Solution C
CSS (Corrugated Steel Structure)
The main problems of the “ASTM A796M Table 33 Pitch 150mm Depth 50mm CSS" used mainly in small structures such as road culverts and underpass are 1) deformation of the section exceeding the deformation standard (allowable displacement 5%, AASHTO) 2) local buckling failure 3) tear of bolt joint steel plate 4) Leakage of Channel connection 5) Deformation of the end treatment (Bevel, Step bevel type).
As a solution to this problem, we have the technical ability to compensate for the above problem (allowable displacement of 2%) by using "ASTM A796M Table 35 Pitch 380mm Depth 140mm CSS and ASTM A796M Table 37 Pitch 500mm Depth 237mm CSS: EXSCor” whose moment of inertia increased by 8 ~ 9 times.
In addition, as a direction of improving the vertical cracking and activity of foundation concrete, which has been a problem in concrete foundation, the base form was changed from a retaining wall type to a block type, and the total weight of the structure was lightened to solve the problem of uneven settlement, For the occurrence of leakage at the connection part, a leakage prevention method was installed at the upper part of the foundation to prevent condensation and inflow water from outside flowing.
If there is enough height in the soil from the top of the CSS to the planned height during the section selection, you can use the Arch shape section with good openness and the BOX section if there is no enough top of cover of height. Simplify the economical process (3 steps ➞ 2 steps) to reduce the construction period by 30% and reduce the construction cost by more than 15%.
Typical CSS Type
2001, Korea
Solution. 1
Tunnel Solution
If the width of the general CSS tunnel is wide (when the total effective width is 20m or more), the 2 row structure will be applied considering the limit of stiffness and the construction conditions of the CSS (ASTM A796M Table 35 Pitch 380mm Depth 140mm).
Since the CSS is concave at the center, even if a longitudinal drain pipe for drainage is installed, the perforated drain pipe becomes blocked due to the inflow of soil or other matter, which causes water to be accumulated at the center part. The width of the center part is narrow in the construction part, it is difficult to use the compaction equipment. Therefore, concrete and sand are used as backfill materials, but the process and cost has been disadvantageous.
In addition, in case of public construction, it is necessary to partially control the vehicle traffic, and since the foundation is installed on the road center separator, there is a drawback in that it is necessary to extend the 4 road traffic width in the tunnel connected to the existing lane. If you adjust the road alignment after the lane width expansion, it will cause the construction cost to increase due to the increase of the required buying land.
Traffic Disturbed
Solution
The EXSCor CSS (ASTM A796M Table 37 Pitch 500mm Depth 237mm) is the CSS with the largest rigidity in the world, which is increased by 8 ~ 9% but the stiffness is increased more than three times by increasing the width and depth of the CSS compared to the existing CSS.
When EXSCor CSS is used, the stiffness can be secured only by the main plate (no reinforcing plate) of 23m. Compared with existing CSS (Pitch 380mm or 400mm, Depth 140mm or 150mm), there is no process such as reinforcement plate assembly for reinforcing rigidity and additional concrete pouring, so it is easy to construct and construction cost is reduced.
Since the foundation is not installed in the center part, various problems caused by installing the center foundation can be solved.
If reinforced plate is used on EXSCor, it can be applied up to 40m span, so it can be crossed by a single span without installing a foundation on the 8th traffic lane road median separator, so construction can be done without disturbing the traffic flow of the existing road as much as possible.
Keep Traffic
Max. 72% Cost Down
This table for the maximum fill height according to diameter according to the corrugation profile (Corrugation Type: 150mm by 50mm, 380mm by 140mm) of CSS Round Shape (with Various Backfill Materials, Compacted Density Ratio and Min. CSS plates assembly regard less bolt use) . If you have any questions, please feel free to contact ChungAm E&C engineer.
CSS installation
In case of Arch CSS, check the footing force (Qmax Value) shown in the design drawing (pile construction if necessary), curing footing concrete, and apply foundation concrete on it. Install the base channel connected to the CSS at the time of foundation concrete construction. After curing the base concrete, fasten the CSS and base channel with bolts and nuts.
For CSS, confirm the marked markings on the inside and outside of the CSS each plate and BP0-00S shown on the drawing, and assemble according to the order. If the end-treatment is a head-wall type, tighten the anchor bolt with the reinforcement of the concrete head-wall to complete the concrete wall and secure the backfill material and the compaction ratio specified in the specification. Before backfilling, waterproofing is carried out between the bolt and CSS’s overlap specified in the drawing with gasket. In case of Bevel, after waterproofing and backfilling process, finish with Ring-Concrete of bevel part.
CSS_Headwall Type
CSS_Bevel Type
Patents Registrated : 10-0512522, 10-0609125, 10-1829819, 10-0448015, 10-0622059, 10-0634019,
10-0799979, 10-0837212, 10-0842029, 10-0875250, 10-0875251, 10-1599811, 10-1620515, 10-1629291, 10-1801053
