1, construction lofting
In this project, the total station is used to accurately set out the culvert foundation, and the central axis and center point of the culvert are accurately determined with small nails on the stakes. Cross piles at each point shall be protected and marked to facilitate the protection of pile positions. In the process of construction, repeated survey is often carried out to prevent pile position deviation.
2. Foundation excavation
The earthwork of culvert foundation is excavated by excavator, manually cleaned and partially trimmed. Slope excavation of foundation pit shall be graded according to 1:0.75. If there is water seepage in the basement, dig a diversion ditch and a ponding well around the basement and pump it out to the outside of the subgrade. After the foundation excavation is completed, the bearing capacity test is carried out, and the bearing capacity is required to reach above 250Kpa. When the bearing capacity of local foundation is insufficient, it should be reported to the supervision engineer for on-site inspection, and measures such as replacing medium-coarse sand, graded macadam and flaky concrete can be taken according to the situation. After foundation treatment, each section shall be paved with macadam cushion as designed, and tamped with rammer to ensure the flatness of the bottom surface of foundation concrete.
3, foundation and wall construction
C30 concrete is used for culvert body and foundation, flaky concrete is used for splayed wall and foundation, and steel formwork is used for construction. The model must be reinforced firmly, with tight joints and no slurry leakage. The contact surface between the model and the concrete must be cleaned and the isolation agent must be brushed. Before concrete construction, the accumulated water and sundries in the model should be cleaned up. The size and strength of the flaky used in concrete should meet the requirements of the specification, and the surface should be clean, and the minimum distance from the model should not be less than 10cm. The quality requirements of model installation are as follows: allowable deviation and inspection method of template installation.
Inspection method of allowable deviation (mm) of serial number items
1 axis position foundation 15 feet shall be measured at not less than 2 places on each side.
Beams, columns, slabs, walls and arches 5
2. The surface flatness is 52m, and there are not less than 3 guide rulers and feeler gauges.
3 elevation foundation plus or minus 20 measurement
Beam, column, slab, wall and arch +/-5
4 template side bending column h/ 1000 drawing ruler number
Beams, slabs and walls L/ 1500
5. The width of the inside of the two templates is+10, and the amount of -5 feet is not less than 3 places.
6 beam bottom die camber +5, -2 stay ruler
The difference in surface height between two adjacent plates is 2 feet.
After the concrete construction, the formwork can be removed only after the concrete strength reaches 2.5Mpa, and it is not allowed to pry directly with a crowbar during formwork removal, so as not to damage the surface quality of concrete. When pouring culvert foundation, settlement joints should be set according to the requirements of drawings, and the width of settlement joints is 2cm, which are separated by foam boards during construction. .
4, protective layer construction
The cover plate is designed to be prefabricated, with 1m 42 pieces and 74cm 2 pieces. The prefabrication site is the cover plate prefabrication site. After the prefabrication yard is hardened, the steel formwork on both sides will be bound after installation, and the next working procedure will be carried out after passing the self-inspection by the inspection supervision engineer.
5. Removal of formwork and support
5. 1 Dismantling of formwork and support
Ⅰ Non-load-bearing side formwork can be removed only when the concrete strength ensures that its surface and edges and corners are not damaged by formwork removal, and generally can be removed only when the concrete strength reaches 2.5Mpa.
Ⅱ. The bearing formwork, supports and bent frames of reinforced concrete structures can only be removed when the concrete strength can bear its own gravity and other possible superimposed loads.
5.2 Formwork dismantling shall follow the order of first supporting and then dismantling, first dismantling and then dismantling. It is forbidden to throw when dismantling.
6, steel structure
There is no crack, mechanical damage, scar, wall crack and other defects on the surface of steel bar. The surface of steel bar should be clean, and the surface oil stain, paint skin and rust scale should be removed before use. Steel bars shall be straight without local bending.
Steel joint adopts lap joint and double-sided welding. When lap arc welding is used for the rebar joint, when the lap ends of two rebar should be folded to one side in advance, the axes of the two connected rebar should be consistent. The weld length on both sides of the joint shall not be less than 5d(d is the diameter of steel bar).
All welded steel bars and plates shall have material certificates or test reports, and covered electrode and flux shall have certificates of conformity. All welding materials shall be stored and properly kept according to material classification, and measures shall be taken to prevent corrosion and moisture deterioration.
Welding or binding joints of reinforced bars shall be arranged in places with small internal force and staggered from each other. For welded joints, there should be no two joints for the same steel bar in the section with the joint length of 35d, and the cross-sectional area of the stressed steel bar joints arranged in the section with the joint length should not be greater than 50% of the total cross-sectional area.
When welding, the welding site should have proper weatherproof facilities.
