1 Module challenge

The interior and exterior module of piers implement large whole-type steel module. It applies thick steel in 5mm as panel. When panel comes to the stage, it will experience cleanup, welding to eliminate grime trace. The membrane removing agent would be applied and after that plastic film would address the module. The staking approach would endure before shaping vertical roller. And then, solidify the modes of inner-supportive and outer including. The very best on pier hollowing portion applies bowl buckle bracket and φ48 steel reinforcement. After the installation, the axial wheel and elevation should get checked to ensure no shape and position change of module and stand with the force brought by concreting. The vertical roller mill integrates both car and manual installation. The plumb should be utilised to check vertical distance right after installation. Total station is utilised to check the surficial position.

2 Rebar installation

The basic foundation anchoring tendons of caps and piers are based on rules and layout requirements to firmly connect. The precision rebar bury position on the bottom should be correct to satisfy the demand of rebar protecting level. The pier and buried rebar should get staggered installation order by 50% of joint length. The pier is with great amount of rebar. In order to secure the construction precision and bundle quality, the tying assignment should be executed on the fixed tire. The shape-fixed plastic or cement mortar in the same standard could be utilised as pad to secure the protector thickness of rebar.

3 Concrete pouring

There are three periods of concrete pouring: pier-end entity section, pier-body hollowing section and pier-top entity section. The roller press applies automatic measuring mix station regarding production, transporting via cars and module shaping via pumps.

Sectional concreting thickness should not exceed 30cm. The vibration tamping should applied tamping rod. The concreting should be sustained. If there is necessary cease, the cease time should be less than the pre-concreting time intended for front-level concrete. The permitted cease time should be confirmed by experiment.

During the concrete pouring, we should check whether the set embedded bolt, set-aside hole, embedded bearing move or not. The position should be rectified if there is any movement.

During the concreting method of high efficiency separator section, pier-body hollowing section and pier-top entity section, the quality and shape of concrete on the connective element between entity and hollow pier should be paid attention to. Especially for the entity segment, in order to prevent the concrete surface breakage, we have to utilize the following measures to lower down concrete's heat of hydration due to excessive amount of concrete pouring:

1) Implement low-level hydration heat proportion

2) Aggregate cooling: applying high-pressure cool water washing ahead of use to lower down the temperature. During the mixing method, the water content should be checked to in-time adjust proportion.

3) Use low-temperature water: underground water pumping is utilised regarding concrete mixing. Condition permitting, ice might be added into mixture. The effect can be better.

4) Cement heat prevention: the cement shed of mixed station should get cooled with sound air condition.

5) Temperature cooling intended for transportation: concrete transporting cars and grapples should get cooled by cold water prior to use.

6) Ahead of pouring method, the cold water can wash connecting concrete surface, rebar and module to drive down temperature.

4 Module uninstallation Pier module can reach the concrete tension above 2.5MPa. In addition, the surface get damaged without uninstallation, the module uninstallation might be executed. During the approach, the order should be: first-completion & demolition, second-completion & uninstallation to remove the module. When taking away modules, surficial and environmental temperature difference of concrete should not be about 15 degrees Celsius.

5 Concrete maintenance

The non-uninstallation of concrete should implement molded package, watering, spray sprinkler to perform moisture keeping, wet caring to ensure the jointer without dryness. In order to secure smooth uninstallation, it can slightly release module after 24 to 48 hours of pouring to undergo water caring. So, the membrane can sustain the moisture in the required period after taking off.