نتایج جستجو برای: prestressed beam and girder
تعداد نتایج: 16856134 فیلتر نتایج به سال:
The segmental prestressed concrete box girder of Koror-Babeldaob (KB) Bridge in Palau, which had a record span of 241 m (791 ft), presents a striking paradigm of serviceability loss because of excessive multidecade deflections. The data required for analysis have recently been released and are here exploited to show how the analysis and design could be improved. Erected segmentally in 1977, thi...
The structural system of prestressed concrete (PC) voided slab deck is intermediate between plate and girder. Therefore, the conventional design method is based on the assumption that the system is similar to the plate system or to the grid system. In this paper, the structural behavior of a continuous PC voided slab deck with three spans was analyzed by using the three dimensional solid finite...
این پایان نامه به تعیین مقادیر بهینه متغیرهای طراحی شاهتیرهای پیش تنیده ساده و وصله شده در پل ها با در نظر گرفتن هزینه طول عمر مفید سازه می پردازد. برای دستیابی به هدف فوق، برنامه ای به نام obpg با استفاده از زبان برنامه نویسی فرترن نوشته شده است که مشتمل بر زیربرنامه های تحلیل، طراحی و بهینه سازی سازه می باشد. در این برنامه برای انجام تحلیل سازه با فرض مقادیر اولیه ای برای متغیرهای طراحی از قب...
The Softened Truss Model Theory applied to a prestressed concrete multiple cell box is developed in this study. In this theory, the concrete torsional problem is solved by combining equilibrium conditions, compatibility conditions and constitutive laws of materials. Up to now the theory has been applied only to the case of pure torsion with single cell section. An algorithm is presented to deal...
The use of heavier trucks demanded upgrading of a twenty-seven year old bridge in Winnipeg, Manitoba, Canada. Analysis of the precast prestressed concrete girders using the current AASHTO Code indicates a deficiency in the shear capacity. Shear strengthening using Carbon Fibre R_einforced Polymer (CFRP) sheets provides a low-cost solution by increasing the speed of construction and reducing tra...
A concrete bridge over Interstate 70 east of Denver, Colorado was impacted by a fork lift being transported by a truck moving at a speed of approximately 75 mph. The forklift impacted the east face of the prestressed concrete I-beam bridge girder, resulting in severe cracking and concrete spalling on both sides of the eastmost girder. Polymer-modified repair mortar was used to repair spalled ar...
Abstract: Based on the characteristics of box girder with corrugated steel webs, the existing prestressing force, the effect of shear deformation of composite girder on the deflection, “folding effect” in longitudinal direction of corrugate steel webs and the arrangement of external tendons were considered comprehensively. With the experiment results of five literatures integrated, N/fcA (the a...
A recent trend in bridge construction has been the optimization of the cost-to-performance ratio. The most effective way to optimize the cost-to-performance ratio is to maximize the efficiency of the superstructure. Currently, many bridge engineers and designers favor two- or three- girder plate superstructures, due to their cost advantages. However, research on the performance enhancements of ...
Testing methods are required for estimating prestress losses in Prestressed Concrete (PC) girder-bridges. They mainly include destructive approaches which cause significant damages. Conversely, dynamic nondestructive unsuitable. Given these findings, a novel method identifying residual force simply supported PC girder-bridges was implemented. Following the vertical load application three-point ...
Since the 1950’s, prestressed concrete beams have become a factor in almost one third of all new bridge construction in the United States. In Michigan, prestressed concrete was introduced in 1954 and the first prestressed concrete side-by-side box-beam bridge was built in 1955. Pontis data indicates 2,054 side-by-side prestressed concrete box-beam bridges in Michigan; 236 are part of the Nation...
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