Construction preparation → survey and lofting → setting protective slips → positioning of drilling rig → drilling and first hole cleaning → placing reinforcing cage, conduit and second hole cleaning → pouring underwater concrete → measuring concrete surface elevation → end of conduit removal.
Second, expand the foundation construction sequence
Construction preparation → survey and lofting → cofferdam pumping → foundation pit excavation → foundation pit size measurement → formwork erection → concrete mixing and pouring → maintenance.
Third, the pile cap pier construction sequence
Construction preparation → survey and lofting → formwork installation → steel bar binding → layered concrete pouring.
Four, tie beam, column, capping beam construction sequence
1, tie beam construction sequence (flowing water)
Construction preparation → cofferdam pumping → installation of bottom formwork and side formwork → steel bar binding → concrete curing.
2, column construction sequence
Construction preparation → scaffolding → binding reinforcement → installing formwork → pouring concrete for maintenance.
3, capping beam construction sequence
Construction preparation → Support erection → Laying bottom plate → Binding steel bar → Installing side formwork → Concrete curing → Dismantling support.
Five, beam slab precast construction sequence (prestressed beam slab)
Foundation treatment → pouring pedestal → installing plate beam and corrugated pipe details → binding steel bars and installing corrugated pipe → concrete pouring bottom plate → placing inner core mould → concrete pouring → taking mould core → hole cleaning and curing → wearing prestressed tendons (steel hinge lines) → tensioning → grouting and pouring concrete for the head.
Six, beam slab precast construction sequence
Measuring lofting → assembling the guide frame in place → transporting the prefabricated beam slab to the site → accurately lofting and installing the bearing in place → installing the beam slab in place → acceptance.
Seven, simply supported before continuous construction sequence
Set up temporary support and install beam slab → permanently support and install bottom formwork → continuously bind steel bars and longitudinal steel bars according to the current structural drawing of pouring section → install prestressed beam bellows → erect side formwork → pour the pouring section (concrete needs water reducer, which is compacted by micro-expansive cement) → keep in good health in time → after the current pouring concrete strength reaches 100% of the design strength.
Tensioning prestressed continuous beam → grouting → dismantling temporary support → transverse connection of beam and slab → laying bridge deck steel mesh (longitudinal reinforcement of steel mesh continuously passes through existing pouring section) → pouring bridge deck concrete.
Eight, the bridge deck engineering construction sequence
Drainage pipe installation → pouring guardrail concrete → binding of bridge deck reinforcement → concrete mixing and pouring → guardrail installation → setting expansion joints.
Nine, the bridge channel construction sequence
Survey and lofting → cofferdam pumping → manual excavation by excavator → foundation pit shaping → flaky concrete foundation pouring → flaky concrete abutment pouring → abutment cap pouring → beam slab lifting → bridge deck system construction and maintenance.
X. Construction sequence of box culvert
Measuring lofting → manual excavation by excavator → foundation pit shaping → concrete laying of bottom plate → formwork erection → first concrete pouring of culvert 30cm above bottom plate → formwork erection → the rest second concrete pouring → maintenance → backfilling.
Extended data:
Matters needing attention
1. Attention should be paid to the construction quality of arch adjustment slope layer. During the construction of this layer, special attention should be paid to the specifications, gradation and mixture ratio of various materials to ensure the smoothness and compactness within the effective width of this layer, which is the basis for ensuring the quality of grassroots construction.
2. Strengthen grassroots maintenance. After the completion of grass-roots construction, use sacks for maintenance or spray asphalt emulsion for protection. If the traffic cannot be closed, the traffic of heavy vehicles shall be restricted, and the speed shall not exceed 20km/h, and attention shall be paid to the damage caused by other traffic facilities to the grassroots. If the car groove (pit groove) is loose, it should be repaired and compacted with the same material. It is forbidden to fill with loose granular materials.
3. In the base construction, we should strictly pay attention to the loose laying thickness, roll with the best water content, minimize the base molding, and carry out artificial renovation after initial pressing, especially to strengthen the compactness of the base edge template. For those that are not rolled in place due to special circumstances, workers' hammers and vibrating rammers should be used for layered compaction to ensure the quality of their structural layers.
4. Strictly control the leveling at the grass-roots level. Before laying the surface, use a 3m ruler to check the smoothness of the base. The sections with poor leveling and large leveling should be leveled. Before paving, the surface layer is polluted by other processes, such as cement dripping into hard slag, which should be removed in time to ensure the smoothness of the surface layer.
5. The construction quality of asphalt pavement also depends on the quality of main materials, the mix design of asphalt mixture and the mixing of asphalt mixture.
6. The mixture ratio of asphalt mixture is unreasonable, and the oilstone is relatively large, so that the paved pavement will produce choking and flooding; The oilstone is smaller, and the road surface will be looser; Poor quality of mineral aggregate, poor aggregate crushing value and stone compressive strength, and high content of slender flat particles reduce the stability of pavement mixture and are prone to various pavement diseases.
7. The asphalt mixture is not evenly mixed. Sometimes, when the mixing equipment has an accident, the furnace has just started, or the material temperature is low and the water content is high, the material temperature will be uneven; Too high temperature causes asphalt aging, which can not guarantee the paving quality of asphalt concrete; When the transportation equipment is not matched or the driver's skill is poor, it will hit the paver, causing the fuselage to move backwards and form steps. The above factors are easy to cause poor flatness and surface compactness.
Emergency measures to deal with construction quality problems.
In the process of road and bridge construction, construction quality problems often occur, and the quality problems in the project are changeable. For those surface quality problems, it is necessary to further find out whether the nature of the problems will change, and for those vicious accidents that may develop into component fracture and collapse, emergency remedial measures should be taken in time. When formulating emergency measures, the following items should be paid attention to in general.
1) For dangerous quality accidents, the warning zone should be closed or set up first. It is not allowed to enter the site for treatment until it is confirmed that it cannot collapse or reliable support is carried out to avoid casualties.
2) For the parts that need to be partially demolished, the influence of the accident on the adjacent area structure should be fully considered to avoid further expansion of the accident, and reliable safety measures and demolition measures should be formulated to prevent the handling of the original accident from causing new accidents.
3) The structural strength, stiffness and stability in the treatment stage should be checked, reliable protective measures should be put forward, and the stability of the structure should be closely monitored during the treatment.
4) When strengthening the structure without unloading, attention should be paid to the influence of treatment methods and construction load on the bearing capacity of the structure.
5) We should fully consider the influence of the additional internal force generated during accident treatment on the structure and the unsafe factors caused by it.
References:
Baidu encyclopedia-bridge construction