1、中文 3680 字 外文翻译 1.1 Earthquake Background Earthquake is a high risk natural disaster which costs injuries and casualties as well as the damages to the infrastructures. It has an ability to deform the earth surfaces thus causing destructions to buildings on it 1.2 Earthquake Phenomenon Earthquake happ
2、ens when there is an earth crust movement due to folding crust. When the earthquake occurs, the soil and crust move randomly to directions. Earthquake happens actually numerous times in a day but the earthquake that affects the most and has great magnitude is seldom to occur, nevertheless once in se
3、veral years. According to the tectonic plate theory, the earth surface is divided into several rigid crusts. They move in such ways, colliding or apart from each other. When the crusts collide, one of them will subdue under one another and the sliding crusts will generate energy. This movement will
4、take years and peoples on it will never aware of this activity and it actually takes only several centimeters in a year. Each time the couple crusts move and slip with each other, it increase and accumulate the energy in the substances around it like rocks. Finally the energy itself will exceed the
5、rock strength, thus make the rocks to move or explode. The exploding rocks will later cause the earthquake means once the earthquake occurs, the forces are subsided. The earthquake magnitude is measured in Richter Scale. A great earthquake is categorized as an earthquake with magnitude of 5.0 and ab
6、ove which surely causes damage to structures. The point where the earthquake origins is called focus or hypocenter which determined by seismic assessment. Earthquake starts with a small shaking followed by a sudden increase of shaking intensity. The small shake is called foreshock, while the great s
7、haking is called mainshock and the rest is called aftershock. A great earthquake usually not done with only one shake, the shakings will remain to happen but there will only the magnitude is decreasing. The starting is called mainshock but the rest is called aftershock. 1.3 Earthquake Waves The eart
8、hquake is a result of an elastic waves. There are 3 types of earthquake waves. Two of them are moving within the rock, while another one moving through earth surface. The P-wave is the fastest wave among the three. It is corresponded as a motion of push and pull and can travel through solid rock or
9、water of the ocean. The S-wave is slower than the P-wave. It shears the rock sideways to the travel direction. It can not travel through the water ocean. While the third wave is the Surface Wave. Surface wave is divided into two types of minor waves. The first is the Love Wave while the second is Ra
10、yleigh Wave. It is similar to the S-wave but with no vertical movement. It moves in horizontal plane with an angle to he travel direction. While the Rayleigh Wave is a wave that travels in both horizontal and vertical direction. 1.4 Effects of Earthquake Earthquake can cause properties damage and ca
11、sualties as well as earth deformations and damaging structures that get in its way. Earthquakes that occur below sea level and have large vertical displacements can give rise to tsunamis, either as a direct result of the deformation of the sea bed due to the earthquake or as a result of submarine la
12、ndslides directly or indirectly triggered by the quake (Bolt, 1978). Earthquake force is acting like a pull and push action resulting the building to receive random excitation. The excitation will transfer force from the foundation to the tip of the building. The sway of the building increases as th
13、e height increases. The top section of the building will experience the most swinging force rather than the bottom part 1.5 Problem Statement In an earthquake event, the most affected things will be the civil structure and buildings. The lost will cost millions in monies as well as casualties. In Ma
14、laysia, there are no such things that had been done to overcome the unexpected disaster. In the current building practice, no earthquake load factor taken into account into the design consideration. Earthquake impact, this study is imperative as a precaution and to prove how important an earthquake
15、design code implemented in Malaysias building and civil structure practices. 1.6 Objectives The objectives of this study are: 1. To study the design capacity of the bridge. 2. To determine the bridge responses (deformation, shear and moment) under various intensity of earthquake. 3. To identify the
16、Damage Index of the bridge. 4. To identify the most critical part of the bridge while transmitting earthquake loading. 5. To model the bridge structure as close as possible to its actual state so that its behavior can be studied. 6. To identify the safer structural design practice to be implemented
17、in bridge structure, in the future. 2.1 Analysis The evolution of seismic analyses in earthquake engineering has followed closely the developments in dynamic structural analysis as a whole. Numerous kind of research done by research team, academic institutes and distinguished researchers regarding t
18、o the earthquake induced structure. All the studies are concern toward finding the best solution to reduce the impact and damage to the structure.Malaysia is a region which free from the seismic activity and has been regarded as a stable area. But there are numbers of major faults have been recogniz
19、ed in the Peninsular. 2.2 Concrete Failure Concrete failure always associated with the air and moisture factor. They can lead the concrete to deteriorate in problems like: i. Cracks ii. Spalling and scaling of concrete due to expansion of steel rebar which transmits tension to concrete. iii. Abrasio
20、n of the steel rebar caused by concrete inadequacies surrounding the section and exposure to crack attack. iv. Inadequate concrete strength. 2.3 Natural Disaster Problem The unexpected natural disaster can cause the bridge structure to fail and collapse. The disaster can lead to problems like below
21、(Kirillov et al., 1962): i. Settling of the soils surround the structure. ii. Slope failure. iii. Lateral crack on superstructures surface. iv. Cracks of retaining wall and settlement of the support. Numerous actions can be taken to overcome this problem. There are four actions to be considered acco
22、rding to Parry, 1976. Those are: i. Use more and bigger bolts to carry the load. ii. Increase the retaining wall strength. iii. Emplace shear or concrete blocks between the girder sections. iv. Increase concrete strength which located in the end of the bridge span. 2.4 Analysis steps There are many
23、techniques used in structural dynamic analysis. One of the essential parts to be focused in is the analysis and the design of the structure to withstand the ground acceleration from the earthquake. Non-linear analysis is used in this study. IDARC 2D is chosen as the non-linear dynamic program to be
24、used to analyze dynamic characteristic of the structure when it failed. While the SAP2000 will analyze the bridge by Response Spectrum analysis, comparing its shear and moment under earthquake loading with the actual design capacity. In this study, the inelastic analysis is considering a bridge wher
25、e an identified box girder bridge will be accounted and analyze with increasing intensity seismic accelerations, to the extent when the bridglastic characteristice shows the ine. 2.5 Time History Analysis The Time History analysis will be carried out by the IDARC program analysis. Time History is a set of graphical data that shows the intensity of the earthquake and contains the acceleration, g of the earthquake event to the period of the event. 2.6 IDARC 2D A Program for Inelastic Structural Analysis.
