Analytical study on evaluation of residual strength for steel-concrete composite girder bridge after fire

2021 ◽  
Author(s):  
Yusuke Takahashi ◽  
Yusuke Imagawa ◽  
Osamu Ohyama
Keyword(s):  
Analytical Study ◽  
Fire Test ◽  
Structural Performance ◽  
Live Load ◽  
Girder Bridges ◽  
Composite Girder ◽  
Before And After ◽  
Loading Tests ◽  
Girder Bridge ◽  
Fire Accidents

<p>Fire damage to bridges occurs frequently in Japan and in other countries. Previous bridge fire accidents suggest that it is important to understand the structural performance of the bridges after their exposure to fire. The authors have studied the evaluation of the stress of the steel- concrete composite girder bridges as a simply supported bridge damaged by fire. First of all, fire test was carried out to clarify the temperature distribution of the composite girder and a static loading tests before and after fire were conducted to confirm the effect of the reduction of rigidity from fire. Next, numerical analysis was carried out to indicate the stress distribution and deflection on the composite girder bridge from live load after fire.</p>

Prameter Study to Validate Buoyancy Preflex Effects on Structural Performance of Floating Structures

2011 ◽  
Vol 94-96 ◽  
pp. 1049-1053
Author(s):  
Du Ho Lee ◽  
Youn Ju Jeong ◽  
Young Jun You ◽  
Yoon Koog Hwang
Keyword(s):  
Analytical Study ◽  
Structural Safety ◽  
Structural Performance ◽  
Live Load ◽  
Analysis Model ◽  
Floating Structure ◽  
Floating Structures ◽  
Compressive Stresses ◽  
Before And After ◽  
Analysis Models

In this study, a Buoyancy Preflex Method was introduced to enhance structural safety and performances for a large floating structure on which recently many studies are actively conducted worldwide. To demonstrate the effect of the Buoyancy Preflex introduced to the floating structure, an analytical study was conducted using parameters such as the ratio of the lengths of center modules to those of end modules. The analysis models for parameter were modeled into 5 cases, then a hydrostatic analysis on live load was selected from Equivalent Static analysis methods, then was conducted. The analysis procedure was divided into two steps, before and after live loading. As The result of this study, first analysis step, it was confirmed by each analysis model that excellent buoyancy preflexes were introduced. Even after the live loading, the 2nd analysis step, compressive stresses occurred at the bottom slabs of all analysis models, which enabled a determination that all analysis models can afford to secure safety and structural performance against live load.

Study of the Effect on Efficiency of External Prestressing and Economy to Box-Girder Bridge with Different Styles of Webs

2012 ◽  
Vol 256-259 ◽  
pp. 1605-1608
Author(s):  
Jin Song Zhu ◽  
Jian Feng Li
Keyword(s):  
Life Cycle Cost ◽  
Quantitative Research ◽  
Design Method ◽  
Structural Performance ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Girder Bridges ◽  
External Prestressing ◽  
Box Girder Bridge ◽  
Girder Bridge

Prestressed box-girder bridges have been applied in modern bridges widely as the perfect structural performance, the design method and calculation theory of prestressed box-girder bridges have been relatively perfect. The self-weight of box-girder bridges is reduced during the process of development from concrete structure to composite structure. The prestressed efficiency and the economy are also improved, simultaneously. But up to now, the quantitative research of the effect on efficiency of external prestressing to box-girder bridge with different styles of webs is lack. This paper illustrates the effect on efficiency of external prestressing and economy to box-girder bridge with different styles of webs. The results show that the box-girder bridge with corrugated steel webs has the highest prestressed efficiency and the lowest life cycle cost and the best economy.

scholarly journals Single-Lane Live Load Distribution Factor for Decked Precast, Prestressed Concrete Girder Bridges

2005 ◽  
Vol 1928 (1) ◽  
pp. 142-152 ◽  
Author(s):  
Jason L. Millam ◽  
Zhongguo (John) Ma
Keyword(s):  
Prestressed Concrete ◽  
Load Distribution ◽  
Live Load ◽  
Distribution Factor ◽  
Girder Bridges ◽  
Girder Bridge ◽  
Live Load Distribution ◽  
Load Distribution Factor ◽  
Precast Prestressed Concrete ◽  
Bridge System

The live load distribution factor equations provided by AASHTO load and resistance factor design specifications for the decked precast, prestressed concrete (DPPC) girder bridge system do not differentiate between a single-lane or a multilane loaded condition. This practice results in a single-lane load rating penalty for DPPC girder bridges. This paper determines distribution factor equations that accurately predict the distribution factor of the DPPC girder bridge system when it is subjected only to single-lane loading. Eight DPPC girder bridges were instrumented. Each bridge was loaded with a single load vehicle to simulate the single-lane loaded condition. The experimental data were used to calibrate grillage models of the DPPC girder bridge system. The calibrated grillage models were used to conduct a parametric study of the DPPC girder bridge system subjected to a single-lane loaded condition. Four new equations that describe the single-lane loaded distribution factor for both shear and moment forces of these bridges are developed in this paper.

Analytical Study of Fatigue-crack Propagation on Web-Gap Plate

2017 ◽  
Author(s):  
Ryo Tobita ◽  
Hirohisa Suzuki
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Analytical Study ◽  
Fatigue Cracks ◽  
Crack Problem ◽  
Steel Structures ◽  
Structural Repair ◽  
Girder Bridges ◽  
Girder Bridge

The study describes behaviour of fatigue-cracks for evaluation of structural repair priority. Around 65% of the total length of the Metropolitan Expressway in Japan is composed of viaducts made of steel. And fatigue crack problem has been occurred on the steel structures. In particular, around 30% of all the fatigue-cracks occurred at “Web-Gap Plate(WGP)” which is attached in plate girder bridges. This study focused on the fact that those cracks do not always induce collapse of the girder bridge immediately, even though the number of cracks, which are needed to repair, is becoming increasing. As a result of the study, repair priorities of around 60% cracks on WGP can be lowered by analysing maintenance data accumulated since 2001.

