This technique involves the Detensionable & Retensionable PSC Girder System which installs a tension-adjustable anchoring device on the tip part of the girders to help construction and maintenance process. By installing this system on the tip part of the PSC girders, this construction technique prevents excessive compression on the center of the girders, which usually happens when replacing the floor plates depending on the durability of both the girders and the plates respectively, and recovers the girder performance through re-tension, as well as improves the common durability life. It not only has acquired the NET certification, but also is registered with the Patent Office (Patent # 10-0724739).
Application of SP panels (half-depth precast deck panels) can reduce the time to dissemble the form-shores for slabs installation, and especially for the zones requiring low girder depth it can reduce the maintenance costs by half compared to the conventional method (pre-flex beam bridge). In addition, it can minimize the incorporated land size according to the optimized road mounding, resulting in prevention of possible environmental damages.
01. Removal of the slabs around the anchor hole
To avoid any impact or damage to the girder, select the waterjet or breaker method depending on the field conditions and remove the slabs around the secondary hole.
02. Detension of the secondary steel wires
By removing the sim place through tension jack installed on the secondary hole, girder detension and stability are secured.
03. Removal of the upper slabs
To avoid any impact or damage to the girder, set up a prearranged plan and remove the damaged slabs following the scheduled process.
04. Retension of the secondary steel wires
Retension the secondary steel wires by installing the SP-panel cradle and the sim plate which was removed at the 2nd step.
05. Protection of the anchor hole outside the block
Install the protection caps on the secondary tension holes, pour some grease, and fill the outside of the blocks around the holes with polyurethane.
Vegetation Method of Reinforced Retaining Wall
This is a reinforced retaining wall block method that forms folding grooves on the longitudinal center of the foldlock strip and puts them on the concrete block directly, while spreading and erecting the end part of the reinforcing material, and bury it in the back-filling soil to improve the passive resistance. It is an eco-friendly technique that can create landscape by mixing vegetation and non-vegetation blocks together.
This method makes possible both vertical construction and creation of sidewall green blocks for the reinforced wall over 10m high, and secures better economic feasibility compared to the existing block reinforced retaining wall method. In addition, it decreases both the foldlock reinforcing materials and the quantity of Dadam Block significantly, and reduces the construction period according to the reduction of blocks per unit area (about 40%), while increasing the ecological area through greening wall scheme.
01. Installation of the first layer block
02. Block masonry
03. Installation of reinforcement materilas
04. Shaping of the vegetation base
05. Planting the appropriate plants
06. Backfill installation and consolidation
07. Finish – Construction case with new technique
Small Bore Drain Pipe Burial Method
This technique allows to build small-scale steel pipe working holes, while preventing sinking of the adjacent ground due to disturbance of the surrounding ground and leak of underground water on the soft ground that has abundant underground utilities, generally in the narrow roads or residential area. In addition, while preventing the pipes’ falling and roads sinking, we can lay small bore drainpipes underground through lead pipe propulsion, screw auger excavation, and jacking the head-pipe first and then the main pipe inside the working holes at the same time, without causing damage and changes of illumination inside the drainpipes.
- Securing the path upon head pipe propulsion, and the leading axis of the screw auger
- Tunnel boring as the auger screw spins with the lead pipe as the pivot
- Tunneling down through the screw
- Proceeding with propulsion as pushing the head pipe
- Using the same diameter as that of the head pipe
- Minimizing the damage of the pipe inside
Key Construction Technique and Method
The Cheongdam Bridge is the 17th bridge over the Han River (23rd incl. railway bridges). It is the first double-level bridge built in Korea, under which Seoul Subway Line #7, a double-track railway, operates connecting Jayang Station and Cheongdam Station and above which Dongbu Expressway passes through connecting Gangbyeon Expressway and Jangji I.C.
Made with various new techniques and special methods, the bridge boasts both the sturdy frame and the beautiful look.
Specification Process of Well-Foundation using Pontoon
General Method of Building Artificial Construction Island
After building the access way, create an artificial island with earth and sand on the well-foundation spot to form the ground level. Link the wells by lot from the ground level and then settle.
New method of Dongbu Corporation
Make a hollow pontoon with open top and bottom according to the size of the upper area of the artificial construction island in the shape of square shell container, and have it sink when flooding and float when draining to facilitate moving and anchoring After anchoring the pontoon, dredge the earth and sand of the Han River to fill the inside and proceed with the well-foundation work by using it as the ground of the artificial construction island.
Gyeongbu High-Speed Railway
Key Construction Technique and Method
Dongbu Corporation builds stronger and safer express railways by adopting the new technologies to PSM-construction of the upper part of the bridge in the zone 3 of Gyeongbu High-Speed Railway.
