نتایج جستجو برای: concrete bridges
تعداد نتایج: 94881 فیلتر نتایج به سال:
Under badly environmental conditions as well as complex loads, corrosion of embedded reinforcing steel bars in concrete is common for reinforced concrete (RC) structures. Fatigue of corrosion reinforcing steel bars is a key problem for old RC bridges. To assess the residual fatigue life of aged existing RC bridges, the most new study information on fatigue of natural corrosion reinforcement is ...
Stimulated by the excessive deflections and collapse of the KB Bridge of world-rercord span, the deflection histories of 56 similar bridges, most of them excessive, have been collected by RILEM TC-MDC. They amount to a wake-up call: The standard creep recommendations of engineering societies have been misleading, and thus their revision is imperative. They also confirm a simple feature: The mul...
Based on the conceptions of energy dissipation, multi-failure and safety protection of structure, a new energy dissipation-based multi-level control system for unseating failure prevention of concrete girder bridges subjected to earthquake is proposed. The control system provides respectively two different functions including energy dissipation-based displacement restriction and unseating preve...
External prestressing has become a primary method for strengthening existing concrete beam and has been increasingly used in the construction of newly erected ones, particularly railroad bridges in recent years. In order to evaluate the effect of this method, the static and dynamic behavior of a T-frame beam reinforced by external prestressed strengthened concrete beam was analyzed by 3D finite...
The problem of concrete bridge deck deterioration on many of our newer as well as older bridges is severe, somewhat perplexing as to cause, and difficult to solve. Furthermore, the cost to highway agencies for their repair, and the cost of delay to the highway user, can be extremely large. The use of precast, prestressed concrete for bridge decks is a con cept of construction or reconstruction...
The National Bridge Inventory (NBI) includes more than 600,000 bridges within the United States of Prestressed concrete girder bridges represent one of the most widely used bridge systems. The majority of these girder bridges were constructed using 0.5 and 0.6 inch diameter strands. The main impediments to using larger strand diameters are: 1) bed capacities, 2) lack of structural knowledge reg...
This paper deals with the economic optimization of prestressed concrete precast pedestrian bridges typically used in public works construction. These bridges are made of a precast concrete beam that integrates an upper reinforced concrete slab for the pedestrian traffic. The beam has a U-shape cross-section. Typical span lengths range from 20 to 40 m and the width ranges from 3.00 to 6.00 m. Th...
Deterioration of concrete members due to corrosion of steel reinforcements is one of the major problems which reduces the service life time of bridges, especially in Canada due to the use of de·icier applications. The cost of correcting corrosion-induced distress in bridges is high compared to the capital cost of the structure. To overcome this problem, the City of Calgary has decided to constr...
displacement coefficient method (dcm) stipulated in the asce 41-06 standard is becoming the preferred method for seismic rehabilitation of buildings in many high-seismic-hazard countries. applications of the method for non-building constructions such as bridges are beyond the scope of this standard. thus its application to this kind of structure should be approached with care. target displaceme...
The research program consists of a series of investigations in the field and in the laboratory. First, four short-span bridges are installed so as to outline the construction-related issues associated with the use of these materials. The bridges are located in a residential area of St. James, Missouri and each bridge utilizes FRP materials in a slightly different way, demonstrating the versatil...
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