1, prestressed reinforcement and prestressed anchorage shall be strictly inspected and accepted in batches and properly kept. In addition to checking the appearance, accuracy and quality certificate of the anchorage, the strength (including fatigue strength) and anchoring capacity of the anchorage should also be sampled.

2. All prestressed steel strands and steel bars are not allowed to be welded, and all prestressed steel strands with joints should be removed and are not allowed to be used. Steel strand and reinforcement shall be derusted before use.

3. All prestress stretching needs extension and tension control. The value of E was determined by experiments, and the design extension was modified. The error between the measured extension and the designed extension shall meet the requirements of construction specifications. The measured elongation shall be deducted from all elongation caused by inelastic deformation.

4. Before prestress tensioning, use initial stress (0. 1 ~ 0.2σ k) to tension once, and then start measuring elongation. The tensioning procedure is: 0→ initial stress → 103% to control the tensioning stress under the design anchor (hold the load for 3min, anchor).

5. In order to ensure the quality of prestress, it is required to strictly control the process of tube drawing, steel bar positioning and tube forming. The specific requirements are as follows:

(1) When installing the pipeline, check the quality of the pipeline and the cross-sectional shapes at both ends. If slurry leakage may occur, the parts should be cut, trimmed and deburred at both ends before use.

(2) Channel positioning must be accurate and reliable, and corrugated pipes are strictly prohibited from floating. The straight line segment is 0.8m on average, and the curve segment is provided with a positioning steel bar every 0.5m.. Each positioning steel bar comprises a supporting steel bar and a U-shaped ring positioned on the supporting steel bar, and the U-shaped ring is connected with the box girder steel bar framework. After positioning, the deviation of pipeline axis is not more than 5 mm.

(3) The flat bending section of prestressed beam must be provided with anti-collapse reinforcement, and the inside of the bending arc of the anti-collapse reinforcement must be attached to the pipeline and fastened with iron wire, and the anti-collapse reinforcement itself is reliably connected with the reinforcement in the main beam.