Secondary elements such as barriers, sidewalks, and diaphragms may increase the load carrying capacity of girder bridges. This in turn affects reliability. The objective of this study is to evaluate the potential benefit of secondary elements on the system reliability of girder bridges, if these elements are designed with the structural system to participate resisting vehicular live loads. Simple span, two lane structures are considered, with composite steel girders supporting a reinforced concrete deck. For structural analysis, a finite element procedure is developed that combines a grillage model of the bridge deck with solid elements for edge-stiffening effects.
Procedure : In this test method, the ultrasonic pulse is produced by the transducer which is held in contact with one surface of the concrete member under test. After traversing a known path length Q in the concrete, the pulse of vibrations is converted into an electrical signal by the second transducer held in contact with other surface of the concrete member and an electronic 2 timing circuit enables the transit time (T) of the pulse to be measured. The pulse velocity (V) is given by : V = L/T 8.3.2 Ultrasonic Pulse Velocity Method This method involves the measurement of velocity of electrostatic pulses passing through concrete from a transmitting transducer to a receiving transducer. The pulse also can be generated by hammer blow. The pulse generator circuit consists of electronic circuit for generating pulses and a transducer for transmitting these electronic pulses into mechanical energy having frequency 15 to 50 kHz.
• Prestressed concrete is a modern material in which the stresses resulting from external loads are counteracted to a desired degree by introducing internal stresses of a suitable magnitude. • In reinforced concrete members, the prestress is commonly introduced by tensioning the steel reinforcement. • The apparent tensile strength of a material like concrete, which is strong in compression but weak in tension, is increased by application of permanent compressive stresses. • ¬¬¬¬Once the initial compression has been applied, the resulting material has the features of ductile high-strength steel when subject to tension forces and high-strength concrete when subjected to any compression forces. The tensile strength of the material increases because the subsequent application of tensile stress must nullify the compressive prestress.
The construction methodology is the same with elastomeric bearings; however, the damping is increased by adding carbon block and other fillers. In addition, it has an adequate resistance to service loads. The damping characteristic is in between hysteric and viscous. The energy dissipation is linear and quadratic for hysteric and viscous, respectively. The energy absorption capability help reduced the earthquake energy transmitted to the superstructure.
In and around Pittsburgh, various pillars and materials are used to support structures. The type of pillar to be used depends on a number of issues, such as the structure to be put up and the period such a structure is to exist. For houses, for instance, engineers tend to use thick round pillars, filled with concrete to give the structure in question the support it needs. The cross-section depends on the width and height of the building, plus its intended purpose. Materials used in such pillars include cement and sand.
For this the mold should be made from high strength preferably of hardened steel. Secondly, for better mechanical properties it is advised that the molded items be annealed. Thirdly, mold release agents if required should only be made from fluorine based compounds to avoid stress cracks. Applications Poly (ether sulphone) has a variety of applications in a vast array of fields. The most successful applications are mentioned below.
The material would then be pulverized, with which you would get a powder. When this powder was mixed with water, it would become as hard as rock. Concrete Concrete made it possible to use bricks and concrete to build massive permanent structures. Concrete took the place of rubble for the filling between the bricks of a wall. Stones that were irregularly shaped could now easily be used to build a wall because they had concrete to
Many failures and disasters occurred in the pontoon bridge history. These failures and disasters include Saint Isaac’s bridge, Hood Canal Bridge, Lacey V Murrow Memorial Bridge and many more others. Besides from the parameters in the research study, renovation and maintenance is a factor to prevent bridge’s failures and disasters. In this stage the researcher will study the proposed renovation and maintenance system for the SR520 Bridge. The SR520 Bridge is a pontoon bridge in the U.S. state of Washington.
Seismic facies analysis Seismic facies represent a group of seismic amplitude variations with characteristics that distinctly differ from those of other facies. A seismic facies is the manifestation of the underlying geologic facies or structural feature in the seismic amplitude data. These can be searched and identified from the seismic data by different approaches. These could be based on analysis of either the seismic waveforms or the seismic attributes. Seismic facies analysis consists of the parameters and reflection configuration studies, which determine a seismic sequence.
Both sides of the bridge are on reclaimed land and foundations are large diameter bored piles to bedrock. Components in the Stonecutters Bridge: The corrosion resistance of these steels is provided by the alloying element chromium; improved resistance is provided by the addition of 2 to 3% of molybdenum. Deck Steel was used on the deck of the main span. It is a twin-box girder arrangement. The box section deck provides convenient anchorages and has significant torsional properties.