Transcript Slide 1
Building Fun http://www.cardstacker.com/gallery.html • You will have 30 minutes to build the strongest structures you can with only the materials you are provided with. • Explain to the class the structure and why you built it that way. http://www.youtube.com/watch?v=mbMT_bFILB8 Building Fun Critique What do you think would happen if we placed a brick on top of each structure? What does the brick represent? 1. The static force of gravity (vertical load) 2. all nonstructural elements of building like floors, wall covering, wiring etc… Background • _______ __________: acceleration determines the forces on a building • As _________ waves move through the ground, the ground moves back and forth • ____________: the rate at which ground movement changes its speed Velocity and Displacement: directly related to acceleration • __: cm/s is the rate of motion at an instant • __: cm: the distance an object has moved form its resting position • Go over the difference between distance and displacement • Ex. Hand waving in front of your face • Mass of hand vs building Overcoming A, V and D: Engineers rely on a small number of components that can be combined to form a complete load path • vertical plane: 3 kinds of structural systems are used to resist lateral forces 1. _________ ________ 2. _________ ________ 3. ___________ __________ or • • • Horizontal plane 1. ___________ 2. ___________ Load • sum of ________ force (gravity) and ____________ forces (shear forces) acting on all the mass of a structure. • broken down into the loads of various parts of the building. • Different parts of a building are designed and constructed to carry different loads. Load Path • The path a load or force takes through the structural elements of a building Vertical Load • The Effect of vertical force (______) acting on the elements of a structure web.ics.purdue.edu/.../building/building.htm Horizontal Load • Sum of horizontal forces ( __________ forces) acting on the elements of a structure • this site is great for lots of additional information • http://www.abag.ca.gov/bayarea/eqmaps/fixit/trai ning.html Horizontal Plane • Diaphragms (generally the floor and roof planes) • Designed the receive ________ __________ between the _________ resistance elements (________ walls or frames) • Horizontal trusses Braces or Bracing • Structural elements built into a wall to add strength. – made of various materials and connected to the building and each other in various ways. • ability to withstand stress depends on the characteristics of the materials and how they are connected. Shear force • Force that acts ____________ (laterally) on a wall. These forces can be caused by earthquakes, and by wind among other things. • Different parts of a wall experience _________ shear forces. Shear Walls: solid walls • In a simple building with shear walls at each end, ground motion enters the building and moves the floor diaphragms • This movement is carried by the shear walls and transmitted back down through the building to the foundation • Walls added to a structure to carry horizontal (shear) forces • Can also be load bearing walls (vertical Forces) http://www.abag.ca.gov/bayarea/eqmaps/fixit/ch3/sld002.htm Structural elements or features • A general term for all the essential, nondecorative parts of a building that contribute structural strength. • Walls, vertical column supports, horizontal beams, connectors and braces __________ frames • Act in the same manner as shear walls , but may not carry as much load depending on their design • Bracing generally takes the form of steel rolled sections ( I beams), circular bar sections (rods) or tubes _________ ____________ • Connections that do not permit any motion of the structural elements relative to each other Moment resistant or Rigid frames • Rely on the capacity of _________ to carry loads from columns to beams • joints are highly stressed during movement the details of their construction is important • As a last resort strategy, rigid frames use the energy absorption obtained by deformations of the structure before it fails • Frame with no walls shear • Frame with shear walls Rigid frames • Offer a certain advantage over shear walls or braced frames because the tend to provide structures that are much less obstructed internally than shear walls • Require special construction and detail • _________ ___________ than shear walls or braced frames due to ________