scholarly journals Analisis Perbandingan Kehilangan Prategang Akibat Variasi Letak Tendon PC I Girder Jembatan Beton Prategang

2020 ◽  
Vol 2 (2) ◽  
pp. 034-042
Author(s):  
Ibham Yamin ◽  
Siswanti Zuraida ◽  
Ilham Ilham
Keyword(s):  
Cross Section ◽  
Prestressed Concrete ◽  
Neutral Axis ◽  
Bridge Structure ◽  
Allowable Stress ◽  
Final Project ◽  
Number Of Factors ◽  
Parabolic Shape ◽  
Prestressed Concrete Bridge ◽  
Over Time

Prestressed force loss always occurs in prestressed concrete (loss prestressed). The most common form used in pre-tensile beams is straight tendons and for post-tensile beams are curved tendons. In planning a prestressed concrete bridge structure, the loss of prestressed force must be considered, because the stress on the prestressed concrete tendon decreases continuously over time. The number of factors that are interrelated, for the effectiveness of the design, location of tendons along the spans need to be considered, so that the tensile strength that occurs in the extreme fiber beam is limited or none at all in the cross section. This final project will examine the shape of the PC beam I Girder with 4 tendon setting conditions namely straight tendon cable which is on the neutral axis so that the eccentricity = 0 (condition1), straight tendon cable which is at 1/6 h so that the eccentricity ≠ 0 (condition 2), tendon cable with draped / parabolic shape (condition 3), and tendon condition with harped shape (condition 4). The biggest prestressed loss results were PC I Girder (condition 2) = 395.81 MPa (26.07%), while the smallest prestressed loss is PC I Girder (condition3) = 367.44 MPa (24.2%). Condition 1 and 2 in girder is not suitable for use because it exceeds the value of the allowable stress at the limit of prestressed and deflection permits on girder are safe for each condition.

Field Damage Inspection and Static Load Test Analysis of Jiamusi Highway Prestressed Concrete Bridge in China

2010 ◽  
Vol 163-167 ◽  
pp. 1147-1156 ◽  
Author(s):  
Ali Fadhil Naser ◽  
Zong Lin Wang
Keyword(s):  
Prestressed Concrete ◽  
Steel Reinforcement ◽  
Load Test ◽  
Concrete Bridge ◽  
Bridge Structure ◽  
Static Load Test ◽  
Box Girder ◽  
Good State ◽  
Prestressed Concrete Bridge ◽  
Corrosion Of Steel

The main purpose of damage inspection of the bridge components is to ensure the safety of a bridge and to identify any maintenance, repair, or strengthening which that need to be carried out. The essential damages that occur in reinforced concrete bridge include different type of cracks, scalling and spalling of concrete, corrosion of steel reinforcement, deformation, excessive deflection, and stain. The main objectives of this study are to inspect the appearance of Jiamusi highway prestressed concrete bridge and describe all the damages in the bridge structural components, and to evaluate the structural performance of the bridge structure under dead and live loads. The field tests that are adopted in this study are the depth of concrete carbonation test, compressive strength of concrete test, corrosion of steel reinforcement test, and static load test. According to inspection of the bridge structure appearance, the overall states of bridge structure in good and there are not serious damages, but there are diagonal and longitudinal cracks in the inside web of box girder within block No.8 and 9. Expansion joints suffer from serious damage such as deformation of expansion joint rubber, dislocating, shedding, and cracking. The field test results show that the concrete of the bridge structure has not carbonation; the strength of concrete in good state; there is not corrosion in steel reinforcement; The values of load test for vertical deflection, strain, and stress are less than the theoretical values and the results of cracks observation show that there is not changing in the length of diagonal cracks in the web of box girder when the load test is applied. This indicates that the working state and carrying capacity of the bridge structure in good state.

