The objective of this PhD is to study the seismic behavior of elastic and inelastic structural systems equipped with viscous and viscoelastic dampers and develop design procedures according to Eurocode 8 for steel buildings. Both types of dampers belong to the category of passive supplemental damping devices. These devices can be used either for new building or for retrofitting purposes of existing buildings. Dampers act by dissipating seismic energy and can significantly decrease the response of structural frame buildings subjected to earthquakes. Building drifts and member forces are substantially reduced by adding damping to the structure and thus both structural and non-structural components are protected. Viscoelastic dampers also add stiffness to the structure. Viscous fluid dampers consist of a hollow cylinder filled with fluid, the fluid typically being silicone based. The damper is attached to the structure within chevron or diagonal bracing. As the damper piston rod and piston head are stroked, fluid is forced to flow through orifices either around or through the piston head. The resulting differential in pressure across the piston head very high pressure on the upstream side and very low pressure on the downstream side can produce very large forces that resist the relative motion of the damper. Viscoelastic solid dampers generally consist of solid elastomeric pads viscoelastic material bonded to steel plates. The steel plates are attached to the structure within chevron or diagonal bracing. As one end of the damper displaces with respect to the other, the viscoelastic material is sheared resulting in the development of heat which is dissipated to the environment. All the proposed literature covers the theory describin... ... middle of paper ... ...representing the yielding structure. Further details are presented for the calculation of the properties for the multi degree-of-freedom system. This method has been incorporated in the American guidelines for new buildings (NEHRP 2000 – FEMA 368). American codes include guidelines for incorporation of viscous and viscoelastic dampers in new and existing buldings since 2000 (FEMA 368, 369, 450) and 1997 (FEMA 273, 274, 356, 357) respectively, by using either linear static or linear dynamic procedure. Further study is needed to propose a design procedure for buildings equipped with linear or nonlinear viscous or viscoelastic dampers but allowing the frame to behave inelastically, since almost all of the research has been conducted on frames to remain elastic. This procedure will be developed according to Eurocode 8, so that in the future it can be incorporated in it.
Cappa, John, Sean Holman, and Ken Brubaker. "Automobiles- Springs and Suspension." Fourwheeler. NC WiseOwl, May 2012. Web. 17 Feb. 2014. .
A connecting rod is a machine member which is subjected to alternating direct compressive and tensile forces. Since the compressive forces are much higher than the tensile force, therefore the cross-section of the connecting rod is designed as a strut and the Rankine formula is used.
Construction of external and internal load bearing masonry walls up to Damp Proof Course (DPC) level.
Today, engineers rely on damping systems to counteract nature's forces. There are many types of damping systems that engineers can now use for structures, automobiles, and even tennis rackets! This site focuses on damping systems in structures, mainly architectural variations of the tuned mass damper.
In 2008, Prop 2 in California was supported by groups such as the HSUS and other groups. Prop 2 has enforced “… Packer/processors, grain producers, suppliers and those in the business of selling food, must recognize this, the organization focuses on different types of animals, such as: dolphins, whales, cats and dogs (Lovvorn & Perry, 2009).” Prop 2 was a law concerning animal holdings. It declared that animal holdings, such as cages, must be large enough for the animals to have room to extend their legs, move around, and not be cramped.. The Humane Society of United States and PETA supported the organizations to inform the people on the sidelines about the different tactics one could take to save the animals. The Humane Society of United States used the ability to spy as a tactic. Therefore the organization used a small pen sized video camera. In the The Barnyard Strategist, “The HSUS released the video in San Bernardino County, district attorney, the story made national headlines.” This can be related to the movie we watched in class “The Cove,” in which a group of men broke into a slaughterhouse of dolphins and whales to catch the ones who were slaughtering the animals. They did not know about the cameras. This helped provide footage to show how the animals were actually treated. The HSUS used merging different organizations such as the smaller animal welfare groups together, this was able to help the organization increase their money to help the company be able to inform others about animal abuse. Pacelle’s strategy consisted of creating a ballot measure that will allow those who are vegetarian and vegan to help reform the ballots. They use media to help get their point across by using a male who is vegetarian who strokes...
