Mechanical Properties Of High Strength Steel Essay

Steel frame structures are made as the name suggest from steel, the material is strong and flexible. When weight is added it bends without cracking. Another characteristic of steel is that its plasticity or ductility, meaning that when force is added it won’t crack however it will lose shape therefore giving warning for people to evacuate the building. A disadvantage of steel is that is loses strength when subject to fire. Studies have shown that it can loose up- to half its strength when subject to fire, therefore making it imperative to cover the steel with boards or spray on.

The change to engineered lumber also means less wood to burn resulting structure collapse much sooner, risking the lives of unaware firefighters. In addition to building techniques, improved technologies have also given rise to many engineered materials that replace traditional materials found in home furnishings such as cotton and wool. Today, homes are constructed and filled with furnishings that have a petroleum base such as plastics and polycarbonates. These engineered materials burn many times hotter and faster than traditional building materials or what is considered legacy furnishings. In an experiment conducted at the NIST laboratory, two same size rooms, filled with matching furnishings. One room was filled with modern home furnishings while the second room was filled with furnishings made of cotton, wool, and solid lumber. Both rooms were ignited simultaneously, the modern room burned rapidly and flashed over in approximately eight minutes whereas the legacy room took twenty minutes to reach flashover. When we consider the length of time to call 911, take the call, dispatch units, drive to the scene, tag a hydrant and pull a line most likely takes longer than eight minutes, the timing until flashover is critical for victims and firefighters. Additionally, there is a significant difference in temperatures generated between the modern and legacy rooms. The legacy room high temperature reached approximately four hundred degrees before

Much to the disappointment of many conspiracy theory advocates and myself, the collapse of the World Trade Centre (WTC) Building 7 on September 11th 2001 was likely due to structural failure cause by uncontrolled fires. It is noted that still to this day, fire has never before reduced a steel sky scraper to rubble. This is because fires do not produce enough concentrated heat and energy for the required amount of time for structural steel member to fail. Further to this, high-rise buildings (including those of the same calibre of the WTC Building 7) typically have –

I have found that earthquake proof construction is a necessary accommodation to all in countries around the ring of fire. Our main worry is saving the

Lightweight construction has been used in building construction for more than thirty-five years. Fire fighters have been dealing with the dangers of this type of construction since it was developed. Lightweight construction is generally considered to be either wood frame or steel building materials, where the roof and/or floor supporting systems are constructed of lightweight prefabricated materials. The main problem with lightweight construction is the decreased load carrying capability and stability of the manufactured members under fire conditions.

Within the United States there are five different types of construction. Firefighters need to know and understand each of them. Every construction type have fire resistant weaknesses, these weaknesses will result in fire spreading in the building. If firefighters understand how the fire will spread, then understand how to extinguish the fire faster and more importantly firefighters are better protected from injuries or worse. In America all buildings are associated with one of the types of construction, identified by Roman number. The building codes are, fire resistant (type I), combustible (type II), ordinary construction (type III), heavy-timber construction (type IV) and wood-frame construction (type V). It is important to remember that all buildings are not the same. Each different building construction type will burn much differently than the others do. In order to be able to size-up a building 's fire hazard, firefighters need to be able to understand a buildings contents and construction. Materials that are stored inside of the building and also materials used to construct the building will both fuel the fire. Also know that if a structure is vacant or if the contents in the building are not combustible, the main fire hazard is the building. The scale of the construction types are scaled according to the fire load of combustible material that was used for its construction. A fire resistant building is constructed with least amount of combustible materials, and a

A very important part of being a firefighter is knowing building construction. Building construction is classified as being type 1-fire resistive, type 2-non-combustible, type 3-ordinary, type 4-heavy timber and type 5-wood framed. One will give an overview of building construction, including the various types and designs, the applications of building and fire codes how it relates to firefighting operations, the awareness firefighters should have on the fire ground and what a firefighter should know concerning building collapse.

