4.
The construction of rubble concrete foundation shall be carried out after all indicators are qualified.
In the process of concrete construction, small rubble shall be added, which shall not exceed 20% of the concrete.
During the construction process, pay attention to control whether the formwork has displacement and deformation, and strengthen the fixation in case of any.
② The accuracy of the starting point and the quality of electric welding shall be strictly controlled for the starting reinforcement of the reinforcement skeleton in the bent cap.
Foundation pit excavation (1) extend the foundation pit control pile to 2m outside the foundation pit and fix it.
The number of reinforcement shall be accurate, and the reinforcement shall be arranged according to the principle of secondary reinforcement giving priority to main reinforcement.
③ The detailed drawing of reinforcement shall be set out accurately according to the drawing, and the broken material matching shall be carried out according to the sample turning sheet.
After the formwork is installed in place, measure and adjust its position, size and perpendicularity.
c.
For the pouring of rubble concrete foundation, the concrete shall be mixed by mixer and transported to the pouring abutment by concrete mixer truck.
If the bearing capacity fails to meet the requirements, it shall be handled according to the instructions of the supervising engineer, and the foundation construction shall be carried out after it is qualified.
The height of bent cap and abutment cap is high.
(2) Excavate to the design elevation + 20cm with excavator, and then manually excavate the remaining 20cm soil to avoid mechanical disturbance of undisturbed soil or over excavation.
(8) Temporary electricity shall be used for the construction site, and temporary reservoirs shall be built on site for the construction water.
The foundation formwork shall be installed after the foundation pit is reported to the supervising engineer for acceptance.
Construction method a Preparatory work (1) before the construction of abutment foundation, the construction access road shall be repaired to ensure smooth traffic.
(5) Various raw material tests and concrete mix proportion tests have been completed.
(3) Before the commencement of abutment foundation, the sub divisional commencement report shall be submitted to the supervising engineer, and the commencement can be carried out after being approved by the supervising engineer.
The immersion vibrator shall be used for vibration in layers.
d.
Concrete test block shall be reserved during construction..
The concrete shall be pumped from the transport vehicle to the formwork by the pump truck, and the concrete shall be poured horizontally in layers, and the layer thickness shall not exceed 30cm.
The concrete shall be mixed in strict accordance with the construction mix proportion, and the measurement of sand, stone, cement, water and admixture shall be accurate to ensure the mixing time.
In order to prevent “loose top” of concrete, the process of “secondary vibration and secondary plastering” is adopted.
It is forbidden to pour from both ends of the cap beam to the center, but from the center of the cap beam to both ends.
The diameter of the steel bar is 10cm, and i-45a I-beam is set as the main longitudinal beam in the transverse direction of the bridge.
(7) Excavators, concrete vibrators and other necessary machinery are in place.
Inspection method and frequency of specified value or allowable deviation of measured items of reinforcement processing and installation 1.
Pay attention to roughening the surface and setting protruding rubble to ensure the connection with the upper foundation and wall body.
2.
b.
During pouring, the material shall be cut in layers, and the thickness of each layer shall not be greater than 30cm.
In order to avoid the displacement of formwork and ensure the construction quality, the through core steel bar method is used for construction.
Cover with Geotextile in time and spray water for curing for no less than 7 days to prevent shrinkage cracks.
When vibrating the upper layer, the lower layer concrete must be inserted for 5 ~ 10cm to ensure the compactness and uniformity of the concrete.
④ The thickness of the protective layer shall be ensured at the bottom and both sides of the beam.
Various materials meet the construction requirements.
The vibration time shall be appropriate without under vibration, over vibration and missing vibration.
(9) The “construction instructions” Board shall be set on the site to indicate the main technical director, on-site quality administrator, test inspector and safety director; Concrete mix proportion, main construction technology and quality standards to guide the construction.
The foundation pouring shall be completed at one time.
The beam adopts 16 channel steel with a spacing of 60cm, which is welded with the main longitudinal beam of 45A I-beam along the longitudinal direction of the bridge to form a section steel grid.
Remove the formwork after reaching a certain strength.
(4) The construction setting out shall be carried out according to the plane position, elevation and geometric dimension designed in the drawing.
The surface of the formwork shall be cleaned and coated with release agent before installation.
The formwork shall be steel formwork with a spacing of 50cm Φ 16 steel bars are connected with tie rods.
Check 2 sections of each member, and measure with ruler the same row of beam slab, arch rib ± 10 foundation, anchorage, pier and abutment, column ± 20 cast-in-place pile ± 202 stirrup, transverse horizontal reinforcement Spiral reinforcement spacing (mm) + 10 check 5 ~ 10 spacing 3 reinforcement skeleton size (mm) length ± 10 spot check 30% width, height or diameter ± 54 bending reinforcement position (mm) ± 20 spot check 30% 5 protective layer thickness (mm) column, beam and arch rib ± 5 for each member check 8 foundations, anchorages, piers and abutments, columns ± 10 slab ± 3 II.
1、 Capping beam and abutment cap 1.
(6) The quantity of concrete required shall be reported to the concrete mixing plant in advance to ensure that the concrete is delivered as planned.
The formwork shall be assembled with combined steel formwork, and the inner support and outer support shall be fixed with steel pipe support combined with wood pile auxiliary support, so as to ensure sufficient strength, stiffness and flatness, and ensure that the dimensions of each part meet the design and specification requirements.
On the 16 channel steel, lay 10 pipes respectively according to the transverse bridge direction of 30cm × 10cm wooden grating, and then 12mm thick steel bottom formwork is laid.
Fabrication of reinforcement framework ① the reinforcement can only be used after passing the inspection after entering the site.
3.
(3) After the excavation of the foundation pit, the bearing capacity of the base shall be inspected.
Abutment foundation construction 1 Process flow site cleaning – foundation pit setting out – Foundation Pit Excavation – setting out of lower rubble concrete foundation – Installation of lower rubble concrete foundation Formwork – concrete pouring of lower rubble concrete foundation – setting out of upper rubble concrete foundation – Installation of upper rubble concrete foundation Formwork – concrete pouring of upper rubble concrete foundation – next procedure 2.
After the concrete is put into the formwork, it shall be vibrated with an immersion vibrator in time.
Construction process: the capping beam is constructed by shear steel bar without support.
After the completion of formwork construction and reinforcement framework construction, the side formwork and end formwork shall be installed.
(2) The required formwork is in place, and the construction and management personnel meet the construction requirements.
Concrete curing shall be covered with geotextile and watered for wet curing.
The spacing of stressed reinforcement (mm) is more than two rows, and the row spacing is ± 5.
For concrete construction, the concrete shall be mixed centrally in the mixing station and transported by concrete tanker.