7, concrete construction
The concrete is mixed in the company's concrete mixing station. Before mixing, the water content of sand and stone should be determined, and the construction mixture ratio should be put forward according to the test results and theoretical mixture ratio. The slump, air content, bleeding rate, water-binder ratio and mixture temperature of the first batch of concrete should be tested and identified. In the process of concrete transportation, it should be ensured that the concrete does not segregate, leak slurry, bleed seriously or lose slump. The transportation, pouring and intermittent time of concrete should not exceed the initial setting time of concrete. In the process of pouring, concrete should be vibrated at any time to ensure its uniformity and compactness.
After the concrete is transported to the construction site, the slump of concrete shall be measured again, and it can be poured only after it is qualified. In the process of concrete pouring, vibrating rods are used for vibrating compaction. After concrete pouring is completed, necessary water conservation measures should be taken to avoid excessive water loss. Covered with straw bags and plastic films, the number of concrete sprinklers should ensure that the concrete surface is fully wet and maintained for not less than 7 days.
8. Backfilling of culvert abutment
Backfilling behind the culvert must be carried out when the mortar or concrete strength of culvert masonry reaches 75% of the design strength, and the filler is medium-coarse sand permeable material. The fill at the top of the culvert and at both sides of the culvert should be compacted symmetrically in horizontal layers, and the relative density should reach more than 96% with small machines. The thickness of fill at the top of culvert must be greater than 0.5 ~ 1m before machinery can pass through.
Chapter II Construction Schedule Arrangement
1, construction period plan
Arrange the construction plan reasonably according to the construction period required by the contract. Different construction methods, such as single operation, parallel operation and flow operation, are adopted to reduce the interference of each process and ensure the project progress. It is necessary to guard against the kind of construction that ignores quality.
Planned commencement date: July 8, 2009
Planned completion date: August 28th, 2009.
2, personnel, machinery, materials.
All kinds of management personnel are in place; Including technicians and skilled production workers.
Mechanical equipment is complete, meet the needs of each process, and prevent the tendency of construction due to lack of materials.
3, the construction progress bar chart
See attached table 1: AK 1+080 2-4× 4m crossing map for construction progress of slab culvert.
Chapter III Quality Control Measures
Carry out the construction in strict accordance with the specifications, organize a full-time quality inspection team and inspectors for unified management, and predict and pre-control the weak links and key parts in the construction of this project. Strictly control the construction quality, actively cooperate with the supervisor to do a good job in construction methods, procedures and construction inspection.
Strictly close the entrance of raw materials. For input of raw materials:
(1), the materials (ground materials) shall be sampled and inspected first, and then transported to the construction site after passing the inspection.
(2) Random sampling of raw materials that have entered the site. Once unqualified materials are found, clean up the construction site immediately to ensure the construction quality.
(3) Mortar shall be prepared in strict accordance with the mixture ratio (weight ratio: a scale shall be placed on site and buried underground, so that the hopper car carrying sand can pass the scale smoothly and accurately).
(4) The site is equipped with a generator (15KW), four vibrators and a mortar mixer.
(5), survey lofting adhere to the double inspection system. Chapter IV Safe and Civilized Construction
1, yard hardening, cement with bulk cement, site drainage.
2, who entered the construction site construction personnel and management personnel must wear safety helmets, management personnel and should wear badges.
3, all kinds of raw materials and construction machinery, tools should be neatly stacked, to ensure the cleanliness of the construction site.
4. Set protection and warning lights around the foundation pit to prevent construction workers from accidentally falling off the foundation pit.
5, scaffolding demolition work is a dangerous working environment, homework personnel must obey the command, in strict accordance with the plan and operating procedures for demolition, to prevent scaffolding collapse and falling objects hurt people.
6. When the scaffold is dismantled, the operation area should be divided, and warning signs should be set up around it with railings. The ground should be commanded by a special person, and non-professionals are strictly prohibited from entering.
7, homework personnel must be dismantled in strict order, generally should follow the principle of top-down, first take before demolition, then take first demolition, step by step, it is forbidden to dismantle at the same time;
8, demolition should be unified command echo up and down, coordinated action, when untied the knot related to another person, should first notify the other party, in case of falling;
9. Before dismantling the support, the reserved ramp and feeding platform should be reinforced to ensure the integrity, safety and stability after dismantling.
10. The removed materials shall be tied with ropes and transported slowly by pulleys. Do not throw them. Materials transported to the ground shall be transported along with the demolition at the designated place, and shall be classified and piled up. Removed fasteners or wires should be collected and disposed of centrally.
1 1, scaffolding demolition process can't touch the building.
12, in the process of scaffolding demolition, it is not allowed to change people halfway. If you need to change people, you should explain the demolition situation clearly before you leave.