scholarly journals STUDY ON SPATIAL STRESS EFFECT OF PC CONTINUOUS THIN-WALLED BOX GIRDER BRIDGE

2021 ◽  
Vol 30 (3) ◽  
Author(s):  
Honglei Zhang

In order to study the influence of spatial stress effect and shear lag effect on the cracking of PC continuous thin-walled box girder bridge, a spatial model was established by using ANSYS finite element software to analyze the internal stress distribution of the bridge. The test results are compared with the analysis results of spatial model and plane link system model through the load test of real bridge. The results show that the longitudinal stress is evenly distributed along the width direction, which means that the spatial stress effect and the shear lag effect have little influence on the downdeflection of the bridge. The shear lag coefficient at the longitudinal axis of midspan bottom plate and the intersection of bottom plate and web are larger than other positions, which is most likely to produce cracks caused by stress concentration, and should be strengthened here in practical engineering. The results of load test show that the results of spatial finite element analysis are more reliable than those of plane link system calculation, and the design and construction based on the results of spatial finite element analysis is safer.

2014 ◽  
Vol 644-650 ◽  
pp. 5054-5060
Author(s):  
Rui Juan Jiang ◽  
Yu Feng Xiao ◽  
Xiao Wei Yi ◽  
Qi Ming Wu ◽  
Wei Ming Gai

There are few studies about the shear lag effect and the effective flange width of the PC (Prestressed Concrete) box girder bridge with corrugated steel webs throughout the world in current time. In the present paper, based on the three-dimensional finite element analysis for a long-span continuous PC box girder bridge with corrugated steel webs and the corresponding conventional box girder bridge with concrete webs, a comparative study on the shear lag effect under vertical loads are carryied out together with the analyslis on the coefficient of the effective flange width. The results show that in the PC box girder with corrugated steel webs, the transverse distributions of longitudinal normal stress on the section of the slabs are obviousely non-uniform and they are different with those in the conventional PC box girder with concrete webs. And moreover, the shear lag effects in top slab of the PC box girder with corrugated steel webs are almost less obvious than those of the conventional PC box girder with concrete webs. However, the shear lag effects in bottom slab of the PC box girder with corrugated steel webs are almost similar to those of the conventional PC box girder with concrete webs, no matter what kind of vertical bending moment the cross section is subjected to


2014 ◽  
Vol 638-640 ◽  
pp. 1092-1098 ◽  
Author(s):  
Rui Juan Jiang ◽  
Qi Ming Wu ◽  
Yu Feng Xiao ◽  
Xiao Wei Yi ◽  
Wei Ming Gai

In the present paper, based on the three-dimensional finite element analysis for a three-span continuous PC box girder bridge with corrugated steel webs and the corresponding conventional box girder bridge with concrete webs, a comparative study on the shear lag effect under self-weight is carryied out together with the analyslis on the coefficient of the effective flange width. The results show that At the sections in the negative bending moment near the intermediate piers, the shear lag effect in the bridge with corrugated steel webs is more obvious than that in the bridge with concrete webs by 8%; and the corresponding effective flange width coefficient in the bridge with corrugated steel webs is even smaller than 0.9, so the shear lag effect at these sections should be considered in the design of this type of bridges. At the mid-span section of the middle span of a three-span continuous bridge either with corrugated steel webs or concrete webs, the shear lag effect can be omitted since the corresponding effective flange width coefficient there is close to 1.0.


2013 ◽  
Vol 671-674 ◽  
pp. 815-819
Author(s):  
Yi Sheng Li ◽  
Jun Ping Wang ◽  
Wei Liu ◽  
Jian Ming Shen

The shear-lag effect of steel box-girder is qualitatively analyzed by using the finite element software ANSYS. Various methods to reduce the shear-lag effect are studied, and the most effective method is changing the web layout and increasing the number of box-room among them. The suggested value of effective width to thickness ratio b1/t1 of the flange without considering the shear-lag effect are obtained in this paper.


2010 ◽  
Vol 163-167 ◽  
pp. 3551-3554
Author(s):  
Wei Peng ◽  
Zhi Xiang Zha

This template Based on cracks observation and finite element analysis of real engineering projects as well as bridge load test after reinforcement, causes and types of cracks in prestressed concrete box girder bridges and treating measurements are systematically studied. The results obtained from the calculation are presented to demonstrate the effect of sensitive factors, such as arrangement of longitudinal prestressed tendons, the magnitude of vertical prestressed force, temperature gradient, etc. The results show that the arrangement of longitudinal prestressed tendons and the magnitude of vertical prestressed force take key roles in cracks control of box girder webs. Lots of treating measurements are presented in accordance with different types of cracks, some of them are applied to a reinforcement engineering of a long span pretressed concrete continuous box girder bridge with cracks. Load test after reinforcement of the bridge demonstrates the reasonability of the treating measurements. Several design recommendations and construction measures about reinforcements and some sensitive factors mentioned above are proposed to control cracks.


2013 ◽  
Vol 351-352 ◽  
pp. 152-155 ◽  
Author(s):  
Shu Fen Ma ◽  
Xie Dong Zhang

In order to study the influencing parameters of the shear lag effects on the box-girder beam, the effective width was analyzed by the ways of looking up the present code and formula. Taking the simply supported and cantilever girder as the example, the parameter sensitivity was studied, such as width/span, cantilever length and span. The results showed that the shear lag effect of mid-span beam is small but the support beam is outstanding; the fixed amount relationship of the parameters and the shear lag effects was put forward. The conclusions will be useful for the design and construction of the box girder bridge.


2014 ◽  
Vol 638-640 ◽  
pp. 937-941
Author(s):  
Jie Jun Wang ◽  
Peng Tan ◽  
Jiang Ya Yuan ◽  
Hai Qing Yuan ◽  
Gui Ming Zhang

This paper simulates the practical engineering, using plexiglass to make a three-span continuous wide curved box girder model by the geometry scale ratio 1:30. With the model load test, measured the strain and deflection of the control cross-sections, got the distribution about the stress and deflection of the wide curved continuous box girder; And we proposed the “uniformity coefficient” to express the uneven force of the curved bridge. Compared the finite element analysis results and experimental data, the results show both are in good agreement.


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