How to do a good job in bridge construction, detailed steps of bridge construction

Nominally, do three things: quality, safety, and progress. The quality is mostly according to the technical specifications and acceptance specifications of bridge and culvert construction.

Personally, as long as you can mix. Construction is just that.

The question you asked was too wide.

Can you be specific?

The bridge construction steps are still very complicated. Different types of bridge methods are different, but the main steps are similar, and a few specific steps are listed below

1. Pile foundation construction, tie beam construction, column construction, cover beam construction, pad stone construction; 2. Prefabrication and installation of box girders; 3. Bridge deck engineering.

1. Substructure construction; Generally includes foundation, cushion cap, pier, pier if the pier is high, there is a tie beam, simply supported beam should have a cover beam, continuous beam pier is generally not provided with a cover beam.

If the foundation construction is to expand the foundation, it is necessary to dig the foundation pit with an excavator, and then tie the steel bar and pour concrete. In the case of pile foundation, drill holes, then lower the reinforcement cage, and pour concrete.

After the foundation is completed, the cushion cap steel bar is tied and the cushion cap concrete is poured. Then carry out the construction of the pier stud, which is also tied to the steel bar to pour concrete, and the template must be used. After that, it is necessary to bury the bearing.

2. Superstructure construction; There are two types of prefabricated and cast-in-place. If it is prefabricated, the prefabricated beam is directly erected on the bridge pier, and if it is cast in situ, it is necessary to tie the steel bar and pour concrete. prefabricated; After the beam is erected, wet joints or hinged joints are generally poured.

Then the bridge deck was prepared.

3. Ancillary works; That is, guardrails, drainage, slope protection, etc. There is still a big difference between road bridges and railway bridges.

Cantilever construction method, rotating construction method, jacking construction method, moving formwork hole-by-hole construction method, bracket cast-in-place method, prefabricated installation method, traversing construction method, lifting and floating construction, etc.

Preparation. 1. The importance of preparing for bridge construction.

1) The preparation work before the construction of the bridge is one of the important links to adhere to the basic procedures and construction procedures.

2) The preparation before construction is one of the main contents of the organization and management of bridge construction.

2. Stages of preparation before bridge construction.

1) The preliminary design of the first stage of the bridge project has been completed, and it is included in the national or regional construction plan, and then it is necessary to carry out bidding and signing contracts and other preparatory work stages.

2) The second stage is the preparatory work stage for the purpose of successfully completing the construction tasks after the construction unit has contracted the construction tasks and before the start of construction.

Precautions. 1.It is necessary to pay attention to the construction quality of the arch and slope adjustment layer, in the construction of the layer, especially to grasp the specifications, gradation and mix ratio of each material, to ensure the flatness and compaction within the effective width of the layer, is the basis for ensuring the quality of the construction of the base.

2.Strengthen the maintenance of the base layer, after the completion of the base construction, the use of sacks for maintenance, can also be used to spray asphalt emulsion protection. If the traffic cannot be closed, heavy vehicles should be restricted, and their speed should not exceed 20km h, and other traffic facilities should be paid attention to the damage to the base layer.

If there is a loose groove (pothole), the same material should be used to repair and compact. It is strictly forbidden to fill with loose pellets.

3.In the construction of the base layer, strictly grasp the thickness of the loose paving, minimize the base forming in the rolling of the best water content, carry out manual renovation after the initial pressure, especially to strengthen the compaction degree at the edge of the base layer, and the worker hammer and vibratory rammer should be used for rolling in place due to special circumstances, and the layered tamping is carried out to ensure the quality of its structural layer.

1. Self-propelled crane hoisting method: This hoisting method mostly uses machinery such as truck cranes, crawler cranes and tire cranes, and is divided into single cranes and double cranes. This method is generally suitable for the installation of simply supported beam plates with a span diameter of less than 30m. There should be enough site for setting up the crane in the on-site hoisting hole span or on the approach road, and the smooth flow of the beam road should be ensured at the same time, and the selection of the crane should fully consider the weight of the beam body and the operating radius before deciding.

2. The installation method of spanning pier gantry arranges tracks along the bridge direction on both sides of the pier abutment, and the gantry crane of spanning pier is placed on it, and the beam body is transported to the erection site in the hoisting state and installed at the predetermined position. This method can generally arrange the prefabricated site of the beam at the bridgehead approach. to shorten the distance between the beams.

Its advantages are: the construction operation is simple and fast, can be quickly constructed, and it is easy to ensure the safety of construction; However, it is required that the terrain of the erection site should be flat and good, the beam body should be able to be carried along the bridge, and the pier should not be too high. Due to the large cost of equipment, the number of hole spans for erection and installation cannot be too small.

3. Bridge erecting machine installation method: This is a typical erection and installation method of precast beams. Set up the installation guide beam in the hole span, and erect the beam body as a supporting beam with this, and the installation beam structure that is used as a supporting beam is called a bridge erecting machine: there are many kinds of bridge erecting machine at present, there are special bridge erecting machine equipment, and there are also the builders who apply standing components (universal rods and Bailey orange sheets, etc.) to assemble by themselves.

