Question

3. You are the project team leader for the design of a single family house in southwest Houston area. Discuss the types of structural loads you think are important and explain why.

Answer 1

The important structural loads that needs to be studied are as follows :

• VERTICAL LOADS:

1. Gravity loads include deadload, live load and snowload.These gravity loads are generally static in nature and usually taken as concentrated load or UDL (uniformly distributed load). Finding a gravity load on a beam or column makes use of  the concept of tributary areas to assign loads to various structural elements.
2. Wind :Wind uplift forces are generated by negative pressures acting in an outward direction from the surface of the roof and this develops in response to the aerodynamics of wind flowing around and over the building.The major difference between gravity loads and wind loads is that wind pressures act perpendicular to the building surface.
3. Seismic and wind (overturning)
4. Seismic (vertical ground motion) Vertical forces are also include forces due to wind and seismic lateral loads acting on the overall building aswell as the building's lateral force resisting systems. Earthquakes similar to gravity loads produce vertical ground motions which accelerates the effect of gravity loads.

• LATERAL LOADS:

1. Wind - Lateral forces from wind are created by wind pressures which are positive on the windward face of the building and those which are negative on the leeward face of the building, creating a combined pushand-pull effect.
2. Seismic (horizontal ground motion)
3. Flood (static and dynamic hydraulic forces) - Flood loads are generally minimized by either elevating the structure with the help of a properly designed foundation or it is avoided by not building in a flood prone area or plain. The overturning moment produced by the lateral loads must be offset by the dead load or by the various connections of the building. Therefore, it is very necessary to consider or take into account the  overturning forces on connections which are designed to restrain components from rotating.   

These are the important loads that needs to be studied and in case of southwest Houston, it is more important to focus on earthquake (seismic) load and flood loads since many areas of Houston are highly prone to these.So these loads or factors must be given importance (or should be taken in special consideration ) while designing residential buildings in this area.