PRESTRESSED CONCRETE BRIDGES
Main information
Our company provides wide range of concrete construction services. We create complete solutions through the process and execution of designing prestressed concrete bridges. Comprehensive prestressing services range from design, forming cable routes, delivery and even stressing. When needed we also provide advanced analysis of construction detail like anchorage area of tensioning cable, or joint between concrete girder and steel launching nose in incremental launching methods.
Structural analysis
Every construction we design and every problem which we solve is analyzed, paying special attention to possibility of optimization. To achieve this goal we use powerful software, SOFiSTiK, in which we are able to analyze local effects of prestressing with cable-by-cable analysis, geometric and material nonlinearity effects, anchorage zones and influence of construction stages on inner forces. Calculations include continuity of losses of friction in the prestressing cable, and shrinkage in cable over long periods of time.
Centric and excentric tendons
One of our main projects was a prestressed concrete bridge MS-36 which was made by the incremental launching method. During our work we had to solve some construction details. To evaluate inner forces and stresses in the utilization stage we made a QUAD model which includes centric and eccentric tendons.
Anchorage area
Another construction model was the detail of the anchorage area at the one of the segments made by BRICK elements. This fragment of cross section has to handle big compression forces from cables. The analysis which we made showed us how the stresses from tendons are distributed in concrete.
The local effects of traveler
To find out the real inner forces form the local effects of traveler, stressing the front cable (of the anchorage block) and the influence of post tensioned cables, we created a Hexahedral BRICK model.
The local effects of prestressing
Analysis of the local effects of prestressing the cross beam from the bridge with box cross section. Real redistribution of internal forces in BRICK model, helped assess the state of stress.
Anchor block
For the incremental launching method we analyzed the anchor block for launching of the last segment. We used BRICK elements and spring connections between the block and segment.
Deviator
Another FEM model made by BRICKs elements was deviator. There were used kinematic constraints to model realistic distribution of the cable load on the curved area of deviator.