The failure of beam-to-column connections in steel Special Moment Resisting Frames had the most to do with most of the damage in these buildings. In response to the pattern of buildings including SMRF's, there have been studies to improve the design and construction practices to allow for better and more improved buildings. The higher building codes wanted engineers to find new ways to allow homes, apartments or skyscrapers the ability to sustain a powerful earthquake. These engineers borrowed the model from New Zealand engineer Bill Robinson. His method was to use lead-rubber bearings, which minimize the vibrations caused by the earthquake, improving its performance during seismic activity. Many of the old buildings that took damage during the earthquake had to be retrofitted. This was done by either infilling the walls, adding braces, adding buttresses, adding new frames, exterior or interior, completely rebuilding or isolating the building. All of these techniques of retrofitting a building all add extra support to the remainder of the building. Most of the residential structures that took damage and were deemed uninhabitable were the apartments or condominiums that were made of light, wood frames. Also, many houses made using stucco took extensive damages. This was due to the fact that the stucco was not properly installed in the first place,
Vernacular architecture in the Dominican Republic has proven to be energy efficient and provide high thermal comfort levels, but opposite to Passive House it relies on a completely open envelope that allows the air to quickly get in and out of the spaces. Unlike Passive House, Dominican vernacular architecture has no scientific proof rather than user experience, therefore is not scientifically rigorous to hold one over the other.
Proper design of foundation required a strong basis on mechanics, but should also be enhanced by the satisfactory performance of the foundation. Soil types can affect structures in different ways, such as strength and stiffness, which will may cause stable foundation or lead to collapse. In fact, history cases helps to avoid such failure may occur in future design of foundations.
Reese, C.D. and Eidson, J.V. (1999). Handbook of OSHA construction safety and health. Boca Raton, FL. CRC Press
Shock absorbers, otherwise known as dampeners, reduce the vertical movement of the car as it drives down a rough surface. Without this piece of the suspension system, your car would rock and sway back and forth viciously. “It would be a traveling deathtrap. Or at least it would be a traveling deathtrap until the incessant vibration caused it to fall apart,” says Longhurst. Shock absorbers have two main functions. They both absorb any over-average bumps in the road, as I mentioned above, and secondly they keep your wheels on the ground as you drive. (Longhurst)
Fanella, D. (2011). Reinforced concrete structures: analysis and design / David A. Fanella. New York: McGraw-Hill, c2011.
Deflection is the distortion or movement of a structure and its elements, such as trusses and beams, from their original positions. It is as significant for a designer to regulate deflections and strains as it is to recognize the stresses due to loads.
Authorities have attempted to implement codes or regulations, but that has proved to be very difficult tasks becasue there are many variables that effect the dynamic response of buildings. One way to try to avoid disaster is to evaluate seismic risk is to look at a buildings hazards, exposure, vulnerability, and location. Hazards are, for example, landslides ad soil type. Exposure is a building's occupancy and function. Vulnerability is the expected performance of a building's system, and location is how often earthquakes occur in the area. (Lagorio)
Multiple literacies "...consist of words, gestures, attitudes, ways of speaking, writing, valuing; ways of becoming with the world. They are about texts that take on multiple meanings and are taken up as visual, oral, written, tactile, olfactory, and in multimodal digital" (Masny, 2010). Before one is to understand what multiple literacy means, one must understand what it means to be literate. In today's society, literacy is defined in many ways whether it be understanding how to read and write, being able to understand the language, or making a meaning using the language. Multiple literacy focuses on understanding how the social environment and the integration of technology attributes to literacy in today's society. This type of literacy connects the classroom to the community, so that authentic learning can occur. Socio-cultural theory is one of the main components to what multiple literacy really means. The socio-cultural theory and multiple literacy share the idea that a child can be literate due to expose from his cultural environment, with or without the academic definition of literacy comprehension. Multiple literacies also lets the students learn outside of school to learn more complex ways with their local and global communities. Since the late 1990's, technology has become more engrossed in our society's life. Technology has made our children become digital literate. Technology is an incredible resource that teachers should embrace within their classrooms because technology is the bridge to effective teaching to our digital society.
Chua, Ian Y. H. Civil and Structural Engineering Resource Web. 29 Jan. 2000. 2 Mar.