نتایج جستجو برای: concrete beam and girder
تعداد نتایج: 16877190 فیلتر نتایج به سال:
Slab-girder structures composed of steel girder and reinforced concrete slab are widely used in buildings and bridges in the world. Their advantages are largely based on the composite action through the shear connection between slab and girder. In order to assess the integrity of this kind of structures, numerous vibration-based damage identification methods have been proposed. In this study, a...
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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...
In this paper the parametric study is carried out to investigate the effect of number of cells in optimal cost of the non-prismatic reinforced concrete (RC) box girder bridges. The variables are geometry of cross section, tapered length, concrete strength and reinforcement of the box girders and slabs that are obtained using ECBO metaheuristic algorithm. The design is based on AASHTO standard s...
16. Abstract Two prestressed high performance concrete (HPC) highway bridges were constructed in Texas utilizing concrete with 56 day design strengths of up to 97 MPa (14,000 psi). The utilization of HPC allowed for longer spans and larger girder spacing than typically used in conventional prestressed concrete bridges. An extensive research program was conducted to monitor the shortand long-ter...
Most of the previous researches conducted on shear lag of box girders were only concerned about simple types of structures, such as simply supported and cantilever beams. The structural systems concerned in these previous researches were considered as determined and unchangeable. In this paper, a finite element method considering shear lag and creep of concrete was presented to analyze the effe...
INTRODUCTION The lower ratio of dead load to live load than existing multi-girder bridges, wide girder spacing and simplified structural system of the twin-girder bridges can give rise to change of dynamic characteristics of the bridges. Wider girder spacing and changing of dynamic features will also effect on a vibration serviceability of the bridges. What is worse, according to running vehicl...
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 ...
همه ساله پلهای زیادی به دلایلی از جمله معضلات ژیوتکنیکی، سازه ای، هیدرولوژیکی، زلزله و ... تخریب میشود که مطمینا در صورتیکه قبل از خرابی در برنامه ریزی های مدون موردارزیابی دقیق قرار میگرفتند. بسیاری از عیوب آنها قابل رفع بود. مشاهدات محلی، بازرسیها و تحقیقات انجام شده در مورد پلهای مورد بررسی در این پایان نامه حاکی از آنست که عوامل عمده در ایجاد نواقص موجود به ترتیب ذیل قابل تقسیم بندی میباشند.
این پایان نامه در قالب یک تحقیق عددی به ظرفیت باربری و مقاومت برشی تیرهای بتن آرمه در چهار مرحله مختلف بتن آرمه، بتن آرمه پیش تنیده، بتن آرمه با خاموت پیش تنیده، بتن آرمه پیش تنیده با خاموت پیش تنیده می پردازد. هدف این پروژه بررسی اثر پیش تنیدگی افقی و قائم بر ظرفیت برشی تیرهای پیش تنیده می باشد. بدین منظور دو پارامتر ظرفیت باربری و زاویه شیب دستک های فشاری در طول تیر مورد بررسی قرار گرفته است....
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