Trusses are now being made of lightweight wood connected by metals gusset plates. These trusses are usually enclosed with particle board that has been breached by utilities and ductwork. This allows for fire to spread quicker and for the truss to be exposed to fire sooner. Wooden-I beams are also made of plywood sheeting and lightweight wood glued together. These I-beams sometimes also may be breached by utilities and ductwork.  Both of these makes it dangerous for the firefighters

In order to evaluate common fire hazards within a building and the risks presented by these, it is essential to have an understanding of where fires start, and what causes them in varying occupancy types. The best process to fulfil this aim is to review existing statistical data. Existing data is a vital tool in analysing areas or functions of a building which have the greatest risk to occupants. In particular, those functions or areas of a building having higher fatality rates historically in buildings of a similar type should be treated with special consideration (i.e. Class 2, Kitchen). It is important to be familiar with these statistics as they play a key role in predicting outcomes of future fires. Using this knowledge, fire safety engineers can identify patterns and high risk factors; and apply appropriate building fire safety systems in an attempt to reduce fire

I have diligently worked on all these projects to attain something new in Structural & Earthquake Engineering. Currently, all that is on my mind is Structural Engineering, and finding a new strategy to increase Structures’ capacity and their stability under different conditions. To improve their seismic performance, to decrease their damages when they are subjected to natural disasters, to decrease the cost of their damages, and their construction, to reach the most effective approach to construct, maintain and rehabilitate different structures, I have so much on my mind, so much to experience, and numerous approaches to try; A complete list of my research interests is enumerated on my

The recent rise in terrorist attacks around the world and use of missiles, rockets, ballistic, nuclear weapons, Hydrogen bombs there is huge competition in power show to project in front of the world threatening, feel of insecurity and disturbing the mindset of people by announcing nuclear weapons, and trial testing a challenge for new generation, The buildings currently offer little in the way of protection from explosions. Those protection needs the desired level of protection the building must provide to its occupants or its ability to function has made protection point of view promoted fast research and development of new construction materials to necessarily enhance the resistance of buildings and infrastructures

The disadvantages of a metal gusset plate’s behavior while being exposed to extreme heat conditions from a fire include th fact that the galvanized metal gusset plate’s teeth do not penetrate the wood all that deep. The wood the plates are connecting, have a charring rate of 1/40 inch per minute. The truss plate’s teeth have a minimum depth of 3/8 inch. So during a typical fire, the wood will lose 3/8 inch of its body in approximately 15 minutes leaving the teeth of the metal truss plate completely exposed. This will then cause the metal truss plate to fall off allowing that joint to lose its integrity. Once a joint on a truss is compromised, the weight it previously carried will be transferred to the next closest joints. These joints in return can not carry the additional load while being exposed to the fire causing them to lose their integrity resulting in a complete failure of the truss assembly. Whereas, the adhesive used for the glued finger-jointed truss will maintain its structural integrity longer than the truss members.

* Toughness-The ability of a material to absorb energy up till it fractures. The shaded area indicates the energy required to fracture the test specimen.

The increase in the number of terrorist attacks especially in the last few years has shown that the effect of blast loads on buildings is a serious matter that should be taken into consideration in the design process. Although these kinds of attacks are exceptional cases, man-made disasters; blast loads are in fact dynamic loads that need to be carefully calculated just like earthquake and wind loads. The use of bombs to attack the cities by terrorist organizations around the world. A bomb explosion within or immediately nearby a building can cause catastrophic damage on the building 's external and internal structural frames, collapsing of walls, blowing out of large expanses of windows, and shutting down of critical life-safety systems. Loss of life and injuries to occupants can result from many causes, including direct blast-effects, structural collapse, debris impact, fire, and smoke. The indirect effects can combine to inhibit or prevent timely evacuation, thereby contributing to additional casualties. Due to the threat from such extreme loading conditions, efforts have been made during the past decades to develop methods of structural analysis and design to resist blast loads. The analysis and design of structures subjected to blast loads require a detailed understanding of blast phenomena and the dynamic response of various structural elements.

The importance of heritage structures from a National standpoint hardly needs expounding. Our built heritage needs conservation from the economic, cultural and environmental viewpoints and the first step towards preservation and restoration of heritage structures involves their structural analysis. Accurate analysis is required in order to arrive at reliable solutions and to avoid unnecessary