Underwater reinforcement of bridge piers
In recent years, bridge safety accidents frequently, the industry to strengthen the operation of the bridge detection, in the completed bridge detection, found that some of the underwater pile Foundation has exposed the phenomenon of rebar, and now has been seriously corroded, in order to ensure the safety of the bridge, the disease serious pile Foundation reinforcement treatment.
In recent years, bridge safety accidents frequently, the industry to strengthen the operation of the bridge detection, in the completed bridge detection, found that some of the underwater pile Foundation has exposed the phenomenon of rebar, and now has been seriously corroded, in order to ensure the safety of the bridge, the disease serious pile Foundation reinforcement treatment. Among them, the method of increasing the section is widely used in this kind of reinforcement project, so this paper mainly discusses the application of the method of increasing bridge pier underwater reinforcement section to underwater Pile Foundation.
Reinforcement construction Sequence
(1) Before construction, it is necessary to investigate the situation of gravel accumulation in the riverbed of Pile foundation, then, according to the riverbed situation, to determine the lowering of the height and the pile side rock and soil.
(2), the surface of the pile of water and loose concrete clean, exposing fresh concrete. Require that the removal of concrete can not exceed the thickness of the reinforcement layer;
(3), drilling on the surface of the pile, planting bar, the installation of steel bar nets, rebar nets need to be welded with the reinforcement bar welding fixed;
(4), the processing of a good two semicircular steel formwork to cover the pile foundation, up to the original steel tube bottom edge of the top 1m, down to now clean up the riverbed line below 1m, steel formwork inside and pile base surface spacing 40cm, and in steel formwork anchor Wing plate on every 2m around with ordinary bolts will be two of semi-circular steel formwork anchor to form piles of steel casing, The rubber waterproof material should be set between the two steel formwork wing plates. The outer steel casing is made of open type, the top of which is 1m higher than the base of the original pile Foundation steel sheath;
(5), in the conveying of concrete by the diver will be transported to the new steel tube bottom before starting to transport, and then according to the flow of concrete slowly lifting catheter, each pile at least two concrete conveying duct, evenly distributed on both sides of the pile foundation, when the concrete conveying at the same time upgrade;
(6), when the construction of steel tube can be prefabricated, the outer steel cover to determine the height of the installation, can not use the vibration of the sinking, can be used by the pressure and auxiliary by the diving method to carry out sinking operations. Steel pipe connection requires no protruding material, should be tensile, pressure, not leaking;
(7), pouring underwater concrete mixer capacity, should meet the outsourced concrete in the specified time to cast finished. If the concrete is cast at intervals, the time interval shall not be longer than the initial setting time of the concrete;
(8), the underwater concrete conveying machine should use concrete pump vehicle, the distance is suitable to use concrete mixer transport vehicle. The use of ordinary vehicle transport, transport containers should be tight and solid, do not leak, do not absorb water, ease of handling, concrete should not segregation.