According to different forms, the bridge erecting machine can be divided into single guide beam, double guide beam, cable-stayed and suspended and so on. Cantilever and span-by-span segmental bridges are also often used. Special bridge erecting machine equipment for construction.

Its characteristics are: it is not affected by the height of the pier of the erection hole span, nor is it affected by the conditions under the beam; The erection speed is fast, the operation safety is high, and it is more advantageous for long bridges with more spans.

4 Lever hoisting method Lever hoisting is a more primitive but simple and easy method, which is more suitable for some small components with light weight, and is rarely used at present. However, in recent years, there has also been experience in using levers to lift large-span (330m) truss arches, with a maximum weight of 200t for a single piece of lifting.

5. Floating hanger methodThis method is generally suitable for the erection and installation of estuaries and long bridges at sea, including the erection of whole holes and the cantilever assembly of segmental blocks. The construction period of this method is shorter, but the reinforcement of the beam body, the reinforcement of the barge and the equipment such as the barge, the large spreader, and the fixture for erection are all larger, and the cost of floating crane is higher.

Commonly used are: bracket cast-in-situ method, prefabricated installation method, cantilever construction method, rotating construction method, pushing construction method, moving formwork hole-by-hole construction method, traversing construction method, lifting and floating construction.

1.Prefabricated simply supported beam method.

2.Stent cast-in-place method.

3.Hanging spelling.

4.Cantilever pouring method, also called hanging basket construction method.

5.The jacking method is also called the section-by-section jacking method.

6.The rotation method is divided into vertical rotation method, horizontal rotation method, and horizontal and vertical combination method.

7.The cable hoisting method is also called the catwalk construction method.

The common ones are here, the specific construction process of each method, the content is too much, do not describe in detail, the name of the above method can be searched in detail on the Internet, you can also see the book "Bridge Engineering".

1. Several situations of foundation pit excavation:

1) Foundation pit excavation without support to reinforce the pit wall.

2) Excavation of the foundation pit with baffle plate to support the pit wall.

3) Use concrete to fix the foundation pit wall of the pit.

2. Types of cofferdams: earth-rock cofferdams, sheet pile cofferdams, steel box cofferdams, double-walled steel cofferdams.

3. Methods of foundation pit drainage: sump drainage method, well point drainage method, curtain method.

4. Foundation reinforcement methods: replacement filling method, pile compacting method, strong compaction method, top pressure method, vibroflotation method, powder jet stirring method, high-pressure jet grouting method, chemical liquid reinforcement method.

5. Positive circulation rotary drill: suitable for cohesive soil, silt, fine, medium and coarse sand, soil and soft rock containing a small amount of sand and gravel, pebbles (content less than 20%); The hole diameter is 80-250cm, and the hole depth is 30-100m.

6. Reverse circulation rebound rotary drill: suitable for cohesive soil, sand soil, containing a small amount of gravel, pebbles (content less than 20%, particle size less than 2 3 diameter of drill pipe soil), hole diameter of 80-300cm, hole depth for the clay soil or expansive soil of vacuum pump 10, the relative density of different soil mud is also different.

The bored pile should wait for the mud to be transported into the hole for a certain amount before starting to drill.

When reverse circulation drilling, attention must be paid to continuous replenishment of mud and maintenance of the head in the casing to avoid collapse.

The drilling should be carried out continuously, without interruption, and the hole diameter and verticality should be checked every 2-3m.

After the final hole inspection is qualified, the hole should be cleaned quickly, and the method of hole cleaning includes slurry pumping method, slurry changing method (used for positive circulation) slag washing method, and the mud performance index and sediment thickness after hole cleaning should meet the requirements of the specification. No matter what method is used to clean the hole and discharge the slag, it is necessary to pay attention to maintaining the water head in the hole to prevent the collapse of the hole.

After the hole inspection is qualified by the supervising engineer, you can devote yourself to the hoisting work of the reinforcement cage. The reinforcement cage must be placed securely.

Conduits in concrete pouring should be subjected to a closed water test before use.

1. Construction of bridge substructure.

Bridge pier construction: integral pier construction, with stone pier abutment, concrete pier abutment; prefabricated pier construction; Block-type pier construction; Column-type pier construction.

Pier foundation construction: open cut expansion foundation construction; pile and pipe string foundation construction; caisson foundation construction;

2. Construction of bridge superstructure.

Construction of bridge bearing structure: cast-in-place method of support; prefabricated installation method; cantilever construction method; Rotary construction method; Pushing construction method; Movable formwork main hole construction method; traversing method; Lifting and flotation method.

3. Construction of beam bridges.

Charpy bridges, continuous beam bridges of equal cross-section, continuous beam bridges of prestressed concrete variable cross-section, continuous steel structure bridges of prestressed concrete, steel girder bridges.