Evaluating the performance of skewed prestressed concrete bridge after strengthening

2013 ◽  
Vol 3 (2) ◽  
Author(s):  
Ali Naser ◽  
Wang Zonglin
Keyword(s):  
Prestressed Concrete ◽  
Structural Response ◽  
Bridge Structure ◽  
Box Girders ◽  
Allowable Limit ◽  
Limit Values ◽  
Structural Responses ◽  
Static And Dynamic Loads ◽  
Prestressed Concrete Bridge ◽  
Strengthening Method

AbstractThe objectives of this paper are to explain the application of repairing and strengthening methods on the damaged members of the bridge structure, to analyze the static and dynamic structural response under static and dynamic loads after strengthening, and to evaluate the structural performance after application of strengthening method. The repairing and strengthening methods which are used in this study include treatment of the cracks, thickening the web of box girder along the bridge length and adding internal pre-stressing tendons in the thickening web, and construct reinforced concrete cross beams (diaphragms) between two box girders. The results of theoretical analysis of static and dynamic structural responses after strengthening show that the tensile stresses are decreased and become less than the allowable limit values in the codes. The values of vertical deflection are decreased after strengthening. The values of natural frequencies after strengthening are increased, indicating that the strengthening method is effective to reduce the vibration of the bridge structure. Therefore, the strengthening methods are effective to improve the bearing capacity and elastic working state of the bridge structure and to increase the service life of the bridge structure.

Creep Relaxation of a Beam of General Cross Section Subjected to Mechanical and Thermal Loads

1978 ◽  
Vol 100 (4) ◽  
pp. 626-629 ◽  
Author(s):  
M. R. Eslami
Keyword(s):  
Cross Section ◽  
Thermal Load ◽  
Opposite Sign ◽  
Neutral Axis ◽  
Allowable Stress ◽  
Sectional Area ◽  
Lower Stress ◽  
Cross Sectional ◽  
The Cross ◽  
Mechanical Moment

Creep relaxation of a beam of general cross-sectional area subjected to mechanical and thermal load is obtained. Temperature is assumed to be a function of Z, the height of the beam, and the mechanical moment on the cross section M. The stress in the beam is obtained as a function of time. It is concluded that the point of zero stress shifts, and therefore, the neutral axis of the beam moves toward the lower stress magnitude portion of the cross section, and as time passes it sharply drops to a large stress of the opposite sign that for a large enough time will exceed the allowable stress, and therefore causes failure of the beam.

Experimental Analysis and Performance Evaluation of Fu Feng Highway Prestressed Concrete Bridge after Strengthening in China

2011 ◽  
Vol 189-193 ◽  
pp. 2346-2352
Author(s):  
Ali Fadhil Naser ◽  
Zong Lin Wang
Keyword(s):  
Prestressed Concrete ◽  
Static Load ◽  
Load Test ◽  
Concrete Bridge ◽  
Bridge Structure ◽  
Structural Members ◽  
Static Load Test ◽  
Box Girders ◽  
Transverse Beam ◽  
Prestressed Concrete Bridge

Fu Feng highway prestressed concrete bridge is located in Changchun City which is the capital and largest city of Jilin province and it located in the northeast of China. The strengthening of the bridge structural members can be attempted by replacing poor quality or defective materials by better quality materials, attaching additional load-bearing materials, and re-distribution of the loading actions through imposed deformation on the structure system. The objectives of this study are to explain the strengthening process of damaged structural members of Fu Feng bridge, and to evaluate the performance of the bridge structure by adopting static load test. The strengthening process of damaged structural members includes three stages. These stages include the strengthening of box girders floor by casting of 10cm of reinforced concrete in the floor of box girder within the location of positive bending moment in the mid-span and edge span, the strengthening of box girders web by pasting steel plates in the inside of the right and left of box girders, and the strengthening of the transverse beam of piers No. 18 and No. 19 by using carbon fiber sheet. The results of static load test show that the values of testing coefficient ( ) of stress range from 0.83 to 0.92 are less than allowable value 1.05. Therefore, these values satisfy the allowable value of standard, indicating that the structural member has a certain strength reserve and the working state of the bridge structure in good state. the ratio between the measured and theoretical deflection is 1.41 and 1.68 for condition 3 more than allowable value 0.8, indicating that the state of stiffness is not good and there are still a serious shortage in stiffness of structure. Therefore, this study recommended that the bridge structural members need to re-strengthen by using other effective technical and materials to increase the stiffness of structural members of the bridge.

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