground. This can be done any of geotechnical engineering firms around the world who offer not only effective construction materials testing but also environmental consulting for various structural design projects.
Other minor design loads include thermal loads and settlement loads. All these loads play a significant role in the construction and building projects. Elements such as structural fatigue, foundation movement, soil and fluid pressure will also impact on the design and materials to be used in different civil engineer services.