Effect of diaphragms on stress reduction in box girder bridge sections

1988 ◽  
Vol 15 (1) ◽  
pp. 127-135 ◽  
Author(s):  
A. H. Siddiqui ◽  
S. F. Ng
Keyword(s):  
Cross Section ◽  
Stress Reduction ◽  
Box Girders ◽  
Box Girder Bridges ◽  
Box Girder ◽  
Girder Bridges ◽  
Loading Tests ◽  
The Cross ◽  
Girder Bridge ◽  
Determine Effect

The purpose of this study is to examine the effect of rigid diaphragms in reducing warping and distortion stresses developed in box girders due to deformation of the cross section. Tests were conducted for two Plexiglas box girder models to determine effect of diaphragms on the behaviour of box girder sections. The results of the tests were compared with values obtained from the so-called “beam on elastic foundation (BEF) analogy,” an analytical procedure that permits the calculation of warping and distortion stresses in box sections due to deformation of the cross section.Each box girder model was tested as a simply supported beam with a 1168.4 mm (46 in.) span. Six separate loading positions were used for each of the three predesigned diaphragm spacings. Thus, 18 separate loading tests were conducted for each model in order to obtain sufficient data to determine the amount of reduction in both warping and distortion stresses. Test measurements included the applied load, deflections, and strains at various locations on the webs and bottom flanges.The results indicate that deformation of a box girder cross section due to eccentric loading may cause substantial warping and distortion stresses, and that these stresses can be effectively controlled by judicious installation of rigid diaphragms along the span of the girder. Also, experimental warping and distortion stresses obtained from both tests compare reasonably well with those predicted by the BEF analogy. Key words: warping, torsional, stresses, deformations, box girder bridges, diaphragms.

Live-Load Girder Distribution Factors for Bridges Subjected to Wide Trucks

2000 ◽  
Vol 1696 (1) ◽  
pp. 144-149 ◽  
Author(s):  
Sami W. Tabsh ◽  
Muna Tabatabai
Keyword(s):  
Finite Element ◽  
The United States ◽  
Live Load ◽  
Wheel Load ◽  
Element Analysis ◽  
Load Effect ◽  
Design Specifications ◽  
Girder Bridges ◽  
Girder Distribution Factors ◽  
Modification Factor

An important problem facing engineers and officials in the United States is the constraint imposed on transportation due to limitations of bridges. These limitations typically constrain vehicles to minimum heights and widths, to minimum and maximum lengths, and to a maximum allowable weight. However, with current demands of society and industry, there are times when a truck must carry a load that exceeds the size and weight of the legal limit. In this situation, the trucking company requests from the state departments of transportation an overload permit. For a truck with a wheel gauge larger than 1.8 m (6 ft), the process of issuing a permit for an overload truck requires a tremendous amount of engineering efforts. This is because the wheel load girder distribution factors (GDFs) in the design specifications cannot be used to estimate the live-load effect in the girders. In some cases, an expensive and time-consuming finite element analysis may be needed to check the safety of the structure. In this study, the finite element method is used to develop a modification factor for the GDF in AASHTO’s LRFD Bridge Design Specifications to account for oversized trucks with a wheel gauge larger than 1.8 m. To develop this factor, nine bridges were considered with various numbers of girders, span lengths, girder spacings, and deck slab thicknesses. The results indicated that use of the proposed modification factor with the GDF in the design specifications can help increase the allowable load on slab-on-girder bridges.

The Influence of Slab Concreting Sequence on a Continuous Composite Girder Bridge

2016 ◽  
Vol 691 ◽  
pp. 96-107
Author(s):  
Tomas J. Zivner ◽  
Rudolf B. Aroch ◽  
Michal M. Fabry
Keyword(s):  
Concrete Slab ◽  
Transverse Cross Section ◽  
Slab Thickness ◽  
Slab Width ◽  
Composite Girder ◽  
Steel Members ◽  
Composite Bridge ◽  
Bridge Girder ◽  
Girder Bridge ◽  
Main Girder

This paper deals with the slab concreting sequence and its influence on a composite steel and concrete continuous highway girder bridge. The bridge has a symmetrical composite two-girder structure with three spans of 60 m, 80 m, 60 m (i.e. a total length between abutments of 200.0 m). The horizontal alignment is straight. The top face of the deck is flat. The bridge is straight. The transverse cross-section of the slab is symmetrical with respect to the axis of the bridge. The total slab width is 12 m. The slab thickness varies from 0.4 m on main girders to 0.25 m at its free edges and 0.3075 m at its axis of symmetry. The center-to-center spacing between main girders is 7 m and the slab cantilever on either side is 2.5 m long. Every main girder has a constant depth of 2800 mm and the thicknesses of the upper and lower flanges are variable. The lower flange is 1200 mm wide whereas the upper flange is 1000 mm wide. The two main girders have transverse bracing at abutments and at internal supports and at regular intervals in every span. The material of concrete slab is C35/45 and of steel members S355. The on-site pouring of the concrete slab segments is performed by casting them in a selected order and is done after the launching of the steel two girder bridge. The paper presents several concreting sequences and their influence on the normal stresses and deflections of the composite bridge girder.

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