Shortening the construction period, easy quality maintenance, costs reduction, securing safety, and increased precision in construction, etc.
- As it builds the sub-grade steel structure and the superstructure simultaneously, it can shorten the construction period by approximately 4 months (ground floor number ÷ 4), resulting in direct/indirect cost reduction as well.
- Efficiency of the supporting aid increases.
- Underground and ground level placement is possible at once by one-time input of the necessary device
- Continuation of work is maintained as it secures the appropriate the workload, resulting in easy and efficient maintenance of labor force
- In the future, request for proposal-type or alternative tenders are likely to be more popular. If we apply our double-up method, we will be able to enhance our competitiveness significantly in public construction sector. (Specialization by Dongbu’s unique framework method: Dongbu Double-Up Method)
- Field safety management is easier as the 2nd floor sleeves function as firm debris net (prevention of falling objects for subgrade structure work)
- Overcoming the limited workspace issue, one of the characteristics in urban construction, by securing safe space for material storing and various works on the ground level (blocking the risk of fallen objects)
Features of the Method
- Compared to the conventional method, it shortens the construction period by ground floor number ÷ 4 months, without a burden of extra costs.
- Compared to the top-down method, operation and quality maintenance during construction is easier and the overall construction costs considerably less per unit price. Also, there is no limitation in the soil cement method for the underground earth work. (For Top-Down method, Slurry Wall method is required without exception)
- The higher the ground floors and the deeper the underground levels, the greater the effect is. (suitable for high-rise office buildings in downtown areas)
- For works by placed order, a thorough review must be made on the structural calculation sheet before commencing the construction or in tendering stage.
Working Order of the Structure Work
After the completion of the earth work, around the time when the RC work is carried out for the foundation level up to the ground level 1 (i.e., when the steel-frame work is executed for about 3-4 ground levels)
The underground RC work is to continuously proceed towards the upper part. At the same time, install a safety cabinet on the ground level 1 steel beam by using beam brackets and single pipe.
Start the steel reinforcement and form installation from the ground level 3 slabs and ground level 1 columns, and continue the super and substructure work simultaneously, proceeding towards the upper levels.
Usually, it takes a week to finish one ground level. Thus, the construction period can be shortened by a quarter (total ground floors÷4 months).
The following images demonstrate the Double-Up method, in a simplified manner, in comparison with the conventional one.
Field Images of Dongbu’s Double-Up Construction Method
Steel Pipe Attached-Smart Pile Method
Construction Method and Technique
This method uses a technique of increasing the tip capacity by attaching steel pipes to the piles’ tips and thus reducing the resistance to make them interpenetrate the base surface by light blow. The technique has both price competitiveness of the PHC piles and interpenetrability of the steel pipes.
Application of the Smart Pile Method can reduce the construction costs owing to the reduced diameter and size of the piles, as well as improve the work quality by minimizing both the chances of the piles’ horizontal position and the bending load.
Operation Mechanisms of Common Extended Pile and Smart Pile
Field Pile Load Test for Verifying the Qualification (Field H of Company D)
Yield Resistance (kN)
Tip Resistance Ratio
Yield Resistance (kN)
Tip Resistance Ratio
Performance of Smart Pile Construction
Composite Rahmen Method
Construction Method and Technique
(Prestressed Concrete (PSC) Girder Composite Rahmen Bridge Method (PCR). After building the wall structure, the builders place the reinforceable PSC girders on the upper part of the wall and unify the girders and the wall, at the same time as placing the floor plate concrete.
Composite Rahmen Method
Corner joints are made by combining PCS girder, rigidly linked-structural steel, embedded reinforcing steel bars (rebars) and the wall structure. Penetrating the embedded rebars through the structural steels to insert, reinforce the wall structure and the slab main bars, and then link the wall structure and the girders by placing floor plates and corner joints’ concrete.
· The combustion gas formed during incineration is sent to a semi-dry reactor (SDR) and then reacts there with slacked lime slurry sprayed minutely.
· As the combustion gas reacts with the slurry, toxic acid gases (hydrogen chloride, sulfur oxides) are eliminated. During this process, the temperature drops to 150~160℃.
· The characteristics of this process are high efficiency, low installation and maintenance costs, and rare occurrence of waste water.
Key Technology and Construction Method of SDR
· The core devices of the SDR are the nozzle that sprays slaked lime slurry and air, which is designed to resist corrosion and to maintain a good spray condition for a long time.
· The difference between the dry reactor method is SDR sprays in not powder but slurry state. The reactor should be designed in the manner that the liquid droplets sprayed upon reaction would dry neither fast nor slowly.
· If a bag filter is installed at the back, spray flow control is required in order to keep the gas temperature at the reactor exit at 160℃ approximately.
Elimination of Dioxin
· Modified Conditioned Dry Sorption (MDC) process is a method that absorbs the dioxin particles to the active carbon void physically to remove them.
· Simple process, low installation and maintenance costs, high utility and reliance are among the characteristics.
Dioxin Elimination Apparatus – Key Technology and Construction Method of MDC
· MDC (Modified Conditioned Dry Sorption) is a useful process to remove the dioxins and heavy metals effectively.
· The particulate matters that absorb pollutants are removed through our devices such as bag filters, etc.
Elimination of Nitrogenous Compound
Non-catalytic denitrification of the Selective Non-Catalytic Reduction (SNCR) mechanism sprays urea directly into the incinerator, and thus dissolve the nitrogenous compound into nitrogen elements and water, both innocuous to humans and water.
Key Technology and Construction Method of SNCR
· The optimal reaction temperature for SNCR is 950~1,100℃, and the residence time is adjusted for 0.5 second at 950℃ in order to achieve at least 75% of denitrification rate.
· The apparatus is designed to drive the equivalence ratio of urea, a reducing agent for nitrogen oxides (NOx), to be kept at 0.8~1.5 and thus prevent white plume issue. It is also designed to prevent unnecessary consumption of the reducing agent (urea).
Elimination of Dust Particles
The bag filter is an apparatus to eliminate dust particles physically by passing the exhaust gas through the filter bag. During this process, not only the particles, but also toxic matters such as SOx, HCI, heavy metals, and dioxins are removed, as well. If scrubber is used together, the effect becomes greater.
Key Technology and Construction Method of Back Filter
· If exhaust gas passes through the filter bag with excellent absorption, the dust particles are collected and absorbed to the filter bag and the layer of these collected particles, too, get to function as filter, resulting in increased efficiency of dust particles’ elimination.
· Among the collected and absorbed dust particles, are included the slacked limes that were unreacted at the previous process of eliminating acidic harmful gases. These are now used for removing chlorine and sulfur oxides.
· To make the bag filter, glass fiber, PTFE fluorocarbon filter, or acryl materials are used mostly. The dust cake of the filter bag should be cleaned regularly, and setting up a proper pulsing air pressure is the key technique to maximize the lifespan and filtering performance of the filter bag.
Recycling Equipment System
Recycling becomes crucial to the public authorities in their administration of household waste treatment. Dongbu Corporation provides a system that selects recyclable materials of higher values at low cost.
In addition, by designing both the waste incineration facility, which is ordered continuously across the country, and the recyclable material selection facility in parallel, Dongbu endeavors to recycle the resources more effectively and strives for completely sanitary treatment thereof.
Key Technology and Construction Method
· Environmental technologies and water treatment methods are widely applied in accordance with the demands of our times. Moreover, to meet the various needs of environmental preservation which result from the complex economic and social structure in the contemporary society, people require more practical and economic solutions through the engineering techniques for waste treatment.
· Waste treatment technique started from unsanitary filling and have developed into sanitary filling, incineration and recycling process recently. Dongbu Corporation focuses on developing the waste and recycling technologies to solve all kinds of complex problems concerning recyclable material selection perfectly.
Technology and Construction Method of Underground-Type Seawater Intake Facility
This technology uses a control apparatus consisting of a double intake pipe to take the seawater in and supply it to the users. It carries out forced cleaning of the floating matters in the filtering sand, as well.
This technology allows easier provision of seawater to the establishments located close to source of demands, such as sushi restaurants, seawater bathhouses, accommodation, and bathing facilities.
Overview Diagram of the Underground-Type Seawater Intake Facility
Detailed Parts of the Facility
Advantages of Underground-Type Seawater Intake Facility
The existing seawater intake facilities took the seawater directly in and thus were vulnerable to water pollution and floating matters, as well as unstable depending on the weather condition, causing high service fees for using seawater. Compared to that, our technology can reduce the floating matters significantly through our unique double-intake pipes, improve the water quality by steady seawater intake, and provide seawater at low cost.
Advantage 01. High Quality Water
Floating matter fisheries water level 2 → Satisfying level 1
Specimen after Intake
Advantage 02. Economic Facility
Long Distance Transmission Pipe, Filter/Storage Tank Unnecessary
Cost Reduction Compared to the Existing Technology (app. 30%), Construction Period Reduction (app. 25%)